海相油气地质2024，Vol.29Issue(4)：372-384,13.DOI:10.3969/j.issn.1672-9854.2024.04.004
川中地区茅二段白云石化作用机制及分布模式
The mechanism and distribution model of dolomitization in the 2nd member of Maokou Formation in central Sichuan Basin
摘要
Abstract
Dolomitization and dolomite distribution are the key factors that restrict the development and distribution of reservoir of the 2nd member of Maokou Formation in central Sichuan Basin.Based on the previous research results of dolomite and the understanding of regional geological background,through the observation of core and thin sections,and the introduction of cathode luminescence,X-ray diffraction,inclusion,C and O stable isotope,Sr isotope and REE analysis,the further study of dolomitization of the 2nd member of Maokou Formation in central Sichuan Basin has been carried out.The results show that:(1)There are three types of dolomite in the study area:very fine-fine crystalline anhedral dolomite,very fine-medium crystalline euhedral dolomite,and saddle dolomite.Very fine-fine crystalline anhedral dolomite is formed by syngenetic evaporative seawater dolomitization.This dolomitization does not produce reservoir space itself,but plays a fundamental role in the formation of dolomite reservoirs.Very fine-medium euhedral dolomite is formed by burial dolomitization in the early diagenetic period,and the intergranular pores and intergranular dissolution pores are developed at the site of dolomitization,which can form dolomite dissolution pore type reservoir.Saddle dolomite is formed by hydrothermal dolomitization in early diagenetic period(Dongwu period).This dolomitization is accompanied by hydrothermal fracture and hydrothermal dissolution,which can lead to the development of dissolution fractures and the formation of dolomite dissolution fracture and cavernous reservoirs.(2)Marginal platform,coupling with the platform margin fault,is the best place to develop syngenetic seawater dolomitization,burial dolomitization and hydrothermal dolomitization in the early diagenetic period,and is also the advantageous development zone of dolomite reservoir.In the intra-platform highland area,syngenetic evaporative seawater dolomitization and burial dolomitization in the early diagenetic period are mainly developed,making it a relatively favorable zone for dolomite reservoir development.However,intra-platform depressions lack favorable conditions for dolomitization,resulting in poor dolomite development.关键词
白云石化作用/白云岩分布/控储意义/茅二段/川中地区Key words
dolomitization/dolomite distribution/the significance of controlling reservoir/2nd member of Maokou Formation/central Sichuan Basin分类
能源科技引用本文复制引用
高兆龙,彭瀚霖,张玺华,陈聪,李天军,李国蓉,何钊,李肖肖,田家奇..川中地区茅二段白云石化作用机制及分布模式[J].海相油气地质,2024,29(4):372-384,13.基金项目
本文受中国石油天然气股份有限公司科技重大专项课题"碳酸盐岩油气富集规律及有利区带研究"(编号:2023ZZ16YJ01)资助 （编号:2023ZZ16YJ01）
