两种毛管压力模型对比的储层孔隙结构分形研究

Fractal Research on Reservoir Rock Pore Structure Based on Two Kinds of Capillary Pressure Models

基于多孔介质分形理论进行Li-Horne毛管压力模型和Brooks-Corey毛管压力模型的推导,证明Brooks-Corey毛管压力模型为Li-Horne毛管压力模型的一种特殊形式。并利用两种毛管压力模型对北部湾盆地不同渗透率岩样的压汞曲线进行拟合,获得孔隙大小分布指数来评价储层的非均质程度,由于Brooks-Corey模型适用于均质储层,而Li-Horne模型对于均质、非均质储层均适用,所以Li-Horne模型拟合结果好于Brooks-Corey模型。同时,根据Li-Horne模型推导出多孔介质孔隙分布的分形概率模型,其指数与分形维数有关,利用该模型计算的孔喉尺寸分布与压汞曲线获得的结果一致。

Based on fractal theory of porous media, Li-Horne capillary pressure model and Brooks-Corey capillary pressure model were deduced. It＇s proved that Brooks- Corey capillary pressure model is a special form of Li-Home capillary pressure model. Through using two kinds of capillary pressure models, mercury injection curves of different permeability rock samples from Northern Gulf Basin were fitted. Pore size distribution index was obtained to evaluate heterogeneity of the reservoir. Because Brooks-Corey model is for homogeneous reservoir and Li-Horne model is applicable for homogeneous and heterogeneous reservoirs, fitted results of Li-Home model are better than those of Brooks-Corey model. At the same time, pore size distribution model of porous media was deduced according to Li-Horne model, the index of which related with the fractal dimension. Pore size distribution calculated by the model is consistent with the result obtained by using mercury injection curves.