What We Offer
Our team based in Doha, Qatar is currently providing oil and gas consultancy services in the Middle East in Petroleum engineering mainly focusing on field development studies, oil and gas production optimization, well design, water production & injection management, flow assurance, artificial lift in oil wells and liquid loading issues in gas wells.
Liquid Loading in Gas Wells
- Liquid loading is the inability of a producing gas well to remove its coproduced liquids from the well-bore.
- The liquid flowing as droplets or film accumulates at the well bottom, thereby imposing back-pressure at the sand-face and couldn’t sustain stable production
- How does a gas well perform from initial production to end of well life?
- What are the different stages in well life?
- What are best lift methods for each stage in well life?
- Monitor production curves for each well on a regular basis
- Liquid loading is indicated if the curve for a normally declining well becomes erratic and the production rate drops
- Compute the critical gas velocity (flow rate) at which liquid can no longer be lifted in the tubing.
- Critical velocity vs. flowing tubing pressure can be constructed for various tubing diameters
Intermittently Flowing or Cycling of the Well
- The regulated intermittent gas production by automated on/off of the wellhead choke, also called "well cycling”.
- When a well show signs of liquid loading, addressed by temporarily stopping and re-starting (cycling or intermitting) production
- In shut-in period pressure increases around the well bore and some liquids may be forced back into the formation
- Reducing the liquid level in the wellbore and the well is returned to production and allowed to flow until the loading again occurs.
- Work effectively in high PI and constant liquid rate wells.
- Only short-term option in order to prolong the well
Velocity string to produce liquid loaded well
- Smaller tubing size can produce a liquid loaded well as it requires low gas rate to operate above critical flow rate.
- Candidate Selection Process: 1.Good Remaining reserves. 2.Conventional work over not viable. 3.No easy WSO opportunities. 4.No aquifer influx, low water rate. 5.Existing tubing dia > 3.5
- Very small tubing small amount of liquid can exert a high back pressure and reduces production rates.
- Unable to access wellbore.
Liquid Loaded Gas Wells Capillary String: Use of Surfactants
- Microstring technology for wells suffering water loading has proved to be extremely successful in alleviating the problem Simple technology for use on wells suffering from liquid loading
- Inject surfactant (soap) near the perforations to assist in lifting produced fluids from a gas well.
- Cheaper alternative to siphon string (velocity string), PCP or rod pump.
- Higher rates than achievable with cycling, can work in wells that don’t respond to cycling
- Small (1/4”) tubing hangs from top of wellhead through master valves.
- Microstring can be sheared by closing valves in an emergency.
- Small check valve and back pressure valve keep well fluids out and support chemical hydrostatic pressure
- Stand alone solar powered electric pump with simple timer to control rate.
- Microstring hardware has long usable life span and relocation to another well is low cost ($10k --$
- Effective tool that can complement other de watering techniques.
- Microstring technology for wells suffering water loading has proved to be extremely successful in alleviating the problem and this technology was further used successfully in Condensate or oil wells by injecting Condensate Condy Foamer
- Well selection criteria is an important factor
- Tubing size, reservoir gas, water cut less than 10
- Bench testing of Chemical foamer with oil sample
- Emulsion issues with high water cut
- Condensate/oil foaming technology had been commercially implemented in many countries
- Coiled tubing gas lift ( is a rigless solution that enables setting GL valves or injection valve at the required depth, during any stage of a well life It allows gas to be injected through CT with production through the CT to tubing annulus
- Well loads up stop flowing after long duration shut in
- Other technologies like well cycling, soap sticks, foamer with Microstring couldn’t produces the wells
- Simple reliable minimal intervention to set up
- Unloading valves/mandrels can be spliced in to coil if required (low injection pressure)
- No moving parts no rod wear nothing to get jammed with Sand
- No rig intervention required, can use existing tubing string
- Locked and packed into any profile nipple Long term strategy for all wells