Downhole Diverter Gas Separator
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7 th Annual Sucker Rod Pumping Workshop Renaissance Hotel Oklahoma City, Oklahoma September 27 - 30, 2011 Downhole Diverter Gas Separator Ken Skinner, Lynn Rowlan, Dieter Becker - Echometer Company A. L. Podio - University of Texas - Austin Jim McCoy
Transcript of Downhole Diverter Gas Separator
7th Annual Sucker Rod Pumping Workshop
Renaissance Hotel Oklahoma City, Oklahoma
September 27 - 30, 2011
Downhole Diverter Gas Separator
Ken Skinner, Lynn Rowlan, Dieter Becker - Echometer Company A. L. Podio - University of Texas - Austin
Jim McCoy
liquid in anchor
pump
slip
gas in anchor
Basic Principles of Downhole Separator
System Gravity separation is the
governing principle for downhole gas separators.
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GAS BUBBLES FLOW UPWARD IN OIL OR WATER AT A RATE OF APPROXIMATELY 6 INCHES PER SECOND. THUS, GAS BUBBLES WILL BE RELEASED FROM A LIQUID COLUMN IF THE DOWNWARD LIQUID VELOCITY IS LESS THAN 6 INCHES PER SECOND.
A LIQUID COLUMN HAVING AN AREA OF 1 SQUARE INCH TRAVELLING AT A VELOCITY OF 6 INCHES PER SECOND IS A RATE OF APPROXIMATELY 50 BPD.
Gas Rise Velocity is approximately 6 inches per second.
Gas Separation from Liquid
Gas Separator Liquid Capacity is based on the Following Principle:
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Natural Gas Anchor
The most efficient downhole gas separators locate the pump intake below the lowest gas entry point.
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Improved Natural Gas Anchor
Maximum flow area in casing annulus below pump.
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Liquid Capacity for Various Annular Areas
Natural Gas Anchor
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“Poor Boy” Gas Separator above perforations
A small, long dip tube within a small diameter separator.
Very poor design with a small outer tube ID and long flow paths.
Only acceptable for low volume wells.
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“Poor Boy” Gas Separator – Very Common
Seating Nipple
Collar
Perforated Sub
Collar Joint of Tubing
Dip Tube Tubing Collars prevent perforated sub from laying against casing wall where liquid accumulates
Casing
Limited Flow Area and Small 3/8 inch holes in a perforated sub limit liquid entry flow and gas exit flow thus reducing separation efficiency
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“Poor Boy” Gas Separator Liquid Capacity
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Collar-Size Separator Increases Liquid Capacity
A good separator must strike a balance between annular flow area, separator flow area, dip tube diameter and pressure drop. Outer barrel OD same as collar OD. Thin wall outer barrel and dip tube. Short flow conduits. Large inlet ports.
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To get gas capacity of a specific installation multiply the table value by the Pressure at the Pump Intake (psi) and divide by 14.7 11
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Packer Gas Separator
Uses gravity separation like the “Poor Boy” except much more separation area and capacity.
Higher cost and higher risk of mechanical and sand problems.
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Concentric Packer Gas Separator
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A concentric packer type gas separator offers additional liquid and gas capacities.
Diverter Gas Separator Animation
Pump
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Diverter Gas Separator Animation
Pump
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Pump
Discharge Port Above Diverter for Reservoir Fluid
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Separator Parts
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Separator Parts
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Premium Rubber Diverter Cups The diverter cups are constructed from high temperature, flexible, wear-resistant, premium elastomer.
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316 Stainless Steel
Separator Parts
Premium Rubber Diverter Assembly
Premium Rubber Diverter Cups Multiple cups can be utilized as desired
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Separator Parts
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Shear Pins
Shear pins are located below the diverter cups. The force required to shear the shear pins is operator selectable. Factory setting is 4000 pounds. If the diverter cups are not retrievable with the gas separator, the cups will be left in the well with the shear pins and shear collar.
Pump
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Sand Accumulation
Sand or debris may deposit above the swab cup flow diverter. If 5 inches of sand accumulates over the diverter between the gas separator and the casing wall, the flow of liquid into the gas separator will cease and production from the tubing will cease. When sand or debris is blocking the gas separator liquid inlet ports, a fluid level test will indicate a high fluid level in the casing annulus and a dynamometer pump card will indicate low or no pump fillage. The well will require servicing.
Pump
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Sand Accumulation When the pump is unseated, liquid in the tubing will flow down the tubing and discharge out of the gas separator through the gas separator liquid inlet ports. The discharging liquid will be at high pressure. This will wash the sand and debris away from above the diverter. The discharging liquid will flow up the casing annulus and carry the sand. Probably ½ of the liquid and sand will flow down through the gas separator into the lower portion of the casing below the diverter. Reseat the pump and pump the well. Perform the liquid level test and dynamometer test to insure the well is operating properly.
Pump
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Sand Accumulation - Shear Pin Sand can accumulate above the gas separator diverter and cause difficulty in removing the gas separator and diverter from the well. Retrieval of the gas separator and diverter may still be a problem even after flushing sand from above the diverter. A shear pin is located at the bottom of the swab cup diverter on the gas separator so that the gas separator can be removed from the diverter and retrieved from the well. The shear pin holds the diverter swab cups to the gas separator. When the shear pin is sheared, the gas separator can be separated from the diverter swab cups and removed from the well. The shear pin will shear at 4000 # (pre-set).
Pump
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Fluid Pressures Surrounding Separator
Pump
58 psi Fluid Discharge Pressure
60.5 psi Liquid Inlet Pressure
60 psi Separator Inlet Pressure Sept. 27 - 30, 2011 24
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Installation Pump
A tubing anchor is installed 3 joints above the separator to prevent tubing and Diverter Gas Separator movement during pump operation.
Water or liquid lubricant can be added to casing annulus or tubing when the rubber diverters are above the liquid level in the well when running the Diverter Gas Separator into the well.
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Diverter Gas Separator Capacity 2.5 OD Outer Separator Barrel ~ 60 Psig Intake Pressure
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Producing BHP Recommendation A PBHP of 10% of SBHP insures producing 97% of Well’s Max Rate
Use Efficient Downhole Gas Separators to:
INCREASE OIL AND GAS PRODUCTION
IMPROVE EFFICIENCY OF THE LIFT SYSTEM
CORRECT ARTIFICIAL LIFT PROBLEMS CAUSED BY INCOMPLETE PUMP FILLAGE DUE TO GAS INTERFERENCE
REDUCE OPERATING COST
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Copyright
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directed by the Workshop Steering Committee. – Place it on a CD for distribution and/or sale as directed by the Workshop
Steering Committee.
Other use of this presentation is prohibited without the expressed written permission of the author(s). The owner company(ies) and/or author(s) may publish this material in other journals or magazines if they refer to the Sucker Rod Pumping Workshop where it was first presented.
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