大宁—吉县上古生界主要砂体储层物性及含气特征

Physical property and gas content characters of sandstone in Daning-Jixian Area Upper Paleozoic

鄂尔多斯盆地东南缘大宁—吉县地区上古生界具有巨大的非常规天然气资源潜力,其中,太2段、山2段、山1段和盒8段为研究区上古生界主要的致密砂岩发育层段。结合大量的钻井资料及储层物性测试数据对研究区4套主要砂体进行了分析,得出研究区从本溪组到盒8段砂体发育规模逐渐增大;孔隙度主要集中在5%~7%,渗透率偏低,大多在(0~0.6)×10-3μm2。运用曲线重叠法对研究区砂岩气层进行了识别与评价,并在考虑到区内砂岩泥质含量较高的基础上,对印尼公式的参数进行一定的优化,计算了该区的砂岩含气量,含气量整体呈现南高北低、西高东低的规律。

Enormous resource potential of unconventional gas has been found in the Daning-Jixian Area of Ordos Basin Upper Paleozoic.The second member of Taiyuan Formation,the second member of Shanxi Formation,the first member of Shanxi Formation and the eighth member of Shihezi Formation were main sandstone reservoirs in the study area.Combined with a large number of drilling data and the physical property analysis of reservoir and based on the analysis of four sets of main sand bodies in the study area,it showed that the sand body was widely distributed in the plane;the porosity main distribution range of 5%~7%;the permeability was low,main distribution range(0~0.6)×10-3μm 2.The sandstone gas reservoirs in the study area were identified and evaluated by the method of curve overlap.The paper optimized the parameters of Indonesia formula.The sandstone gas content was calculated,and gas content as a whole appeared a rule of"South high north low,west high east low".