渤海海域环渤中地区沙一二段混积岩优质储层差异及成因  

Differences and Genesis of High-Quality Reservoirs of Mixed SiliciclasticCarbonate Rocks in the Es12around Bozhong Depression, Bohai Sea

作　　者：庞小军 牛成民 杜晓峰 王清斌 代黎明 Pang Xiaojun;Niu Chengmin;Du Xiaofeng;Wang Qingbin;Dai Liming(Bohai Petroleum Research Institute,Tianjin Branch of China National Offshore Oil Corporation Limited,Tianjin 300459,China)

机构地区：[1]中海石油(中国)有限公司天津分公司渤海石油研究院,天津300459

出　　处：《地球科学》2020年第10期3853-3869,共17页Earth Science

基　　金：国家科技重大专项(No.2016ZX05024-003)。

摘　　要：渤海海域环渤中地区沙一二段发育混积岩储层,其中发现了大量的油气,但储层物性差异较大,非均质性较强,其差异及成因方面的研究较少,严重制约了该类型储层的进一步勘探评价.利用钻井及常规物性、铸体薄片、全岩、黏土矿物等分析化验资料,探讨了环渤中地区沙一二段混积岩优质储层的差异及成因.研究结果表明:(1)环渤中地区沙一二段发育以生物碎屑为主的混积岩、以陆源碎屑为主的混积岩和以化学沉淀碳酸盐为主的混积岩储层,前2类储层中发育大量的螺壳和介壳.其中,生物碎屑为主的混积岩储层以生物体腔孔为主,白云石化作用强,物性最好;陆源碎屑为主的混积岩储层以溶蚀孔为主,生物体腔孔和原生孔次之,泥晶包壳发育、白云石化作用强、含大量中酸性火山岩岩屑、埋藏浅的储层物性好;化学沉淀碳酸盐为主的混积岩储层方解石胶结作用强,物性较差.不同构造混积岩储层类型及物性具有明显的差异性.(2)研究区混积岩储层差异主要受母岩类型、基底岩性、沉积水体环境、沉积相、大气淡水淋滤、埋深压实作用、胶结作用、溶解作用以及构造作用的共同控制,但每个构造的优质储层均具有独特的控制因素组合.非碳酸盐岩母岩区,原生沉积期-火成岩基底、含大量生物碎屑混积岩,准同生期-大气淡水淋滤、早期白云石化,以及深埋藏期-强溶解、裂缝发育是环渤中坳陷沙一二段混积岩优质储层形成的共性.混积岩优质储层差异及成因分析为陆相断陷湖盆中深部油气勘探和评价过程中优质储层的预测具有重要的借鉴意义.The mixed siliciclastic-carbonate rock reservoirs are developed in the Es12 around Bozhong depression,Bohai Sea,in which a large amount of oil and gas have been found.The reservoir physical properties show great differences,and strong heterogeneity.However,there are few studies on the differences and causes,restricting further exploration evaluation of this type of reservoir.In this paper,the differences and genesis of the high-quality reservoirs of the Es12 around Bozhong depression in Bohai Sea are discussed based on the data analyses of drilling,conventional physical properties,casting thin sections,whole rocks and clay minerals.The results show follows.(1)There are three types of reservoirs,namely bioclastic-based mixed siliciclasticcarbonate rocks,mixed siliciclastic-carbonate rocks dominated by terrigenous clastics,and mixed-rock reservoirs dominated by chemically precipitated carbonates,respectively,in Es12 around Bozhong area.A large number of snail and ostracod fossils are developed in the first two types of reservoirs.Among them,the mixed siliciclastic-carbonate rock reservoir dominated by bioclastic development has a large number of biological cavity pores,and the dolomitization has strong effect and the best physical properties.The mixed rock reservoir dominated by terrigenous clastics is mainly composed of dissolution pores,followed by biological cavity and primary pores,which is characterized by the development of mud-crystal cladding,strong dolomitization,containing a large amount of intermediate-acid volcanic rock debris,and shallow buried reservoirs have good physical properties.Calcite in cemented rock reservoirs dominated by chemical precipitation has strong cementation and poor physical properties.There are obvious differences in reservoir types and physical properties of different structural aggregate rocks.(2)The differences of mixed siliciclasticcarbonate rock reservoirs in the study area are mainly controlled by the parent rock type,basement lithology,sedimentary water environment,sediment

关 键 词：成岩作用 淋滤作用 混积岩 沙河街组 环渤中 渤海海域 沉积 

分 类 号：P618.13[天文地球—矿床学]