Gas lift can be installed in producing wells within a CO2 flood utilizing the nearly pure injection CO2 or the mixed hydrocarbon/CO2 gas returning to the production station. Lift gas injection rates can be varied to correspond to the water content resulting from the water-alternating-gas (WAG) results.

The lift equipment configuration options are:

  • standard installation with gas on the casing passing through a valve mandrel(s)

  • gas conveyed by coiled tubing (strapped to the main tubing) to the valve mandrel

  • coiled tubing hanging inside the main tubing with production flow in the annulus of these strings

Field installations of the two options at the top of the list have given good service and the last option is a common configuration for velocity strings in gas wells.

Gas lift as an artificial lift method can eliminate failures in pumps due to the CO2 or due to the gassy nature of the produced fluid. Chemical treatments can be transported downhole with the lift gas and used to control corrosion, paraffin, or asphaltine.

Gas lift is a flowing process, which must have adequate reservoir, and wellbore pressure to flow the fluids to the surface facility, whereas the pumping process has energy transmitted downhole to raise the fluid pressure. Wellbore pressure for pumps can be lower since the fluid need only flow from the reservoir to the pump intake.

Keywords:
enhanced recovery, upstream oil & gas, spe 52163, production monitoring, production control, injection gas, john martinez spe 52163, installation, society of petroleum engineers, coiled tubing
Subjects:
Artificial Lift Systems, Well & Reservoir Surveillance and Monitoring, Improved and Enhanced Recovery, Gas lift, Completion Installation and Operations
Copyright 1999, Society of Petroleum Engineers
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