时频电磁法时域激电参数提取与应用

时频电磁法可同时研究电阻率和极化信息，适用于频域资料中极化信息的提取及利用。但通常从时域信息中提取激电参数更方便，其油气指示特征也更直接、明显。本文引入频域等效介质激电（GEMTIP）模型，对其进行简化和拉氏反变换，得到时域GEMTIP模型；分析模型时域特征后，将耦合与极化模型组合方式应用于激电真参数反演，实现了GEMTIP激电谱参数反演；针对华北油田文安斜坡-大城凸起区时频电磁法02测线，提取其面极化参数曲线，并与已处理的频域相位参数和反演极化率剖面进行对比，发现异常形态与位置对应一致，表明GEMTIP激电谱参数提取方法有效，同时也增强了油气检测结果的可靠性。由于GEMTIP激电谱参数提取过程便捷且效果明显，使得时频电磁法在油气检测中更具应用前景。

IP parameter extraction from TFEM data in the time domain

Both resistivity and polarization information are discussed in the time and frequency electromagnetic (TFEM) data.Usually only the frequency domain information such as polarization information is extracted and used for hydrocarbon exploration.However,some time-domain induced polarization (IP) parameters may be easier to be extracted,and they are more sensitive to hydrocarbon.Based on simplification of generalized effective-medium theory of induced polarization (GEMTIP) model in the frequency domain,GEMTIP model in the time domain is derived with inverse Laplace transform.The combined coupling and induced-polarization model is built and used to inverse true IP parameters.The proposed method is applied to Line 02 TFEM data acquired at the structure of Wenan Ramp-Dacheng Up-lift in the North China.Curves of interface induce polarization parameters are extracted.Comparing with chargeability profiles and phase parameters in the frequency domain obtained from the same TFEM data,we discover the great accordance in the anomaly position and size.Our results prove the effectiveness of the proposed method and enhanced reliability of hydrocarbon detection.This method features easy extraction,quick inversion,and obvious validity,which may provide great help for oil and gas detection with TFEM.