Methods and Systems for Improving Microseismic Event Detection and Location

摘要

Methods and systems for location and/or direction of a hypocenter. The methods may involve one or more of: a) computing a joint probability density function (PDF) which includes polarization PDF and onset time PDF or a time integral of product of detection transforms to estimate the location and/or direction of a hypocenter, where the polarization PDF is generated using a weighted average of differences between measured and computed polarizations; b) computing a time integral of product of modified detection transforms associated with onset times from received data in Coalescence Microsesimic Mapping where modified detection transform is defined as (ε, fd(t)−1); c) resolving 180 degree ambiguities in polarization estimated according to Hodogram; d) using polynomial interpolation to tune the location of a hypocenter; and e) computing an integration time interval of 4-D (t,x,y,z) PDF or product of modified detection transform and the restriction on grid nodes.