DAS VSP in Deepwater GoM for Reservoir Monitoring - Lessons Learned

Abstract

Seismic monitoring of Deepwater fields with ocean bottom nodes (OBN) has proven to deliver very high quality 4D data that impact field-development decisions and ensure the safety and efficiency of operations. However, the frequency of 4D OBN surveys is limited by the cost of acquisition, constraining its applicability to well and reservoir management (WRFM). A lower-cost 4D solution is needed for WRFM, such as Distributed Acoustic Sensing Vertical Seismic Profiles (DAS VSP). We proved the concept of reservoir monitoring with DAS 4D VSP in Deepwater GoM by achieving an NRMS of 7% and getting 4D VSP images comparable to those from the 4D OBN seismic in a wide range of depths. In addition to their monitoring value, recorded DAS VSP data have been used to explore the impact of various factors on DAS-VSP images, including fiber type and length, well flow conditions, and different airgun strengths. This paper will focus on lessons learned from the processing and acquisition of the DAS data, and the path forward on how to make the monitoring with DAS VSP even more affordable.