基于DIRECT算法的微震震源快速网格搜索定位方法研究

Grid-search method on micro-seismic source fast location based on DIRECT algorithm

微震监测定位技术的精度及效率是微震监测中的核心技术问题,震源扫描算法作为一种稳定、可靠的方法被广泛用于微震监测定位中,但是在多事件、多参数反演中,其反演效率严重制约其应用.本文将震源扫描算法与DIRECT算法思想结合,提出基于DIRECT算法的微震快速网格震源搜索定位方法,即在求解震源扫描算法目标函数最优解时,采用DIRECT搜索策略,无需划分网格大小,直接搜索目标函数最优解.通过地面及井中微震监测模型测试表明,基于DIRECT算法的微震快速网格震源搜索定位方法比传统的震源扫描算法搜索次数少、计算耗时短、计算精度高,尤其适合大空间内多事件、多参数的震源反演,为水力压裂微震监测过程中大量数据的实时、快速、准确定位提供了可能.

The accuracy and efficiency is the key technical problem in micro-seismic monitoring. The source scan algorithm is stable and reliable and is widely used in micro-seismic location,but in multievent and multi-parameter inversion,its low efficiency is a great setback for its wider application. The author combines source scan algorithm and DIRECT algorithm,put forward a grid-search method on micro-seismic source fast location based on DIRECT algorithm.In this method,DIRECT search strategy is used when searching for the optimal solution of the objective function,and thus the gridding stage is omitted,and the optimal solution of the objective function can be directly searched. Through the model study of surface and borehole micro-seismic monitoring,the author finds that the gridsearch method based on DIRECT algorithm is better than traditional source scan algorithm at less search times,less computation time,higher accuracy, and especially suitable for multi-event, multiparameter micro-seismic inversion in large scale space. This method can provide possibility for real-time, fast, accuracy location in Hydraulic fracturing micro-seismic monitoring.