Innovative In-Situ Foam Generation and Injection Strategy Using Greenhouse Gases for Conformance Control

Mobility control is one of the most pressing challenges facing greenhouse gas injection for enhancing oil recovery (EOR). A promising solution for this issue was portrayed in employing foam technology due to its favorable mobility ratio and ability to delay the breakthrough of the injected gases. However, the costs pertaining to the utilization of expensive foaming chemicals have prompted economical complications for the wide scale application of the foam EOR techniques. In this study, we compared different foam injection strategies with the economical aspect in mind and introduced a novel injection approach with superior techno-economic performance in generating CO₂ and CH₄ foam in-situ at harsh pressure and temperature conditions. Four foam injection strategies were evaluated in terms of their impact on the mobility reduction of the in-situ generated CO₂ and CH₄ foams. In the methane foam case, the co-injection mode produced high mobility reduction factor (MRF) compared to the single cycle surfactant alternating gas mode (1-SAG). However, the multicycle strategies including the SAG and the proposed gas alternating foam (GAF) outperformed the co-injection mode yielding MRFs of 289 and 336, respectively. The steady state co-injection of CO₂ and surfactant solution, however, produced less mobility control compared to the 1-SAG mode. The multicycle SAG and GAF strategies provided more favorable mobility ratio, with MRFs of 99 and 120 respectively, when compared with the other injection strategies of CO₂-foam. Consequently, the novel GAF injection and in-situ foam generation strategy displayed the most prominent mobility control potential for both gases. Besides, this injection strategy decreased surfactant consumption by more than 70% compared to the other injection strategies shedding light on its worth as the most promising economical foam generation strategy in EOR field applications.