f 3D Monte Carlo residual statics

Stacking of common mid-point gathers assumes that reflectors corrected for normal move-out (NMO) and dip move-out (DMO) will align across the gather. If reflections do not align due to incorrect statics the stacked traces will be degraded. Static corrections for land seismic data calculated from measurements made in the field have limited accuracy so it is standard practice to pass all land data through a residual statics process before stack. The residual statics process estimates the difference between the field statics and the "true" statics required to align the reflectors. Wiggins, Larner and Wisecup (1976) described how the residual statics could be resolved into surface consistent components and this method is now called conventional residual statics. Ronen and Claerbout (1985) showed how surface consistent components could be calculated directly from stacked correlations and allowed larger residual statics to be estimated. Rothman (1985) extended this work by describing a method of estimating residual statics using simulated annealing (Monte Carlo residual statics). All three techniques were originally designed for 2-D seismic data. The conventional residual staties method generalised to 3-D seismic data with only minor modifications. The upgrade of the Monte Carlo method to accept 3-D data was more difficult and is the subject of this presentation. Real 2-D and 3-D data examples are shown which demonstrate the effectiveness of this technique.