鄂尔多斯盆地下寺湾地区山西组页岩气储层特征与评价

Research on evaluation methods and characteristics of shale gas reservoirs in Shanxi formation in Xiasiwan area, Ordos basin

为了研究下寺湾地区山西组页岩储层特征,建立一套适用鄂尔多斯盆地的页岩气储层评价标准,文章以试验分析数据为基础,结合钻井资料、野外露头和已有的研究文献,从岩石矿物学、有机地球化学,物性、储集空间和含气性特征等方面进行研究,建立了一套适用于鄂尔多斯盆地上古生界页岩气储层的评价标准和方法。结果表明:(1)山西组页岩矿物学和力学性质适中,脆性矿物平均超过40%,泥页岩杨氏模量10-80GPa,泊松比0.20-0.40,具有较高的弹性模量和低泊松比特征,有利于后期开发;(2)山西组泥页岩以Ⅲ型干酪根为主,TOC平均值3.12%,Ro值平均值2.63%,是优质的气源岩;(3)相比北美典型页岩,山西组页岩孔隙度偏低,平均为0.77%,渗透率较高,平均为0.03999×10^-3μm^2,页岩总含气量平均为1.19cm^3/g,达到商业开采价值。以上成果认识对鄂尔多斯盆地页岩气勘探和同类盆地页岩气储层评价具有重要指导意义。

In order to study Xiasiwan area of shanxi formation shale reservoir characteristics,to establish a set of evaluation standard for shale gas reservoir of Ordos basin,the article on the basis of experimental analysis data,combined with drilling data,field outcrop and the existing research literature,from organic geochemistry,mineralogy,rock physical property,reservoir space and gas-bearing characteristics research,establish a set of suitable for shale,upper palaeozoic gas reservoir of Ordos basin evaluation standard and methods.The results show that:(1)The shale of shanxi formation has moderate mineralogy and mechanical properties,and the average brittle mineral content exceeds 40%.The young s modulus of shale is 10-80gpa and poisson s ratio is 0.20-0.40.It has high elastic modulus and low poisson s ratio,which is beneficial to the later development;(2)Shanxi formation shale is given priority to withⅢtype kerogen,TOC average 3.12%,average 2.63%Ro values,is of high quality gas source rock;(3)compared with the typical shale in North America,the shale in shanxi formation has a low porosity with an average of 0.77%,a high permeability with an average of 0.039 99×10^-3μm^2,and a total gas content of 1.19 cm^3/g,reaching commercial production value.The above achievements have important guiding significance for shale gas exploration in Ordos basin and shale gas reservoir evaluation in similar basins.