Gas Well Deliquification

Kees Veeken 

Business context

Gas well performance is dictated by the combination of inflow and outflow performance. The outflow performance of any gas well is at risk as soon as the gas rate becomes insufficient to lift the associated liquid water and condensate to surface. This condition is referred to as liquid loading and invariably causes intermittent production and significant loss of well capacity and reserves. Liquid loading can be mitigated by different types of gas well deliquification such as compression, velocity string, plunger lift, foam-assisted lift, gas lift and downhole pump. This course first shows how to predict and recognize liquid loading and then describes how to select, design, install and operate the best sequence of deliquification measures. It also considers deliquification in case of other production threats like water production and halite blockage.

Who should attend

Production engineer, surveillance engineer, completion engineer, production/process chemist, reservoir engineer, production programmer, production operator; responsible for selecting, installing, operating, monitoring and optimizing deliquification.

Prerequisites: Basic knowledge of petroleum engineering and gas well performance. This course utilizes Excel worksheets introduced in the Gas Well Performance course, and could be scheduled consecutively. To derive maximum learning value, participants are encouraged to use their own field data and to complete unfinished exercises prior to the next session. A list of data requirements will be shared so data can be collected beforehand. Also, the instructor will be available to discuss any remaining queries after the course is finished.

Course content

Develop skills and tools to understand and model gas well liquid loading and deliquification. Get familiar with principles and practicalities of different deliquification methods. Learn how to compare, select and apply deliquification measures.

Day by day programme

Day 1 - Refresh Gas Well Performance

  • Inflow performance
    • Calculate inflow resistance
    • Calculate water of condensation
  • Outflow or vertical lift performance
    • Calculate hydrostatic and friction outflow parameters
    • Calculate liquid loading gas rate
  • Well performance
    • Calculate well capacity
    • Calculate liquid loading reservoir pressure
  • Reservoir performance
    • Predict liquid loading date
    • Make exponential production forecast

 

Day 2 - Consider Gas Well Deliquification

  • Do-nothing baseline, (automated) intermittent production, 2-tank model
    • Discuss (A)IP uptime
  • Sustain and maximize capacity and reserves
    • Characterize and compare compression, deliquification, stimulation, water shut-off, wellbore cleanout and well integrity repair
  • Intermittent and continuous kick-off and deliquification techniques,
    • Discuss compression, velocity string, plunger lift, foam-assisted lift, gas lift, downhole pump and swabbing operations
  • Deliquification scenarios, economics
    • Discuss number, sequence and timing of deliquification measures

 

Day 3 - Describe Compression, Velocity String and Plunger Lift

  • Compression location, type, pressure ratio, capacity, cost estimate
    • Calculate new well capacity and incremental reserves, make forecast
  • Velocity string size, alternative flow path, design for next measure, cost estimate
    • Calculate new well capacity and incremental reserves, make forecast
  • Plunger lift cycle, decompression volume, check valve only, cost estimate
    • Calculate new well capacity and incremental reserves, make forecast

 

Day 4 - Describe Foam-Assisted Lift, Gas Lift and Downhole Pump

  • Foamer lab and field testing, downhole deployment, surface processing, cost estimate
    • Calculate new well capacity and incremental reserves, make forecast
  • Gas lift source, downhole deployment, economic limit, cost estimate
    • Calculate new well capacity and incremental reserves, make forecast
  • Downhole pump type, gas rate, economic limit, cost estimate
    • Calculate new well capacity and incremental reserves, make forecast

 

Day 5 - Apply Gas Well Deliquification

  • Select deliquification scenario, plan deliquification measure
    • Compare well capacity, reserves, total cost and economics
  • Consider water production, halite blockage, well integrity, impairment etc.
    • Discuss impact on deliquification selection, design and timing
  • Installation, operation and maintenance of deliquification measures
    • Review measure specific practicalities
  • Prepare new wells for future deliquification
    • Review measure specific new well design elements