Driling Fundamentals

7/27/2019 Driling Fundamentals

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B. Engeser/Fundamentals of Drilling (1)

Fundamentals of Drilling Course Outline

(1)Basics of Rotary Drilling(2)Rotary Operations/Coring(1) Basics of Rotary Drilling(3)Directional Drilling-Rotary Process(4)Fishing -(5)Casing/Cementing and Well Control-Drill String

(6)Principles of Drilling Fluid Technology-Drilling Fluid(7)Principles of Borehole Stability-Rig

(8)Principles of Hydraulic Testing

Bit


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Fundamentals of Drilling

Drilling means to makea hole in order to getaccess to the earths

subsurface

gaining information about the subsurfacefrom sampling/testing/logging

Objectives may be

Monitoring of subsurface properties

(aquifer pressure, stress state etc)

Objectives define Hole/Well Construction

-> hole discarded

-> hole completed into well

-> hole completed into well

Production/injection of fluids/gases

(oil/gas/water)


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Fields of Drilling Applications

Exploration/Productionof Natural Resources

-Oil and Gas

-Water

-Geothermal Energy

Site Investigation

-Environmental

-Scientific

-Foundation/Construction

Mining Exploration

Blast Hole/Seismic

-Quarry


4/41B. Engeser/Fundamentals of Drilling (1)

Drilling Techniques Classification by Hole Making Methods

ContinuousProcess

DiscontinuousProcess

Soft formation only



Principles of Drilling Techniques Percussion Cable Tool Drilling

!Suitable only for hard rock!Total Efficiency of Drilling Process

is fairly low

Phase 1: Rock DrillingFree Falling Bit strikes the Bottom

with a heavy Blow - Repeated

Lifting and Dropping makes the bit

drill

Phase 2: Removal of CuttingsInterruption of Drilling to

remove Cuttings by Bailing

Very old drilling technique (appliedmore than 2000 years ago by the

Chinese)

2-Phase Technique (discontinuous)

Bit movesup and down



Principles of Drilling Techniques - Rotary Drilling

Continuos Drilling Operation

Operations requirea Rotary Drilling Rig

Drilling Fluid is circulated by beingpumped down the drill string

The Drill String is rotated to turn thebit.It is fed down as the bit penetrates

Bit is pushed into the bottom androtation makes it cut

Return circulation carries cuttings up

the annulus between the drill string andthe wall of the hole

Key Elements

!Drill Bit!Drill String

!Drilling Fluid



Types of Rotary Bits

Medium HardVery Hard SoftSoftRock Characterization

Performance Parameters of Drill Bits:Penetration Rate (Drilling Speed: m/h)Bit Life (Meters drilled)

Diamond Bit

Natural DiamondsDiamond Bit

Polycrystalline

Diamond Compact

Cutters

Roller Cone Bit

Tungsten Carbide

Inserts

Roller Cone Bit

Milled Steel Tooth



Cutting Action of Rotary Drill Bits

Chip Making

Chip Clearing

Chip Making

Roller Cone Bits

Percussion Bits

Roller Cone BitsDiamond Bits

Nozzles of RollerCone Bits

Roller Cone Bits with OffsetDiamond Bits

C f



Cutting Action of Rotary Drill Bits

Gouging and scrapingCrushing

Roller cone bit with no offset Roller cone bit with offset

Direction of RotationHard Rock Soft Rock

Cones ofRoller Bits do

not only roll

on the bottom

but alwaysslide, tearand

gouge

Offset of

cones

increases

sliding, tearinggouging

action

El t f R ll C Bit



Cone Inserts

Shank

Jet Nozzle

JournalBearing

Ball Bearings

LubricantReservoir

Threaded

Joint

PressuredCompensator

Elements of Roller Cone BitsShape Types of Inserts

IADC R ll C Bit Cl ifi ti



IADC Roller Cone Bit Classification

First Figure Second Figure Third FigureSeries Hardness Design Option

(1 4)

3 Figures:

Example: 5-1-7

Hardness Class1 Soft2 medium3 hard4 Very hard

Example: 5-1-7Example: 5-1-7

Sealed Journal BearingRoller Cone Bit with TungstenCarbide Inserts

IADC-Code: 5-1-7

B tt H l Cl i f R ll C Bit



Bottom Hole Cleaning of Roller Cone Bits

Effect of Nozzle Velocityon Rate of Penetration

IncreasingNozzle velocity

ROP

WOB

Schematic of Nozzles Action

Typical Operating Parameters for Roller Cone Insert Bits


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Typical Operating Parameters for Roller Cone Insert Bits

high WOB

low RPM

7 7/8- 8

Size

Cutting Action of Diamond Bits


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Cutting Action of Diamond Bits

Cutting Size

Shearing

PDC-Bit

Grinding

ImpregnatedDiamond Bit

Plowing

Surface setdiamond bit

Cutting Action of Diamonds


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Cutting Action of Diamonds

Exposure

Sizes and Texture of Hard Rock Cuttings dependent on Bit Type


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Sizes and Texture of Hard Rock Cuttings dependent on Bit Type

fineflour

coarse

chips

Operating Parameters of Diamond Bits


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Operating Parameters of Diamond Bits

Low WOBHigh RPM

Rotational Speed

300 600 RPMMainly used withDownhole Motors/Turbines

Typical Rotary Drill String Assembly


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!Stabilizers

!Drill Pipe: Steel Pipe withPin/Box threaded Tooljoints:

Main Components

!Drill Collars: Thick Wall Steel Pipewith Pin/Box threaded Connection

Typical Rotary Drill String AssemblyRig

Bit

Drillpipe(DP)

The Drillstring is the Mechanical AssemblageConnecting the Rotary Drive on Surface to the

Drilling Bit on Bottom of the Hole

!Flow Line for Circulating Drilling Fluid

!provides Weight on Bit!transmits Rotation and Torque to Bit

!guides and controls trajectory of the bit

Functions of the Drillstring

Ancillary ComponentsDC

DC

Drill Collars(DC)

!Crossover subs

!Reamers

BHA

!Shock absorbers

!Downhole Motor/Turbine

!Jar

Rotary Drillpipe Characteristics


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Rotary Drillpipe Characteristics

Steel Gradesof Pipe BodyE-75X-95G-105S-135

Nominal Weightof Pipe Body

Wall Thickness

Rotary DP is standardized by API

Outer Diameterof Pipe Body5 5

4 43 2 7/82 3/8

Tool Joints Steel Grade: 120000 psiThread TypeNC 50NC 38

Friction welded with upsetpipe body annealed andmachined

Pipe LengthRange 1: 18-22 ftRange 2: 27-30 ftRange 3: 38-45 ft

Stands of 3Thribble

Pipe body

welded

Rotary DP needs sufficient annularclearance due to Tooljoint Sizes

18shoulder for Elevator

Pin and Box TooljointTooljoint

Design Criteria for Rotary Drill Pipe


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Design Criteria for Rotary Drill Pipe

Drill Pipe is the most stressedcomponent of rotary equipment

Drill Pipe has to be designed for:

Tension

Tooljoint/

Torque

Twist off

Burst(Inside Pressure)

ReversalStresses

Fatigue

BendingWhile Rotation

Drillpipe Stands and Drillcollars set on the Rig Floor


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Drillpipe Stands and Drillcollars set on the Rig Floor

Drill CollarsDrill Pipe

Putting Weight on Bit by Drill Collars


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Putting Weight on Bit by Drill Collars

Tension

com

pression

Tension

Buckling of Drillpipeunder compressional load

Typical Examples for Stabilized


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Typical Examples for StabilizedBottom Hole Assemblies (BHA)

Drilling Fluid why its called Mud


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Drilling Fluid why it s called Mud

Mud coming out of hole(beneath shaker screens)

Mud going into hole

(Suction pit)

Drilling Mud A Multipurpose Fluid


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Drilling Mud A Multipurpose Fluid

Major Functions

(1)Bottomhole Cleaning

(2)Cuttings Transport

(3)Borehole Wall Support(4)Balancing Formation Pressure

(5)Cooling the Bit(6)Hydraulic Power Transmission

(7)Data Transmission (MWD)

(8)Reducing Friction

(9)Corrosion Protection

(10)Scientific Information Carrier

Principal Functions of a Rotary Drilling Rig


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p y g g

Rotate the Bit

Put Weight on the Bit/Handling the Drillstring

Circulate Fluid/

Solids Contol

Power Supply

HoistingSystem

Pumping/Circulation

System

Rotating

System

Main Components of the Hoisting System


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p g y

crown block

derrick/ mast

travelling blockwith hook

drawworks

drilling line

Fast Line

deadline anchor(where hookload ismeasured)

Dead Line

Schematic of a Rotary Rigs Block and Tackle


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y g

Drilling line work

Is the product of the loadtimes the distance travelled

Hoisting System of Drilling Rigs Hoisting Tower


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MastHeight governs the maximumlength of Drillpipe Stands

2-joint stands (18 m)3-joint stands (27 m)

Derrick

Structural tower

assembled/

dismantled piece

by piece

Square shaped

Rig floor

Assembling/

Dismantling is

time consuming

derrickman

platform

Used mainly

offshore

A-shaped structure

which can be pulled or

lowered to a upright

position by the drawworks

without completelyassembling or

disassembling

Good mobilityUsed mainly with

onshore rigs

Height governs the maximum length ofDrillpipe Stands2-joint stands (18 m)3-joint stands (27 m)

Types of Rotary Rig Drawworks


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the drawworks is the heartof the drilling rig

Capacity of the drawworks

characterizes a rig and defines depth rating

chain driven drawworks

Modern gear driven drawworks

yp y g

Advantages of gear drivendrawworks:High performanceHigh availability

Less noiseLess vibrationIncreased safety

Methods of Rotating the Bit


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g

Rotating the Bit using aDown Hole Motor/Turbine

Rotating the Drillpipe directlyby a Top Drive or Power

Swivel which moves downwith the pipe

Rotating a Rotary Table whichturns the Drillpipe as it slidesthrough

S i lRotating the Drillstring with a Rotary Table


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Swivel

Bail

sustains weight of

drill string

permits rotation

provides passageway

for drilling fluid

Rotating seal allows

drilling fluid to beinjected under

pressure

Kelly

square hexagonal

Standard Length40 ft (12.2 m)

Rotary Table

Rotating the Drillstring with a Top Drive


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!Drill string can be pulled out while

Rotating and circulating -> Back Reaming

!Can be reconnected to the drill string at

any mast height during tripping

!Drilling with 3-joint stands of drill pipe is

Possible

!With hydraulic driven power swivel static

torque can be applied for much longertime

Advantages of a Top Drive System

Top Drive means a Power Swivel which directlyturns the drillstring without need for a kelly and

rotary table

Saves timeSafer and easier operation

Requires trolley beam guide system tobe installed in the derrick

Circulation and Solids Control System of a Rotary RigFlow Scheme and Main Components


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Flow Scheme and Main Components

Drilling Fluid Circulating PumpsTypical Operating


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Triplex Type Pump

Typical OperatingParameters

17 : 3500 l/min

12 : 2500 l/min

8 : 1500 l/min

6: 600 L/min

max. pressure: 35 MPa

heavyweight rigs

2 pumps 1200 kW each

lightweight rigs

2 pumps 600 kW each

M h i l P T i i Old T h l

Power Supply System of Rotary Drilling RigsEl t i P T i i M d T h l


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Multi Engine Chain DriveCompound

Mechanical Power Transmission Old TechnologyElectric Power Transmission Modern TechnologyPower Demand

!AC-DC/SCR-Concept

!DC-DC Concept

Classification of Drilling Rigs


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Classification by HorsepowerRule of Thumb:Every 100 ft of boreholeRequires 10 hp at drawworks

Classification by Depth RatingLightweight Rigs: 1500 2000 mIntermediate Rigs: 3500 mHeavyweight Rigs: 6000 mUltraheavy Rigs: 8000 10000 m

DiamondDrilling Rig

LightweightLightweight RigsRigs: 650: 650 hphpIntermediateIntermediate RigsRigs: 1300: 1300 hphp

HeavyweightHeavyweight RigsRigs: 2000: 2000 hphp

UltraheavyUltraheavy RigsRigs: 3000: 3000 hphp

Typical Rig Organization Scheme


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Drilling Contracts


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Footage ContractsOperator pays the contractor a stipulated amount foreachfoot or meterdrilled regardless of how long it takes the

contractor to drill it. Contractorassumes many of the risksof drilling

Daywork Contracts

Operator pays a stipulated amount per hourbased on

the work the rig and crew are doingDrilling time

Standby Time (Logging, Testing, etc)

CombinationContracts

Combination of Footage and Dayrate Contracts

Turnkey Contracts

Operator pays an agreed-on amount when the

contractorcompletes the well. Contractor furhishes allequipment, material and personnel to drill the well.

Contractorcontrols the entire drilling operation withlittle or no supervision. Contractorassumes all the risksand adjusts the price charged to reflect these risks.Operatorbenefits by not assuming any risks.

Average Meter Costs dependent on Depth


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2000

2500

3000

3500

4000

4500

0 500 1000 1500 2000 2500 3000

Avg. Cost ($/m)

Dep

th(m)

Deepwater Gulf

Europe Onshore

South Louisiana

Offshore LA

Federal OCS

North Louisiana

Source:1999 Joint Association Survey on Drilling Costs

Semisubmersible : 160 000 $


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Semisubmersible : 160 000 $Drillship (Dyn. Pos): 150 000 $KTB-Rig: 90 000 $

Documents

Driling Fundamentals