砂岩储层孔隙结构分形特征描述

在前人对孔隙结构分形特征研究的基础上,利用分形几何理论,建立了描述储层孔径分布的分形几何公式和储层毛管压力曲线的分形几何公式;利用岩心压汞测试资料,建立了描述孔隙结构的分形几何模型,探讨了砂岩孔隙结构的分形特征.研究表明孔隙的分形特征是分区域的,分形维数可以定量描述孔隙的非均质性,分形维数大,砂岩孔隙分布的非均质性强.依据建立的孔隙分形模型,在考虑孔隙结构、润湿性变化的基础上,根据函数公式和毛管束模型,推导出了油水相对渗透率的理论预测公式.根据所得到的理论预测公式,进行了相对渗透率曲线预测.预测结果表明,预测曲线与理论曲线是一致的.同时,可用于长期水驱后油水相对渗透率的预测和不同储层相渗曲线的归类,指导油田开发.

Study on fractal features of the porous structure in sandstone reservoirs

On the basis of the researches of the fractal features done by forefathers, the pore size distribution fraetal formula and the capillary pressure curve fractal formula are established under the guidance of fractal geometry theory. Based on the mercury injection capillary pressure data, the porous structure fraetal model is established, and the fractal features of sandstone porous structure are explored. It is found that fractal features are different in different areas, and fractal dimension can be used to describe the heterogeneity of porous structure quantitatively. And it is found that the heterogeneity of sandstone pore distribution is strong as the fractal dimension is great. According to the porous structure fractal model and the changeability of porous structure and wettability, a theoretical forecast formula of the oil and water relative permeability is derived with the help of formula of function and capillary model. The relative permeability curve is forecasted depending on the theoretical forecast formula, and the forecasting results show the curves of theoretic and realistic are similar. Meanwhile, the formula can be used to forecast the oil and water relative permeability, classify the relative permeability curves of different formations after long water drive and guide the oilfield production.