东濮凹陷沙三段储层微裂缝发育特征及意义

摘要

利用微观薄片、物性、流体包裹体分析等,对东濮凹陷沙三段储层微裂缝的类型、特征、成因及其参数进行了研究.结果表明,东濮凹陷沙三段储层中发育穿粒缝、贴粒缝和粒内缝3种微裂缝.微裂缝的成因以构造作用为主,此外还有异常高压作用及成岩作用.东濮凹陷沙三段储层中的微裂缝规模中等、密集,平均长度为5.6mm,平均面密度为0.66cm/cm2,平均地下开度为8.6μm.微裂缝是该区重要的储集空间,对改善低孔低渗透砂岩储层的储集性能起重要的作用.%The types,characteristics,origin and parameters of the microfractures in Es3 reservoirs of Dongpu depression were studied by such means as microscopic thin section analysis,physical property analysis and fluid-inclusion analysis.The results show that three types of microfractures,i.e.,transgranular fractures,grain edge and intragranular fractures,are developed in Es3 reservoirs of Dongpu depression, and tectonism played a dominant role in the formation of microfractures, followed by diagenesis and overpressure. The scale of microfractures is medium,but they are developed intensively in Es3 reservoirs of Dongpu depression.The average length of the microfractures is 5.6mm with average density of 0.66cm/cm2and average opening of 8.6μm. The microfractures are the major reservoir space in the study area and play an important role in improving the porosity characteristics of the ultralow permeability sand-stone reservoirs.