CYCLONE* DOWNHOLE MOTOR SERIES HANDBOOK · 2019. 10. 25. · The P3 Tools Engineering PowerDrill* motors are Positive Displacement Motor (PDM) steerable systems. The main application

CYCLONE* DOWNHOLE

MOTOR SERIES

HANDBOOK

P3 Tools Engineering /Table Of Contents.

1.0 Introduction 8

2.0 Specification 9

2.1 Physical and Operating Specifications 9

2.2 Connections and Make-up Torques 15

2.3 Power Output Curves. 16

2.4 LCM, Solids and Mud Additives. 20

2.5 RPM Limits. 20

2.5.1 RPM Recommended Limits While Drilling. 20

2.5.2 Running a Motor Outside the Recommended Limits When On-Bottom. 22

2.5.3 RPM Recommended Limits When Off-Bottom. 22

2.5.4 Running a Motor Outside the Recommended Limits When Off-Bottom. 23

2.5.5 Recommendations when Running a Motor Outside the Recommended RPM Limits. 24

2.5.6 Performance Drilling RPM Limits. 24

2.5.7 Recommended RPM Limits. 25

2.6 Hydraulics Considerations. 27

2.6.1 Differential Pressure. 27

2.6.2 Nozzled Rotors. 29

2.6.3 Bit Pressure Drop. 30

3.0 Preparing Equipment. 31

3.1 Configuring the P3 Tools Engineering Cyclone* Steerable Motor . 31

3.1.1 Motor Size. 31

3.1.2 Top Sub. 31

3.1.3 Power Section . 32

3.1.4 Bend Setting. 32

3.1.5 Bearing Section. 34

3.1.6 Motor Catcher. 35

4.0 Operating Guidelines 36

4.1 Making up the bottom hole assembly. 36

4.1.1 Adjusting the bent housing. 37


4.1.2 Making up the stabilizer. 37

4.2 Performing a surface function test. 38

4.3 Running in hole. 38

4.4 Reaming. 39

4.5 Drilling operations. 39

4.5.1 Reaching bottom/starting the run. 39

4.5.2 Off bottom circulating. 40

4.5.3 Orienting and sliding. 40

4.5.4 Stabilizer hanging. 40

4.5.5 Surveying. 41

4.5.6 Severe conditions. 41

4.6 Pulling out of hole (POOH). 42

4.7 Back reaming. 42

4.8 Staging procedures. 43

5.0 Performing the job. 44

5.1 Making up the BHA. 44

5.1.1 Picking up the BHA. 44

5.1.2 Adjusting the Bent Housing. 44

5.1.3 Making up the Stabilizer. 48

5.2 Surface Checks. 49

5.3 Surface Function Test. 50

5.4 Running in Hole. 51

5.5 Reaming. 52

5.6 Drilling Operations. 53

5.6.1 Reaching Bottom/Starting Run. 53

5.6.2 On Bottom Drilling. 53

5.6.3 Off Bottom Circulating. 55

5.6.4 Orienting and Sliding. 56

5.6.4.1 Orienting a Motor with MWD. 56

5.6.4.2 Orienting a Motor with Single Shots. 57


5.6.4.3 Stabilizer Hanging. 59

5.6.5 Surveying. 59

5.6.6 Severe Conditions and Non-Standard Operations. 60

5.6.6.1 Harsh Drilling Conditions. 60

5.6.6.2 Running Tools Below Motors. 61

5.6.6.3 Back Reaming. 61

5.6.6.4 Jarring. 62

5.6.6.5 Fishing. 62

5.6.6.6 Drill String Vibration／ Resonance. 62

5.7 Laying down the BHA. 64

5.8 Tripping across a Sidetrack. 65

5.9 Operating in Cold Locations. 66

6.0 Maintaining P3 Tools Engineering PowerDrill* Motors. 68

6.1 Checking the well site. 68

6.2 Post-run maintenance. 68

6.3 Changing the Rotor nozzle. 69

7.0 Troubleshooting. 70

7.1 Motor Troubleshooting during operations. 70

7.1.1 Large instantaneous pressure increase. 70

7.1.2 Moderate constant pressure increase. 72

7.1.3 Pressure fluctuations. 73

7.1.4 Large instantaneous pressure decrease. 73

7.1.5 Moderate constant pressure decrease or continuous pressure decrease. 74

7.1.6 Loss of differential pressure. 74

P3 Tools Engineering /Introduction.

1.0 Introduction.

The P3 Tools Engineering PowerDrill* motors are Positive Displacement Motor (PDM) steerable

systems. The main application of a PDM is directional drilling. During directional drilling the

drillstring is not rotated at surface. A bend in the motor (which is adjustable at surface) is

orientated downhole in the desired direction. Because the drillstring is stationary in relation to the

formation, the motor will drill in the direction of the bend; this is called a slide.

When the drillstring is rotated the bend in the BHA has no directional affect, and the motor drills

straight, this is called rotating.

PDMs can also be used for straight hole drilling, coring, under-reaming, milling, and other

operations. In straight hole drilling, motors function as a drilling performance tool to increase the

rate of penetration (ROP) and reduce casing wear by minimizing the drill string rotation.

Top Sub

Power Section

Surface Adjustable Housing

Bearing Section

Figure 1-1: P3 Tools Engineering Cyclone* Motor sub-assembly

P3 Tools Engineering

2.0 Specifications.

2.1 Physical and Operating Specifications.

Table 2.1 - 9.625” 7:8 4.0 Specifications

Model 9.625” 7:8 4.0

Fixed Adjustable

OD (in) 9-5/8 9-5/8

Lobes 7:8 7:8

Stages 4 4

Bearing Section Mud Mud

Flow (gpm) 600-1200 600-1200

Max Flow w/Bypass (gpm) 1200 1200

Rev/unit volume (rpg) 0.105 0.105

Speed (rpm) 63-126 63-126

Torque at max. horsepower (ft-lb) 19452 19452

Maximum operating differential pressure (psi) 769.2 769.2

Max horsepower（hp） 388.6 388.6

Max Weight on Bit（LBS） 582020 258020

Length (ft) 30.7 31.7

Bend to Bit Box (ft) 6.2 8.1

Stabilizer to Bit Box (ft) 2.7 2.7

Weight (lbm) 5166 5280

Hole OD (in) 12-1/4 to 17-1/2 12-1/4 to 17-1/2


Table 2.2 - 8” 5:6 6.0 Specifications

Model 8” 5:6 6.0

Fixed Adjustable

OD (in) 8 8

Lobes 5:6 5:6

Stages 6 6


Flow (gpm) 300-900 300-900



Speed (rpm) 78-233 78-233


Maximum operating differential pressure (psi) 1277 1277

Max horsepower（hp） 500 500


Length (ft) 29.4 30.6



Weight (lbm) 2824.6 2961.8

Hole OD (in) 9-7/8 to 12-1/4 9-7/8 to 12-1/4


Table 2.3 - 6.75 7:8 6.0 Specifications

Model 6.75 7:8 6.0

Fixed Adjustable

OD (in) 6-3/4 6-3/4

Lobes 7:8 7:8

Stages 6 6


Flow (gpm) 300-600 300-600



Speed (rpm) 84-168 84-168





Length (ft) 26.7 27.8



Weight (lbm) 2216 2485.4

Hole OD (in) 8-1／2 to 9-7/8 8-1／2 to 9-7/8



Model 4.75 5:6 5.0

Fixed Adjustable

OD (in) 4-3/4 4-3/4

Lobes 5:6 5:6

Stages 5 5


Flow (gpm) 100-275.1 100-275.1

Max Flow w/Bypass (gpm) 275.1 275.1


Speed (rpm) 122-335 122-335

Torque at max. horsepower (ft-lb) 2360.2 2360.2




Length (ft) 17.2 18.1



Weight (lbm) 714.4 738.9

Hole OD (in) 5-7／8 to 7-7/8 5-7／8 to 7-7/8



Model

3.125 5:6 4.0

Fixed Adjustable

OD (in) 3-1/8 -

Lobes 5:6 -

Stages 4 -

Bearing Section Mud -

Flow (gpm) 60-120 -

Max Flow w/Bypass (gpm) 120 -

Rev/unit volume (rpg) 2.33 -

Speed (rpm) 140-280 -

Torque at max. horsepower (ft-lb) 608.5 -

Maximum operating differential pressure (psi) 655.57 -

Max horsepower（hp） 32 -

Max Weight on Bit（LBS） 65170 -

Length (ft) 11.45 -

Bend to Bit Box (ft) - -

Stabilizer to Bit Box (ft) - -

Weight (lbm) 198.42 -

Hole OD (in) 3-3/4 to 4-3/4 -


Figure 2-1: P3 Tools Engineering Cyclone* Motor


2.2 Connections and Make-up Torques.

Table 2-6, Connections and Make-Up Torque shows the connections and make-up torque

values for the various motor sizes.

Bit box connections

Use the bit manufacturer’s recommended make-up torque values. If they exceed the

maximum recommended API make-up torque specified in Table 2-6, then use the

maximum API connection make-up torque.

Table 2-6: Connection and Make-up Torque

Motor

Size

Top Sub

Adjusting Ring

Stabilizer Sleeve

Bit Box

Connection

ft-lbf

N·m

ft-lbf

N·m

ft-lbf

N·m

Connection

ft-lbf

N·m

9-5/8”

6-5/8REG

53386

72071

8148-

9626

11000-

13000

10370

-

11200

14000-

15000

6-5/8REG

28000

37800

8”

6-5/8REG

30099

53386

6700-

8900

9000-

12000

8148-

9626

11000-

13000

6-5/8REG

28000

37800

6-3/4”

4-1/2IF

22350

30355

3703-

5185

5000-

7000

6700-

8900

9000-

12000

4-3/4REG

12000

16200

4-3/4”

NC38

7390

10037

3703-

4500

5000-

6000

5925-

6700

8000-

9000

3-1/2REG

7000

9450

3-1/8”

2-3/8REG

3470

4700

2510

3400

2.3 Power Output Curves.

The curves represent the expected characteristics of each power section under the surface

test conditions. The actual power characteristics achievable downhole may differ from

those under surface conditions due to the effects of pressure, temperature, BHA dynamics,


wellbore geometry and mud chemistry by:

• Altering the geometry of the cavities such that torque generation is no longer

maximized. This could reduce the output torque, and therefore horsepower, for a

given differential pressure, and also could reduce the stall pressure as compared

to the surface conditions.

• Adversely affecting the mechanical properties of the stator elastomer reducing the

ability of the cavity to hold pressure. This leakage reduces the total differential

pressure that can be achieved by a power section as compared to surface

conditions.

Note: Testing method

During surface testing the motors were run in static conditions, without stator rotation, in

ambient air, without cooling from drilling fluid on the OD of the stator. The motors were

tested at minimum, medium and maximum published flow rate.

For each of the three flow rates (minimum, medium, and maximum), the procedure was

the same:

1. Establish the flow with no load

2. Gradually increase the torque load on the brake until the motor stalls

3. Monitor and record flow, pressure, rpm, torque, and temperature continuously

The flow was accurately controlled to prevent significant variation from the nominal value.

A full test at the three flow rates lasted typically thirty minutes or less, so the dependency

from environmental changes and increases in the drilling fluid temperature was minimized.

However, the temperature of the elastomer increased sharply with the differential pressure,

affecting both torque and rpm during test.

Interpreting the Power Curves

The motor power curves show the output rpm, torque and horsepower versus differential

pressure under surface conditions. The actual downhole rpm, torque and power curves will

likely have shapes similar to the curves presented, with lesser amplitude, and lower stall

pressure for the reasons detailed above. The surface condition curves presented can be

used to predict downhole behavior of the motor, bearing in mind their limitations.

Reading the Power Curves



As the power section operating differential pressure increases so does the pressure

drop per stage. Increasing the differential pressure means that we are increasing the

stress on the elastomer.

The maximum recommended operating differential pressures which should be used

to preserve reliability are:

• 100 psi/stage for NBR-HR stators

• 125 psi/stage for ERT stators.

These recommended differential pressures will give a lower total power section

differential pressure compared to the values in the Physical and Operating

Specifications, and guide the Field to achieve a balance between power section

performance and reliability.

Note

The power curves are generated at ambient temperature under test conditions detailed

above. The full differential pressure may not be achievable under certain downhole

conditions, for example, at high temperature or when using oil-base or other drilling fluids

that soften the stator elastomer.

9-5/8" Lobes 7:8, 4 stage


8" Lobes 5:6, 6 stage






2.4 LCM, Solids and Mud Additives.

Lost Circulation Material (LCM) can cause two problems when pumped through a motor:

• The material can plug off inside the motor, usually at the top of the upper radial

bearing, resulting in a reduction of cooling flow across the motor bearings.

• LCM can cause stator wear.

It is not recommended to pump cement through a BHA containing a P3 Tools

Engineering Cyclone* motor. The motor will shear the slurry which could cause

immediate setting.

However, LCM can be used with P3 Tools Engineering Cyclone* motors if certain

precautions are followed:

· Add the LCM evenly—avoid pumping a large slug of material.

· Minimize the use of hard, sharp-edged materials such as nut plug, coarse mica

and calcium carbonate chips because these can cause stator wear by abrasion.

· If possible do not pump concentrations greater than 50 pounds per barrel medium

nut plug or equivalent.

Although these guidelines help minimize the plugging problems associated with LCM, they

cannot completely eliminate the possibility of plugging the motor or bearing section.

The mud lubricated bearing section is compatible with most mud systems. Highly abrasive

mud systems can cause excessive wear on the entire bearing pack (radial and axial).

Examples of highly abrasive muds include muds with more than 2% sand and systems that

use hematite or similar substances for weighting material.

Highly abrasive mud systems can also result in premature failure of the seals in sealed

bearing motors.

2.5 RPM Limits.

2.5.1 RPM Recommended Limits While Drilling.

RPM limits are dependent on the curvature of the hole. Hole curvature is greatest


when the hole is drilled when sliding. Higher hole curvature means greater alternating

stresses when the motor is rotated, so the recommended rpm is lower to reduce the

number of stress cycles incurred. Rotation of the motor within a slide section occurs

when drilling the "transition zone". The "transition zone" occurs with the initiation

of rotation after completing a slide section. It is where the hole transitions from the

high DLS of the slide section to the lower DLS of the straight section. The length of the

transition zone, through which the lower rpm limit recommendation applies, varies with

motor size. It is a maximum of 15 feet for the larger motors.

RPM limits are also dependent upon the bent angle of the motor. The higher the angle,

the greater the alternating stresses, and therefore the lower the acceptable limits. At

a certain bent housing angle fatigue stresses become too high and rotation is no longer

allowed.

Note: RPM Limits

The rpm limits are based on getting a tool life equivalent to a maximum of 20 full

transition sections at the given bend angle when drilling at 20 ft. /hr.

Obviously, the model used to generate the rpm limits is a simplification to try and show

motor users the rpm ranges that will most likely prevent a failure. It is not a guarantee,

it is a guideline.


Motor BHA in build, transitional and tangent section and stresses.

A — Build Section where the motor is sliding. No cyclic stresses are induced because

there is no string rotation.

B — Transition Section where rotation is initiated. Cyclic stresses (one per rotation)

are induced on the connections, illustrated (and exaggerated) by the dotted lines that

represent the motor position if unconstrained by the stabilizers and well path. Because

the assembly is constrained, these cyclic stresses are absorbed by the motor. There

is more stress induced by rotating the motor in the transition zone (Fig. b) than in the

tangent (Fig. c). This is indicated by the size of the red arrows, which is why the

reduced motor rpm limits apply in the transitional zone.

2.5.2 Running a Motor Outside the Recommended Limits When

On-Bottom.

There should be no reason to run higher than the recommended rpm limits within the

transition zone—that is, when starting rotation after completing a slide, every effort

should be made to stick within the transition zone rpm limits for the short distance.

2.5.3 RPM Recommended Limits When Off-Bottom.

The fatigue rpm limits calculated for on-bottom activities, rotary drilling out of the build

or tangent drilling, would still apply to off-bottom activities with regards to connection

fatigue life. That is to say you could back ream at the same rpm rates as recommended

for drilling for your motor size, bend setting, and hole curvature, and still achieve the

same fatigue life expectancy. However, alternating stress induced fatigue is not the

primary concern when rotating off bottom, fatigue induced by shock is, which is why

there is a 40 rpm recommended limit to motor rotation when off bottom.

Field experience has shown that rotating off bottom (reaming and back reaming) very

often creates high shocks. Shocks experienced by the motor are not well monitored,

as motors are not instrumented. MWD/LWD shock sensors are not located at the

motor and may not see similar shock amplitudes to the motor due to their different


position in the BHA. The MWD/LWD tool may be at a node or be otherwise dampened.

Any shock measurement is definitely a better indication of shocks at the motor than

none, but a lack of MWD/LWD shock does not necessarily mean no shocks at the

motor.

The off bottom/back reaming RPM limit of 40 is a conservative value imposed because

the drill string has greater freedom of motion, as it is not constrained by WOB, and

therefore has a greater capability for shock generation. Shock loading of the BHA

components causes high stress and tool joint fatigue, which can lead rapidly to failure.

Also, when the connections are not in compression, back off is possible – particularly

in a high shock/stick-slip environment.

Recommending that the RPM is kept below 40 is a catch-all method that reduces the

energy in the system decreasing the incidence of significant shock, therefore lowering

the probability of damage and tool failure. It is not a matter that the motors cannot be

rotated faster than 40 rpm off bottom, but doing so reduces the risk of damage due to

shock.

2.5.4 Running a Motor Outside the Recommended Limits When

Off-Bottom.

If your well-conditions are such that other factors outweigh the risk of tool damage due

to shocks, such as the need for agitation of the cuttings for hole cleaning in ERD, then

it may be wiser to rotate the drill string faster than 40 rpm as this reduces the greater

risk of getting stuck. Having a 40 rpm limit, and making the decision with the client's

consent to run at a higher rate, acknowledges that the tools are being run in a

potentially damaging environment.


2.5.5 Recommendations when Running a Motor Outside the

Recommended RPM Limits.

Typical failure modes experienced due to operating for extended time above the


recommended rpm are:

· Chunked stators

· Fatigued connections.

Stalling at high rpm with larger motors and aggressive PDC bits has an added risk of

twist off.

RPM limits are in place to protect the tool from fatigue failures (i.e. twist-off) due to

reverse bending, shocks and vibrations. However there are occasions when it may be

necessary to run at a high RPM.

This section recommends actions to reduce the risk when running P3 Tools

Engineering PowerDrill* at high rpm. The specified limits do not give ‘infinite life’ but

they reduce the risk of twist-off to a reasonable level.

Risks of running high rpm

Each time the motor bends, the alternating stress consumes fatigue life of the housing

and connections. This bending is caused primarily by rotating through a transition

section (the curved section between a sliding and straight section), or by vibration,

whirling and shocks as the tool oscillates in the well-bore. As the drill string is rotated

faster there is more energy in the system and vibration/shock risks are increased,

which are made worse by the eccentricity of the bent tool.

Stresses are usually highest in the housing connections. If these or other parts of the

motor twist-off then there is a potential LIH event.

2.5.6 Performance Drilling RPM Limits.

Performance drilling with a straight motor housing has a recommended maximum drill

string rotation of 160 RPM. This is not applicable to motors with an adjustable bend

angle set to “0.00”. Their recommended maximum is 100 RPM or less as indicated in

Table “Recommended Maximum Drill String RPM in Tangent or Straight Sections.”

2.5.7 Recommended RPM Limits.

The following tables provide the recommended RPM limits.


Recommended Maximum Drill String RPM in Transition Section

Motor

Size

Hole

Size

Bend Angle

Distance

（ft）

0.00

0.39

0.78

1.15

1.5

1.83

2.12

2.38

2.6

2.77

3.0

3-1/8 3-7/8 100 100 100 100 100 100

8

4-3/4

6

90

90

50

40

40

10

6-3/4

8-1/2

80

80

50

40

40

13

8”

12-1/4

100

100

80

70

40

15

9-5/8

12-1/4

90

90

60

50

40

15

Notes:

1. These recommendations are for an ROP of 20 ft/hr. If the ROP is consistently

lower, decrease the RPM limit proportionally.

2. The RPM limit is based on getting a tool life equivalent to a maximum of 20 full

curve sections at the given bend angle.

3. These RPM limits are based on a static bending stress fatigue analysis. Fatigue

and failure can occur due to excessive vibration. Decrease the RPM if need be,

based on local conditions.

4. RPM Limits are for the given hole sizes. If hole sizes are smaller, the RPM Limit

will, in general, decrease. Contact Engineering for recommendation.

5. "Distance" refers to the distance from the end of the curve to the point after which

RPM may be increased to tangent section values.

6. Rotating P3 Tools Engineering PowerDrill* motors with bend angles

corresponding to the gray regions is not recommended.

7. For 0-2 degree adjustable bends, use the value of the closest bend angle listed.


Recommended Maximum Drill String RPM in Tangent or Straight Sections.

Motor

Size

Hole Size

in.

Bend Angle

0.00

0.39

0.78

1.15

1.5

1.83

2.12

2.38

2.6

2.77

3.0

3-1/8 3-7/8 100 100 100 100 100 100

4-3/4

6

100

100

100

100

100

6-3/4

8-1/2

100

100

100

100

100

8

12-1/4

100

100

100

100

70

9-5/8

17-1/2

100

100

100

80

60

Note:

1. These recommendations are for stabilized assemblies in the given hole

sizes.

2. Fatigue and failure can occur due to excessive vibration. Decrease the

RPM if need be, based on local conditions.



4. For 0 to 2 degree adjustable bends use the value of the closest bend

angle listed.

Absolute Maximum Drill String RPM in Transition Section or Straight Sections

Motor

Size

Hole Size

in.

Bend Angle

0.00

0.39

0.78

1.15

1.5

1.83

2.12

2.38

2.6

2.77

3.0

3-1/8

3-7/8

160

160

160

150

130

100

4-3/4

6

160

160

160

140

120

6-3/4

8-1/2

160

160

160

140

120

8

12-1/4

150

150

130

120

70

9-5/8

17-1/2

140

140

120

80


Note:

1. These recommendations are for stabilized assemblies in the given hole

sizes.

2. Fatigue and failure can occur due to excessive vibration. Decrease the

rpm if need be, based on local conditions.



4. For 0 to 2 degree adjustable bends use the value of the closest bend

angle listed.

Example 6-3/4” Mud Motor; Bend: 1.5°; Hole Size: 8-1/2 in

2.6 Hydraulics Considerations.

2.6.1 Differential Pressure.

The difference between on-bottom and off-bottom drilling pressure is defined as the

differential pressure. The rotor/stator section of the motor generates the pressure

difference when weight is applied to the bit and torque is demanded from the motor.

The larger the pressure difference, the higher the torque output of the motor and the

lower the output shaft speed.


As a rule of thumb the maximum recommended operational differential pressure is:

· 100 psi/stage for standard NBR-HR stators

· 125 psi/stage for ERT stators.

Establishing the optimum differential pressure to use depends on the power section

type, the downhole conditions, and the objectives of the run.

Unfortunately the optimum working point is not easily identifiable today with the

measurements available on surface.

It is critical not to run too much differential pressure per stage as although higher

torque is generated the increased pressure also places significantly greater stress on

the stator elastomer that can reduce working life. Motors that are run with too much

differential pressure per stage may experience premature chunking (within as few as

6 pumping hrs) in a manner similar to stators that have too much interference

(compression) between the rotor and stator.

Stalling also greatly reduces the working life of the stator elastomer. The differential

pressure applied must therefore, be lower than stall pressure by a sufficient margin to

allow for variations in formation response without causing frequent stalling. It is

recommended that the maximum differential pressure run be no higher than 80% of

the differential pressure that gives maximum horsepower under the downhole

conditions of the run.

Note

Running a motor at or close to its maximum differential pressure severely reduces the

life of the stator. It is good practice to reduce the differential pressure in line with an

increase in BHCT.

Part of the role of the directional driller is to establish, at any time during drilling

operations, what is the optimal differential pressure to run on a motor that will meet

the run objectives, in terms of rate of penetration, tool face control and trips. Focus

must be on achieving an optimized ROP rather than a maximum ROP, as the maximum

ROP achievable may not be sustainable over the duration of the run. Studies indicate

that ROP can be optimized for roller cone bits with as little as 30% of the differential

pressure required for maximum horsepower. This figure increases to


60% for PDC bits.

Drill off testing can be used to help establish the pressure that gives the optimum ROP,

as often there is little appreciable increase in ROP as WOB/differential pressure

applied is increased beyond the optimum. The directional driller will gradually increase

the differential pressure by applying more WOB and observe the level where the rate

of penetration reaches a maximum and will take note of this differential pressure. In

some cases, the motor may stall before a drop of ROP is observed. In this case the

directional driller will apply less WOB allowing continuous drilling without stalling.

Tip

When a motor is newly run in the hole it can take some time for the motor components

to adjust to the environmental conditions. It is recommended not to run the intended

full differential pressure.

2.6.2 Nozzled Rotors.

Motors with nozzled rotors are often over pumped when off-bottom. The amount of

fluid bypassed depends greatly on the pressure drop generated by the power section.

This pressure drop is generally only 100 to 150 psi when off-bottom, whereas nozzles

are sized assuming a power section pressure drop of 300 to 500 psi. Nozzled rotor

motors should not be operated at flow rates higher than normal (non-nozzled rotor)

pump limits when circulating off-bottom.

Most P3 Tools Engineering PowerDrill* rotors are bored and can be fitted with a nozzle

that bypasses part of the flow to extend the motor's capacity and enhance flexibility in

matching motor performance to other hydraulic or downhole conditions. The amount

of fluid bypassed is determined by the nozzle size, the pressure drop through the

power section and the fluid density.

For performance drilling in larger diameter hole sections, adding a rotor nozzle allows

increasing the total flow to clean the hole and remove cuttings. In special applications

such as spudding, under-reaming or hole opening in large-size holes, adding a rotor

nozzle reduces the bit speed at high flow rates. Keep in mind that bypassing some of


the flow through a rotor nozzle will also reduce the available torque and the differential

pressure at stall. A simple hydraulics calculation is used to determine the size of the

rotor nozzle:

Rotor Nozzle Size Determination

The variables used in this equation are as follows:

Term Definition

BypassFlow Is the fluid flow rate in gallons per minute (GPM) to be bypassed through the rotor. It is the difference between the total flow needed and the maximum allowed for the motor without nozzle.

MW Is the mud weight in units of pounds per gallon (ppg)

P Is the total pressure drop, in units of (psi), through the power section (this includes the friction pressure drop required just to rotate the motor off-bottom)

TFA is the total flow area required (sqi), in square inches, for these by-pass specifications

2.6.3 Bit Pressure Drop.

Bit pressure drop supplies the force acting to push mud through the radial and axial

bearings. The fluid flow passing through the bearings must be at a high enough rate

to cool and lubricate them, but too much flow will wash out the bearings. Because they

are designed to restrict flow, the radial bearings allow a high bit pressure drop (1500

psi). The minimum bit pressure drop is 250 psi for standard bearings and 80 psi for

low-bit-pressure-drop bearings.

Problems can occur with too little pressure drop, particularly when motors are surface

tested without a bit, because virtually no fluid passes through the bearing section and

the radial bearings can overheat rapidly. Motors should not be surface tested for more


than 1 min without the minimum 80 or 250-psi pressure drop.

3.0 Preparing Equipment.

3.1 Configuring the P3 Tools Engineering

PowerDrill* Steerable Motor .

3.1.1 Motor Size.

Hole diameter and flow rate will normally dictate the diameter of the P3 Tools

Engineering PowerDrill* steerable motor to be used, as well as the client's

drilling procedure. Ensure that all motor housings are fishable in the planned

hole size. Motor stabilization needs to be carefully considered as several

sleeves can be coupled with one motor size. There have been instances

where the wrong stabilizer sleeve is sent to the rig and the hole size drilled is

not common. In some cases, sleeve stabilizer needs to be reworked to have

the needed dimensions.

3.1.2 Top Sub.

The use of flex sub is recommended on all jobs unless special requirement

regarding BHA tendency is not in favor of flex sub. It is proven that flex sub

inclusion reduces stress on different motor connections. The use of motor

catcher is also recommended on all jobs. There are top subs that give both

functionality as a flex and motor catcher. Discuss with the client any

requirement for a float valve placement in the BHA. If a float valve is to be

fitted in the top sub of the motor, top subs can have bore to accumulate

standard float valves. Length and ID of float bore needs to be checked to

ensure it matches the used float.

Check for compatibility between the top-sub connection and the connection

of the immediate BHA components.


3.1.3 Power Section .

Choose the power section configuration that best suits the bit requirements

and/or the objectives of the run. Archive and evaluate run data.

Check what type of mud will be used. Obtain an estimate for the sand and

solid contents, as well as oil/water ratio for oil based drilling fluids.

Choose the power section configuration that best suits the bit requirements

and/or the objectives of the run. Archive and evaluate run data.

Check what type of mud will be used. Obtain an estimate for the sand and

solid contents, as well as oil/water ratio for oil based drilling fluids.

Note

Muds with similar names from different environments or places can have

different chemical impacts and different fit calculations.

Obtain a good estimate for the circulating temperature. Typically,

oversized stators will be needed for wells with circulating temperatures

above 200 degF [93 degC]. Check flow limitations for the selected

configuration and consider a rotor nozzle.

3.1.4 Bend Setting.

Select the bend setting and stabilizer(s) gauge and position based on BHA

modelling, historical data, and experience.

Fixed: 0°-2.5° 0.25°increments

These ABH four options for bent housing configuration are detailed below:

0° to 2°

0° to 3°


Maximum settings for bend housings

0° to 2° ABH Housing Bend Setting

Degree Max.rpm

0.00 200

0.26 170

0.52 140

0.77 120

1.00 90

1.22 60

1.41 40

1.59 40

1.73 40

1.85 Not Recommended




Recommended RPM = 80% max.

0° to 3° ABH Housing Bend Setting

Degree Max.rpm

0.00 200

0.39 160

0.78 120

1.15 60

1.50 40









Recommended RPM = 80% max.


Guidelines for bend setting

Consider these guidelines when bend setting:

• Minimize bend setting.

• Plan for a minimum of 60% sliding in build-up or correction

section, and minimum 80% rotary mode in slant section.

Planning for less will mean generation of high localized DLS

values over the sliding intervals inducing undue stresses.

• Anticipate lower DLS at kick-off from low inclination or start of

correction. Consider planning the well with two different BUR in

the build-up section.

• Confirm your choice by running related DLS prediction

programs, and by studying previous experiences, slide sheets

and continuous DNI logs.

• Consider the differing responses through the different

formations expected to be drilled through.

3.1.5 Bearing Section.

If a slick assembly is run, either a slick housing or the sleeve threaded-type

bearing housing must be used with the protector made up. When stabilization

is used, 1/8 in or 1/4 in undergauge size is recommended.

For most motor sizes there is a choice between 3 blade spirals or 5 blade

straight stabilizer sleeves. It is generally easier to slide with a straight blade

stabilizer, however the spiral option reduces drag while rotating and would

more likely provide more consistent directional performance in rotary mode.

Rotating near bit stabilizers (RNBS) are available as a replaceable sleeve on

the drive shaft bit sub or as a short sub run below the motor. The subs can be

used with both mud-lubricated and oil-seal bearing motors. All RNBS

stabilizers have spiral blades to reduce drag while rotating.

RNBS stabilizers help to mitigate hole spiraling and reduce drag while sliding.


This increases overall ROP although in some circumstances a reduction in

dog leg capability results and their use may encourage a dropping tendency

in rotary mode.

Warning

Rotating near bit stabilizer assemblies are uncommon for this configuration

and must not be used with the stabilizer on the bearing housing. There have

however, been few instances where this configuration has been run in specific

environments where it was deemed to be necessary. Consult with InTouch and

sustaining if this configuration is needed.

Heavy duty, short or long gauge are some of the other options available.

Review the stabilization options currently available given in section 3.8:

Stabilization.

Avoid the use of cross-overs between the bit and the drive shaft of the P3

Tools Engineering PowerDrill* steerable motor. When planning to use the

same P3 Tools Engineering PowerDrill* steerable motor in two or more

consecutive runs with different bit connection threads, select the drive shaft

connection which will minimize the rotary mode when the cross-over is made-

up.

3.1.6 Motor Catcher.

Many motors can be configured to include a motor catcher. The motor catcher

is designed to help retrieve the rotor and bearing section in the event of a

twist off below the top sub e.g. the stator adaptor. For more information on the

Motor Catcher refer to the P3 Tools Engineering PowerDrill* Maintenance

Manual.

The Motor Catcher stem is available with either a solid or a scalloped head.

The scalloped head has bypass slots machined into its side which allow fluid

to circulate if the motor catcher engages.


Downhole view of a motor catcher stem with scallops (optional)

Note

The Motor Catcher has replaced the Rotor Catcher.

The rotor catcher design relied on the catcher plate catching on the top of the

elastomer. In twist-off cases the rotor catcher plate would pump through the

stator ripping the elastomer out on the way. The motor catcher stem can be

nozzled or blanked. Nozzle part numbers and all required field parts are

included in the maintenance manual, which describes the procedure to

change the rotor nozzle.

Specify both the Motor Catcher requirement and the nozzle size to be

included. Blank rotor nozzles are available as regular, cone-cylindrical, or

cone-hex type.

The Motor Catcher stem is available with either a solid or scalloped head. The

scalloped head has bypass slots machined into the side of the head which

allow fluid to be circulated if the motor catcher engages.

4.0 Operating Guidelines

4.1 Making up the bottom hole assembly.

4.1.1 Adjusting the bent housing.

1. Have the weight supported by elevators, not slips


2. Use tongs in the tong area. Back-off the stator adapter two full turns.

3. Lift the adjusting ring to disengage the alignment teeth.

4. Place a back-up tong on the offset housing and set the required bend.

5. Release the adjusting ring and re-engage the alignment teeth. Make-up the

stator adapter to the torque as shown in section.

6. Communicate with MWD, Steering Tool or Survey engineer and confirm the

tool face position.

4.1.2 Making up the stabilizer.

1. Hang the motor in the elevator.

2. When applicable, remove the bearing housing thread protector.

3. Screw-on the sleeve that has been previously gauged or gauge integral

blade stabilizer.

4. Make-up sleeve (or protector) to the recommended torque as shown in the

specifications tables in section 2.1: Physical and Operating Specification.


4.2 Performing a surface function test.


2. Make-up the bit if acceptable by the client.

3. Ensure a surface screen is placed in the string.

4. Make up the kelly or top drive. Use a crossover if necessary.

5. Engage the rotary bushing or place back up tongs on kelly saver sub

before turning on the pumps.

6. Lower the motor below the rotary table and turn on the rig pumps.

7. Record the flow rate at which the motor turns on.

8. Keep the flow rate constant. Pull out the motor to observe mud flow

through the bearing.

9. Lower the motor back to its previous position.

10. Shut down the pumps.

11. Measure the offset angle between the motor and MWD scribe lines

before running in hole.

4.3 Running in hole.

1. Make sure that the driller fills the pipe regularly while running in hole.

2. Control the tripping speed to avoid motor damage.

3. Trip slowly through casing shoes, liner hangers or casing windows. The

Directional Driller must be on the rig floor for any of these operations

4. In deep holes or at high temperatures, break circulation periodically in

open hole to prevent tool plugging and cool the mud.

5. Do not tag bottom.


4.4 Reaming.

Leave written instructions with the driller (copy Company representative) on

procedures to follow if you are reaming through a tight hole section. The Directional

Driller must be on the rig floor for any reaming operations.

• Pull out one joint or stand.

• Insert the surface screen, connect the kelly or top drive, unlock rotation to let

motor self-orient.

• Start circulating gently, moving the pipe 20 feet up and down and varying the

depth interval to prevent a ledge forming. Do not circulate in the same position

because the formation may become washed out and cause a sidetrack. Use

75% flow rate.

• Observe the pressure after circulation has started and wait until the pressure

stabilizes.

• Run in hole, rotating slowly while monitoring the pressure and any WOB

increases to prevent sidetracking - take appropriate action.

• For long reaming sections, take MWD surveys periodically to make sure

involuntary sidetracks do not occur.

4.5 Drilling operations.

4.5.1 Reaching bottom/starting the run.

• Ream/wash down the last stand.

• Record the off-bottom pressure at working flow rate.

• Follow the instructions from the bit supplier regarding new bit break-in.

• Follow the maximum rpm guidelines described in Table: Recommended

Maximum Drill String RPM in Tangent or Straight Sections

• Increase WOB gradually to recommended differential pressure. See section

2.6.1: Differential Pressure

• If the motor stalls, instruct the driller to reduce the flow by half while stopping


rotary and applying top drive break. Then pull off bottom.

• Resume drilling, as above, but with lower differential pressure to prevent

further stalling.

4.5.2 Off bottom circulating.

• Avoid off bottom circulation for extended periods. If this is unavoidable, reduce

the flow rate to lessen off bottom bearing wear.

• Frequently observe and record the off-bottom pressure.

• If compensated readings are decreasing with time, check for washout.

4.5.3 Orienting and sliding.

• Be present on the rig floor, and be prepared. Know exactly the desired angle

of turn.

• Record the previous tool face position (mark on the pipe), depth and time.

• After significant re-orientation, work pipe.

• Make sure that the person at the brake understands your requirements.

• Be patient after orientation.

• Record the MD at the start and end of any sliding section.

• Report the maximum build-up rate achievable/rotary drilling tendency.

• Follow the rpm recommendations in Table “Recommended Maximum Drill

String RPM in Transition Section for the transition zone.

4.5.4 Stabilizer hanging.

• Record the depth for correlation and future reference. Mark tool face

reference on drill pipe.

• Unlock the rotary table or top drive. Drill 3 to 5 feet at rpm as indicated

in Table “Recommended Maximum Drill String RPM in Transition”

• Re-orient the tool face using reference on drill pipe. Resume sliding.


4.5.5 Surveying.

• Normal frequency is one survey per stand.

• Request one survey per joint during kick off, landing in a horizontal

drain or correction.

• Take a survey anytime where a change of steering mode occurred.

• Check the noise interference with MWD. If this persists, consider

changing the flow rate or replacing the motor.

• Do not attempt to slide for more than 10 ft. (or 3m) without a reliable

Tool Face reading.

4.5.6 Severe conditions.

• Minimize back reaming.

• Avoid drilling in conditions of shock and vibration.

• If this occurs, modify parameters as required and return to drilling.


4.6 Pulling out of hole (POOH).

• Control the tripping speed to avoid motor damage.

• Trip slowly through casing shoes, liner hangers or casing windows.

4.7 Back reaming.

Leave written instructions with the driller (copy Company representative) on

procedures to follow if back reaming through a tight hole section. The Directional

Driller must be on the rig floor for any back-reaming operations.

• RIH one extra joint or stand.

• Insert the surface screen, connect the kelly or top drive, unlock rotation to let

motor self-orient.

• Start circulating gently, moving the pipe 20 feet up and down and varying the

depth interval to prevent a ledge forming. Do not circulate in the same position

as the formation may become washed out and cause a sidetrack. Use 75%

flow rate.

• Observe the pressure after circulation has started and wait until the pressure

stabilizes.

• Keep rotation to below 40 rpm.


4.8 Staging procedures.

P3 Tools Engineering PowerDrill* motors, like MWD and LWD drilling tools, might

need to be staged. This is because the stator rubber swells with temperature. For this

reason, time is required for the rubber to swell to its optimum characteristics for the

required performance. If the rubber is not given sufficient time to achieve its peak, the

motor may deliver less power, be prone to stalling and become more susceptible to

damage. To protect the motor and other BHA components in high temperature

environments, it is necessary to define a “Staging In” procedure, following the steps

below as a guideline:

1. Tripping in can be carried out as normal where the static bottom hole temperature is

expected to be no more than 94 degC (200 ºF).

2. Break circulation and continue circulating for 20 minutes or until the MWD

temperature stabilizes.

3. Continue RIH in 1000' stages circulating at least the minimum flowrate of the MWD

tool for 20 minutes or until the MWD tool temperature decreases and then stabilizes.

4. Step 3 should be continued until the static bottom hole temperature reaches 121

DegC (250 ºF) or above and circulation should be established every 5 stands for 10

minutes or by washing down every second stand if the well profile and surface drilling

configuration makes this a more efficient method.

Several locations around the world may have their own local procedure for staging,

which is a variation from the above steps and is aimed at reducing the damaging

effects of high temperatures.


5.0 Performing the job.

5.1 Making up the BHA.

5.1.1 Picking up the BHA.

The directional driller must be present when our motor is lifted.

1. It is recommended that the motor is stored with the adjustable bent

housing in position 0.

2. Supervise crane lifting of motor from rack to rig floor.

3. Check the serial number of the motor.

4. Make-up the lifting sub on top of the motor before lift if possible.

5. Place the protector on the bottom box thread and on bearing sleeve

threads when applicable.

6. Mark the center of gravity of the motor.

7. Place slings or straps at equal distance from center of gravity, not on a

loose part of the motor (drive shaft or loose sleeve). Ensure motors are

"tailed" from rack to rig floor.

8. Record and/or report any damages caused while lifting. Note the

damages on the corresponding Daily Activity Report.

5.1.2 Adjusting the Bent Housing.

Follow these rules when making the bent housing adjustment:

• Wear heavy duty safety gloves when adjusting the bent-housing.

• Use chain tongs for larger diameter motors.

• When making an adjustment, the adjusting ring can be turned in either

direction as necessary provided the markings on the adjusting ring

and the offset housing always overlap.


• Never turn the adjusting ring a complete revolution and align the

markings again.

• Tool face measurement is critical.

Explain the procedure to the driller before making-up the motor and BHA.

1. Mark the Stator Adapter/Adjustment ring connector with a chalk.

2. Break connection with rig tong.

Breaking Connection with Rig Tong

3. Back-off the stator adapter two full turns.

Back off Stator Adapter


4. Lift the adjusting ring vertically using the chain tong to disengage the

alignment teeth.

Lifting Adjustment Ring

5. Place a back-up tong on the offset housing. While holding the adjusting

ring in the upper position, turn it until the required bend is achieved (by

matching the lower and upper bend indication shown in degrees).

6. Drop down the adjustment ring to engage with the alignment ring.

7. Check to make sure the required bend setting is still lined up correctly.

Bend Setting

Example, shows the high side (HS) lined up with a value of 1.15 deg


Example of lining up the bend setting at 1.15 deg

8. Make-up the stator adapter to the torque value as per spec.

9. Check the bend setting again to make sure that it has been selected

correctly.

Confirming Bend Setting

Note:

When making an adjustment it is recommended not to use the slips, but to

have the motor hanging in the elevator. When the Kelly/top drive is made up,

or if drill collars are made up on top of the motor, the torque necessary to turn

the adjusting ring will increase.

If slips are used, they should be set on the offset housing. Ask the driller to

slack off some weight until the adjusting ring turns easily.

When turning the adjusting ring, it is recommended to stop just before the


desired setting is reached. Lower the adjusting ring so it gently rests on the

top of the alignment teeth, and slowly resume turning until the adjusting ring

falls in the required position. The adjusting ring should normally be rotated

using chain tongs, although rig tools could be necessary for large diameter

motors.

5.1.3 Making up the Stabilizer.


2. When applicable, remove the bearing housing thread protector.

3. Screw on the sleeve, which has been previously gauged. When integral

blade stabilizer is used, gauge stabilizer using ring or Homco caliper.

Record gauge on BHA Data sheet. (Minimum 1/16 in precision).

4. Grease the sleeve (or protector) and make-up as per Table

“Connections and Make-Up Torques using rig tongs.” Use same

procedure as that used for sleeve type stabilizer. Make-up plates are

available.

5.2 Surface Checks.

1. Check for loose connections, particularly the top sub. Loose connections

should be indicated on the documentation sent with the motor.

2. Make-up any loose joints

3. Hang motor free in elevator, measure the distance between the lower part of

the bearing housing section and the top of the bit box.

4. Repeat Step 3 with the full weight of the motor sitting down on the rotary

table. Record clearance again.

5. Record the absolute value of the difference between the distances measured

in Step 3 and 4.

6. Verify rotor nozzle size or blank and confirm that the nozzle is tightened to

the correct torque.


7. Remove the bit box protector and make-up the bit. Some clients request that

the surface test, if any, is performed without the bit, to prevent damage to BOP,

riser or even the bit itself. Check with your client representative, and go to next

step. Use a bit breaker.

8. Use tongs on rotating bit box only.

P3 Tools Engineering PowerDrill* Thrust Bearing Clearance

Measurement.

Maximum allowable axial bearing clearance

Motor Size 90°contact

3-1/8 0.16 in（4 mm）

4-3/4 0.20 in（5 mm）

6-3/4 0.24 in（6 mm）

8 0.32 in（8 mm）

9-5/8 0.32 in（8 mm）

5.3 Surface Function Test.

Note:

Using a rotor nozzle can lead to over-speeding of the power section when it is off

bottom. To avoid over-speeding, reduce the flow to the maximum recommended for


that motor without a rotor nozzle before picking it up off bottom.


2. For mud lubricated motors, make up the bit, if acceptable to clients. A

pressure drop at the bit is necessary to ensure proper cooling of the bearings.

3. Install a safety clamp on top sub.

4. Ensure a surface screen is placed in the string (use lifting sub when threaded

on the top - a special short screen may be needed in this case).

5. Make up Kelly / Top drive. Use a crossover if necessary.

6. Ensure BOP Rams are open and lower motor down to the point where the

ports of the dump valve are below the rotary table, but still visible.

Warning:

The dump valve functionality cannot be checked by pushing on the

mechanism, as the spring is too stiff.

If there is insufficient bit pressure drop, the motor should not be rotated in

excess of one minute during the surface test due to possible poor lubrication

of the bearings.

Take additional precautions when rotating inside the riser or casing with PDC

and/or bi-center bits.

7. Turn on the rig pumps, and slowly increase the strokes.

8. Record the flow rate and stand-pipe pressure when the dump-valve closes.

9. Keep flow rate constant, pull out the motor to observe mud flow diverted

through the bearing (from 4 to 10%) of the total flow. Observe bit rotation.

10. Lower motor back to previous position.

11. Shut-down the pumps. Since the hydraulic loop is very small, the dump-valve

may remain closed. In this case, the mud should be bled off from the stand

pipe.

12. In case a substitute bit was used, break it out and make up the bit.

13. If a float sub is required, place it immediately above the motor. Check to make

sure that the float valve is installed correctly to allow flow through the motor.

14. Prior to running in the hole, measure and record the offset angle between the


motor scribe line and the MWD reference axis. Document the measurements

and confirm that the MWD has entered the offset correctly into the MWD

initialization inputs.

5.4 Running in Hole.

Do not tag bottom with a motor because this will damage the tool.

1. Ensure the driller fills the pipe regularly while running in hole.

2. Drillers should control the travel speed while tripping in so as not to damage

the motor. This is to prevent damaging the tool when encountering any tight

spots. Use previous trip information to locate tight spot sections. Ream

through any tight spot slowly.

3. Run in slowly through casing shoes, liner hangers and casing windows when

a bent sub or bent housing is in the drill string.

4. When tripping in to extreme depths or with high downhole temperature,

periodic stops are recommended to break circulation. This prevents tool

plugging or damage from high temperatures.

5. The trip should be stopped occasionally to fill the pipe if:

• No dump valve is used which is most commonly the case.

• In wells where fluid characteristics prevent easy flow through the dump

valve.

5.5 Reaming.

Never rotate the string without circulation. This could result in a number of problems,

including packing off the drill-string and premature bearing failure in the motor.

Remember that with adequate circulation, the bit is rotating and therefore potentially

drilling an unwanted side-track can be initiated at any time. This is particularity true in

very soft formations which are usually drilled without significant differential pressure

on the motor.

Leave written instructions with the driller (copy to Company representative) on


procedures to adopt in case drag increases while running in hole. This written

instruction must include that no reaming must be attempted without the directional

driller physically on the rig floor. When the drag increases above acceptable limits,

reaming a section of open hole may become necessary. If the bit is in a section with

high dog leg severity:

1. Pull out one joint or stand.

2. Insert surface screen, connect Kelly or top drive, unlock rotation to let the

motor self-orient.

3. Start circulating gently, moving the pipe 20 ft. up and down.

4. Observe pressure after circulation has started at the flow rate which will be

used while reaming. Record the pressure reading. This pressure will be used

as reference to check for accidental side-tracking. When the bit is in a section

of hole with low dog leg severity, skip steps 5 and 6 below.

5. Run in hole, monitoring the pressure. Unless the pressure increases, keep on

running in hole. If an increase of WOB is observed without simultaneous

increase of pressure, then the stabilizers are hanging. Try to force the way

gently.

6. If WOB continues to increase without further improvement, and without a

pressure rise, check the tool face with the MWD and orient in the hole direction.

7. If still no progress, rotate the pipe at 40 rpm, monitoring the pressure.

8. When the tight spot is passed shut down circulation and resume RIH without

Kelly. Record depth for correlation and future trips.

5.6 Drilling Operations.

5.6.1 Reaching Bottom/Starting Run.

1. Ream the last stand.

a. The hole should be adequately cleaned before starting to

orientate because motor reactive torque can be affected by poorly


conditioned hole.

b. Fill can be cleaned out of the well bore by slowly rotating the

tool or by staging the tool full circle (30 degree to 45 degree at a time).

This prevents ledge buildup.

c. During hole cleaning maintain normal circulation rate.

2. Record off-bottom pressure at working flow rate.

3. Follow instructions from the bit supplier regarding new bit break-in.

5.6.2 On Bottom Drilling.

The optimization of drilling parameters when using a positive displacement

motor is a complex issue. Unfortunately the optimum working point is not easily

identifiable today with the measurements available on surface. It is

recommended to run the motor at 80% of its maximum operational parameters

to maximize the life of the motor. It is recommended to use (and adapt to the

local environment) the following rules of thumb:

1. Record off-bottom, pressure at working flow rate.

2. Increase WOB gradually to bring differential pressure up to the optimal

value.

Note

On some SCR rigs, when adding WOB, the stand-pipe pressure remains flat

and the pump stroke rate decreases. In this case the pump strokes must be

carefully monitored and adjusted accordingly.

3. Avoid rotation of the string from surface above 100 rpm. Follow the

maximum recommended rpm guidelines.

4. Maintain constant differential pressure on the bit to ensure a constant

torque throughout the entire motor run.

5. Adding or subtracting weight will cause both pressure and torque to

increase or decrease accordingly. Therefore, the rig pressure gauge


enables the operator to tell at a glance how the motor is performing

and also serves as a drilling weight indicator.

6. In addition, maintaining constant weight and pressure will also assure

constant orientation of the tool-face.

7. For an extended motor run, an optimum hydraulic thrust and bit weight

is important to maximize the motor bearing life and drilling efficiency.

8. If the driller overloads the bit and the motor stalls, do the following:

a. Immediately shut down the rotary and apply the rotary break

b. Reduce the flow by half

c. Pull off bottom

d. Refer to the Troubleshooting chapter for further actions.

Caution

On some SCR rigs, when adding WOB, the stand-pipe pressure remains flat.

5.6.3 Off Bottom Circulating.

1. Avoid off bottom circulation for extended periods. If unavoidable,

reduce flow rate to reduce off-bottom thrust bearing wear.

2. Frequently observe and record off-bottom pressure at least once every

30 ft (or 10 m). Compensate for TVD changes, flow rate changes and

mud weight changes. Check for abnormal down trends, which could

be related to a washout.

3. If compensated readings are decreasing with time, the probability of a

washout in the string is high. Observe flow rate pressure and check

surface system. Act quickly and decisively if a washout is suspected

and the system checks out OK. A washout can accelerate and develop

into a twist off within a very short period of time.

4. POOH if wash-out is confirmed, avoiding rotation (even when breaking

stands).

Warning


If an open nozzle is fitted in the rotor the off bottom flow rate must be

reduced to prevent over speeding of the rotor. Do not exceed the

normal non-nozzle rotor pump limits when circulating off bottom.

5.6.4 Orienting and Sliding.

1. Be present on the rig floor, and be prepared. Know exactly the desired

angle of turn and tool face required.

2. Record previous tool face position (mark on the pipe), depth and time.

3. Ensure the person at the brake is experienced and understands what

is required. Be patient with the driller.

4. Be patient after orientation. It will take some time before the torque is

transmitted from the surface. When no change in tool face is observed,

move the pipe up and down over 10 to 15 ft.

5. Record MD at the start and end of any sliding section, even if only a

few feet have been drilled. Estimate the average tool face and drilling

parameters during the sliding section. Note them on the Bit Run

Summary. Interpolate survey at the MD where drilling mode has

changed. Estimate sliding mode build-up rate.

6. Report your estimate for the maximum build-up rate achievable with

the BHA in use, as well as the rotary drilling tendency for future

reference. Discriminate by type of formation when necessary.

5.6.4.1 Orienting a Motor with MWD.

1. Make up the Kelly / top drive onto the drill string. Slowly fill the pipe to

break annular circulation with the bit about 30 ft. from bottom.

2. Increase SPM to the desired flow rate for hole cleaning.

3. Rotate the motor slowly and lower it to bottom while circulating. Tag

bottom slowly, mark the kelly and record hole depth in the pipe tally


book.

4. Pull the drill string to about 3 ft off bottom. Shut down the pumps and

wait for the standpipe pressure to decrease to zero.

5. Lock the rotary table and brake. With the pipe stationary turn on the

pumps at low SPM, slowly increasing to required drilling flow rate for

an MWD survey.

6. Record the hole inclination and direction.

7. Wait for a few tool face values to get a stable reading, and record the

tool face.

8. Orient the drill string to the required direction. Check readings from the

rig floor CRT to monitor tool face. When the tool face frames have

stabilized record the reading in the pipe tally book, lock the rotary table

and drill ahead. The tool face readings should be updated continuously

on the CRT screen while drilling.

9. Stop drilling to reorient the pipe and repeat the above process as

required if the tool face reading deviates from the desired direction.

10. If in doubt about MWD tool face values:

a. Wait for a few tool face values to stabilize and record the tool face.

Then rotate pipe 90° and wait for the tool face to stabilize. Record

the new tool face.

b. Repeat the above procedure a further three times to complete the

360º turn.

c. After obtaining tool face readings for the 4 different quadrants

check and confirm that the MWD tool face is working properly.

5.6.4.2 Orienting a Motor with Single Shots.

1. Make-up the kelly/topdrive onto the drill string. Slowly fill the pipe to

break annular circulation with the bit about 30 ft. from bottom.

2. Increase the SPM to the desired flow rate for hole cleaning.


3. Rotate slowly and lower the motor to bottom while circulating.

4. Tag bottom slowly, mark the kelly and record the depth in the pipe tally

book.

5. Stop rotating, pull slowly off bottom, shut down the pumps and place

the drill string in slips. Remove the kelly, mark a vertical line on the

pipe joint with chalk. DO NOT rotate the rotary table anymore.

6. Take a single shot survey.

7. Once the tool face reading has been obtained from the survey, orient

the motor to the desired direction, either to the left or to the right,

taking into account the motor roll-off effect.

8. Carry out the following steps:

a. Make up kelly onto the drill string and pull out of slips.

b. Slowly lower the drill string, mark a vertical chalk line on the kelly

bushing to align with the previous vertical line on the drill pipe.

c. Engage the kelly bushing in the master bushing. Mark another

chalk line on the master bushing to align it with the kelly bushing.

d. Draw an offset line on the non-rotating part of the rotary table. This

represents the angle from the master bushing line, that is, the

angle required to turn the drill string and orientate the motor.

e. When the bit is about 2 ft to 3 ft from bottom of the hole rotate the

drill string so that the bushing line is in alignment with the non-

rotating part of the rotary table.

f. Lock the rotary table, work the pipe slowly up and down about 5 ft

to relieve any pipe stress. This allows transmission of pipe rotation

down to the motor. Do not allow the kelly bushing to leave the

master bushing.

g. Unlock the rotary table to make sure that all the angle has been

transmitted to the motor. The drill string should not rotate.

h. Lock the rotary table again, turn pumps on and drill ahead.

i. Another method of orienting the tool face is as follows:


• After making up the kelly on the string, use the rig tongs and

cathead to rotate the pipe slowly clockwise to the proper

position.

• Move the drill string slowly to relieve stress in the pipe.

• Use this method of tagging bottom before engaging the kelly

bushing into the master bushing.

j. For deep hole orienting:

• Lock the traveling block hook with the drill string in slips.

• Free the elevators from the pipe and swing the block either

to the left or right (whichever direction of the tool face

required).

• Now engage the elevators and lift the string off the slips

• Relieve the stress in the pipe and replace the slips.

k. To verify that the tool face is correctly orientated take a survey

check shot. This is compulsory for deep holes.

Tip

Sometimes it is necessary to reduce the flow rate to achieve sufficient

DLS, notably in poorly consolidated sands and washable shales, due

to hole enlargement. Advise Company Representative and Mud

Engineer when applicable.

5.6.4.3 Stabilizer Hanging.

Stabilizer hanging is a recurrent problem inherent to stabilized steerable systems in

sliding mode. Normally stabilizer hanging translates into a reduction of ROP and

difficulty in increasing the pressure drop across the motor. When stabilizer hanging

is suspected, proceed as follows:

1. Record depth for correlation and future reference.

2. Mark tool face reference on drill pipe and rotary table.

3. Unlock rotary table or top drive


Tip

4. Drill 3 ft. to 5 ft. at 40 rpm to 60 rpm.

5. Re-orient tool face using reference on drill pipe.

6. Resume sliding.

Stabilizer hanging negatively affects the build-up rate (BUR).

Higher bend settings, although potentially producing high BUR, are more prone to

stabilizer hanging, and therefore actually less BUR efficient than lower settings.

5.6.5 Surveying.

1. Normal frequency should be one survey per stand unless specified otherwise by the

client or FSM.

2. Report surveys every hundred feet on the survey calculation sheet.

3. Request one survey per joint during a kick-off, landing in a horizontal drain, or during

a correction run;

4. It is good practice to take a survey anytime the D&I package is at a depth where a

change of steering mode occurred (from sliding to rotary or vice-versa).

5. Experience has shown that downhole motors can generate downhole noise, which

interferes with the MWD signal. Generaly the noise perturbs the MWD signal when

the motor is drilling (on bottom). If signal detection problems are present, modify the

pump strokes, keeping the flow rate constant.

6. Do not attempt to slide for more than 10 ft (or 3 m) without reliable MWD Tool Face

information. When dog leg severity in excess of 15 degree/100 ft (or 5 degree/10 m)

is expected, this limit must be reduced to 5 ft. (or 1.5 m).

7. If the noise problems persist, and if all signal detection improvement techniques are

ineffective, POOH and inspect the condition of the BHA components. Causes of

downhole noises can be damaged bit or damaged BHA component e.g. reamer. Junk

on top of the MWD modulator or broken internal components within the BHA tool can

also result in a noisy signal.


5.6.6 Severe Conditions and Non-Standard Operations.

5.6.6.1 Harsh Drilling Conditions.

Rotating a motor in a curve produces cyclic bending stresses in the motor and

connections. Lateral vibrations, in straight or curved sections can also cause cyclic

bending stresses. If drilling conditions are harsh, and the stresses exceed the

endurance limit of the material, metal fatigue, cracks, and eventual failure will be the

result. Refer to 4.5.1: Harsh Drilling Conditions for more information.

5.6.6.2 Running Tools Below Motors.

Many different types of subs or crossovers have been run below P3 Tools

Engineering PowerDrill* motors. The main concern is not to damage the radial or

axial bearings due to the additional bending and axial loads. If possible, a rotating near

bit stabilizer (RNBS) should be run just below the bearing section to take the side

loads off the lower radial bearing. Also, greater care needs to be taken when back

reaming with this assembly, since the thrust bearing is much more likely to see

impact loads. In general, the thrust and radial bearing life will be shorter when

running a sub below the motor.

Another concern is the rotary build and drop tendencies of the motor with the longer

bit to bend distance.

5.6.6.3 Back Reaming.

1. Back reaming causes a number of unique stresses on the motor.

2. The tension on the motor reduces the shoulder compression on the

connections making them susceptible to backing off.

3. It is very easy to exceed the capacity of the thrust bearings when circulating

off bottom and back reaming. Refer to the relevant thrust balance chart in

section 3.7.4: Thrust Balancing and reduce the flow rate as appropriate to


help extend bearing life.

4. Rotation off bottom causes the motor to wobble and flex which damages the

motor connections. The bit does not act as an anchor making the BHA more

susceptible to lateral vibrations.

5. The side load from the bit on the output shaft causes increased radial

bearing wear and the lack of weight on bit results in unbalanced wear at the

thrust bearings.

6. To reduce the stresses, it is recommended to keep rotary speeds below 40

rpm while back-reaming.

5.6.6.4 Jarring.

Unless the circulation was never lost and the stuck point was above the mud motor,

it is recommended to replace a downhole motor which has been subjected to jarring.

5.6.6.5 Fishing.

Tip

1. Refer to the diagrams and dimension tables.

2. Fishing of a downhole motor is generally successful but the fishing method

depends on where the back-off occurs.

3. When the rotor is left in the hole, try to fish on the motor body rather than on

the rotor itself as this method gives a stronger 360 degree bite. Extensions

have to be used in this case. A joint of casing or wash-over pipe may be

used as a substitute for numerous extensions.

If the rotor or motor is left in the hole and it was equipped with a rotor catcher, make

sure that the fishing tool operator is provided with its dimensions.

4. Fishing on a non-stabilized motor may prove delicate due to the bearing

section allowing the free rotation of the housing, even when high WOB is


applied.

5. When fishing a string including a motor, remember that the reactive torque

and the vibrations tend to tighten the fish in the overshot after circulation has

resumed.

5.6.6.6 Drill String Vibration／Resonance.

There are 3 major vibration generation mechanisms:

1. Resonance—the string is rotated at a natural frequency of the string, this

occurs at specific rotary speeds and is countered by changing rpm. It is likely

that this kind of resonance in itself does not cause significant damage but

may cause wall contact, which, under the right circumstances, can lead to

chaotic whirl.

2. Whirl—Several forms of whirl exist:

Term Definition

Synchronous Forward Whirl

The whirl rate is such that it keeps the same point of the drill-string on the bore-hole wall, resulting in uniform wear on drill string components. It is evidenced by higher than anticipated torque requirements. The solution is to stop rotating and change rpm.

Backwards Whirl Eccentric motion of the center of mass in the opposite direction to the direction of rotation. Fatigue results but should not be a major problem until wall contact occurs, then, if the formation has a high coefficient of friction, chaotic whirl will result.

Chaotic Whirl If the drill string hits with enough force on the bore-hole wall and it has a high coefficient of friction (e.g. sandstone, limestone and casing) the string will bounce off in the opposite direction to the rotation, and may make subsequent impacts. These are typically very high energy and cause significant damage. They will not stop when the rpm is changed and typically result in high downhole shock and high and erratic surface torque. If the rpm is increased sufficiently the drill-string will 'run' around the inside of the hole like a planetary gear. At this point the shocks will disappear but the torque will remain high and a twist off will almost certainly occur. Avoid pendulum assemblies and long spans between stabilizers, make the string stiffer, and reduce WOB. Stop the drill-string, pull off bottom and ensure the driller goes back to bottom smoothly.

3. Slip Stick- Usually a bit phenomenon typically caused by having a bit that is

too aggressive for the formation. Evidenced by high torsional shocks and


erratic torque though the mean torque should not be higher.

The solution is to decrease WOB and increase rpm.

5.7 Laying down the BHA.

The decision to re-run or lay-down a motor should be based on a number of criteria:

1. Attempt to estimate the efficiency of the power section by doing an off bottom test

before tripping out of the hole at the same depth the motor started the run. Compare

results.

2. Check the thrust bearing clearance.

3. The estimated duration of the upcoming bit-run.

4. The status of the motor inventory at the rig-site and the back-up situation from town.

Note

Never keep a motor on the rig that you have no intention of re-running-send it back to town

for maintenance.

After the decision has been made to lay down the motor proceed as follows:

1. Set SAB angle to zero following the procedure detailed in section 7.1.2: Adjusting the

Bent Housing above.

2. Flush the motor with clean water before laying down. This is recommended, and is

critical in a corrosive environment.

Caution

High chloride muds are particularly corrosive to chrome, in this case it is essential that the

motor be flushed with clean water prior to laying down.

3. If there is any doubt as to the operational status of the motor, or if LCM has been

pumped during the previous run, perform a surface test before laying down to verify

the functionality of the motor and that it is a working backup.

4. Lay down the motor using lift sub on top connection.

5. Install the bit box thread protector.


5.8 Tripping across a Sidetrack.

To minimize the chances of accidental sidetracking across a junction, adhere to the following

procedures:

1. No major working of the string during the first stand of sidetrack should take place to

avoid disturbing the sidetrack area. If the hole conditions dictate, then the motor

should be oriented with the same orientation as the hole direction and the string

worked up and down gently maintaining this Tool Face.

Note

The above action should always apply when tripping in the future across the sidetrack

zone – always control the tripping speeds.

2. If hanging-up is experienced, heavy work across the interval should be avoided and

light parameters should always be used.

3. If any restriction has been encountered on the way out of the hole, it should be worked

through. Also make sure that the string can be tripped on elevators before pulling to

the surface.

4. If a restriction has been encountered on the way in and cannot be passed without

pumps, use low flow (1-2 m3) and rpm as low as possible (20-30) with a fast

movement down trying to force the bit into the hole. This way, if unsuccessful, the

worst can happen is the motor will stall, but having no real power it will minimize the

risk of cutting a new hole.

5. Never use full drilling parameters across the junction while reaming the string down.

In a worst case scenario, orient the string with the hole 'TF' and slide it in watching

parameters.

6. Contact the DD Coordinator in town to discuss the problem immediately.

5.9 Operating in Cold Locations.

When operating in cold weather locations, the following must be considered to ensure safe

operating conditions for P3 Tools Engineering PowerDrill* motor tools and associated


components.

• If an assembled motor is stored outside in a cold climate warm it before it is operated

(this includes running a Surface Function Test (SFT) before going in the hole.

• At the rig, if possible, store the motor in a pipe shed to prevent it from freezing.

• If mud is pumped through a cold／frozen motor the mud can freeze inside the motor.

To prevent this from happening warm the motor before pumping mud.

• Warm the motor by covering it with a tarpaulin or herculite, and placing a steam hose

alongside the motor to warm the body. Heat will be trapped in the herculite and warm

the body.

Note

Do not place the steam hose into the end of the motor as this will only warm the connection

and may damage the elastomer. Heat should not be concentrated in one area; the whole

motor must be warmed together.

• Warm the connections before breaking i.e. to adjust the bend.

• To test if a motor is still frozen, remove the heat source for 2 hours and pour a cup of

water over the body of the motor. If the water freezes on the surface of the motor then

the motor is still frozen and requires further warming. Wearing gloves, touch the

surface of the motor from top to bottom to identify any cold areas that have not been

warmed sufficiently.

• If you have not been able to warm the motor before picking it up to the rig floor, before

conducting the Surface Function Test (SFT) and pumping on the motor, run the BHA

into the well. The temperature of the mud will warm the elastomer.

• Begin to pump on the motor with a reduced flow to allow the power section to warm

gradually.

• Once you reach the desired flow rate, do the Shallow Hole Test as quickly as possible

to limit the time the motor is exposed to cold operating conditions.

• The motor will be warm, as the BHA is being run in hole.

• When the motor is back at the surface, remove as much mud out of the motor as

possible, and then make sure the motor is drained. Any mud or water left in the


assembly can freeze, damaging the inside of the tool, and potentially splitting the

stator. It is therefore important to keep the motor warm when it is laid down to prevent

freezing, especially if it is going to be re-run. A frozen motor can take several hours

or days to thaw out. Before picking up the motor, test the temperature by pouring

water on the surface, as described above.

Tip

Treat every motor as if it is potentially frozen.


6.0 Maintaining P3 Tools Engineering

PowerDrill* Motors.

This section describes maintenance that can be carried out at the wellsite.

6.1 Checking the well site.

Maintenance should not be required before running in the hole. The motor should be

received on the rig as per the specifications.

1. When the motor is received, the engineer in charge must check the configuration

against the requirements:

a. Tool size and serial number

b. Stator S/N for lobe configuration and elastomer type and size

c. Stabilizer gauge and/or sleeve to be made-up

d. Bottom/top connections

e. Dump valve ports/plugs. Although Dump valves are uncommon, they are not yet

obsolete.

f. Nozzle on rotor (check with flash light)

2. The box threads are shoulder damage prone, and must remain protected at all times.

3. The lifting sub should be used while making-up or laying down the motor. Lifting with

hooks in the threads is prohibited.

4. A visual inspection must be performed to detect any defects/damages while shipping

immediately after reception at the rig site.

6.2 Post-run maintenance.

1. If the motor has been run in a corrosive environment it is recommended to wash with

fresh water (if available) after the run is completed. This is normally done when with a

hose when the motor hangs in the elevators. Turn the drive shaft clockwise (looking

downhole), with a back-up tong holding the bearing housing.


Water-based or salt-saturated mud: It is very important to flush the motor immediately

after being run in water-based mud or salt-saturated mud because corrosion is

accelerated when the motor is exposed to air. Corrosion can occur in a few hours causing

pitting of the rotor. This pitting will damage the elastomer when re-run downhole.

Oil-based mud: With oil-based mud, drain the motor. Flushing it with water is not

necessary as it is recommended to reline a stator run in OBM after 24 operating hours.

2. Before stacking, mineral oil should be poured into the motor, using the same technique.

This should prevent sticking between rotor and stator, and will allow some lubrication of

the mud lubricated bearing before the next run or maintenance. Never use diesel.

3. Minimize direct sun exposure, especially in tropical/equatorial areas.

4. Store the motor away from possible chemical contaminants, and at least three feet

above the deck level.

6.3 Changing the Rotor nozzle.

1. The replacement of the rotor nozzle on the rig is not considered a normal procedure.

Depending on how the motor is dressed, it may require a nozzle wrench that is not

normally shipped to the rig with the motor. It also requires that the dump valve or top sub

is broken on the rig floor before the motor is laid down.

2. If a nozzle is to be installed/replaced, this is best accomplished on the pipe rack. The

dump valve, previously broken on the floor, must be removed.

3. To fit a rotor nozzle, remove the old nozzle or blank plug. Remove the used O-ring,

clean the surfaces, insert a new O-ring, grease the thread with multi-purpose grease,

and make-up the nozzle using the wrench, to applicable torque.

Warning

Failure to apply the correct torque to the new nozzle may lead to failure of the motor

downhole due to the rotor nozzle backing off and passing through the stator causing

catastrophic damage to the elastomer.


7.0 Troubleshooting.

7.1 Motor Troubleshooting during operations.

This section describes the troubleshooting steps which should be taken during

operations and the recommended actions.

7.1.1 Large instantaneous pressure increase.

Immediate action: reduce the flow rate by half. Pick off bottom. Re-

establish previous parameters. Investigate the difference if any is

evident.

If the pressure increase is due to a stall in the power section, this stall is going to

increase the torque output, which is much higher than the normal operational

torque. This torque is going to be passed down the string to all connections.

It is not uncommon for the immediate reaction after a stall to pick off bottom without

reducing the flow. This immediately relieves the torque on the bit so the torque is

released in the motor assembly, potentially causing a back off in the BHA including

motor components. By reducing the flow to half, you are reducing the torque

generated by the stator which will in turn reduces the torque in the BHA and

minimize the chance of a back-off. After picking up, the first parameter to evaluate

is being able to re-establish the previous off bottom pressure and flow.

Isolated: motor stall; proceed with care

Being able to re-establish the previous off bottom hydraulics (PP and flow rate)

is confirmation of a stall and if it is not repeated, it could have happened for

several reasons. If the stall was a result of a large instantaneous WOB increase,

work with the driller to avoid this happening again.

Frequent motor stalling: inter-bedded formations, weak motor, hanging, or

incorrect drilling practices.


For frequent motor stalling, relate it to a root cause. Frequent stalls might occur

for several reasons:

• Formation related: Drilling through inter-bedded formations with poor WOB

control can cause stalling when the harder layers are encountered.

• Weak motor: Look into the possibility of the motor being too weak for the

downhole condition — is the fit too loose? Is the fit appropriate for the

downhole temperature?

• Hanging Up: Look into solutions to reduce hanging, including local working

practices e.g. adding mud lubrication agents to the system.

• Incorrect drilling practices might cause stalling, often in a difficult sliding

environment. Investigate local knowledge and best practices developed by

DDs to help improve sliding effectiveness.

Permanent stall with circulation: Crushed / jammed bearing, partial

plugging, severe debonding or surface issue

If you are still able to circulate and are not able to re-establish the original

pump pressure, analyze the pressure difference. If the pressure increase is

quite high, the bearing assembly may have collapsed/jammed, which is

leading to a stalled motor. The motor/string could be partially plugged or there

may be a problem with the power section, immediate e.g. debonding in very

rare cases. Also don’t rule out a possible surface system issue, this needs to

be fully explored before taking a decision to POOH.

If you are not able to circulate: Surface system issue or plugged string

including motor plugged


If you are not able to establish circulating again, this may be due to a plugged

string including surface system and in very rare cases the motor may be plugged

with debris e.g. elastomer, cement scale or LCM.

When at the surface, look closely for clues as this might not be a motor issue.

If you have to POOH, inspect the BHA while POOH and after the BHA reaches

the surface. Check the float valve, filters and inside the drill bit for any debris.

7.1.2 Moderate constant pressure increase.

No immediate action: monitor the parameters for other clues: off bottom

parameters. Changes to the surface system.

No immediate action is required in this case, except for the investigation process

to find out the reason behind this increase.

Possible plugged nozzle / nozzles; calculate pressure drop through nozzles

and compare.

It is good to have an estimation of pressure increase expected in the case of one

or several plugged nozzles. This will help to identify if the pressure increase is

coming from a plugged nozzle. Nozzles can get plugged with objects that are not

necessarily stator elastomer.

Possible higher ECD

Are mud parameters changing? Is the hole loading with cuttings? Has torque

and drag increased? Check pick-up and slack-off weights each stand to see if

there is a correlation of increased weight with PP increase. Effective hole

cleaning is essential during drilling.

Observe shale shaker for rubber, loss of cuttings, cavings, etc.

After discussing with related parties, continue drilling if the situation permits

Once on surface, look closely for all clues as this might not be a motor

issue

If POOH, inspect the motor, bit and the BHA once on surface.


7.1.3 Pressure fluctuations.

No immediate action:

Monitor for other clues: Surface system (pumps and pulsation dampeners

condition), mud system (weighting up/down mud), shale shakers (any elastomer

present), torque fluctuations, inter-bedded formations, off bottom parameters.

Possible hole integrity issues:

Hole packed with cuttings and cavings. Cuttings bed formation. Avalanching

cuttings beds.

Dirty mud:

Re-circulation of cuttings can cause pressure fluctuations.

Accidental loss of bit cutting structure: broken blade.

Usually off bottom pressure behavior will not be fluctuating in this case.

Might be a motor issue: elastomer pieces circulating through the bit,

monitor shale shakers for elastomer show.

This will be important to define further actions. In many cases, motors continue

to deliver good power for considerable time after this starts happening.

7.1.4 Large instantaneous pressure decrease.

Immediate action: Pick off bottom, reduce rpm and reduce flow.

This will need immediate reaction by picking off bottom, reducing flow and rpm

to minimum. If not stop both.

Rig should troubleshoot the surface system

Immediate troubleshooting of surface system should start while you do your own

troubleshooting/analysis of the situation and DML data.

If loss of string weight is observed, client will decide on proceedings

including trying to re-latch on the fish.

Under no circumstance should drilling be resumed without reaching a

conclusion about the pressure drop.


7.1.5 Moderate constant pressure decrease or

continuous pressure decrease.

Immediate action: Inform company man/client and driller, monitor other

clues: Changes to the surface system, mud system.

Immediately start monitoring other parameters and try to find the reason behind

the pressure drop, including changes to the mud system/mud mixing, etc.

If no reason is detected or the pressure keeps decreasing, pick off bottom

and continue troubleshooting. Don’t proceed with drilling before finding

out the reason of the pressure drop— be firm on this. Keep checking on the

drop for deterioration.

If no reason has been found for the pressure decrease, pick of bottom, reduce

rpm before continuing to troubleshoot while checking on the parameters.

A washout can develop into a twist off in a very short space of time (<10

mins).

Pressure loss needs to be handled quickly and decisively. Delayed

troubleshooting is likely to result in a LIH event.

7.1.6 Loss of differential pressure.

Loss of differential pressure is loss of torque generation by power section.

If there is no differential pressure from the start of the run, suspect

assembly error/too loose fit/drilling while stalled.

Can vary from complete to partial loss of differential, gradually or sudden.

Can happen anywhere from the bit to power section. Drilling on junk (e.g. bit

cutters) can prevent the bit from biting into the formation. If the bit has lost all

cutting structure there will be low differential pressure and no ROP.

Will be accompanied with very low ROP values or no ROP at all. (Except

drilling with very low WOB in very loose formation).

Gradual loss is usually indicative of loss of bit cutting structure,


bit balling or loss / erosion of elastomer. Check drilling torque values.

Check shakers for elastomer.

If the BHA is hanging up and the bit is not actually on bottom. (Check DLS

changes, formation changes & correlate with stabilizer position in BHA).

Sudden complete loss is indicative of mechanical twist-off between the

power section and the bit including the bit itself. Will be accompanied by

complete loss of ROP

Low ROP values are usually accompanied by reduction in differential

pressure.

In some instances, you could lose some of the differential pressure due to drilling

in very hard formation with little bit penetration. To help you identify these

situations, compare offset data and local experience to see if that is expected or

has been seen before.

In case of low to very low ROP values, investigate further, examine offset

data before taking costly decision.

Documents

CYCLONE* DOWNHOLE MOTOR SERIES HANDBOOK · 2019. 10. 25. · The P3 Tools Engineering PowerDrill* motors are Positive Displacement Motor (PDM) steerable systems. The main application