Inversion of 1D frequency- and time-domain electromagnetic data with convolutional neural networks. (April 2021)

• Record Type: Journal Article
• Authors: Puzyrev, Vladimir; Swidinsky, Andrei
• Is Part Of: Computers & geosciences. Volume 149(2021)
• Publication Date: 2021-04
• Subjects: Electromagnetic -- Controlled source -- Inversion -- Deep learning -- Convolutional neural network; Environmental policy -- Periodicals; 550.5
• DOI: 10.1016/j.cageo.2020.104681
• Languages: English
• ISSNs: 0098-3004

Abstract

Abstract: Inversion of electromagnetic data finds applications in many areas of geophysics. The inverse problem is commonly solved with either deterministic optimization methods (such as the nonlinear conjugate gradient or Gauss-Newton) which are prone to getting trapped in a local minimum, or probabilistic methods which are very computationally demanding. A recently emerging alternative is to employ deep neural networks for predicting subsurface model properties from measured data. This approach is entirely data-driven, does not employ traditional misfit optimization methods and provides a guess to the model instantaneously. In this study, we examine the feasibility of using deep convolutional neural networks for the inversion of marine frequency-domain controlled-source electromagnetic (CSEM) data as well as onshore time-domain electromagnetic (TEM) data. Our approach yields accurate results both on synthetic and real data and provides them instantaneously. Using several networks and combining their outputs from various training epochs can also provide insights into the uncertainty distribution, which are found to be higher in the regions where resistivity anomalies are present. The proposed method opens up possibilities to estimate the subsurface resistivity distribution in exploration scenarios in real time. Highlights: Convolutional neural networks (CNN) applied to 1D electromagnetic (EM) inversion. CNN predicts resistivity distribution from measured data instantaneously. Frequency-domain controlled-source EM (CSEM) and time-domain EM (TEM) examples. Application to real data in good agreement with deterministic inversion results.