东海盆地西湖凹陷中央反转构造带花港组盖层特征  

CAPROCK OF THE HUAGANG FORMATION IN THE CENTRAL INVERSED STRUCTURAL ZONE OF XIHU SAG,EAST CHINA SEA BASIN

作　　者：张宙 赵洪 罗仁春 张武 朱虹浩 ZHANG Zhou;ZHAO Hong;LUO Renchun;ZHANG Wu;ZHU Honghao(Shanghai Branch of CNOOC China Limited,Shanghai 200335,China;CNOOC Marketing Shanghai Co.Ltd.,Shanghai 200335,China)

机构地区：[1]中海石油(中国)有限公司上海分公司,上海200335 [2]中海油销售上海有限公司,上海200335

出　　处：《海洋地质前沿》2020年第10期50-56,共7页Marine Geology Frontiers

基　　金：“十三五”国家科技重大专项“东海深层低渗-致密天然气勘探开发技术”(2016ZX05027001)。

摘　　要：针对西湖凹陷中央反转构造带花港组盖层封闭机制及影响因素不明确的现状,采用岩心观察、镜下观察、X衍射、岩性特征分类及成岩演化等方法进行盖层有效性因素分析,并在此基础上进行了突破压力试验与分析。沉积影响因素分析表明,中央反转构造带花港组泛滥平原相盖层总厚度最大,分流间湾相次之,水道间微相最小;成岩作用研究表明,压实、胶结与交代作用为建设性成岩作用,溶蚀与泥质收缩作用为破坏性作用,不同成岩作用在不同深度下对孔隙发育的影响程度不同,直接影响了盖层的封闭能力。研究区泛滥平原相为最有利的盖层发育沉积相,胶结与压实作用为最有利的成岩作用。结合盖层岩性与突破压力的分布特征,建立了研究区盖层4级评价标准。The sealing mechanism of the Huagang Formation caprock and its influencing factors in the central inversed structural belt of the Xihu Sag remain unclear up to date.In this paper,we used various methods,such as core observation,microscopic examination,X-ray diffraction,and the methods specially designed for study of lithology and diagenesis to assess the quality of a caprock and its influencing factors in order to know more about the caprock in the region.Breakthrough pressure testing was also made.The analysis of influencing factors suggests that the total thickness of the cover of flood plain facies in the Huagang Formation of the region belt is the largest,followed by the facies of the distributary bay,while the total thickness of the cover between waterways is the smallest.The study of diagenesis suggests that the diagenesis of compaction,cementation and metasomatism is constructive,while that of dissolution and shale contraction is destructive.Diagenesis has strong effects on the development of pores at different depths,which directly effects the sealing ability of the caprock.In the study area,the facies of flood plain is the most favorable facies,and cementation and compaction are the most favorable diagenesis for caprock development.Combined with the distribution characteristics of caprock and breakthrough pressure,a four-level system for caprock assessment is established in this paper.

关 键 词：盖层 突破压力 沉积成岩 西湖凹陷 东海盆地 

分 类 号：P618.13[天文地球—矿床学]