裂缝性储层的电各向异性响应特征研究

以水平裂缝分布的孔隙介质模型为基础，建立了水平裂缝面的平行裂缝分布和带粗糙表面的点接触裂缝模型，导出了两类裂缝模型的水平和垂直电阻率响应关系，分析了两类裂缝模型在没有围压和存在围压条件下的水平电阻率、垂直电阻率变化规律和电各向异性系数的变化特征.讨论了裂缝开度、裂缝密度和裂缝粗糙度等裂缝特征参数对裂缝性储层电各向异性的影响.为简化讨论，所有电性响应特征的分析都忽略了裂缝和孔隙表面的导电性和极化的影响.利用平行分布水平裂缝面模型和带粗糙面的裂缝模型，考察了围压条件下的裂缝性岩石的电各向异性响应特征，得到了对实际应用有意义的结果.

Study on the anisotropic characteristics of the electric response to fractured reservoir

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.