东非鲁伍马盆地深水海底扇储集层质量差异及主控因素  

Quality variations and controlling factors of deepwater submarine-fan reservoirs,Rovuma Basin,East Africa

作　　者：王敏[1] 张佳佳[2] 王瑞峰[1] 徐庆岩[1] 文思颖 曹全斌 余季陶 王黎[1] WANG Min;ZHANG Jiajia;WANG Ruifeng;XU Qingyan;WEN Siying;CAO Quanbin;YU Jitao;WANG Li(PetroChina Research Institute of Petroleum Exploration&Development,Beijing 100083,China;College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;PetroChina Hangzhou Research Institute of Geology,Hangzhou 310023,China)

机构地区：[1]中国石油勘探开发研究院,北京100083 [2]中国石油大学(北京)地球科学学院,北京102249 [3]中国石油杭州地质研究院,杭州310023

出　　处：《石油勘探与开发》2022年第3期491-501,共11页Petroleum Exploration and Development

摘　　要：以东非鲁伍马盆地X气田下始新统深水海底扇为例,综合岩心、地震及测井资料处理解释,分析海底扇储集层质量差异原因及主控因素。研究表明,沉积组构、岩相差异及成因单元特征是研究区储集层质量差异的主控因素。在胶结作用较弱的情况下,海底扇储集层孔隙度和渗透率分别受控于岩石分选和泥质含量。5种主要类型岩相的物性差异与沉积组构、胶结强度密切相关,其中块状中粗砂岩相钙质胶结作用弱,物性最好,随着粒度变粗或变细储集层物性均变差。底流改造作用可形成具层理构造的岩相,极大改善微观孔隙结构与储集层物性。不同类型、位置和期次成因单元的岩相组合关系存在差异,控制海底扇储集层质量的差异分布样式,水道轴部或朵叶主体储集层物性优于水道或朵叶边缘,远源砂岩较近源砂岩分选及物性均逐渐变好。多期次砂体叠置情况下,后期比前期砂体砂泥比增加,储集层物性变好。The mechanisms causing quality variations and key control factors of submarine-fan reservoirs in the gas field X of the Rovuma Basin,East Africa are analyzed based on core and well-log data in this paper.Depositional fabric,lithofacies difference and characteristics of genetic units are the fundamental reasons of reservoir quality variations.In the case of weak cementation,porosity and permeability of submarine-fan reservoirs are controlled by grain sorting and clay content,respectively.Reservoir quality variations for 5 main lithofacies are related to variable depositional fabrics and calcite cementation.Among them,massive medium-coarse sandstones with weak cementation have the highest porosity and permeability,and coarser or finer sandstones have poorer reservoir quality.The existence of bottom current can develop laminated sandstones,improving the pore structure and physical properties greatly.Lithofacies vary among different types,locations and stages of genetic units,and they control the distribution patterns of submarine-fan reservoir quality:the physical properties of channel shaft or lobe main body are better than those of the channel or lobe edge.The sandstone sorting and physical properties are gradually improved from near-source to far-source.When multi-stage sand bodies are superimposed,the sand-mud ratio in the later stage is higher than that in the earlier stage,making the physical properties get better in the later stage.

关 键 词：深水 海底扇 重力流 沉积组构 岩相 成因单元 储集层质量 始新统 东非鲁伍马盆地 

分 类 号：TE122.1[石油与天然气工程—油气勘探]