西湖凹陷平北地区平湖组下段烃源岩分布地震预测  

Seismic prediction of source rock distribution in the Lower Member of Pinghu Formation in the Pingbei area of Xihu Sag

作　　者：朱茂林 刘震[1] 张枝焕[1] 刘畅[1] 杨鹏程[2] 李佳阳 崔凤珍 ZHU Maolin;LIU Zhen;ZHANG Zhihuan;LIU Chang;YANG Pengcheng;LI Jiayang;CUI Fengzhen(School of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;Institute of Exploration and Development,SINOPEC Shanghai Offshore Oil&Gas Company,Shanghai 200120,China)

机构地区：[1]中国石油大学(北京)地球科学学院,北京102249 [2]中国石油化工股份有限公司上海海洋油气分公司勘探开发研究院,上海200120

出　　处：《海洋地质与第四纪地质》2022年第1期170-183,共14页Marine Geology & Quaternary Geology

基　　金：中海石油(中国)东海西湖石油天然气作业公司项目“平北地区优质烃源岩生烃潜力评价”(HX20200148)。

摘　　要：西湖凹陷平北地区现有钻井稀少且分布不均,采样分析资料缺乏,不同层段烃源岩非均质性极强,导致烃源岩分布特征尚不明确。针对上述难题,基于地化、测井、录井、地震等资料,运用地震相-沉积相-有机相转化法和地震速度-岩性分析法对西湖凹陷平北地区平湖组下段烃源岩有机相特征及厚度分布进行了研究,并对有利烃源岩的分布进行了预测。结果表明:(1)平湖组下段烃源岩有机相可划分为潮控三角洲前缘A相、潮间带B相和局限海C相三种类型,其中平下上亚段潮控三角洲前缘A相最为发育,位于研究区的中部区域,而平下下亚段潮间带B相最为发育,主要位于研究区的西部区域;(2)平下下亚段烃源岩具有东西分带、西薄东厚的特征,最大厚度可达500余米;而平下上亚段烃源岩总体上具有西北薄东南厚的特征,向东南方向厚度最高可达1 000余米;(3)烃源岩综合评价分析认为,平下下亚段有利烃源岩主要分布在研究区的中东部区域,平下上亚段有利烃源岩主要分布在研究区的东南部区域。Drilling wells are rarely and unevenly distributed in the Pingbei area of the Xihu sag and sample analysis data are also lacking.However, the heterogeneity of source rocks is very strong in different layers, which has made it unclear the distribution pattern of source rocks.In order to solve the problem, this paper studied the characteristics of the organic facies and the thickness distribution patterns of the source rocks in the Lower Member of Pinghu Formation taking the Pingbei area as a case, based on the integration of geochemical, logging and seismic data. The method of seismic facies-sedimentary facies-organic facies transformation and the method of seismic velocity and lithology analysis are adopted for prediction of favorable source rocks. The results show that:(1) The organic facies of source rocks in the Lower Member of the Pinghu Formation can be classified into three facies types, i.e. tidal delta front A, intertidal zone B and confined sea C. The tidal delta front A facies, located in the center of the study area, is the most developed one in the Second Member of Lower Pinghu Formation, while the intertidal B facies is the most developed in the First Member of Lower Pinghu Formation, which is mainly located in the western region of the study area.(2) The thickness distribution pattern of the source rocks in the Lower Pinghu Formation are clarified. The source rocks in the Second Member of Lower Pinghu Formation are zonated from east to west, thinner in the west and thicker in the east, and the maximum thickness may be over500 meters;while the source rocks in the First Member of Lower Pinghu Formation are generally thin in the northwest and thick in the southeast, with a maximum thickness more than 1 000 meters in the southeast;(3) The integrated evaluation and analysis of source rocks suggest that the favorable source rocks in the Second Member of Lower Pinghu Formation are mainly distributed in the southeast of the study area, and the favorable source rocks in the First Member of Lower Pinghu Forma

关 键 词：烃源岩 地震相 有机相 平湖组 地震预测 西湖凹陷 

分 类 号：P744.4[天文地球—海洋科学] TE122.1[石油与天然气工程—油气勘探]