Wavelet Control Allows Differencing of 3D from 2D—ENTEC/Lloyd Weathers
Time-lapse seismic is sometimes referred to as 4-D seismic with calendar time between successive 3-D surveys as the fourth dimension with the objective of monitoring depletion and bypassed pay by acoustic changes due to fluid production. But what if no reference 3-D survey was acquired before production started? Production began in many of today's fields before 3-D seismic was commonly available, but old 2-D seismic is almost always available. The ability to produce accurate difference sections between such disparate surveys expands the potential applicability of time-lapse seismic.