基于扩径校正和新的气敏感因子的杭锦旗致密砂岩气层识别方法

Tight sandstone gas reservoir identification method based on diameter expansion correction and new gas sensitive factor in Hangjinqi area,Ordos Basin

杭锦旗地区十里加汗区带是中石化高度关注的地区,但其下石盒子组和山西组存在储层井眼条件差、储层致密物性差、岩性复杂、地层水矿化度变化较大等问题,导致气水层识别难.分析了前人研究工作存在的问题,提出削弱或排除井眼扩径影响,突出流体贡献,构建流体识别的气敏感因子和综合多种敏感测井参数进行综合识别的思路和方法,并将其应用于十里加汗区带下石盒子组和山西组的气水层识别.研究实例显示,该方法识别气水层的符合率由68%提高到92%,具有地质应用效果明显.

Shilijiahan region located in Hangjinqi area is a highly concerned region by Sinopec. However, there are some difficult problems, such as poor wellbore conditions, poor reservoir quality, complex lithology, large variation of formation water salinity, and difficulty in identification of gas layers and water layers in the lower Shihezi formation and Shanxi formation from it. In this paper, the existing problems in previous studies are analyzed, and the new ideas and methods are proposed to weaken or eliminate the influence of borehole enlargement on accurate porosity, to build gas sensitive factors for fluid identification on highlight the contribution of fluid, and to synthesize various logging sensitive parameters for comprehensive fluid identification. The ideas and methods are applied to the identification of gas layers and water layers in the lower Shihezi formation and Shanxi formation in the Shilijiahan region. The research example has showed that the coincidence rate of this method is increased from 68% to 92%, which has obvious geological application effect.