鄂尔多斯盆地致密砂岩储层成岩作用及孔隙演化——以七里村油田延长组7段为例  

Diagenesis and pore evolution of tight sandstone reservoir in Ordos Basin:taking the seventh Member of Yanchang Formation of Qilicun Oilfield as an example

作　　者：孙嘉鑫 赵靖舟 汤延帅[3] 刘星 李政胤 SUN Jiaxin;ZHAO Jingzhou;TANG Yanshuai;LIU Xing;LI Zhengyin(School of Earth Sciences and Engineering,Xi′an Shiyou University,Xi′an 710065,China;Shaanxi Key Laboratory of Petroleum Accumulation Geology,Xi′an Shiyou University,Xi′an 710065,China;Qilicun Oil Production Plant,Yanchang Oilfield Co.,Ltd.,Yan′an 716000,China)

机构地区：[1]西安石油大学地球科学与工程学院,陕西西安710065 [2]西安石油大学陕西省油气成藏地质学重点实验室,陕西西安710065 [3]延长油田股份有限公司七里村采油厂,陕西延安716000

出　　处：《断块油气田》2024年第4期611-619,共9页Fault-Block Oil & Gas Field

基　　金：中国博士后科学基金项目“鄂尔多斯盆地三叠系延长组7段泥页岩氧化还原参数阈值校正及底水氧化还原条件重新评价”(2022MD713801)。

摘　　要：鄂尔多斯盆地是我国致密油资源最富集的盆地之一,资源量大,分布范围广,勘探开发前景广阔,但对七里村油田致密砂岩储层的研究较为薄弱。文中综合分析了研究区测井曲线及铸体薄片、扫描电镜、阴极发光等镜下观察资料,并结合全岩X衍射等实测数据,精细研究了七里村油田长7段储层岩石学特征、物性特征、成岩作用类型及孔隙演化规律。结果表明:研究区长7段储层以长石砂岩为主,表现为特低孔-超低渗和超低孔-超低渗的特征;孔隙类型以溶蚀孔、粒间孔为主,发育少量晶间孔和微裂缝;成岩作用对孔隙演化有较大影响,在成岩作用过程中,压实和胶结作用使储层物性变差,而溶蚀作用对储层具有建设作用。研究区长7段砂岩储层孔隙演化定量计算结果表明:初始孔隙度平均为36.54%,压实作用、胶结作用造成的减孔率分别为51.60%,43.75%,溶蚀作用对长7段储层物性起建设性作用,增孔率为11.97%。Ordos Basin is one of the basins in China with the most abundant tight oil resources,having large resources which are widely distributed,and broad prospects for exploration and development.However,research on tight sandstone reservoir of Qilicun Oilfield is relatively weak.By comprehensively analyzing the logging curves,thin sections,scanning electron microscopy,cathodoluminescence and other microscopic observation data in the study area,combined with measured experimental data such as whole rock X-ray diffraction,this paper finely studied the petrologic characteristics,physical properties,diagenetic types and pore evolution laws of the Chang 7 Member reservoir in Qilicun Oilfield.The results show that the Chang 7 Member reservoir in the study area is mainly composed of feldspar sandstone,with characteristics of extra-low porosity and ultra-low permeability and ultra-low porosity and ultra-low permeability.The main pore types are dissolution pores and intergranular pores,with a small amount of intercrystalline pores and microfractures.Diagenesis has a significant influence on pore evolution,and during the diagenetic process,compaction and cementation reduce the physical properties of the reservoir,while dissolution plays a constructive role to the reservoir.Quantitative calculation of pore evolution in the Chang 7 Member reservoir in the study area shows that the average original porosity is 36.54%,and the porosity reduction rate caused by compaction is 51.60%,while the porosity reduction rate caused by cementation is 43.75%.Dissolution has a construc-tive effect on the physical properties of the Chang 7 Member reservoir,with the porosity increase rate of 11.97%.

关 键 词：致密砂岩储层 储层特征 成岩作用 孔隙演化 七里村油田 

分 类 号：TE122.2[石油与天然气工程—油气勘探]