苏里格气田东区致密砂岩气藏储层物性下限值的确定

鄂尔多斯盆地苏里格气田东区下二叠统山西组山2段、山1段及下石盒子组盒8段致密砂岩储层具有典型的低孔、低渗特征，目前使用的储层物性下限值可能偏高。为此，采用经验统计法、孔隙度-渗透率交会法、最小流动孔喉半径法、测井参数法等多种方法对该区物性下限开展了进一步研究，并通过单层试气成果和产能模拟法验证了新确定的下限值。结果表明：盒8段砂岩孔隙度下限值为5.0%，渗透率下限值为0.10 mD，含气饱和度下限值为55%；山1段孔隙度下限值为4.0%， 渗透率下限值为0.075 mD，含气饱和度下限值为55%；山2段砂岩孔隙度下限值为3.5%，渗透率下限值为0.075 mD，含气饱和度下限值为45%。重新认识和确定储层物性下限值，对该区油气勘探后备储量的精确计算具有重要意义。

Determination of lower limits of porosity and permeability of tight sand gas reservoirs in the eastern block of the Sulige Gas Field

The tight sand gas reservoirs in the 1st and 2nd members of the Permian Shaanxi Formation and the 8th member of the Permian Shihezi Formation are featured by low porosity and low permeability.However,the currently used lower limits of porosity and permeability might be too high.Several methods such as experimental statistical method,porosity-permeability crossplotting method,minimum flow pore throat radius method,and logging parameter method,were used to further determine the optimal lower limits of porosity and permeability for reservoirs in this block.The results show that the lower limit of porosity for the sandstone reservoirs in the 8th member of the Shihezi Formation is 5.0%,the lower limit of permeability is 0.10 mD,and the lower limit of gas saturation is 55%.As for the 1st member of the Shanxi Formation,these values are 4.0%,0.075 mD and 55% respectively,and as for the 2nd member of the Shanxi Formation,these values are 3.5%,0.075 mD and 45% respectively.These values are of great importance to the accurate calculation of reserves in this block.