鄂尔多斯盆地寒武纪层序岩相古地理特征及对储集体的控制作用  

Lithofacies paleogeographic characteristics of Cambrian sequence and their control over reservoir in Ordos Basin

作　　者：卢意 张春林[2] 由雪莲 聂宇晗 LU Yi;ZHANG Chunlin;YOU Xuelian;NIE Yuhan(China University of Geosciences(Beijing);PetroChina Research Institute of Petroleum Exploration and Development;The Fourth Oil Production Plant of PetroChina North China Oilfield Company)

机构地区：[1]中国地质大学(北京),北京市海淀区100083 [2]中国石油勘探开发研究院 [3]中国石油华北油田公司第四采油厂

出　　处：《海相油气地质》2025年第2期119-132,共14页Marine Origin Petroleum Geology

基　　金：中国石油“十四五”重大科技项目“鄂尔多斯盆地风险勘探领域和目标研究、工程技术攻关及现场试验”(编号:2023YQX10105);中国科学院战略性先导科技专项(A类)“深层油气形成与分布预测”(编号:XDA14010403);国家科技重大专项“大气田富集规律与勘探关键技术”(编号:2016ZX05007-002)联合资助。

摘　　要：鄂尔多斯盆地寒武系具有天然气勘探的潜力。为明确有利相带与储集体的分布规律,综合分析单井、野外露头、地震等资料,在鄂尔多斯盆地寒武系识别出不整合面和岩性转换面2种层序界面,由此将寒武系划分为2个二级层序(SS1、SS2)和8个三级层序(SQ1—SQ8),每个三级层序由海侵体系域和高位体系域组成。并以三级层序为编图单元,系统编制了寒武系三级层序格架内的8张岩相古地理图,分析三级层序格架下的岩相古地理展布特征。鄂尔多斯盆地寒武系经历2个沉积阶段:SQ1—SQ4为海进阶段,发育碳酸盐缓坡沉积;SQ5—SQ8为海退阶段,发育浅水型碳酸盐台地沉积。受控于层序岩相古地理演化,鄂尔多斯盆地寒武系储层纵向上主要分布于SQ6—SQ8,储层类型主要包括白云石化鲕粒滩储层、表生岩溶储层及断溶体储层。受控于台缘相和高位体系域白云石化作用、古隆起的分布及断裂作用,平面上白云石化鲕粒滩储层主要分布于盆地西部、南部的台缘带,表生岩溶储层分布于古隆起周缘,断溶体储层孤立地分布于盆地中。The Cambrian in Ordos Basin has the potential for natural gas exploration.To clarify the distribution pattern of favorable sedimentary facies zones and reservoirs,by comprehensively analysing core,outcrop and seismic data,two types of sequence boundaries,unconformities and lithological transition surfaces are have been identified in the Cambrian of the Ordos Basin.The Cambrian strata can be divided into two 2nd-order sequences(SS1,SS2)and eight 3rd-order sequences(SQ1-SQ8),each 3rd-order sequence consists of a TST and a HST,lacking a LST.The unconformity surfaces of the bottom and top of the Cambrian system serve as the bottom and top boundaries of SS1 and SS2.The lithological transition surface is the 3rd-order sequence boundary.Eight lithofacies palaeogeoguaphic maps were systematically compiled to analyze the lithofacies paleogeographic distribution characteristics under 3rd-order sequence stratigraphic framework of Cambrian in Ordos Basin.The Cambrian in the Ordos Basin has gone through two sedimentary stages.SQ1-SQ4 is the stage of transgression,developing carbonate ramp sedimentary system.SQ5-SQ8 is the stage of regression,developing shallow water carbonate platform sedimentary system.Controlled by the evolution of sequence lithofacies paleogeography,the Cambrian reservoirs in Ordos Basin are mainly distributed longitudinally in SQ6-SQ8,and the good reservoirs of Cambrian in Ordos Basin include three types:dolomitizational oolitic shoal reservoir,supergene karst reservoir and fault-dissolution reservoir.Due to the control of the platform margin and high-level system tract,as well as the distribution and faulting of ancient uplifts,the oolitic shoal reservoir is mainly distributed in the western and southern platform margin of the basin,the supergene karst reservoir is distributed in the periphery of the palaeouplift,and the faultdissolution reservoir is isolated in the basin.

关 键 词：层序 岩相古地理 沉积体系 储集体 寒武纪 鄂尔多斯盆地 

分 类 号：TE122.2[石油与天然气工程—油气勘探]