February 5 & 6, 20022002 Spring Gas-Lift Workshop1 2002 Spring ASME/API Gas-Lift Workshop Gas-Lift...

February 5 & 6, 2002 2002 Spring Gas-Lift Workshop 1

2002 Spring2002 SpringASME/API Gas-Lift WorkshopASME/API Gas-Lift Workshop

Gas-Lift SurveillanceGas-Lift SurveillanceIn Search of Hidden Production and EfficiencyIn Search of Hidden Production and Efficiency

ByBy

Dan Dees, AppSmithsDan Dees, AppSmithsCleon Dunham, Oilfield Automation ConsultingCleon Dunham, Oilfield Automation Consulting

Burney Waring, Shell EP TechnologyBurney Waring, Shell EP Technology



Surveillance is a Process Surveillance is a Process

It is a process of planning and designing for It is a process of planning and designing for optimumoptimum operations; then continually looking for, operations; then continually looking for, finding, and addressing opportunities to finding, and addressing opportunities to overcome inefficiencies, weaknesses, and faults overcome inefficiencies, weaknesses, and faults in these operations so that improvements can be in these operations so that improvements can be made and maintained. made and maintained.



True gas-lift surveillance is a comprehensive True gas-lift surveillance is a comprehensive process that empowers trained gas-lift staff process that empowers trained gas-lift staff to to optimizeoptimize the artificial lifting of oil wells the artificial lifting of oil wells with gas-lift. with gas-lift.

The difference between poor and optimized gas-The difference between poor and optimized gas-lift systems and wells can be hundreds of barrels lift systems and wells can be hundreds of barrels of oil, and therefore thousands of dollars of of oil, and therefore thousands of dollars of income per day.income per day.



Goal of gas-lift surveillance --- keep the Goal of gas-lift surveillance --- keep the entire gas-lift system entire gas-lift system (wells, gathering system, (wells, gathering system, treating system, compression system, distribution treating system, compression system, distribution system, and injection system)system, and injection system) operating operating optimally, all of the time.optimally, all of the time.

This can This can notnot be done by traditional means. It be done by traditional means. It requires state-of-the-art tools and skilled requires state-of-the-art tools and skilled personnel who are committed to and focused on personnel who are committed to and focused on the task.the task.



CautionCaution

This paper is intended to provide gas-lift This paper is intended to provide gas-lift operating companies with specific information on operating companies with specific information on how to develop a comprehensive surveillance how to develop a comprehensive surveillance process to optimize their gas-lift operations. process to optimize their gas-lift operations.

In some cases, we mention specific goods, products, and In some cases, we mention specific goods, products, and services when, in our opinion, they represent state-of-the-services when, in our opinion, they represent state-of-the-art, yet field proven solutions that can be applied today. If art, yet field proven solutions that can be applied today. If we fail to mention other products and services that are we fail to mention other products and services that are also effective, we apologize.also effective, we apologize.



Gas-lift surveillance is difficult but rewarding Gas-lift surveillance is difficult but rewarding work. work. • Typical (field proven) gains can be:Typical (field proven) gains can be:

– 10% or more oil production, plus10% or more oil production, plus– 10% or more savings in lift gas, plus10% or more savings in lift gas, plus– Often reductions in CAPEX and other OPEXOften reductions in CAPEX and other OPEX

For example:For example:• Field with 100 wells capable of 600 BOPD per wellField with 100 wells capable of 600 BOPD per well

– Produces 55,000 BOPD or less (potential 60,000 BOPD)Produces 55,000 BOPD or less (potential 60,000 BOPD)– Potential gain is $100,000 per day ($35MM per year) or Potential gain is $100,000 per day ($35MM per year) or

moremore



Primary goals of gas-lift:Primary goals of gas-lift:• Continuous gas-liftContinuous gas-lift

– Inject as deep as possibleInject as deep as possible– Inject on a continuous, stable basisInject on a continuous, stable basis– Inject at optimum rateInject at optimum rate

• Intermittent gas-liftIntermittent gas-lift– Inject optimum volume of gas beneath a column of Inject optimum volume of gas beneath a column of

liquidliquid– Inject each cycle at the optimum time (frequency)Inject each cycle at the optimum time (frequency)



Continuous gas-lift surveillanceContinuous gas-lift surveillance• Most important goal --- depth of injectionMost important goal --- depth of injection

– Role of surveillance systemRole of surveillance system– Assure mandrel spacing is correct, as well matures.Assure mandrel spacing is correct, as well matures.– Assure valves support unloading & then close as needed.Assure valves support unloading & then close as needed.– Assure well works down and stays there.Assure well works down and stays there.

• Second goal --- stabilitySecond goal --- stability– Role of surveillance systemRole of surveillance system

– Detect any instability.Detect any instability.– Assist in analyzing and trouble shooting cause(s) of Assist in analyzing and trouble shooting cause(s) of

instability.instability.



Continuous gas-lift surveillanceContinuous gas-lift surveillance• Third goal --- optimum rateThird goal --- optimum rate

– Role of surveillance systemRole of surveillance system– Always "know" the optimum rate(s) for the well and its Always "know" the optimum rate(s) for the well and its

gas-lift equipment --- they may not be the same.gas-lift equipment --- they may not be the same.– If well changes (and it will), operation and/or equipment If well changes (and it will), operation and/or equipment

must also be changed to maintain optimum operation.must also be changed to maintain optimum operation.– Keep the well as close to optimum as possible, while Keep the well as close to optimum as possible, while

keeping system in balance.keeping system in balance.

• Other goalsOther goals– Role of surveillance systemRole of surveillance system

– Continuously check for leaks, blockages, failed valves, Continuously check for leaks, blockages, failed valves, etc.etc.



Intermittent gas-lift surveillanceIntermittent gas-lift surveillance• First goal --- system stabilityFirst goal --- system stability

– Role of surveillance systemRole of surveillance system– Keep system stable, even in face of inherent intermittent Keep system stable, even in face of inherent intermittent

instability.instability.

• Second goal --- optimum injection volume and Second goal --- optimum injection volume and timetime– Role of surveillance systemRole of surveillance system

– Precisely measure Precisely measure andand control injection volume and time. control injection volume and time.– Adjust injection cycle (size and frequency) as needed.Adjust injection cycle (size and frequency) as needed.



Intermittent gas-lift surveillanceIntermittent gas-lift surveillance• Third goal --- optimum liquid recovery per Third goal --- optimum liquid recovery per

injection cycleinjection cycle– Role of surveillance systemRole of surveillance system

– Monitor, and if possible, measure each liquid slug.Monitor, and if possible, measure each liquid slug.– Provide information to assist in optimizing intermittent Provide information to assist in optimizing intermittent

injection cycle volume and frequency to maximize daily oil injection cycle volume and frequency to maximize daily oil recovery. recovery.

• Other goalsOther goals– Role of surveillance systemRole of surveillance system

– Continuously check for leaks, blockages, failed valves, Continuously check for leaks, blockages, failed valves, etc.etc.



Surveillance process --- what is needed?Surveillance process --- what is needed?• People --- the gas-lift teamPeople --- the gas-lift team

– Gas-lift championGas-lift champion– Gas-lift engineer(s)Gas-lift engineer(s)– Gas-lift technician(s) or programmer(s)Gas-lift technician(s) or programmer(s)– Well analyst(s)Well analyst(s)– Well servicesWell services– OperatorsOperators– OthersOthers

Whether these functions are performed by one or Whether these functions are performed by one or several people, by company or contract staff, several people, by company or contract staff, they are all essential.they are all essential.



Surveillance process --- what is needed?Surveillance process --- what is needed?• ProcessesProcesses

– Have an effective work process and work as a team.Have an effective work process and work as a team.– Meet frequently --- in person or "electronically."Meet frequently --- in person or "electronically."– Provide an adequate training process.Provide an adequate training process.

– ClassroomClassroom– Training models --- both physical and computer-basedTraining models --- both physical and computer-based– One-on-one mentoringOne-on-one mentoring– Train the trainerTrain the trainer– On-line and web-based trainingOn-line and web-based training– Conferences and workshopsConferences and workshops

There must be a complete, continuous training There must be a complete, continuous training processprocess for people to acquire and maintain needed skills.for people to acquire and maintain needed skills.



Surveillance process --- what is needed?Surveillance process --- what is needed?• InformationInformation

– Reservoir information --- PVT data, pressure, IPRReservoir information --- PVT data, pressure, IPR– Well information --- physical well designWell information --- physical well design– System informationSystem information– Economics --- optimize income, not productionEconomics --- optimize income, not production– Pressure surveysPressure surveys

– Pressure build-upPressure build-up– Static pressureStatic pressure– Flowing pressure survey to evaluate current performanceFlowing pressure survey to evaluate current performance– Flowing pressure survey to determine IPRFlowing pressure survey to determine IPR



Surveillance process --- what is needed?Surveillance process --- what is needed?• Information Information (Continued)(Continued)

– Well testsWell tests– Accurate well testsAccurate well tests– Or if possible, continuous well production rateOr if possible, continuous well production rate

– Real-time informationReal-time information– Need to haveNeed to have

• Distribution system gas pressure and availabilityDistribution system gas pressure and availability• Well injection rate and injection pressureWell injection rate and injection pressure• Well production pressureWell production pressure

- Nice to haveNice to have• Manifold pressureManifold pressure• Downhole flowing bottom-hole pressureDownhole flowing bottom-hole pressure



Surveillance process --- what is needed?Surveillance process --- what is needed?• ToolsTools

– Gas-lift design toolsGas-lift design tools– Use modern, computer-based design tools.Use modern, computer-based design tools.– But, know what they are doing.But, know what they are doing.

– Quality assuranceQuality assurance– Check every valve before it is run and after it is pulled.Check every valve before it is run and after it is pulled.

– Monitoring systemMonitoring system– Gather gas-lift information Gather gas-lift information once per minuteonce per minute..– Process and summarize the data so people can be Process and summarize the data so people can be

presented with actionable information.presented with actionable information.– Present it to people when and where they need it.Present it to people when and where they need it.



Surveillance process --- what is needed?Surveillance process --- what is needed?• Tools Tools (Continued)(Continued)

– Control systemControl system– Keep system in balance, under all conditions.Keep system in balance, under all conditions.– Keep wells as close as possible to optimum at all times.Keep wells as close as possible to optimum at all times.– Keep wells stable during well tests.Keep wells stable during well tests.– Maintain required unloading rates.Maintain required unloading rates.– Keep injection cycles as designed.Keep injection cycles as designed.

– Analysis Analysis – Analyze the Analyze the causecause of each problem so it can be fixed of each problem so it can be fixed

correctly this time and prevented from happening again.correctly this time and prevented from happening again.



Surveillance process --- what is available?Surveillance process --- what is available?• Good newsGood news

– Excellent goods, tools, and services are available to Excellent goods, tools, and services are available to help optimize each company's gas-lift operations.help optimize each company's gas-lift operations.– See See www.wellanalysis.comwww.wellanalysis.com and and www.alrdc.comwww.alrdc.com

• PeoplePeople– It is essential to have some "company" people who are It is essential to have some "company" people who are

focused on gas-lift --- this is "core" business.focused on gas-lift --- this is "core" business.– And, there are several service companies that can provide And, there are several service companies that can provide

excellent assistance --- either short or long term.excellent assistance --- either short or long term.



Surveillance process --- what is available?Surveillance process --- what is available?• ProcessesProcesses

– Work processWork process– Each company must develop its own work process with Each company must develop its own work process with

which it is comfortable.which it is comfortable.

– Classroom trainingClassroom training– Several good courses are available --- check with Shell, Several good courses are available --- check with Shell,

Weatherford, EPS, and others.Weatherford, EPS, and others.

– Training modelsTraining models– Free computer-based training models are available --- Free computer-based training models are available ---

check with Shell, Weatherford, Schlumberger, and others.check with Shell, Weatherford, Schlumberger, and others.– A physical model can be developed --- check with the A physical model can be developed --- check with the

authors.authors.



Surveillance process --- what is available?Surveillance process --- what is available?• Processes Processes (Continued)(Continued)

– One-on-one training, and "train the trainer"One-on-one training, and "train the trainer"– Each company should have at least one person --- Each company should have at least one person ---

company or contract --- who can train local staff on a one-company or contract --- who can train local staff on a one-on-one or one-on-few basis.on-one or one-on-few basis.

– On-line, web-based trainingOn-line, web-based training– Excellent tools are becoming available to provide highly Excellent tools are becoming available to provide highly

leveraged training –-- when and where it is needed. Check leveraged training –-- when and where it is needed. Check with Shell and others.with Shell and others.



Surveillance process --- what is available?Surveillance process --- what is available?• InformationInformation

– Each company must acquire the necessary information Each company must acquire the necessary information on its own reservoirs, systems, and wells.on its own reservoirs, systems, and wells.– Several important references are listed in the paper.Several important references are listed in the paper.– Especially refer to API RP 11V8 --- Recommended Practice Especially refer to API RP 11V8 --- Recommended Practice

for Gas-Lift System Design and Performance Prediction.for Gas-Lift System Design and Performance Prediction.• This is to be released in the near future.This is to be released in the near future. • It can be seen on the It can be seen on the www.wellanalysis.comwww.wellanalysis.com web site. web site.



Surveillance process --- what is available?Surveillance process --- what is available?• ToolsTools

– DesignDesign– We recommend the Shell WinGLUE program. There are We recommend the Shell WinGLUE program. There are

other excellent design programs available from EPS, other excellent design programs available from EPS, Baker Jardine, Petroleum Experts, and others.Baker Jardine, Petroleum Experts, and others.

– WinGLUE uses gas-lift valve performance models WinGLUE uses gas-lift valve performance models developed by the Valve Performance Clearinghouse.developed by the Valve Performance Clearinghouse.

– It uses an SQL database. All information, once entered, is It uses an SQL database. All information, once entered, is kept on line for future use.kept on line for future use.

– It uses "wizards" to assist in easily running the design It uses "wizards" to assist in easily running the design process.process.

– It supports designing with choked unloading valves, if It supports designing with choked unloading valves, if desired.desired.



Surveillance process --- what is available?Surveillance process --- what is available?• Tools Tools (Continued)(Continued)

– Quality assuranceQuality assurance– We recommend fully testing every gas-lift valve, both We recommend fully testing every gas-lift valve, both

before it is run and after it is pulled.before it is run and after it is pulled.– We recommend a new tool called the Gas-Lift Valve, We recommend a new tool called the Gas-Lift Valve,

Automatic Validation Tester.Automatic Validation Tester.– Each valve can be fully tested in about five minutes.Each valve can be fully tested in about five minutes.– Any faulty valve can be rejected before it is run.Any faulty valve can be rejected before it is run.

– MonitoringMonitoring– Excellent real-time SCADA (production automation) Excellent real-time SCADA (production automation)

systems are available from Shell and eProduction systems are available from Shell and eProduction Solutions. Others are also available.Solutions. Others are also available.



Surveillance process --- what is available?Surveillance process --- what is available?• Tools Tools (Continued)(Continued)

– ControlControl– These same systems can also provide the needed gas-lift These same systems can also provide the needed gas-lift

system and well controls.system and well controls.– We have first-hand experience with the Shell system for We have first-hand experience with the Shell system for

controlling both large and small, complex gas-lift systems controlling both large and small, complex gas-lift systems that contain both continuous and intermittent wells.that contain both continuous and intermittent wells.

– AnalysisAnalysis– The Shell WinGLUE program supports a full suite of tools The Shell WinGLUE program supports a full suite of tools

for analyzing the performance of gas-lift wells and helping for analyzing the performance of gas-lift wells and helping to determine the causes of problems with these wells.to determine the causes of problems with these wells.

– There are other effective analysis tools available.There are other effective analysis tools available.



ConclusionConclusion• Comprehensive surveillance is essentialComprehensive surveillance is essential

– It is highly profitableIt is highly profitable– It is feasible and economic for any size companyIt is feasible and economic for any size company

• It requires dedicated, motivated, highly trained It requires dedicated, motivated, highly trained staffstaff

• And it requiresAnd it requires– Effective work processesEffective work processes– Excellent, on-going trainingExcellent, on-going training– Good, current informationGood, current information– Excellent tools and the skills to use themExcellent tools and the skills to use them

February 5 & 6, 20022002 Spring Gas-Lift Workshop1 2002 Spring ASME/API Gas-Lift Workshop Gas-Lift...

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