基于简单模型的大地电磁测深法薄层识别与约束反演

Thin layer identification and constrained inversion of magnetotelluric sounding based on simple geomodel

薄层识别一直是大地电磁测深法(MT)数据反演解释的重点和难点。约束反演能有效提高大地电磁测深对薄层的识别能力,这里采用在井资料约束上覆地层与围岩的电性条件下,进行MT约束反演。通过约束浅部地层,提高对深部地层的反演识别能力,达到对目标层的准确识别与精确探测。通过模型设计与计算,讨论了地电参数约束类型、约束数量、以及测量噪音和测井资料质量对约束反演的影响,得出在井资料约束上覆地层与围岩的电性条件下进行MT约束反演,能有效提高对目标薄层的识别能力,提高资料处理抗噪能力以及加快反演迭代收敛速度等作用,验证了该约束反演的有效性。

Thin layer identification of magnetotelluric sounding(MT)is one of the important and difficulty scientific problems.MT constraint inversion can effectively improve the ability of thin layer identification.Under such a condition,it is carried out using well data constrain the electrical properties of overlying strata and surrounding rocks in this study.Through the MT constraint inversion used to improve the sensitivity of deeper layers,it can realize the accurate identification and detection of target layer.Using model design and calculation,the influence of geoelectric parameters constraint type and constraint numbers on constraint inversion has been discussed in this paper.Meanwhile the influence of measurement noise and logging data quality has discussed.We concluded that this MT constraint inversion can improve the identification ability of the target thin layer,and it can improve the anti-noise ability of data processing and accelerate the convergence speed of the inversion iteration.Therefore,it verified the effectiveness of the constraint inversion.