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Beam Lift Optimization and Troubleshooting
• What factors influence beam lift operation?
• What data is needed to optimize lift?
• What actions optimize the lift system?
• What are the best workover candidates?
This presentation uses many slides directly from a beam lift presentation by by John C. Patterson, Phillips, and James V. Curfew, at the BP Deliquification Meeting in 2002.
8/25/2015 1 George E. King Engineering
GEKEngineering.com
Beam Lift Productivity Variables • Pump stoke and speed:
– efficiency is improved by minimizing
liquid level over the pump without
pumping-off or evacuating wellbore
– Match stroke and speed to depth and
fluid viscosity
• Remove obstructions in flow path:
• scale, wax, asphalt, gathering line
restrictions and back pressures.
• Minimize rod drag
• Gas movement: route free gas away
from pump. Avoid gas locks.
• Pump performance – wear, friction,
solids, dissolved gas
8/25/2015 2 George E. King Engineering
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Tubing and Casing Influences on Beam Lift
• Important points: – Large casing and
vertical wells give better gas separation.
– Large tubing allows bigger pumps.
– Small casing decreases anchor size and gas separation ability (downward vertical velocities too high) and increases formation backpressures.
Source – John C. Patterson and James V. Curfew
8/25/2015 3 George E. King Engineering
GEKEngineering.com
Beam Lift Optimization – Gas Separation
• Gas Separation
– Free gas separation before the pump
– Dissolved gas separation in the pump
– Deviation effects on pump lockup by gas
Setting the pump deeper may improve gas separation where the down-flow velocity of fluids towards the pump is slow enough that the gas will separate and rise by density segregation.
In smaller diameter casing and in wells with high gas-liquid-ratios, gas separation becomes more difficult.
Source – John C. Patterson and James V. Curfew 8/25/2015 4
George E. King Engineering GEKEngineering.com
Rod Pump Cycle
Start of up-stroke.
Traveling valve closed: fluid in tubing being picked up by rods.
Standing valve open: drawing fluid into pump.
End of up-stroke.
Traveling valve will open next as rod string drops.
Standing valve will close as rod string starts down.
Start of downstroke.
Traveling valve open: fluid in pump being forced into tubing.
Standing valve closed.
Source – John C. Patterson and James V. Curfew
8/25/2015 5 George E. King Engineering
GEKEngineering.com
Gas Separation – The ideal set depth depends on several factors.
Deep Set Pump – allows gas separation
Shallow set – gas locked pump.
Gas Locking Pump
0
200
400
600
800
1000
1200
1400
1-May-05 21-May-05 10-Jun-05 30-Jun-05 20-Jul-05 9-Aug-05 29-Aug-05
BL
PD
8/25/2015 6 George E. King Engineering
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Time estimate to break a gas lock
0 psig or
1 atm
200 psi or
13.6 atm)
0 psig or 1
atm
200 psi or
13.6 atm)
Pump
Discharge at
3000 ft
1,311 psi (89
atm)
1511 psi
(102.8 atm)
41 psi
(2.8 atm)
1248 psi
(84.9 atm)
DP across
pump
1280 psi
(87 atm)
1480 psi
(100.7 atm)
38 psi (2.6
atm)
1245 psi
(84.7 atm)
Slippage, 7.9 gal./day
(29.9 l/day)
9.1gal/day
(34.4 l/day)
0.04 gal/day
(0.15 l/day)
7.3 gal/day
(27.6 l/day)
Time to
break the
gas lock
4 hours 3.5 hours 5 days 4 hours
No significant gas production
1.0 mcf/d
8/25/2015 7 George E. King Engineering
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The expansion of the gas is the reason:
The volume that the gas expands to is a function of both the pressure drop and the final pressure.
8/25/2015 8 George E. King Engineering
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Gas in Beam Pumps -
Typical rod pumping
problems Gas Locking
Fluid
Gas
Gas or
Vacuum
Fluid
Fluid Pound
Gas
Fluid
Gas Pound
Gas expansion is the key:
Source – John C. Patterson and James V. Curfew
8/25/2015 9 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Well construction – larger casing size increases options
Can run 5-1/2”
casing for mud
anchor. • (+) Improves gas
separation.
•(-)Reduced casing
annular space could
increase formation
back pressure.
Tubing size limits pump size. Casing size limits mud anchor size.
Source – John C. Patterson and James V. Curfew
8/25/2015 10 George E. King Engineering
GEKEngineering.com
Optimizing Rod Pumps
• Separate Gas From the Pump
– Use a “dip” tube below the pump intake to receive fluids below the
perforations. Don’t get too long or two small a tube – minimize gas
breakout,
– Set the pump below the perfs,
– Use simple separators for low rate wells when the pump must be set above
the perfs.
• Down-flow in annulus < 0.5 ft/sec (0.15 m/sec) for wells with <<150 B/d (24
m3/d)
– If pump landed above perfs – consider separators such as packer
separator, filter element or vortex.
– Ensure a good CR (compression ratio) on down-stroke and high flow area
through the valves.
– Use specialty pumps where needed. Some mechanically open traveling
while other remove load from the traveling valve.
Source SPE 72095, Jim Lea and Henry Nickens
8/25/2015 11 George E. King Engineering
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Other Considerations
• Two stage compression pumps
• Tapered barrel or “Panacea pump” –
enlarged barrels to allow liquid flow on down
stroke to prevent gas lock.
• Backpressure regulator to prevent gas locks
– will hold a back pressure on the formation
so use with care.
• Match the pump to the well with pump-off
controllers or speed controllers.
Source SPE 72095, Jim Lea and Henry Nickens
8/25/2015 12 George E. King Engineering
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Compression Ratio
• CR =
Swept Volume + Spacing Volume + Dead Space Volume
Spacing Volume + Dead Space Volume
Swept
Vol.
Spacing
Dead Space
Source SPE 72095, Jim Lea and Henry Nickens
8/25/2015 13 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Mud anchor/gas anchor – separate gas before inlet • Creates an “annular” space to separate gas.
• Most efficient design uses the production casing and rat hole.
• Larger diameter is better; lowers fluid velocity
Perforated nipple (intake to mud anchor)
Mud anchor (size based on casing)
Gas anchor (fluid intake to pump)
Downward fluid velocity (target 0.5 ft/sec)
Source – John C. Patterson and James V. Curfew
8/25/2015 14 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
Mud anchor/gas anchor – separate gas before inlet
Poor boy gas separator (bottom hold-
down)
• Does the gas separator configuration
change with a top hold-down pump?
One to
Two Pump
Volumes
Bottom
hold-down
pump
Top hold-down
pump
Source – John C. Patterson and James V. Curfew
8/25/2015 15 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Mud anchor/gas anchor – separate gas before inlet
2 7/8” x 4 ½” swedge to collar
2 rows of 4 slots cut 1/8” wide x 10” long at 90deg with four ½”
diameter vent holes in swedge. Total inlet area = 10.8 in2
• Original installation - 3 ½” tubing with 1 ¼” dip tube and two
½” x 6” inlet slots. Production 100 to 200 BWPD plus 50 to 100
MSCFD up tubing. 3 ½” gas separator downward velocity 0.16
to 0.32 ft/sec at 200 BWPD. Casing -150 MSCFD
• New installation (as shown) – 413 BWPD and no gas up tubing
and 361 MSCFD up casing. 5 ½” gas separator downward
velocity 0.21 ft/sec at 413 BWPD.
•Improvement due to: slower velocity or smaller inlet openings
or vent holes or inlet location in open hole?
24’
2’
7” csg 2 7/8” SN
PC pump
1 ¼ ” x 24’ gas anchor
5 ½”, 15.5” casing (4.950” ID) mud anchor with bull
plug on bottom. Total cross section area = 18 in2
Source – John C. Patterson and James V. Curfew
8/25/2015 16 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Well construction – minimize gas at pump intake
The best gas separation is
when “rat hole” or a casing
sump is available below the
bottom perforation or slot. perforations
Rat hole
50 to 100+
feet. Also
provides for
solids storage
Blank liner joints
on bottom. Take
even one joint; more
is better.
open hole
slotted liner
Source – John C. Patterson and James V. Curfew
8/25/2015 17 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
Mud anchor/gas anchor – separate gas before inlet
Do tubing anchor catchers excessively
restrict annular gas production?
Nozzle calculations
using effective diameter
Source – John C. Patterson and James V. Curfew
8/25/2015 18 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Types of pumps to handle gas
• High compression ratio pumps
• Backfill the compression chamber
• Unload the traveling valve – Remove fluid load
– Push traveling valve off seat
8/25/2015 19 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
Two stage “gas chaser” pump
100:1 compression ratio 1) On upstroke, fluid and gas drawn into
compression chamber above SV.
2) On downstroke, the fluid and gas is compressed into upper chamber.
3) On next upstroke, the fluid in the upper chamber is further compressed and transferred above standing valve.
Dow
nstr
oke
Full
Positive
Seal
Upstr
oke
Production
Fluid Flow
I
N
1
2 3
Source – John C. Patterson and James V. Curfew
8/25/2015 20 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Two stage hollow valve rod pump
Dow
nstr
oke
U
pstr
oke
Production
Fluid Flow
I
N
Bypass
Fluid
Purges
Upper
Chamber
Source – John C. Patterson and James V. Curfew
8/25/2015 21 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
Variable Slippage Pump by HF
• Tapered barrel purges gas from compression chamber at the top of the upstroke by dumping fluid load.
• Can change slippage depending on position in tapered barrel.
• No fluid pound with adequate slippage.
Stroke
Length
Tapered
Barrel
Low
Pressure
High
Pressure
Source – John C. Patterson and James V. Curfew
8/25/2015 22 George E. King Engineering
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OR IS IT?
Obviously this pump
is gas locked.
Dewatering Gas Wells with Rod Pumps
9:28 PPRL = 19,870
MPRL = 6,400
9:59 – no valve action
10:10
10:13 TV
failure
TV seats
10:20
10:24 PPRL = 19,751
MPRL = 6,519
11:11 – no valve action
PPRL = 11,029
MPRL = 7,129
Source – John C. Patterson and James V. Curfew
8/25/2015 23 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Is the pump problem due to gas locking or solids?
Pumping Cycle
load
length
Peak polished rod load
Minimum polished rod load
Surface Dynamometer Card
TV
SV
TV check = Wrf + Fluid
SV check = Wrf
Gas Locking
Fluid
Gas
What should the load be:
If gas locked? • Wrf + Fluid = TV check
• Repeatable, gradual change
If TV is leaking? • Wrf (+) = SV check
• Solids - very erratic
If SV is leaking? • Wrf + Fluid = TV check
• Solids - very erratic
• Delayed seating << Wrf
Source – John C. Patterson and James V. Curfew
8/25/2015 24 George E. King Engineering
GEKEngineering.com
Dewatering Gas Wells with Rod Pumps
Is the pump problem due to gas locking or solids?
“Most reported gas locking conditions rarely prove
to be gas locked. The problem is usually due to
erratic valve action or gas heading in the tubing
from gas interference, not gas locking.”
Ken Nolen, Lufkin Automation
New Mexico
42%
19%
39%
rods tubing pumps
1039 total failures39% of the pulls were for
pump problems.
Many of these failures could
not identify a failure cause.
Assumption – gas locked???
Source – John C. Patterson and James V. Curfew
8/25/2015 25 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
Handling Sand and other particulates
8/25/2015 26 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
Handling Sand and other particulates
Handling solids through the pump.
8/25/2015 27 George E. King Engineering
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Dewatering Gas Wells with Rod Pumps
What problems do we encounter when solids are produced through the pump?
• Erratic valve action causing intermittent pumping – many times considered as “gas locking”.
• Wear and grooving of the plunger.
• Settling of solids above the pump – stuck plungers and sticking a pump in the tubing.
Recognize that handling solids and gas together is a difficult combination. The high compression “two stage” pumps do not like
solids.
Other approaches may include “Moyno” or progressive Cavity Pumps.
8/25/2015 28 George E. King Engineering
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FL
UID
LIF
TE
D T
OW
AR
D S
UR
FA
CE
Valve seated 0.030” clearance
Traveling valve API pattern ball and seat
ball guide
Valve seated 0.090 to 0.200” clearance
1-1/4” to 2-3/4” pumps
Traveling valve Alternate pattern
Valve held off seat
sand or
trash
Options: alternate pattern traveling and standing valves (increased clearance
between the ball and guides) and double valve the traveling and standing valves.
Solids and Valve Action What happens if the valves do not seat?
Source – John C. Patterson and James V. Curfew
8/25/2015 29 George E. King Engineering
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