Steam foam processes can improve the thermal efficiency and overall economics of steam-based oil recovery methods. Foam reduces steam mobility, thus mitigating steam channelling and energy loss, particularly in presence of thief zones. This paper describes an integrated EOR study to develop a steamfoam process for the Ratqa Lower Fars (RQLF) heavy oil reservoir in Kuwait with more focus on chemical selection, formulation design and reservoir simulation.
A variety of foaming surfactants were extensively evaluated in the lab based on the reservoir properties and operating conditions of the RQLF reservoir. This involved lab evaluation of thermal stability, adsorption, foam generation ability and foam rheology to select appropriate foaming surfactants. In parallel, multi-well/pattern steam-flooding simulations were performed to investigate the benefits of injecting foaming surfactants with steam. Different scenarios were considered and simulated mainly by varying the timing, duration and foaming surfactant concentration.
A fit-for-purpose foaming formulation was successfully developed for the RQLF reservoir. Thermal stability of the selected chemicals was validated. Furthermore, the adsorption of the selected foaming formulation on reservoir rock using injection water was found to be very low. Long-term foam stability was also confirmed in the presence and absence of crude oil. Based on these results, high foam apparent viscosity is expected in the planned core-flood experiments that will be performed to validate the ability of the selected surfactants to generate robust foam.
Simulation results showed that using foaming surfactants with steam can delay steam breakthrough and increase oil production, thus reducing steam-to-oil ratio. Furthermore, simulation results showed that it is beneficial to inject foam shortly prior to steam breakthrough rather than injecting it at the onset of steam injection. Basic economic evaluation was performed and the results indicate that foam addition to steam makes steam-flooding more cost-effective.
This paper discusses, for the first time, the results of an integrated study to evaluate the application of a steam-foam process for the RQLF reservoir in Kuwait. Valuable insights are presented on the design and simulation of foaming surfactants that can be used to improve the performance of steam-based oil recovery methods. The findings of this study are expected to pave the way for potential field trials in the future.