Micro-seismic event location based on Newton iterationmethod and grid-search method

Abstract

In order to make the optimization algorithm convergent globally and quickly when locating micro-seismic events,considering the good performance of grid-searching method on global convergence and advantages of Newton iteration method for calculation speed and accuracy,a location method based on grid-searching method and Newton iteration method is proposed.First an approximate location result is obtained by grid-seaching method with sparse discretized grids in the monitoring area and the result is the initial iteration value for Newton iteration method;second Newton method is applied for the accurate location result.The influences of anisotropy of the velocity model and velocity measure error are analyzed in simulation experiments and the proposed method is compared with Newton iteration method,grid-searching method and simulated annealing method about location accuracy,efficiency and stability.The location results show that the proposed method can locate microseismic events accurately,efficiently and stably.The proposed method is also tested with field data. The location result is less than 4 m. So the method is practical for microseismic event locations.

Keywords

• grid-search method
• newton iteration method
• micro-seismic events location