SOTEM一维等效源反演方法

电性源短偏移距瞬变电磁法( SOTEM)是一种探测深度大、精度高的瞬变电磁工作形式,一维反演是目前SOTEM数据处理解释的主要手段。从电性源瞬变电磁场的扩散理论出发,研究了针对SOTEM的一维等效源反演方法。研究表明,传统的等效源反演方法对于实施近源观测的SOTEM并不完全适用,在早期会造成反演电阻率严重偏离真实值的情况。针对上述情况,提出了采用全期视电阻率进行校正的方法。理论模型的计算和河北某金矿的实际应用表明,经过校正后的反演算法在全期内都能很好地反映地层的真实电性分布。

1-D image source inversion of SOTEM data

The short?offset transient electromagnetic method ( SOTEM) is one of TEM devices with great detection depth and high de?tection precision. 1?D inversion is the main way of its data processing and interpretation. In this paper, a modified image source inver?sion scheme is proposed for SOTEM data. Studies indicate that the conversional image source inversion scheme is not completely appli?cable to the SOTEM and may yield resistivity estimates that are biased at early time region. In this study, all time apparent resistivity was used to modified the inversed resistivity at early stage and a good result was obtained. Synthetic data and an application case both prove the effectiveness of this scheme.