川东石炭系气藏不同类型岩石孔隙度下限及其对储量的影响

石炭系是川东地区的主力产层,储量、特别是容积法储量是制定开发方案的基础。在储量计算的有关参数中,有效储层下限的确定直接影响有效储层厚度、孔隙度和含气饱和度三个参数。研究发现,由于储集岩类型不同,其孔隙类型也就不同,孔喉结构存在较大差异,因此,对不同储集岩,有效储层应有不同的孔隙度下限。通过对川东地区七里峡、大天池、大池干井、高峰场、云安厂、福成寨等构造石炭系209个岩样的压汞资料分析研究,得出不同储集岩的有效储层孔隙度下限,以此计算了川东石炭系8口气井的容积法储量,与不同储集岩采用相同的有效储层孔隙度下限比较,计算结果相差6.22%,结果更接近地层实际情况。

Different Rock Porosity Lowers Limit of East Sichuan Carboniferous Gas Reservoir and the Impact on Reserves

Carboniferous system is the main production layer of East Sichuan and reserves, especially volumetric method reserves is the base of developing production plan . The corroboration of effective reservoir lower limit in reserves calculation respects parameters influence effective reservoir thickness, porosity and gas saturation directly. It is discovered that because different storage type lead different hole type and different hole structure , there is different porosity lower limit in different effective reservoir. In this paper , through analysis of 209 carboniferous rock mercury penetration data of qilixia, datianchi, dachigan, gaofengchang,yun'anchang,fuchengzai etc of East Sichuan , derive differ reservoir rock, effective reservoir porosity lower limit ,and calculated 8 wells of east Sichuan carboniferous volumetric method reserves. Based on these lower limits and compared with the different effective reservoir porosity lower limit of different reservoir rock , the result discrepancy 6. 22 % . Because reserves calculation in this method considered rock type, pore types and pore throat structure characteristic, the result is more closer the real formation.