Inversion of 1D frequency- and time-domain electromagnetic data with convolutional neural networks

TL;DR

This paper demonstrates that deep convolutional neural networks can rapidly and accurately invert 1D electromagnetic data, providing real-time subsurface resistivity models and insights into uncertainty, outperforming traditional methods.

Contribution

The study introduces a novel deep learning approach for 1D electromagnetic data inversion, enabling instant, accurate, and uncertainty-aware subsurface modeling.

Findings

Neural networks produce accurate inversion results on synthetic and real data.

Combining outputs from multiple networks offers uncertainty estimates.

Method enables real-time subsurface resistivity estimation.

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 gradient-based techniques and provides a guess to the model instantaneously. In this study, we apply deep convolutional neural networks for 1D 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 is 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.