7 th Annual Sucker Rod Pumping Workshop Renaissance Hotel Oklahoma City, Oklahoma September 27-30, 2011 Downhole Diverter Gas Separator Jim McCoy Ken Skinner, Lynn Rowlan, Dieter Becker - Echometer Company A. L. Podio - University of Texas - Austin
Basic Principles of Downhole Separator System Gravity separation is the governing principle for downhole gas separators. pump slip liquid in anchor gas in anchor 2
Gas Separation from Liquid Gas Separator Liquid Capacity is based on the Following Principle: Gas Rise Velocity is approximately 6 inches per second. 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. 2011 Sucker Rod Pumping Workshop 3
Natural Gas Anchor The most efficient downhole gas separators locate the pump intake below the lowest gas entry point. 2011 Sucker Rod Pumping Workshop 4
Improved Natural Gas Anchor Maximum flow area in casing annulus below pump. 2011 Sucker Rod Pumping Workshop 5
Natural Gas Anchor Liquid Capacity for Various Annular Areas 2011 Sucker Rod Pumping Workshop 6
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. 7
Poor Boy Gas Separator Very Common 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 Tubing Collars prevent perforated sub from laying against casing wall where liquid accumulates Seating Nipple Collar Casing Perforated Sub Dip Tube Collar Joint of Tubing 2011 Sucker Rod Pumping Workshop 8
Poor Boy Gas Separator Liquid Capacity 2011 Sucker Rod Pumping Workshop 9
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. 2011 Sucker Rod Pumping Workshop Large inlet ports. 10
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 2011 Sucker Rod Pumping Workshop
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. 2011 Sucker Rod Pumping Workshop 12
Concentric Packer Gas Separator A concentric packer type gas separator offers additional liquid and gas capacities. 2011 Sucker Rod Pumping Workshop 13
Pump Diverter Gas Separator Animation 14
Pump Diverter Gas Separator Animation 15
Pump Separator Parts Discharge Port Above Diverter for Reservoir Fluid 2011 Sucker Rod Pumping Workshop 16
Separator Parts 2011 Sucker Rod Pumping Workshop 17 17
Separator Parts 316 Stainless Steel Premium Rubber Diverter Assembly 2011 Sucker Rod Pumping Workshop Premium Rubber Diverter Cups The diverter cups are constructed from high temperature, flexible, wear-resistant, premium elastomer. 18
Separator Parts 2011 Sucker Rod Pumping Workshop Premium Rubber Diverter Cups Multiple cups can be utilized as desired 19
Pump 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. 2011 Sucker Rod Pumping Workshop 20
Pump 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. 2011 Sucker Rod Pumping Workshop 21
Pump 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. 2011 Sucker Rod Pumping Workshop 22
Pump 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 # (preset). 2011 Sucker Rod Pumping Workshop 23
Pump Fluid Pressures Surrounding Separator 58 psi Fluid Discharge Pressure 60.5 psi Liquid Inlet Pressure 60 psi Separator Inlet Pressure 2011 Sucker Rod Pumping Workshop 24
Pump Installation 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. 2011 Sucker Rod Pumping Workshop 25
Diverter Gas Separator Capacity 2.5 OD Outer Separator Barrel ~ 60 Psig Intake Pressure 2011 Sucker Rod Pumping Workshop 26
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 2011 Sucker Rod Pumping Workshop 28
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