Traveltime computation using a supervised learning approach

Abstract

In real-time microseismic monitoring, the ability to efficientlycompute source-receiver traveltimes can help in significantlyspeeding up the model calibration and hypocenter determina-tion processes, thus ensuring timely information about the sub-surface fractures for use in effective decision making. Here,we present a supervised-learning based traveltime computationapproach for layered 1D velocity models. First, we generatenumerous synthetic traveltime examples from a combinationof source locations and layered subsurface models, coveringa broad range of realistic P-wave velocities (2500–5000 m/s).Next, we train a multi-layered feed-forward neural network us-ing the training set containing source locations and velocitiesas input and traveltimes as corresponding labels. By doing so,we aim for a neural-network model that is trained only onceand can be applied to a wide range of subsurface velocitiesas well as source-receiver positions to predict fast and accu-rate traveltimes. We apply the trained model on numeroustest examples to validate the accuracy and speed of the pro-posed method. Based on the comparisons with acoustic finite-difference modeling and a ray-shooting method, we show thatthe trained model can provide faster and reasonably accuratetraveltimes for any realistic model scenario within the trainedvelocity range.