The Correlated Leakage Method – It's Application to Better Quantify Timing Shifts on 4D Data

We present a new methodology for estimating time shifts between 4D surveys, the Correlated Leakage Method (CLM). Its ability to provide accurate estimates of time shifts for a wide range of window size makes it an attractive alternative to existing algorithms. Timing shifts are calculated from the gradient of a line fitted to a cross plot of: the amplitude difference between baseline and monitor against the amplitude difference between the baseline and monitor survey average and a time shifted version of this average. The nature of the fitting process of the CLM suppresses the time shift noise and makes it stable. Additionally the CLM calculations can be implemented in 1D, 2D and 3D and can be easily modified to estimate vertical or lateral shifts between time lapse surveys. Here we review the CLM theory and discuss the advantages and limitations of this method.