论文部分内容阅读
针对低孔渗储层渗透率主要受孔隙结构影响致使利用常规孔隙度和束缚水饱和度等参数预测渗透率精度低的难题,依据低孔渗岩石孔隙中流体渗流的特点,考虑岩石孔隙空间中对流体渗流贡献最大的那一部分孔隙,引入有效流动孔隙概念,以提高低孔渗岩石渗透率计算精度.考虑岩性、物性、电性变化,设计岩石物理实验,根据压汞实验数据计算岩样对应不同孔隙半径的进汞孔隙度与渗透率之间的相关系数,制作相关系数与孔隙半径交会图,将相关系数达到某一值(如0.8)对应的孔隙半径确定为有效流动孔隙半径下限,其对应的进汞孔隙度确定为有效流动孔隙度实验分析值.依据水流与电流流动相似性原理,从导电角度推导有效流动孔隙度的计算公式.对于含水低孔渗泥质岩石,将束缚水和粘土水看成不导电干骨架,采用能够描述孔喉比的等效岩石元素模型推导出只有可动水孔隙存在的低孔渗岩石地层因素的公式;根据有效流动孔隙的含义,只有可动水孔隙存在的低孔渗岩石的有效流动孔隙可以等效为具有相同岩石体积和地层因素且由骨架和弯曲毛细管组成的岩石结构中的毛管孔隙,根据弯曲毛管模型推导出地层因素与有效流动孔隙度关系式,结合两式可得到有效流动孔隙度的表达式.根据实验数据采用最优化方法确定公式中参数,从而给出有效流动孔隙度计算式.统计有效流动孔隙度实验值与岩心分析渗透率关系,回归得到低孔渗泥质岩石渗透率的计算式.对B区X1、X2井低孔渗储层进行处理,从实际应用效果方面证实该方法提高了低孔渗泥质储层渗透率计算精度.
The permeability of low porosity and permeability reservoir is mainly affected by the pore structure, which makes it difficult to predict the permeability with conventional porosity and irreducible water saturation. According to the characteristics of fluid seepage in the pores with low porosity seepage, The concept of effective flow pore is introduced to improve the calculation precision of permeability of rock with low porosity and permeability.Considering lithology, physical property and electrical property change, the rock physics experiment is designed and the rock sample is calculated according to the mercury intrusion experiment data Corresponding to the correlation coefficient between the correlation coefficient and the pore radius, the pore radius corresponding to a certain value (for example, 0.8) is determined as the lower limit of the effective flow pore radius, The corresponding mercury intrusion porosity was determined as the experimental value of effective flow porosity.According to the similarity principle of water flow and current flow, the calculation formula of effective flow porosity was deduced from the conduction angle.For the water-bearing low-permeability muddy rock, the irreducible water And clay water as non-conductive dry skeletons, using equivalent rock element models that describe pore-throat ratios derived only According to the meaning of effective flow pore, only the effective flow pore of low porosity seepage rock with movable water pore can be regarded as the equivalent pore volume with the same rock volume and formation factor, which is composed of skeleton and According to the curved capillary model, the relationship between formation factor and effective flow porosity is derived, and the expression of effective flow porosity can be obtained by combining the two equations.According to the experimental data, the optimal method is used to determine the formula Parameters to give the effective flow porosity calculation formula.According to the relationship between the experimental value of effective flow porosity and core analysis permeability, It is proved from the practical application results that this method improves the calculation accuracy of permeability of low porosity and permeability muddy reservoirs.