鄂尔多斯盆地马家沟组中-下组合岩相古地理演化及储层分布规律  

Paleogeographic evolution of the middle and lower assemblages of the Majiagou Formation in the Ordos Basin and the pattern of reservoir distribution

作　　者：牛小兵[1,2] 吴东旭 刘新社[1] 任军峰[1] 李程善[1] 周进高 于洲 李维岭 王龙[1] Niu Xiaobing;Wu Dongxu;Liu Xinshe;Ren Junfeng;Li Chengshan;Zhou Jingao;Yu Zhou;Li Weiling;Wang Long(PetroChina Changqing Oilfield Company,Xi'an 710018;National Engineering Laboratory for Exploration and Development of Low‑Permeability Oil and Gas Fields,Xi'an 710018;PetroChina Hangzhou Research Institute of Geology,Hangzhou 310023;National Key Laboratory of EnergyCarbonate Rock Oil and Gas,Hangzhou 310023;PetroChina Key Laboratory of Carbonate Reservoir,Hangzhou 310023)

机构地区：[1]中国石油长庆油田公司,西安710018 [2]低渗透油气田勘探开发国家工程实验室,西安710018 [3]中国石油杭州地质研究院,杭州310023 [4]国家能源碳酸盐岩油气重点实验室,杭州310023 [5]中国石油集团碳酸盐岩储层重点实验室,杭州310023

出　　处：《地质科学》2024年第3期625-636,共12页Chinese Journal of Geology(Scientia Geologica Sinica)

基　　金：长庆油田重大专项“鄂尔多斯盆地中元古界-长城系构造沉积演化、成源机制及勘探新领域研究”(编号:ZDZX2021);中国石油天然气集团有限公司科技项目“海相碳酸盐岩油气规模增储上产与勘探开发技术研究”(编号:2023ZZ16YJ01)资助。

摘　　要：岩相古地理研究是储层刻画和油气勘探的基础。前期对鄂尔多斯盆地碳酸盐岩岩相古地理的认识成果,有效指导了奥陶系马家沟组顶部的风化壳储层勘探,已探明近万亿方储量规模。然而,限于资料和认识程度,原来的储层分布图无法满足日益深入的天然气勘探工作需求。因此,笔者基于最新的地质基础资料,综合运用岩相古地理分析和储层预测技术,通过编制马家沟组中-下组合重点层段的沉积相图和储层分布图,明确了中-下组合有利储层发育的主控因素和分布规律。研究表明:1)马家沟组中-下组合主要发育蒸发台地、局限台地和台地边缘3大相类型,以及8种亚相和16种微相;其中台内颗粒滩、微生物丘、台缘颗粒滩、含膏云坪是储层发育的有利微相。2)中-下组合白云岩储层微观储集空间主要有粒间孔、晶间孔、溶蚀孔、微裂缝等,主要受控于丘滩和膏云坪沉积、准同生溶蚀作用和后期充填作用3种因素。3)马二段、马四段、马五9亚段、马五7亚段以丘滩相的粒间孔和晶间孔储层为主,马三段、马五6亚段以膏云坪的溶蚀孔储层为主。结论认为,中-下组合储层类型多样、层系多、厚度大,是下一步天然气勘探的重点层系。Petrographic paleogeography study is the basis of reservoir delineation and hydrocarbon exploration.The results of the previous understanding of the petrographic paleogeography of the carbonate rocks in the Ordos Basin have effectively guided the exploration of the weathered crust reservoir at the top of the Ordovician Majiagou Formation,which has been proved to have nearly one trillion cubic meters of reserve size.However,limited to the data and the degree of understanding,the original reservoir distribution map can not meet the needs of the increasingly in-depth natural gas exploration work.Therefore,based on the latest geological data,the author comprehensively utilized petrographic paleogeographic analysis and reservoir prediction techniques,and clarified the main controlling factors and distribution rules of favorable reservoir development in the middle and lower part of Majiagou Formation by compiling sedimentary phase maps and reservoir distribution maps in the middle and lower part of the formation.The study shows that:1)the middle and lower part of Majiagou Formation mainly develops three major phases,namely evaporation plateau,confined plateau and plateau edge,as well as eight subphases and 16 microphases.Among them,the granular beach,microbial mound,granular beach at the edge of the platform,and gypsum-bearing dolomitite flats are favorable microphases for reservoir development.2)The microscopic storage space of the dolomite reservoirs in the middle and lower assemblages mainly consists of intergranular pores,intercrystalline pores,dissolution pores,microcracks,etc.,which are mainly controlled by three factors:deposition of mounds,beaches,and gypsum-bearing dolomitite flats,penecontemporaneous dissolution,and post filling effect.3)The reservoirs of Ma2,Ma4,Ma59 and Ma57 are mainly intergranular pores and intercrystalline pores of mound-shoal facies,and the reservoirs of Ma3 and Ma56 are mainly dissolved pores of gypsum-bearing dolomitite flats.It is concluded that the middle-lower assemblage reservoirs

关 键 词：储层分布 沉积微相 岩相古地理 中-下组合 马家沟组 鄂尔多斯盆地 

分 类 号：P531[天文地球—古生物学与地层学] P539.2[天文地球—地质学]