山西省域石炭二叠纪煤系泥页岩气储层评价指标体系

针对煤系泥页岩气地质资源量估算偏大的问题,选择山西省域石炭二叠纪煤系泥页岩气储层,通过页岩气日均产气量衰减率和经济下限产气量分析,提出了独立储层和组合储层的概念;基于492件实测泥页岩样品,评价了煤系泥页岩干酪根类型和TOC含量;通过泥页岩单位TOC含量吸附量和实测泥页岩含气量评价了泥页岩有机质成熟度和含气量的关系;基于与海相页岩气剖面资源量等量原则评价了煤系泥页岩厚度;基于煤层Ro、含气饱和度与埋深的正相关趋势,将煤系泥页岩埋深划分为1 000,1 000~1 500和1 500 m三种类别;基于128件实测泥页岩样品,将煤系泥页岩脆性矿物含量划分为30%,30%~40%和40%三个类别。基于煤系泥页岩有机质成熟度、总有机碳含量、含气量、埋深、厚度及脆性矿物含量6个参数,将山西省域石炭二叠纪海陆交互相煤系泥页岩储层划分为组合有利储层、组合较有利储层和组合不利储层。

Evaluation index system for the Permo-Carboniferous mud shale reservoirs of coal measures in Shanxi Province

Aiming to solve the issues of over estimation in geological resources of mud shale gas,the conceptions of independent reservoir and combined reservoir were put forward according to the analysis of the economic limit of gas production and the average daily gas production attenuation rate of shale gas in the Permo-Carboniferous mud shale reservoirs of coal-bearing strata in Shanxi Province.The Kerogen type and the total organic carbon content(TOC) of coal-bearing mud shale reservoirs were investigated through 492 mud shale samples.And according to the TOC-normalized methane adsorption capacity and measured gas content,the relation of organic matter maturity and gas content of mud shales were evaluated.The thickness of coal-bearing mud shale was evaluated based on the principle of profile resources equivalent compared with marine shale.A classification of buried depth of coal-bearing mud shale was put forward according to the positive correlations between buried depth with RO and gas saturation.It was divided into three types such as <1 000 m,1 000~1 500 m and >1 500 m.Total 128 measured mud shale samples were investigated in their mineral content.And based on the investigation,the brittle mineral content of coal bearing mud shale were divided into three levels of ＜30%,30%~40% and >40%.Finally,six parameters such as the organic matter maturity(Ro),total carbon content(TOC),buried depth,mud shales thickness,gas content and brittle mineral content were used to classify the marine-terrigenous facies coal-bearing mud shale reservoirs into the favorable,relatively favorable and unfavorable assemblage reservoir.