西湖凹陷平湖斜坡带K区平湖组-花港组油气成藏主控因素及成藏模式  

Main controls and hydrocarbon accumulation model of the Pinghu Formation-Huagang Formation in Area K of the Xihu Sag Pinghu slope zone

作　　者：廖响 徐昉昊[1] 徐国盛[1] 刘建斌 黎建 张喜淳 李坤[1] LIAO Xiang;XU Fanghao;XU Guosheng;LIU Jianbin;LI Jian;ZHANG Xichun;LI Kun(State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan610059,China;Cnooc(China)Co.,LTD.Shanghai Branch,Shanghai 200335,China)

机构地区：[1]成都理工大学油气藏地质及开发工程全国重点实验室,四川成都610059 [2]中海石油(中国)有限公司上海分公司,上海200335

出　　处：《矿物岩石》2024年第4期138-150,共13页Mineralogy and Petrology

基　　金：国家自然科学基金青年科学基金项目(批准号:42302186)。

摘　　要：基于丰富的油气资源储量及勘探前景,西湖凹陷平湖斜坡带古近系平湖组-花港组一直是西湖凹陷油气勘探开发的重点地区之一,但前人对该地区油气成藏方面的研究程度普遍较低,制约了该地区下一步的勘探工作。本次研究基于斜坡带K区已有的三维地震、测录井、地化、物性、包裹体等资料,剖析了K区的油气成藏地质条件、分析了该区成藏主控因素并建立了成藏模式。研究表明K区烃源岩主要分布于平湖组中下段暗色泥岩中,以Ⅲ型干酪根为主,成熟度较高,油气分布呈现“上油下气”和“内油外气”的特征,油气为“先油后气”两期充注。平湖组大量发育中低孔隙度、渗透率储层,储层砂体表现为高成分成熟度,石英、长石含量较高,结合黏土矿物分析,平湖组储层处于中成岩A、B期,有利于优质储层的发育与保存,K区普遍发育的区域盖层及局部盖层,也为油气的聚集提供了有利条件。该区成藏主控因素为烃源控区、斜坡引导、汇脊控聚、封堵控藏。其中,烃源灶的位置和烃源岩埋藏深度决定了油气成藏纵横向分布范围,斜坡引导油气向构造高位运移,汇聚脊作为低势区使斜坡大面积引导的油气汇聚并高速运移,断层封堵作用形成构造圈闭捕获汇聚运移的油气成藏。主要油气产区成藏模式为烃源灶近源充注-宽陡继承型斜坡引导-地层汇聚脊控输-反向断裂封堵控藏。The Pinghu Formation and Huagang Formation in the Pinghu slope zone of the Xihu Depres-sion have long been key areas for oil and gas exploration and development,owing to their abundant re-serves and promising exploration potential.However,understanding of oil and gas accumulation in this ar-ea is generally limited,which has restricted further exploration success.Based on the existing 3D seismic,logging,geochemical,physical properties,inclusions and other data in the slope Area K,this paper analy-zes the geological conditions of hydrocarbon accumulation in Area K.It is aiming to identify the main con-trols of reservoir formation,and to establish a reservoir formation model.The study shows that the source rocks of hydrocarbon in Area K are mainly distributed in the dark mudstone of the middle and lower mem-ber of the Pinghu Formation,characterized by a high maturity III kerogen.The distribution of oil and gas in Area K presents with a pattern of"upper oil and lower gas"and"inner oil and outer gas".The oil and gas are charged in in an order of"first oil and then gas".The Pinghu Formation hosts numerous reservoirs characterized by medium to low porosity and permeability.The reservoir sand bodies exhibit high compo-sitional maturity with elevated quartz and feldspar content.In combination with clay mineral analysis,the Pinghu Formation reservoirs are in the A and B stages of medium diagenesis,which favor the development and preservation of high-quality reservoirs.Additionally,the widespread regional and local cap beds in Ar-ea K provide favorable conditions for oil and gas accumulation.The primary factors controlling hydrocar-bon accumulation include source area,slope guidance,ridge convergence,and fault sealing.The location and depth of hydrocarbon source rocks determine the horizontal and vertical distribution of oil and gas ac-cumulations.Slopes promote the migration of hydrocarbons to structurally high positions,while conver-gence ridges,functioning as low-potential zones,facilitate the rapid gathering and transpo

关 键 词：K区 主控因素 成藏模式 平湖斜坡带 西湖凹陷 

分 类 号：TE122.2[石油与天然气工程—油气勘探]