Study on the anisotropic characteristics of the electric response to fractured reservoir
裂缝性储层的电各向异性响应特征研究

Based on the model of porous medium with horizontal fractures, two fractured reservoir models have been suggested which considered smooth-surface parallel fractures and point-welded rough-surface fractures, and the vertical and horizontal electric resistivity response equations have been derived from the Ohm law. According to the response equations derived above, the variation characteristics of the horizontal and vertical resistivity and electrical anisotropic coefficient of the two fractured models under the conditions of free pressure and confining pressure have been analyzed. Furthermore, we have discussed the effect of geometrical parameters, such as fracture aperture, fracture density and fracture surface roughness and others, on electric anisotropy of the fractured reservoir. For simplifying the discussion, we have ignored the influences of surficial conducting mechanism and polarization effect of the fracture and pore surfaces on the electric anisotropy. Finally, we have examined the response characteristics of the electric resistivity and electric anisotropy under condition of confining pressure based on the smooth fracture model and welded rough fracture models, and meaningful results which can be applied to practical application have been obtained.