The view about the higher porosity with the higher permeability has guided high porosity and high permeability reservoir production operations,but in the low porosity and low permeability reservoirs,there often appears the phenomenon contrary to this view,the capacity difference is very large in almost the same porosity reservoir.Experiment data from 250 rock samples indicate that permeability is not obviously controlled by the total porosity in the low porosity and low permeability rock,traditional porosity-permeability calculation method is no longer applicable.In the low porosity and low permeability rock,permeability is mainly controlled by pore structure,the pore with different pore sizes has different contribution to the permeability,the pore sizes and the corresponded proportion in the pores control the permeability value together.On this basis,the nuclear magnetic resonance logging is used to depict the pore size ranges,then the interval porosity is used to calculate the permeability.This method not only improves the permeability calculation accuracy in the low porosity and permeability reservoir but also develops the traditional formula,it can effectively guide the productivity evaluation of low porosity and low permeability reservoirs in the future.%孔隙度越高渗透性越好的观点一直指导中-高孔隙度渗透率储层生产作业,但在低孔隙度低渗透率储层中常出现与该观点相违背的现象,孔隙度基本一致的储层产能差异非常大.通过256块岩样实验发现,低孔隙度低渗透率岩石的渗透率受总孔隙度控制作用不明显,传统的孔隙度—渗透率计算方法已经不再适用；低孔隙度低渗透率岩石渗透率主要受控于孔隙结构,不同孔径尺寸孔隙对渗透率贡献不同,渗透率大小受孔径尺寸大小及其相对应孔隙的比例高低共同控制.提出利用核磁共振测井刻画孔径尺寸区间,根据岩石压汞实验中的孔隙分布直方图数据,参考实验室毛细管压力测量孔隙半径(R)分级方法,将孔隙分为4个区间,分别建立4个区间孔隙与岩样渗透率交会图.利用区间孔隙度计算渗透率的方法不仅提高了低孔隙度低渗透率储层渗透率计算精度,同时也是对传统公式的改进和完善,对低孔隙度低渗透率储层产能评价有很好的指导作用.
展开▼
