大地电磁静态效应模拟研究

STUDY ON THE SIMULATION OF MAGNETOTELLURIC STATIC EFFECT

通过数值模拟分析模型宽度、厚度、埋深、电阻率等参数对视电阻率、视相位的影响,发现TM模式受静态效应影响严重;异常体产生的静态效应畸变随埋深变浅而增大,地表异常造成的畸变尤为严重;异常体与围岩的电阻率差异越大造成的静态效应越明显;相比厚度,同比改变异常体的宽度对视电阻率的影响更大.通过曲线拟合各参数与视电阻率的相关函数,估算参数计算异常体对视电阻率的影响程度,以达到改正的目的.

Wi th analysis on the effect of parameters such as model width, thickness, depth and resistivity on apparent resistivity and apparent phase by numerical simulation, it is found that the TM mode is seriously affected by static effect.The static distortion caused by anomalous bodies increases while the burial depth becomes shallow. The distortion caused by surface anomaly is particularly serious. The greater the resistivity difference between the anomaly and wall rock is, the more obvious its static effect is. Compared to thickness, the change of anomaly width has a greater effect on apparent resistivity. The correlation function between the parameters and apparent resistivity based on curve fitting is used to estimate the influence of anomalies on resistivity for the purpose of correction.