This project is one of the first successful field tests and commercial implementation of enhanced gas recovery (EGR) for a depleted gas reservoir by injecting a natural high-carbon dioxide (CO2) gas stream in the Gulf of Thailand. It has demonstrated that injection of CO2-containing gas stream into a natural gas reservoir is a promising win-win technology for ultimate recovery improvement of natural gas in depleted reservoirs and CO2 sequestration. To evaluate the effectiveness of EGR, the test was conducted in depletion-drive sandstone gas reservoirs. EGR was initiated when the primary gas recovery was mostly realized. Injection of natural gas with around 60% CO2 from deeper formations in the same area yielded an incremental gas recovery of 8% to 10% of original gas in-place in one successful candidate, demonstrating the recovery enhancement potential in such reservoirs.

Increasing ultimate recovery of a depleted gas reservoir and enhancing hydrocarbon recovery helps supply extra energy to the Kingdom of Thailand and power more electricity generation. The additional production has generated multi-million USD in revenue not only for the country mainly in form of royalty and petroleum income tax, but also for the company. Another obvious benefit of this project is a positive environmental impact. Its outcome helps reduce the emissions of greenhouse gas in the atmosphere by sequestering large amounts of CO2 in a depleted gas reservoir. This underground storage option is considered economical and have a low environmental impact. Therefore, the project delivers positive environmental change.

Besides the fact that we are implementing this pilot, we believe this project can also be adopted by operators in other fields on a very broad sense and scale. With favorable size of opportunities, it can be economic to inject high CO2 gas from surface compressors. This will enable the operator more flexibility in term of source of high CO2 gas and injection rate. Along with all those mentioned above, the project contributes to sustainability and innovation for the exploration and production industry in Thailand.

Keywords:
geologist, sedimentary rock, gas injection method, sandstone, dumpflood, complex reservoir, shale gas, co 2, clastic rock, subsurface storage
Subjects:
Improved and Enhanced Recovery, Unconventional and Complex Reservoirs, Storage Reservoir Engineering, Environment, Gas-injection methods, Shale gas, CO2 capture and sequestration, Climate change
Copyright 2024, Offshore Technology Conference DOI 10.4043/34888-MS
You can access this article if you purchase or spend a download.