一种定量描述气藏储层非均质性的新方法

A new quantitative description method of gas reservoir heterogeneity

提出了一种综合微相定量系数、渗透率变异系数、突进系数、级差、夹层频数、夹层分布密度、砂层厚度、分层系数、砂岩系数、有效厚度、有效厚度系数、渗透率、孔隙度、饱和度等14种影响储层非均质性的主要参数,并采用随机多步建模技术建立定量的气藏三维非均质储层综合指数模型的新方法。将储层非均质性综合指数模型应用到苏53区块气藏储层非均质和剩余气分布规律描述中。研究表明,盒8段非均质性强于山1段,盒8下段非均质性强于盒8上段,剩余气饱和度高值区与储层非均质综合指数具有较好的对应关系,剩余气储量富集于储层非均质性较强向较弱过渡的区带,即综合指数适中的区域是剩余气分布的有利相带。综合指数大于0.5的区域原始储层物性及含气性较好,对应较高渗带。而剩余气主要集中在非均质综合指数大于0.4低于0.5的区域。

A new method of establishing an aggregate index model of quantitative 3D heterogeneous gas reservoir is presented by using random multi-step modeling techniques and combining 14 influencing factors of reservoir heterogeneity,including quantitative microfacies coefficient,permeability variation coefficient,mutation coefficient,permeability ratio,sandwich frequency,sandwich density,sand thickness,stratification coefficient,sandstone coefficient,effective thickness and effective thickness coefficient,permeability,porosity and saturation.The aggregate index model of reservoir heterogeneity has been applied to description of gas reservoir heterogeneity and remaining gas distribution for the Su 53 block.The study shows that the heterogeneity in the He 8 formation is more severe than in the Shan 1 formation,and the lower He 8 is more severe than the upper He 8.There is a good corresponding relationship between high residual gas saturation zone and reservoir heterogeneity index.Residual gas reserves concentrate in the transition belt from high to low heterogeneity,i.e.the zones with moderate aggregate index are favorable facies of residual gas distribution.The zones with aggregate index greater than 0.5 have good reservoir quality and gas-bearing property,corresponding to high permeability zones,while residual gas mainly concentrates in the zones with the index between 0.4 and 0.5.