致密砂岩油储层裂缝发育特征及其对剩余油挖潜的启示——以鄂尔多斯盆地新安边地区延长组长722段为例
Fracture Development Characteristics in Tight Sandstone Oil Reservoir and Its Inspiration on Remaining Oil Recovery: A Case Study on the Chang-722 Layer of Yanchang Formation in Xin’anbian Area, Ordos Basin

摘要 通过岩芯观察、井间示踪剂测试和水驱前缘测试, 研究鄂尔多斯盆地新安边地区长7致密砂岩油储层的裂缝发育特征。结果表明: 1) 新安边地区长7致密砂岩油储层最大水平主应力方向为NE60°~80°, 裂缝类型以高角度缝或垂直缝为主, 裂缝走向为NE75°~85°, 倾角为70°~85°; 2) 动态监测数据分析显示, 研究区致密砂岩油储层广泛发育的微裂缝在增加渗流通道和提高基质渗透率方面发挥了重要作用, 油水易沿裂缝形成窜流, 导致生产井见水较快; 3) 三维地质建模结果显示, 研究区致密砂岩油储层含油饱和度与裂缝发育程度匹配度较高, 可以有效地佐证裂缝对油气储集和成藏的控制作用。
Abstract Through the core observation, inter-well tracer test and water flooding front test, the fracture development characteristics of Chang-7 tight sandstone reservoir in Xin’anbian area of Ordos Basin are studied. The results show that maximum horizontal principal stress direction of Chang-7 tight sandstone oil reservoir in Xin’anbian area is NE60°？80°. The fracture type is mainly high angle fractures or vertical fracture, and fracture direction is NE75°？85°, the dip angle is 70°？85°. Dynamic monitoring data analysis shows that the micro fracture research area of tight sandstone oil reservoir developed widely and plays an important role in increasing the seepage channel and improving the permeability of matrix, water channeling easily along the fracture formation, resulting in the production of well water is fast. 3D geological modeling results show a high degree between oil saturation of tight sandstone oil reservoir in the study area and the degree of fracture development, which can effectively support the fracture of oil and gas reservoir and accumulation.