Carbon Utilization and Storage of Associated and Enriched Gas | AIChE

Carbon Utilization and Storage of Associated and Enriched Gas

Authors 

Konstantinos, K. - Presenter, University of houston
Salman, M., University of Houston
Sharma, P., University of Houston

In recent years, gas injection has become the preferred enhanced oil recovery (EOR) method onshore USA, with CO2 being the most widely–used gas with the added benefit that a greenhouse gas (GHG) is sequestered. Much research has gone into improving CO2 floods, in areas of conformance control. Improving conformance and mobility control will improve sweep efficiency which increases the oil recovery ratio. The use of CO2 has some drawbacks: it can lead to significant corrosion issues; the supply may not always be commercially accessible, especially to fields located far from gas supply pipelines. Therefore, there is a strong driver to investigate alternative gas injectants.

Hydrocarbon gasses are more attractive for ease of handling, availability, and economic value. In many cases, associated gas (a GHG) that is produced at a field is vented or flared, when it could be utilized for EOR. To date, limited research has been conducted on possible enhancements to simple hydrocarbon gas injection, such as creating foam with surfactants and injecting gas in supercritical condition. To explore this potential, displacement tests were performed using ethane and compared with carbon dioxide. Aqueous stability, salinity scan, and static foam tests were performed to identify a surfactant formulation suitable for use with ethane. Foam quality and coreflood displacement tests in heterogeneous carbonate outcrop cores were conducted to compare the recovery efficiencies of three displacement processes. Our work shows that miscible ethane injection processes can result in significant recovery even under gravity-unstable conditions. The addition of foam further enhances overall recovery at laboratory scale. Results demonstrate that miscible ethane foam can be generated to address conformance issues and could lead to the wider use of associated gas for EOR while sequestering a GHG.