中上扬子地区石炭系-二叠系颗粒灰岩类型及储集性能

Classification of Grain Limestone and Reservoir Property of Carboniferous and Permian in the Middle Upper Yangtze Region

中上扬子地区是我国主要的天然气产区,油气资源丰富,石炭-二叠纪的碳酸盐岩地层是其主要的储层发育段。综合运用岩石学、沉积学及地球化学等方法,结合区域沉积背景、地层岩石学特征分析、镜下薄片观察等多种手段,对区内灰岩类型及其储集性能进行了分析。研究表明:根据灰岩的颗粒类型及原始沉积特征,将其划分为生物碎屑灰岩、砂-砾屑灰岩、粉屑灰岩、球粒灰岩、鮞粒灰岩、藻粒灰岩等6种类型;灰岩储集空间组合类型以裂缝-孔隙型为主;储集性能以颗粒灰岩和粗晶灰岩最好,其次为细-粉晶灰岩。通过对区内不同储集岩物性参数的对比研究初步发现了有利油气勘探区分布。

The Middle-Upper Yangtze Region was the main area of natural gas production in China,it had rich oil and gas resources.The main reservoirs were developed in Carboniferous and Permian carbonate.The petrology,sedimentology and geochemistry methods were integratedly used to analyze limestone types and reservoir property in the studied area in combination with regional sedimentary background and formation lithology characteristics and the microscopic observation of thin sections.The result indicated that based on the types of grain limestone particles and the original sedimentary characteristics,it was divided into six types,such as bioclastic limestone,gravel limestone,powder limestone,pellet limestone,oolitic limestone and algal grain limestone.The combination type of the limestone reservoir space was mainly of fracture-pore type,the best reservoir properties were grain limestone and coarse grain limestone.Fine and powder limestone was the next.Granular structure and coarse grain structure of limestone pore structure are the best,followed by fine powder crystal limestone.Based on the different physical parameters of reservoir rock,the distribution of favorable exploration area is preliminarily found out.