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Gas Well De-Liquification WorkshopDenver, Colorado
February 27 - March 1, 2006
Problem Identification, Candidate Selection, & Selection of Artificial Lift Technique
Rick Hornsby – Breakout Coordinator
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Good surveillance & identification of problem wells
• What specific data do we need to look at (tubing size, casing size, liner size, flowing tubing pressure, etc.)?
• How do we determine a well’s critical liquid loading rate?
• What can we learn from evaluating historical production plots?
• What do the liquid (water, condensate) rates, or lack thereof, tell us?
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Discussion Summary – Identification of Potential Candidates for Artificial Lift
–Chemical composition, salinity of water?
–Condensate or oil?
–Reservoir temperature
–Baseline – production when well was flowing OK.
–Tubing pressure, casing pressure, tubing size.
–Casing and tubing integrity.
–Corrosion inhibition needed?
–Fluid level.
–Well’s IPR, Static BH Pressure, Flowing BH Pressure.
– Well’s decline rate.
– Decline rate vs. cum’l production.
– Nodal analysis.
– System analysis.
– GLR.
– Calculated gas velocity.
– Presence of slugging.
– Available facility.
– Gathering lines, compression.
– Compare actual performance vs. model of gas well performance.
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Selection of those problem wells where artificial lift will result in an economical investment
• What can we learn from our lease operators about well performance?
• What operations techniques lead us to believe a well is a good artificial lift candidate (soap sticking, intermitting, stop-cocking, venting, swabbing, etc.)?
• What low cost actions can be taken to ‘prove up’ a good candidate (soap sticks, batch soap treatments, swabbing, flowing bottomhole pressure surveys, etc.)
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Discussion Summary – Selection of Candidates for Artificial Lift
– Obtain Operator’s feel on liquid cuts, or gas and liquid rates.
– Obtain Operator’s feel on sensitivity to back pressure.
– Understand Operator’s problems keeping wells on production – soaping, stop cocking, etc.
– Hold well reviews. Talk to Operators. Supplement well file.
– Provide field training of engineers.
– Run integrity surveys – check for fill.
– Use coiled tubing with N2 or CO2 cleanout.
– Use stimulation to reduce water blocks in near-wellbore area. Do lab analysis first.
– Can’t necessarily count on batch treatment to confirm or rule out suitability for cap tube. Be careful.
– Can use a portable cap tube to reduce “testing” cost.
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Selection of the most appropriate type of artificial lift
• What makes a good plunger lift candidate?
• What makes a good surfactant injection candidate?
• When is it necessary to consider more costly types of artificial lift (rod pumps, ESP’s, jet pumps, progressing cavity pumping, gas-lift, wellhead compression, etc.)?
• Do ongoing operating expenses matter and can the answer to this question determine the selection of the technique in the first place?
• How important are electronic flow measurement and automation (remote well control) to the success of the system?
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Discussion Summary – Selection of Type of Artificial Lift
• For plungers:
– ROT is 400 cf/bbl/1000 ft.
– Not below 2 3/8 or 2 7/8 tubing size.
– No holes in tubing, or insert profiles.
– Not too high GLR.
– Conventional vs. slim hole completion – communication with annulus.
– Plunger depth vs. depth of perfs.
– Up to 30o from vertical, not have doglegs.
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Discussion Summary – Selection of Type of Artificial Lift
• For surfactant:
– High WCR.
– Holes in tubing don’t rule it out.
– Tubing ID doesn’t need to be unobstructed.
– High deviation is OK.
– Low Operator / Service Company crew availability.
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Discussion Summary – Selection of Type of Artificial Lift
• For pumps: – Need to obtain very low FBHP.
– Electricity or other power source at well site.
– Amount of water that needs to be produced – beyond limit for plunger or chemical.
– Gas interference is a problem.
– Intervention costs may be high.
– Safety issues with sour gas wells.
– CAPEX.
– Subterranean hydraulic driven rod lift a possibility.
– Depth limits, deviation, dog legs, rod wear must be considered.
– May choose PCP if have solids.
Feb. 27 - Mar. 1, 2006 2006 Gas Well De-Liquification Workshop Denver, Colorado
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Discussion Summary – Selection of Type of Artificial Lift
• Automation:
– Needed regardless of type of artificial lift.
– High value of gas.
– Pressure on operating staff.
– Essential for focus on HSSE.