致密砂岩储层小尺度非均质性与石油富集特征  

Small-scaled heterogeneity of tight sandstone reservoirs and oil accumulation characteristics

作　　者：杨智峰[1,2] 曾溅辉[1,2] 冯枭[1,2] 冯森[1,2] 张译丹[1,2] 乔俊程[1,2] 

机构地区：[1]中国石油大学油气资源与探测国家重点实验室,北京102249 [2]中国石油大学地球科学学院,北京102249

出　　处：《中国矿业大学学报》2016年第1期119-127,共9页Journal of China University of Mining & Technology

基　　金：国家自然科学基金重点项目(40772088;41172128)

摘　　要：以鄂尔多斯盆地合水地区长6储层为例,运用岩心、扫描电镜、高压压汞、微-纳米CT技术,从毫米、微米和纳米3个尺度分析致密储层的非均质性,揭示致密砂岩储层小尺度非均质性对致密油富集的影响,明确了小尺度非均质性的特征及其对致密油富集的影响,确定了含油孔喉半径的下限.结果表明：致密储层毫米尺度下层理缝、块状层理与粒序层理发育,岩心内存在钙质胶结与大量的泥质条带.微米尺度下粒间孔隙（2~50μm）与微裂缝（50~300μm）发育,纳米尺度下粒内孔隙（50~500nm）发育.毫米尺度下,层理缝的发育导致致密油的局部富集.其中块状层理最有利于石油的富集,正韵律与中间突进韵律影响致密油的分布,钙质胶结与泥质条带不利于致密油的富集.微纳米尺度下,致密油主要发育在较大的条带状孔隙中,孤立的孔隙如果有微裂缝的沟通也有致密油的富集.致密储层的孔喉半径下限为50~80nm.Based on core observation,SEM image,high-pressure mercury injection and micronano CT reconfiguration technique,the tight reservoir heterogeneity and influences on tight oil accumulation of Chang 6section of Yanchang formation in Heshui area were studied on the millimeter,micron and nanometer scale.Besides,the pore-throat radius threshold of tight reservoir was determined.The results show that bedding fracture,massive bedding and graded bedding are well developed in millimeter scale.Calcareous cementation and plentiful argillite bands are widespread in the core.Inter-granular pore（2—50μm）and micro-crack（50—300μm）are well developed in micron scale.Intra-granular pore（50—500nm）is well developed in nanoscale.In millimeter scale,local enrichment of tight oil is controlled by bedding fracture,among which massive bedding is the most beneficial to oil accumulation,and the distribution of tight oil is controlled by the positive rhythm and composite rhythm.Both calcareous cementation and argillite bands are not good for tight oil accumulation.In micro-nano scale,tight oil is not only distributed in larger stripped pores,but also in isolated pores with micro-crack development.The pore-throat threshold of tight reservoir is 50 to 80nm.

关 键 词：小尺度 微纳米 非均质性 致密砂岩 长6段 合水地区 

分 类 号：TE122.2[石油与天然气工程—油气勘探]