Construction of a foaming agent containing hydroxysulfobetaine and α-olefin sulfonate for clastic reservoirs with high temperature and high salinity

High-temperature and high-salt reservoirs are often accompanied by serious gas channeling in gas flooding, which will greatly affect the effect of gas injection development, so in-situ foaming of temperature-resistant and salt-resistant foaming agents is commonly used to control gas channeling. The feasibility of the compound system of dodecyl hydroxyl sulfobetaine (HSB12) and α-olefin sulfonate (AOS) as foaming agent for sandstone reservoir was studied at 130 °C and 22 × 10⁴ mg/L. The results showed that the foaming agent (HSB12 and AOS were compounded in a 6:1 mass ratio, in this article, this foaming agent is simply referred to as SA61) had good solubility in 22 × 10⁴ mg/L simulated formation water. Besides, the foaming volume of SA61 and HSB12 was similar, but the foam decay half-life of SA61 was 10–25 times higher than that of HSB12. The foaming performance of SA61 on the surface of quartz sand remained above 90% of that before adsorption. The strong interaction between HSB12 and AOS in the compound system SA61 was demonstrated by surface rheological measurements and NMR studies of surfactants. The results of core flow test showed that SA61 had better mobility control ability than HSB12 under the same surfactant concentration. In addition, SA61 showed a selective mobility reduction in 2005.30 and 632.00 mD cores. The above research results can guide the selection and application of foaming agent in clastic reservoir.