天然气勘探与开发2023，Vol.46Issue(4)：57-68,12.DOI:10.12055/gaskk.issn.1673-3177.2023.04.006
川东地区茅一段储层地质特征及勘探潜力分析
Geological characteristics and exploration prospects of the first Member of Maokou Formation in eastern Sichuan Basin:An example from XT1 well
摘要
Abstract
The first member of Middle Permian Maokou Formation in Sichuan Basin was always regarded as a set of carbonate source rocks not as reservoirs for evaluation in previous exploration practices.So,XT1well,one risk exploration well,was taken as an objective to deeply figure out the natural-gas exploration potential of the first Member of Maokou Formation in eastern basin.Moreover,both mineral petrology and geochemistry were explored on the basis of core data through some methods,like physical property testing,thin section identification,and scanning electron microscope and organic geochemical analysis.Finally,characteristics as both reservoir rocks and source rocks were gained.Results show that(i)this member in eastern Sichuan Basin is dominated by medium or thin-medium layered dark-gray to gray-black argillaceous micritic bioclastic limestone and marlstone,and medium-thick to thick layered gray to dark-gray micritic bioclastic limestone and argillaceous micritic bioclastic limestone.Its depositional waterbody is relatively deep.A kind of"eyeball structure",which is formed by the interbedded micritic bioclastic limestone,argillaceous micritic bioclastic limestone and marlstone,is developed;(ii)for core plugs,their helium porosity ranges from 0.24%to 6.98%,1.39%on average,and the permeability from 0.0014 mD to 1.72 mD,0.083 mD on average,respectively,belonging to low-porosity and low-permeability reservoirs.Among which,the eyelid-shaped limestone boasts better physical properties,for example the porosity between 0.24%and 6.98%,and the reservoir space mainly consisting of sheet-like talc intercrystalline micropores and microfractures.While the eyeball limestone possesses poor storage performance with the porosity from 0.24%to 3.41%,resulting that this sort of reservoir rocks is not developed;(iii)with TOC between 0.17%and 1.63%,the eyelid limestone in this well enjoys certain hydrocarbon-generating ability.The source rocks of first Member of Maokou Formation in eastern basin are generally thicker than 80 m,thus suggesting good hydrocarbon-generating conditions;(iv)in this area,it can develop into argillaceous limestone and marlstone gas reservoirs with self-generation and self-storage as well as multiple source rocks with the favorable exploration area of 2×104 km2 and the pre-dicted resources over 2,000×108 m3,displaying large exploration prospects.关键词
四川盆地/川东地区/茅一段/储层特征/烃源特征/勘探潜力Key words
Sichuan Basin/Eastern Sichuan Basin/first Member of Maokou Formation/Reservoir characteristics/Source-rock char-acteristics/Exploration prospect引用本文复制引用
李亚,钟佳倚,汪华,戴鑫,安虹伊..川东地区茅一段储层地质特征及勘探潜力分析[J].天然气勘探与开发,2023,46(4):57-68,12.基金项目
中国石油西南油气田公司科学与技术开发项目"四川盆地二叠系资源潜力与成藏条件研究"(编号:20220301-03-01). （编号:20220301-03-01）
