Origin of the penecontemporaneous sucrosic dolomite in the Permian Qixia Formation, northwestern Sichuan Basin, SW China

作     者：LU Feifan TAN Xiucheng ZHONG Yuan LUO Bing ZHANG Benjian ZHANG Ya LI Minglong XIAO Di WANG Xiaofang ZENG Wei LU Feifan;TAN Xiucheng;ZHONG Yuan;LUO Bing;ZHANG Benjian;ZHANG Ya;LI Minglong;XIAO Di;WANG Xiaofang;ZENG Wei

作者机构：State Key Laboratory of Oil and Gas Reservoir Geology and ExploitationSouthwest Petroleum UniversityChengdu 610500China Department of Key Laboratory of Carbonate Reservoirs of CNPCSouthwest Petroleum UniversityChengdu 610500China Institute of Petroleum Exploration and ExploitationPetroChina Southwest Oil and Gas Field CompanyChengdu 610041China Northwest Sichuan Gas MinePetroChina Southwest Oil and Gas Field CompanyJiangyou 621741China Key Laboratory of Surficial GeochemistryMinistry of EducationSchool of Earth Sciences and EngineeringNanjing UniversityNanjing 210023China PetroChina Hangzhou Institute of Petroleum GeologyHangzhou 310023China 

出 版 物：《Petroleum Exploration and Development》 (石油勘探与开发（英文版）)

年 卷 期：2020年第47卷第6期

页      面：1218-1234页

核心收录：

学科分类：0808[工学-电气工程] 0709[理学-地质学] 0819[工学-矿业工程] 081803[工学-地质工程] 07[理学] 08[工学] 070901[理学-矿物学、岩石学、矿床学] 0818[工学-地质资源与地质工程] 0807[工学-动力工程及工程热物理] 0708[理学-地球物理学] 0815[工学-水利工程] 0816[工学-测绘科学与技术] 0813[工学-建筑学] 0814[工学-土木工程] 

基　　金：Supported by the National Science&Technology Major Project of China(2016ZX05004002-001) Natural Science Foundation(41802147) Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance 

主　　题：sucrosic dolomite penecontemporaneous dolomitization seawater cyclic hydrothermal fluid eogenetic karstification Qixia Formation Permian Sichuan Basin 

摘      要：The characteristics,formation time,and origin of the sucrosic dolomite reservoirs in the Permian Qixia Formation of northwestern Sichuan Basin are *** and outcrop description and microscopic analysis of the sucrosic dolomite samples are carried *** is found that the dolomite has typical features different from other kinds of dolomites:(1)This dolomite is generally medium-coarse in crystal size,and often associated with very finely to finely crystalline dolomite and cave-filling dolomite.(2)Typical identification marks of eogenetic karstification are developed at the top of the upward-shallowing sequence.(3)The medium-coarse crystalline sucrosic dolomite is cut by the early diagenetic karst fabric,and is characterized by dolomite with dissolution edge,dolomite vadose silt in pores,and transgression clay filling between the medium-coarse dolomite *** medium-coarse crystalline sucrosic dolomite was formed earlier than the eogenetic *** sucrosic dolomite with occasional cloudy core and clear rim has bright cathodoluminescence,high inclusions temperature,significant negative skewness carbon and oxygen isotopic compositions,and rare-earth element(REE)pattern similar to seawater,indicating it experienced two periods of dolomitization,evaporative concentration reflux-infiltration and penecontemporaneous seawater circulation hydrothermal fluid *** study results not only update the understanding on the dolomitization time of Qixia Formation,demonstrate that the sucrosic dolomite can be formed in the penecontemporaneous stage when seawater reflux superimposed with hydrothermal fluid effects,but also show that the taphorogenesis in the Dongwu period began in the Early ***,the dolomite controlled by the grain bank migration and terrain in the slope break appears in bands of large scale,this knowledge provides basis for expanding the exploration field of this type of reservoirs.