Beam Lift Optimization and Troubleshooting

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

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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


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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


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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

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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.



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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


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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


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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.


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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:



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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.



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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


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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.



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Compression Ratio

• CR =

Swept Volume + Spacing Volume + Dead Space Volume

Spacing Volume + Dead Space Volume

Swept

Vol.

Spacing

Dead Space



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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)



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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



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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



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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



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Do tubing anchor catchers excessively

restrict annular gas production?

Nozzle calculations

using effective diameter



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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


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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



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Two stage hollow valve rod pump

Dow

nstr

oke

U

pstr

oke

Production

Fluid Flow

I

N

Bypass

Fluid

Purges

Upper

Chamber



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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



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OR IS IT?

Obviously this pump

is gas locked.


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



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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



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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???



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Handling Sand and other particulates


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Handling Sand and other particulates

Handling solids through the pump.


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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.


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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?



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Beam Lift Optimization and Troubleshooting

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