Wang Weihao, Gao Wenyang, Liu Jinxia, Cui Zhiwen, Kundu Tribikram
Department of Acoustics and Microwave Physics, College of Physics, Jilin University, Changchun 130012, China.
College of Petroleum Engineering, Panjin Vocational & Technical College, Panjin 124010, China.
J Acoust Soc Am. 2022 Aug;152(2):765. doi: 10.1121/10.0013217.
In this paper, we construct a borehole model with an impermeable/permeable wall and study the seismoelectric responses. First, we define the boundary conditions at the borehole wall, then the acoustic field and electric field are simulated by the real axis integral method. In order to have a comprehensive analysis of the body wave components, we use the secant integral method to simulate the body waves and give the excitation intensity spectrum in the frequency domain. The results show that the impermeability of the borehole wall significantly increases the amplitude of the acoustic field generated by Stoneley waves. This is because the closed pores at the boundary make Stoneley waves energy leak more slowly and hence attenuating less. The impermeable borehole wall weakens the electromagnetic interface response. Besides, both P wave and S wave and their accompanying electric field properties are affected by boundary connectivity. This investigation provides a theoretical basis for qualitatively judging borehole wall permeability by the seismoelectric signals.
在本文中，我们构建了一个具有不透水/透水壁的钻孔模型并研究了震电响应。首先，我们定义了钻孔壁处的边界条件，然后通过实轴积分法模拟了声场和电场。为了全面分析体波分量，我们使用割线积分法模拟体波并给出频域中的激发强度谱。结果表明，钻孔壁的不透水性显著增加了斯通利波产生的声场振幅。这是因为边界处的封闭孔隙使斯通利波能量泄漏更慢，因此衰减更小。不透水的钻孔壁削弱了电磁界面响应。此外，P波和S波及其伴随的电场特性都受到边界连通性的影响。这项研究为通过震电信号定性判断钻孔壁渗透率提供了理论依据。
