Lithology identification from well log curves via neural networks with additional geological constraint
We propose a machine learning framework to solve the lithology classification problem from well log curves by incorporating an additional geological constraint. The constraint is a stratigraphic unit, and we use it as an dditional feature. This method demonstrates the possibility of solving the lithology identification problem from a multi-scale data source because stratigraphic unit information can be obtained through tying well logs to seismic data. Our experiments show that adding an additional geological constraint improves the performance of models significantly. Currently, most researchers use their own well log curves to solve the lithology classification problem. The well log data used in our experiment, which are from the North Sea area, are publicly available, and thus future studies can continue to utilize them to perform further comparisons.We evaluated different types of recurrent neural networks, i.e., bidirectional long shortterm memory (Bi-LSTM), bidirectional gated recurrent unit (Bi-GRU), GRU-based encoderdecoder architecture with attention (ABi-GRU), one-dimensional convolutional networks, i.e., temporal convolutional network (TCN) and multi-scale residual network (MsRNet), and multi-layer perceptron (MLP) on the task. Our experiments revealed that the overall performance of RNN-based networks is better and more consistent. Since our experiments are based on one single dataset, additional experiments are required in the future to better elucidate how each network works on the lithofacies classification problem.