鄂尔多斯盆地庆阳气田二叠系山西组山_(1)^(3)沉积相类型论证  

Demonstration of Sedimentary Facies Types of Shan_(1)^(3) in Qingyang Gas Field,Ordos Basin

作　　者：王龙[1] 李娅[1] 董倩云 范倩倩 刘平[1] 单敬福 WANG Long;LI Ya;DONG Qian-yun;FAN Qian-qian;LIU Ping;SHAN Jing-fu(Research Institute of Exploration and Development,PetroChina Changqing Oilfield Company,Xi an 710018,China;National Engineering Laboratory for Exploration and Development of Low Permeability Oil and Gas Fields,PetroChina Changqing Oilfield Company,Xi an 710018,China;School of Earth Sciences,Yangtze University,Wuhan 430100,China)

机构地区：[1]中国石油长庆油田分公司勘探开发研究院,西安710018 [2]中国石油长庆油田分公司低渗透油气田勘探开发国家工程实验室,西安710018 [3]长江大学地球科学学院,武汉430100

出　　处：《科学技术与工程》2024年第18期7510-7526,共17页Science Technology and Engineering

基　　金：中国石油天然气股份有限公司重大科技专项(2023ZZ25)。

摘　　要：鄂尔多斯盆地庆阳气田山1段是其主力产层,其沉积环境及其相类型一直争议较多,不同认识导致各个沉积相域内砂体对比模式和砂体分布形态存在着一定差异,从而给勘探井位部署增加了难度。在前人研究成果基础上,综合地震、测井、岩心、露头及室内分析化验等资料,结合地震反射结构揭示的溯源退覆特征、岩心显示的岩性粒度与层理构造、测井沉积旋回特征、现代沉积学的比较等等多视角证据链,对该区山_(1)^(3)小层的沉积相进行了详细论证、分析和描述。研究结果表明,研究区岩性以中粗砂岩为主,多发育块状、板状及小型槽状交错层理,测井相既有河流“二元结构”发育完整的井段,也有只发育下部粗粒端元河流“二元结构”发育不完整的井段,前者揭示发育曲流河,后者则与辫状河发育有关;粒度分析结果显示主要以跳跃粒度成分为主,说明古水动力强;研究区周边露头资料显示既有曲流河发育也有辫状河发育,说明山1段沉积期曲流河和辫状河是同期存在的;现代卫星照片揭示,曲流河和辫状河共生共存发育是普遍存在的,综合上述证据,最终确定研究区山31发育相类型为河流相,且表现为曲辫共存特征,曲流河的频繁侧积以及平面多种河型共存,垂向河道的多期叠置是导致砂体分布复杂化和横向相变化快速的主控因素。The Shan 1 member in the Qingyang Gas Field,Ordos Basin,constitutes one of the primary production layers.However,debates persist regarding its sedimentary environment and facies types.Divergent interpretations have resulted in discrepancies in sand body correlation patterns and distribution within each sedimentary facies,posing challenges in well-location exploration.Leveraging existing research,the author integrates seismic,logging,core,outcrop,and laboratory data.Employing diverse methods,including seismic reflection structure analysis,core-based examination of lithological grain size and bedding structure,logging sedimentary cycle characteristics,and comparisons with modern sedimentology,the sedimentary facies of the Shan _(1)^(3) strata were discussed,analyzed,and described comprehensively.Results indicate that the lithology in the study area is predominantly medium to coarse sandstone with planar and small trough cross-bedding.Logging facies encompass sections with a characteristic upward thinning sequence,indicative of meandering fluvial depositions,and sections with coarse-grained sediments,associated with the sedimentation of braided rivers.Particle size analysis reveals a prevalence of coarse particles,indicating robust paleohydrodynamic forces.Field outcrop data demonstrate the concurrent development of both meandering and braided rivers during the deposition period of the Shan1 member.Modern satellite images showcase the widespread development of meandering and braided rivers.In conclusion,the study identifies the sedimentary environment of Shan 31 as fluvial facies,characterized by the coexistence of meandering and braided rivers.Key factors contributing to the complexity of sand body distribution and rapid lateral facies changes include frequent lateral accretion of meandering rivers,planform changes in river patterns,and the multiple-phase stacking of vertical channels.

关 键 词：庆阳气田 曲辫共存 野外露头 沉积模式 

分 类 号：P534[天文地球—古生物学与地层学]