低渗透油藏表面活性剂微乳液驱数值模拟理论研究

发布时间：2018-07-10 04:13

本文选题：低渗透油藏 + 微乳液驱油　；参考：《东北石油大学》2017年硕士论文

【摘要】：随着油田开发进程的不断推进,我国常规油田大部分已经入高含水或特高含水阶段且采出程度较高,进一步提高采收率潜力不大。近年来,我国新发现的区块以低渗透油藏居多,因此,实现对低渗透油藏的有效开发对于我国的能源安全及发展具有重要意义。低渗透油藏具有孔隙极其狭小、孔喉比较大、迂曲度较大、孔隙壁对流体性质影响不可忽略等特点。由于边界层流体的存在,使得孔隙内流体存在启动压力梯度,其流动规律不再符合达西渗流,使得低渗透油藏需要较高的注采压差才能够实现流体的有效动用。针对大庆外围榆树林油田扶杨油层存在的注水困难、动用效果差等问题,本文开展了低渗透油藏表面活性剂微乳液驱数值模拟理论研究。应用天然岩心,测得其微观孔隙结构特点及其微乳液驱条件下启动压力梯度。在物模岩心实验研究基础上建立了相应的非线性渗流方程。由于微乳液体系具有超低界面张力、改变油藏润湿性降低启动压力梯度、较好的流度控制、改变油水相对渗透率等提高采收率作用机理,本文在实验研究的基础上得到表面活性剂吸附、粘度变化、相态变化、界面张力以及相对渗透率曲线的定量描述。综合考虑表面活性剂在油藏内的吸附与扩散,建立了低渗透油藏表面活性剂微乳液驱三维三相五组分数学模型,并应用隐压、显饱、隐浓度的方法得到其数值解并编译了相应的模拟软件。应用平板岩心进行微乳液驱油实验对该模型进行验证并在此基础上对扶杨油层微乳液驱过程中的表面活性剂浓度、助剂浓度、盐浓度进行参数优选。本文研究结果对于有效开发低渗透油藏具有重要意义。
[Abstract]:With the continuous development of oil fields, most of the conventional oilfields in China have entered the stage of high water cut or super high water cut, and the degree of recovery is relatively high, so the potential for further improvement of oil recovery is not great. In recent years, the newly discovered blocks in China are mainly low permeability reservoirs. Therefore, it is of great significance to realize the effective development of low permeability reservoirs for the energy security and development of our country. Low permeability reservoirs are characterized by extremely narrow porosity, large pore throat, large degree of detour, and the influence of pore wall on fluid properties can not be ignored. Due to the existence of the boundary layer fluid, there is a starting pressure gradient in the pore fluid, and the flow law no longer accords with Darcy percolation, which makes the low permeability reservoir need higher injection-production pressure difference to realize the effective use of the fluid. In view of the difficulties of water injection and poor production effect in Fuyang reservoir of Yushulin oilfield around Daqing, the numerical simulation theory of surfactant microemulsion flooding in low permeability reservoir is studied in this paper. The characteristics of micropore structure and the starting pressure gradient under the condition of microemulsion flooding were obtained by using natural cores. The corresponding nonlinear seepage equation is established on the basis of the experimental study of the core. Because the microemulsion system has ultra-low interfacial tension, changing the wettability of reservoir to reduce the starting pressure gradient, better mobility control, changing the relative permeability of oil and water, etc. On the basis of experimental study, the quantitative description of surfactant adsorption, viscosity change, phase state change, interfacial tension and relative permeability curves are obtained. Considering the adsorption and diffusion of surfactants in the reservoir, a three-dimensional three-phase five-group fractional model of surfactant microemulsion flooding in low permeability reservoir is established, and the implicit pressure is applied. The numerical solution of hidden concentration is obtained and the corresponding simulation software is compiled. The model was verified by microemulsion flooding experiment with flat core, and the parameters of surfactant concentration, additive concentration and salt concentration in Fuyang oil layer microemulsion flooding process were selected. The results of this paper are of great significance for the effective development of low permeability reservoirs.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357.46

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