Enhance offshore pilot test operations

An operator was conducting field tests to assess the feasibility of CO₂ injection to enhance recovery from a heavy oil reservoir offshore Vietnam. Test results showed substantial potential for increasing oil production while reducing CO₂ emissions by extracting the CO₂ from industrial waste.

To confirm field applicability, the operator decided to conduct a small-scale CO₂-injection flowback (huff ‘n’ puff) pilot test. In this test, CO₂ was injected into the reservoir to produce the reservoir fluid and the injection gas together. The main objective of the test was to acquire the production data to identify any uncertainties that should be considered before field application. Another objective included monitoring fluid changes and ensuring optimal flaring efficiency.

Redesign conventional well test design and flare

Schlumberger offered recommendations on designing temporary surface facilities, conducting detailed fluid analysis on produced fluids, and overcoming the issue of efficient flaring of high- CO₂ fluids. Three major steps were taken to optimize the flowback methods chosen to complete the offshore test.

Flow high CO₂ concentrations with no interruption

The flare system redesign enabled efficiently burning hydrocarbon with no interruption in operations. Concentrations of CO₂ were measured from pressurized separator oil every half hour using PVT Express onsite well fluid analysis service. During flowback, CO₂ concentrations as high as 97% were measured, an amount that gradually declined to 0% at the end of the test because the CO₂ injected for soak had been recovered. Additionally, the optimized flare design allowed the operator to flare continuously without spillage into the sea.