薄互层地层震电波场响应特征

震电耦合产生的伴随震电场（CS）和震电界面场（IR）具有不同的强度，且能够反映地下地质体界面信息的震电界面响应一般较弱，而震电界面响应场可能在薄互层地质背景下能够出现较强的振幅值.目前还未有针对薄互层震电波场响应特征分析，且纵波引起的震电界面响应场是否对薄互层敏感有待探究.本文基于体积电荷密度的震电耦合理论数值模拟了平行薄互层（VTI）和倾斜薄互层（HTI）地质背景下的震电波场响应特征.结果表明，伴随纵波传播而产生的CS震电场几乎不受平行薄互层和楔形薄互层的影响.纵波在界面处诱导产生的IR震电场对垂直薄互层不敏感，但水平薄互层和楔形薄互层模型的厚度和薄互层的层数均能影响IR震电信号，薄互层单层厚度减小和薄互层层数增加会导致IR信号的增强.结果有力证明了纵波引起的震电界面响应场在薄互层地质体处会产生振幅异常，而水平和垂直薄互层的震电波场差异也有将助于探究层理方向有显著差异的页岩等储层中产生的震电信号.

Wavefield characteristics of seismoelectric effects in thin-interbeds

The Coseismic Field (CS) and the seismoelectric Interface Response (IR) generated by seismoelectric coupling have different signal strengths. The seismoelectric interface response which can reflect the interface information of the underground geological body is generally weaker than CS signals, while it may be strong in a thin-interbed geological case. At present, there is little detailed analysis on the wavefield characteristics of seismoelectric effects in thin interbeds, and whether the seismoelectric interface response caused by P-waves is sensitive to thin-interbeds remains to be examined. Based on the seismoelectric coupling theory of the charge per unit pore volume as an alternative to the zeta potential-based model, the wavefield characteristics of seismoelectric coupling are simulated under the geological background of horizontal and inclined thin-interbeds. Results show that the CS signals propagating along with the P-wave propagation are almost not affected by horizontal and wedge-shaped thin-interbeds. The IR field induced by P-waves at the interface are not sensitive to Vertical Thin-Interbeds (VTI), but the thickness and number of layers of Horizontal Thin-Interbeds (HTI) and wedge-shaped thin-interbeds have a notable effect on this field. The decrease of the thickness of a single layer in thin-interbeds and the increase of the number of layers of thin-interbeds can lead to the enhancement of IR signal. Results clearly prove that the seismoelectric interface response field caused by P-waves can produce an amplitude anomaly in thin-interbeds, also, the differences of seismoelectric wavefields between the horizontal and vertical thin-interbeds may have a potential to gain insight into the seismoelectric signal produced in shale or other reservoirs with significant differences in bedding direction.