A Simple Method to Optimise Repeatability for Multi-vintage 4D Projects

With 4D (time-lapse) seismic becoming a routine reservoir monitoring tool, it is common for 4D processing projects to consist of multiple monitor surveys acquired regularly during the production of a field. Dealing with theses multiple seismic vintages creates a dilemma during 4D processing: Optimise the repeatability between each of the different time steps in order to create the best possible data for interpretation or maintain the 4D consistency between all time steps? We have developed a simple workflow that allows repeatability to be optimised between all vintages, preserves 4D signal and produces a single set of consistent datasets that may be 4D differenced in any way. The process requires only additional migrations of a reference dataset and is robust to noise, structural complexity, and acquisition differences. Furthermore, if we have a reference survey that is consistent with different acquisition designs then we are able to correct for acquisition differences between other 4D surveys. The method can also be used to improve processing turnaround without compromising quality, when additional monitor surveys are acquired and need to be added to existing 4D products.