Transcript Unloading Water from Montana Oil Wells utilizing Air

®
Unloading Water from
Oil Wells Using Air
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Background
®
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Drilling horizontal wells in the Rocky
Mountain Region
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Drilling operation incurred high drilling
fine and fluid losses in formation

Operator was using rod pumps to
produce wells; Severe plugging of
pumps and tubing with drilling fines
common
– RESULT - repeated workovers and had
a consequential cost impact
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Clean Out Issues
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Before producing wells with rod pumps,
operator needed a way to
– clean out drilling fines
– unload large volumes of water from the
formation
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Different types of artificial lift methods
were considered
Gas lift was determined to be best lift
method when considering large volumes
of fluid, producing fines, and cost
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Injection Gas Source
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Natural gas was not available in this
area
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Screw compressor availability; used in
this area for underbalanced drilling
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Air considered as injection source

Spontaneous combustion issue
– Hydrocarbons-Pressure-Temperature
– HP 3000 psi / BHT 200 / high water cuts
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
COMPRESSOR
®
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Gas Lift Considerations
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Well Completion – 2 7/8” tubing inside
5 ½” 17# casing
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Fluid rate range of 300 to 2500 BFPD

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Screw compressors using air allowed
operating pressures up to 1600 psi and
injection volumes of 1.5 mmcf/day
Maintain velocities to produce drilling
fines
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Gas Lift - First Attempts
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Rig would land tubing at 2000’
Air injection through open ended tubing
and fluid produce out of casing until
blown dry
Rig lowered tubing 1000’ to 1500’ and
continued air injection / unloading
process
Eventually air injection through tubing
was at 8000’ and well clean up
Obtained good results, but at high cost
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Gas Lift Design Considerations
®

Determined annular lift to be best
method to produce high fluid rates and
drilling fines
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1” IPO valves inside a slimhole SPM
were used due to casing constraints
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Valve ports were sized to inject up to
1.2mmcf/day
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Operation
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Drilling rig runs tubing with gas lift
mandrels; rig moves off location
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Compressors are set on location
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Well is unloaded and monitored until
solids were cleaned out and a
percentage of oil was seen
Workover rig is moved in to pull tubing
and remove gas lift mandrels; tubing
and rods are run in well for rod pump
operation
Gas lift mandrels are used for next well
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Pit Gator
®
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Problems / Maintenance
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Corrosion inhibitor plugged IPO valves
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Due to environment of injecting air,
equipment life was shortened

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Side pocket mandrels were replaced
every 15 to 20 wells; valves replaced
every 3 wells
Trained operator to pull and run IPO
valves in side pocket mandrels; valve
and latch stock is kept at field location
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.
Results
®

Unloading process is shortened
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Greater rod and pump life
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Improved wellbore deliverability
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Flow back helps optimize rod pump
design
ARTIFICIAL LIFT SYSTEMS
© 2002 Weatherford. All rights reserved.