基于原子力显微镜表征的含油储层微观孔隙结构分析及应用

为研究岩心微观孔隙结构在强碱三元复合驱替过程中的变化特征,以大庆油田南5-4-检725井855.0m处岩心为对象,通过原子力显微镜观察岩心形貌特征,定量分析孔喉宽度和深度;分析驱替过程中岩心样品的面孔率、孔喉宽度和深度、分形维数等参数变化反映的微观孔隙结构变化规律.结果表明:原子力显微镜获得的图像可以真实反映储层岩石微观形貌特征,储层微观孔隙结构具有二段式分形特点.微观孔隙结构变化特征在驱替初期,主要表现为岩石粒间颗粒运移;在驱替中后期,主要表现为强碱三元驱替剂与岩石相互作用,生成驱替剂残留或其他产物.该研究结果对分析强碱三元复合驱替后剩余油分布规律、制定后续开发方案具有指导意义.

Analysis and applications of microscopic pore structure characterization of oil reservoir by atomic force microscopy

Micro-pore structure characteristics of the cores(855.0m) from the well of Nan 5-4-J725 in Daqing Oilfield and their changes after Alkaline-Surfactant-Polymer(ASP) flooding were studied by using atomic force microscope.The study found that the atomic force microscope image can truly reflect the morphology characteristics of the reservoir rock,thus quantitative spatial scales analysis can be made effectively.By these presentations,two-stage fractal characteristic of micropore structure of the reservoir was found.In the early ASP flooding,the changes in the microscopic pore structure was mainly caused by particle migrating,but in the late ASP flooding was mainly caused by new production and residual reagents of ASP.The results are important to analyze the distribution law of residual oil after ASP flooding and to develop a reasonable success development program.