Panthi Krishna, Aitkulov Almas, Mohanty Kishore K
Hildebrand Department of Petroleum & Geosystems Engineering, The University of Texas at Austin, 200 E Dean Keeton, Austin, Texas 78712, United States.
Hilcorp Corporation, 3800 Centerpoint Drive, Suite 1400, Anchorage, Alaska 99503, United States.
ACS Omega. 2024 Dec 22;10(1):1401-1410. doi: 10.1021/acsomega.4c08999. eCollection 2025 Jan 14.
Alkali-surfactant-polymer (ASP) flooding can reduce oil-water interfacial tension to ultralow values and mobilize oil in petroleum reservoirs. Surfactant is consumed by adsorption/retention which is significant in clay-rich reservoirs. Alkali can be added to surfactant-polymer formulations to minimize surfactant adsorption. The goal of this work is to study the effect of alkali and surfactant concentrations on surfactant-brine-oil phase behavior and minimize the amount of surfactant and alkali while mobilizing oil in a clay-rich sandstone reservoir (at a temperature of 75 °C). Many surfactants were studied for ASP formulations, and a mixture of two surfactants was identified that can produce ultralow IFT (∼0.001 mN/m) with the oil at low surfactant concentrations. Ten different ultralow IFT formulations were identified, but only two formulations were evaluated for oil recovery and surfactant retention in core floods. The optimal salinity decreased when the surfactant concentration was reduced. The cumulative oil recovery was high (>94%) for three types of cores (Berea sandstone, Leopard sandstone, and a reservoir core). The surfactant retention was in the range of 0.11-0.22 mg/g of rock for high clay content (>8%) cores due to the presence of alkali. Decreasing the surfactant concentration (while keeping the total amount of surfactant the same) did not change the surfactant adsorption or oil recovery but delayed the oil production.
碱-表面活性剂-聚合物（ASP）驱油可将油水界面张力降低至超低值，并驱替油藏中的原油。表面活性剂会因吸附/滞留而消耗，这在富含黏土的油藏中较为显著。可在表面活性剂-聚合物配方中添加碱，以尽量减少表面活性剂的吸附。本研究的目的是研究碱浓度和表面活性剂浓度对表面活性剂-盐水-油相行为的影响，并在富含黏土的砂岩油藏（温度为75℃）中驱油时尽量减少表面活性剂和碱的用量。针对ASP配方研究了多种表面活性剂，并确定了两种表面活性剂的混合物，该混合物在低表面活性剂浓度下就能与原油产生超低界面张力（约0.001 mN/m）。确定了十种不同的超低界面张力配方，但仅对两种配方进行了岩心驱替实验以评估原油采收率和表面活性剂滞留情况。当表面活性剂浓度降低时，最佳盐度也随之降低。三种岩心（ Berea砂岩、豹纹砂岩和油藏岩心）的累积原油采收率较高（>94%）。由于碱的存在，高黏土含量（>8%）岩心的表面活性剂滞留量在0.11-0.22 mg/g岩石范围内。降低表面活性剂浓度（同时保持表面活性剂总量不变）不会改变表面活性剂的吸附或原油采收率，但会延迟原油产出。
