Digital-core-based method and digital-core-based device for acquiring electrical parameters of rocks

Abstract

The invention discloses a digital-core-based method and a digital-core-based device for acquiring electrical parameters of rocks. The method includes the following steps: 1) performing CT scanning oncore samples, acquiring greyscale images of the core samples and constructing three-dimensional digital cores; 2) extracting pore radius distribution of the cores on the basis of the three-dimensionaldigital cores; 3) calculating the communication porosity in the X, Y and Z directions on the basis of the three-dimensional digital cores; 4) representing fluid distribution in pore space on the basis of the core pore radius distribution and the communication porosity; 5) calculating tortuosity of the pore space on the basis of the fluid distribution in the communicated pore space; 6) calculatingformation factor values of formation water during complete saturation; 7) calculating resistance enlargement coefficients under different water saturation degrees. By the method and the device, the difficulty in acquiring the electrical parameters of the rocks due to failure to displace rocks with core displacement difficulty, such as compact sandstone, can be solved.

Description

technical field [0001] The invention relates to the technical field of well logging in petroleum exploration and development, and more specifically, to a method and device for acquiring rock electrical parameters based on digital cores. Background technique [0002] Based on Archie's formula and starting from the equivalent rock simplified model (Yong Shihe, Zhang Chaomo. Logging data processing and comprehensive interpretation [M]. East China: University of Petroleum Press, 2007), scholars at home and abroad have given the same Quantitative calculation formulas related to rock electrical parameters: [0003] [0004] [0005] Among them, F—rock formation factor; R 0 —Resistivity of the rock when it is fully saturated with formation water; R w —Resistivity of formation water; L w —Length of current passing through equivalent pores; L—rock sample length; φ—effective porosity; τ—tortuosity of rock pore space saturated with formation water; RI—resistance increase coeff...

AI Technical Summary

Problems solved by technology

On the one hand, the amount of research on tight sandstone is relatively small, and on the other hand, the accuracy of the research cannot meet the requirements

[0007] The inventors found that the existing rock-electric calculation formulas only considered the influence of tortuosity and electrical parameters, and did not consider the pore-throat radius

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