Chen Fuzhen, Gu Jianwei, Jiang Hanqiao, Yao Xue, Li Yuan
School of Petroleum Engineering, China University of Petroleum Qingdao China 266580
State Key Laboratory of Petroleum Resources and Prospecting, China University of Petroleum Beijing China 102249.
RSC Adv. 2018 Jul 25;8(47):26476-26487. doi: 10.1039/c8ra03454k. eCollection 2018 Jul 24.
Alkali-surfactant-polymer (ASP) flooding, which can reduce interfacial tension (IFT) and the mobility ratio between oil and water phases, has been proven to be effective for enhancing oil recovery in laboratory experiments and field pilots. However, the study of interactions within alkali-surfactant-polymers for chemical flooding is neither comprehensive nor complete until now. Laboratory experiments were conducted and a corresponding numerical simulation model was established to characterize multiple component interactions during the ASP flooding process. Synergistic effects of multiple component interactions on viscosity variation, IFT reduction, and multicomponent adsorption were studied separately. ASP solution viscosity shows non-linear variation behavior with an increasing polymer concentration. Alkali decreases the molecular hydraulic radius of a polymer, and then limits its contribution to viscosity. Oil-water interfacial tension decreases with the join in of polymer which can act as an alternative effect to replace surfactant adsorbed on a mineral surface. Petroleum acid will react with alkali and produce petroleum soap to perform a synergetic action with the surfactant on IFT reduction. Adsorption fraction and diffusion rate of a surfactant will diminish due to rheology improvements caused by a polymer. Alkali can protect a surfactant from adsorption consumption by competitive adsorption. A viscosity non-linear logarithm mixing method, IFT reduction-relative permeability curve interpolation method, and a multicomponent adsorption isotherm model were developed to characterize and simulate the synergistic effects obtained by experiments. A novel ASP flooding numerical simulation model was constructed which coupled the synergistic effects simulation methods of viscosity variation, IFT reduction, and multicomponent adsorption. The numerical simulation result based on the proposed model has better agreement with experiment results compared with that of the traditional model. Validation results proved the effectiveness of the proposed model which can be used to enhance a synergistic mechanism study and field application of ASP flooding.
碱-表面活性剂-聚合物（ASP）驱油技术能够降低界面张力（IFT）以及油水相之间的流度比，在实验室实验和现场试验中已被证明对提高原油采收率有效。然而，迄今为止，对于化学驱油中碱-表面活性剂-聚合物之间相互作用的研究既不全面也不完整。开展了实验室实验并建立了相应的数值模拟模型，以表征ASP驱油过程中的多组分相互作用。分别研究了多组分相互作用对粘度变化、IFT降低和多组分吸附的协同效应。ASP溶液粘度随聚合物浓度增加呈现非线性变化行为。碱降低了聚合物的分子流体力学半径，进而限制了其对粘度的贡献。聚合物的加入会降低油水界面张力，其可起到替代作用，取代吸附在矿物表面的表面活性剂。石油酸会与碱反应生成石油皂，与表面活性剂在降低IFT方面发挥协同作用。由于聚合物引起的流变学改善，表面活性剂的吸附分数和扩散速率会降低。碱可通过竞争吸附保护表面活性剂不被吸附消耗。开发了粘度非线性对数混合法、IFT降低-相对渗透率曲线插值法和多组分吸附等温线模型，以表征和模拟实验获得的协同效应。构建了一个新型的ASP驱油数值模拟模型，该模型耦合了粘度变化、IFT降低和多组分吸附的协同效应模拟方法。与传统模型相比，基于所提模型的数值模拟结果与实验结果具有更好的一致性。验证结果证明了所提模型的有效性，其可用于加强ASP驱油的协同机理研究和现场应用。
