Abstract—The specific features of the electrical response of rocks to vibration in the 0.7–10 kHz frequency range were studied for Berea sandstone cores weakly and inhomogeneously saturated with polar and nonpolar fluids. Fluid was added to the samples with a pipette through a puncture in a protective film. In this case, a strong lateral saturation inhomogeneity was created at the lateral edge of the cylindrical core. During saturation, kerosene (as the nonpolar fluid) and saline aqueous solutions (as the polar fluid) were used in a volume of ~6% of the pore space. The physical modeling results showed that the electric response contains intense second harmonics, the amplitude of which at low frequencies is comparable to the amplitude of the first harmonics. When a 0.5% NaCl solution was added, a significant change in the electrical response in comparison to the response of the core in the initial state was observed only in the 5.45–7.15 kHz frequency range. When kerosene and a 0.05% saline solution was added to the core, an equally strong increase in the electrical response was observed at all frequencies; however, the nature of the spectral change and its temporal dynamics for polar and nonpolar fluids significantly differ. The presented physical modeling results will be useful for understanding seismoelectric processes in a heterogeneous, structurally inhomogeneous natural massif, and may also be the basis for new remote technologies to determine the type of rock saturation.

中文翻译：

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弱非均匀流体饱和条件下岩石对振动的电响应特征

摘要—研究了​​在极性和非极性流体中弱饱和和不均匀饱和的​​Berea砂岩岩心在0.7-10 kHz频率范围内岩石对振动的电响应的特定特征。用移液管通过保护膜上的刺孔将液体添加到样品中。在这种情况下，在圆柱芯的横向边缘会产生强烈的横向饱和不均匀性。在饱和期间，煤油（作为非极性流体）和盐水溶液（作为极性流体）的使用占孔隙空间的6％。物理建模结果表明，电响应包含强烈的二次谐波，在低频时其幅度与一次谐波的幅度相当。当添加0.5％NaCl溶液时，仅在5.45–7.15 kHz频率范围内，观察到电响应与磁芯在初始状态下的响应相比有显着变化。当将煤油和0.05％的盐溶液添加到岩心中时，在所有频率下均观察到电响应的同样强劲的增加；但是，对于极性和非极性流体，光谱变化的性质及其时间动态差异很大。提出的物理模拟结果将有助于理解异质，结构不均匀的自然地块中的电波过程，也可能是新的远程技术确定岩石饱和度类型的基础。将05％的盐溶液添加到岩心中，在所有频率下均观察到电响应的同样强烈的增加；但是，对于极性和非极性流体，光谱变化的性质及其时间动态差异很大。提出的物理模拟结果将有助于理解异质，结构不均匀的自然地块中的电波过程，也可能是新的远程技术确定岩石饱和度类型的基础。将05％的盐溶液添加到岩心中，在所有频率下均观察到电响应的同样强烈的增加；但是，对于极性和非极性流体，光谱变化的性质及其时间动态差异很大。提出的物理模拟结果将有助于理解异质，结构不均匀的自然地块中的电波过程，也可能是新的远程技术确定岩石饱和度类型的基础。