SIAPES的合成及低温油藏原位乳化驱油体系构建与性能

Synthesis of SIAPES and Construction and Performance of In-situ Emulsification Oil Displacement System in Low-temperature Oil Reservoirs

W/O型乳液驱油是一项有效提高老油田采收率技术。但低温条件下常用的乳化体系不能同时满足形成W/O型乳液和降低界面张力。本文合成并表征了异构十三醇聚氧乙烯醚磺酸钠(SIAPES),并与椰子油烷基二乙醇酰胺(CEDA)复配构建了低温油藏原位乳化驱油体系,评价了体系的乳化性能、降低了油水界面张力并改善了岩石润湿性能力。同时利用在线NMR驱替系统揭示了原位乳化驱油体系在低温油藏条件下提高采收率的潜力。结果表明:原油-地层水自乳化相变点为60%,利用原位乳化驱油体系对油水自乳化进行干预后,乳液相变点提高到65%,且发生相变后乳液黏度明显高于自乳化乳液的黏度,流度控制能力增强;原位乳化驱油体系能将油水界面张力由12.00 mN/m降低至0.12 mN/m,改善亲油岩心润湿性至亲水;在渗透率级差为12,水驱至经济极限的条件下,0.6 PV的原位乳化驱油剂驱和后续水驱使采收率提高了26.8%。

W/O emulsion flooding is an effective technology to improve oil recovery in mature oilfields,while the comment emulsion system cannot meet the requirements of W/O emulsion formation and interfacial tension reduction at low temperature.In this paper,sodium isomeric dodecanol polyoxyethylene ether sulfonate(SIAPES)was firstly synthesized and characterized.Then,a low-temperature oil reservoir in-situ emulsification flooding system was constructed by compounding with coconut oil alkyl diethanolamide(CDEA).And then,its emulsifying performance,interfacial tension reduction ability,and wettability improvement ability were evaluated.Meanwhile,the enhanced oil recovery potential of system was revealed using an online NMR displacement system.The experimental results showed that the phase transition point of crude oil-formation water emulsification was 60%,while after the intervention of oil-water self emulsification with the in-situ emulsification displacement system,the phase transition point increased to 65%,and the viscosity of emulsion after phase change was obviously higher than that of the self emulsification emulsion,and the mobility control ability was enhanced.In addition,the in-situ emulsification system could reduce the interfacial tension of oil and water from 12.00 mN/m to 0.12 mN/m,and improve the wettability of oil-wet core sample.Moreover,under the condition of permeability ratio was 12 and water flooding reaches the economic limit,0.6 PV in-situ emulsification flooding and subsequent water flooding could increase the recovery rate by 26.8%.