Study On The Conductivity Model For Deep Conglomerate Reservoirs In Xujiaweizi Area

With the development of exploration and exploitation in oil field, reservoirs with low porosity and permeability have become the focus, and evaluation on low porosity and permeability reservoirs has been a primary problem for log interpretation. Since the deep conglomerate and sand reservoirs in Xujiaweizi area are characterized by low porosity, low permeability, serious heterogeneity, and complex pore structure, we give methods to determinate the values of a, m, n, b in the areas with experimental study of conglomerate, sandstone conductance law. Based on experiment of rock resistivity in Xujiaweizi area, symmetrical effective medium conductance theory is introduced and new effective medium conductivity models for deep conglomerate reservoirs and deep sand reservoirs are proposed. Also, series-parallel conductivity model, improved Archie equation, dual water conductivity model are given for comparison. Also the influence of percolation exponent, percolation rate on the effective medium models is analyzed. Parameters of the effective medium models such as percolation rate and percolation exponent are determined with experimental data of rock samples. Advantage and disadvangtage of each model are given with theoretical comparison of three models for conglomerate and sandstone reservoirs. By comparison of interpretation results with gas-testing results, symmetrical effective medium conductance models for deep conglomerate and sandstone reservoirs are most suitable for calculation of gas saturation for deep conglomerate and sandstone reservoir in Xujiaweizi area. The interpretation results for log data show the proposed models can improve the accuracy of gas saturation for conglomerate and sand reservoirs, and meet the needs of exploration and development for conglomerate and sand reservoirs in Xujiaweizi area.