渤海湾盆地滨海地区古近系沙河街组一段滑塌型湖底扇储集层特征及主控因素  

Reservoirs properties of slump-type sub-lacustrine fans and their main control factors in first member of Paleogene Shahejie Formation in Binhai area, Bohai Bay Basin, China

作　　者：蒲秀刚[1] 赵贤正[1] 王家豪[2] 吴佳朋 韩文中[1] 王华[2] 时战楠 姜文亚[1] 张伟[1] PU Xiugang;ZHAO Xianzheng;WANG Jiahao;WU Jiapeng;HAN Wenzhong;WANG Hua;SHI Zhannan;JIANG Wenya;ZHANG Wei(Dagang Oilfield Company,PetroChina,Tianjin 300280,China;Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education,China University of Geosciences,Wuhan 430074,China)

机构地区：[1]中国石油大港油田公司,天津300280 [2]中国地质大学构造与油气资源教育部重点实验室,武汉430074

出　　处：《石油勘探与开发》2020年第5期913-924,共12页Petroleum Exploration and Development

基　　金：中国石油天然气集团有限公司重大科技专项(2018E-11);国家重大专项大型油气田及煤层气开发子课题(2016ZX05026003)。

摘　　要：渤海湾盆地歧口凹陷滨海地区近年来在古近系沙河街组一段陆续钻遇高产油气,提供了断陷湖盆中部发育中-深层优质储集层的典型实例。采用岩心、薄片、扫描电镜和物性等资料,分析储集层的沉积相、物性及主控因素。结果表明,储集层砂岩普遍含泥岩碎块,具滑塌变形构造和鲍马序列,指示为滑塌型湖底扇沉积。其储集性好,包括较多中孔低渗和少量中孔高渗类型;储集空间主要为原生粒间孔隙、长石和岩屑颗粒的粒间-粒内溶蚀孔隙、构造微裂缝。优质储集层的主控因素包括:①有利的沉积微相。包括重力流主水道和近端分支水道微相,其沉积物粒度粗,以砂质碎屑流为主要搬运-沉积机制。随着埋深的增加,沉积作用对物性的影响相对减弱。②中等结构成熟度。湖底扇属滩坝砂体滑塌、再沉积成因,含较多分选中等的砂岩,有利于原生孔隙存留。③高含量的中-酸性火山岩岩屑。砂岩岩屑含量高且成分多样,特别是火山岩岩屑,有助于溶蚀孔隙发育。④有机酸溶蚀作用。对应于中成岩A亚期,该时期烃类成熟。⑤早期形成且持续存在的超压。中-深层整体为一个大型超压封存箱,与厚层深湖相泥岩的欠压实和生烃增压相关,原生孔隙得以大量保存。⑥张扭性区域构造作用。有利于构造微裂缝的发育。High-yielding oil wells were recently found in the first member of Paleogene Shahejie Formation, the Binhai area of Qikou Sag, providing an example of medium-and deep-buried high-quality reservoirs in the central part of a faulted lacustrine basin. By using data of cores, cast thin sections, scanning electron microscope and physical property tests, the sedimentary facies, physical properties and main control factors of the high-quality reservoirs were analyzed. The reservoirs are identified as deposits of slump-type sub-lacustrine fans, which are marked by muddy fragments, slump deformation structure and Bouma sequences in sandstones. They present mostly medium porosity and low permeability, and slightly medium porosity and high permeability. They have primary intergranular pores, intergranular and intragranular dissolution pores in feldspar and detritus grains, and structural microcracks as storage space. The main factors controlling the high quality reservoirs are as follows:(1) Favorable sedimentary microfacies of main and proximal distributary gravity flow channels. The microfacies with coarse grains were dominated by transportation and deposition of sandy debris flow, and the effect of deposition on reservoir properties decreases with the increase of depth.(2) Medium texture maturity. It is shown by medium-sorted sandstones that were formed by beach bar sediment collapsing and redepositing, and was good for the formation of the primary intergranular pores.(3) High content of intermediate-acid volcanic rock debris. The reservoir sandstone has high content of debris of various components, especially intermediate-acid volcanic rock debris, which is good for the formation of dissolution pores.(4) Organic acid corrosion. It was attributed to hydrocarbon maturity during mesodiagenetic A substage.(5) Early-forming and long lasting overpressure. A large-scale overpressure storage box was caused by under-compaction and hydrocarbon generation pressurization related to thick deep-lacustrine mudstone, and is responsible

关 键 词：断陷湖盆 滑塌型湖底扇 储集层 古近系沙河街组 孔-渗结构 歧口凹陷 渤海湾盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]