Small acoustic sources for low-cost reservoir monitoring offshore

Abstract

Two 4D seismic data sets are compared which were acquired simultaneously in a deepwater field but with differently sized acoustic sources with 2450 in3 and 360 in3 volumes. The data sets were processed using similar runstreams, enabling side-by-side comparison of the 4D features. Compared with the large-source data, the small-source data showed similar 4D signals, albeit with higher but acceptable levels of 4D noise. An overprint of the acquisition methodology was found to detrimentally impact the small-source data, but this was mitigated in processing. Opportunities for improvement of the small-source data in future dedicated surveys are proposed. A cost–benefit analysis is presented to show the relative value increase by using smaller, lower-cost surveys for frequent reservoir monitoring.