3D Alford rotation analysis for the Diamond M Field, Midland Basin, Texas

AbstractThe 2C by 2C S-wave survey generated significant excitement in the mid-1980s, but then it fell out of favor when S-wave splitting initially attributed to fractures was also found to be associated with an anisotropic stress regime. In general, 2C by 2C data require more expensive acquisition and more processing effort to obtain images comparable to 1C “compressional wave” data acquired with vertical component sources and receivers. Because S-waves are insensitive to fluids, and hence the water table, the effective S-wave weathering zone is greater than that for compressional waves, making statics more difficult. S-wave splitting due to anisotropy complicates residual statics and velocity analysis as well as the final image. S-wave frequencies and S-wave moveout are closer to those of contaminating ground roll than compressional waves. Since Alford’s introduction of S-wave rotation from survey coordinates to the principal axes in 1986, geoscientist and engineers retain their interest in fractures bu...