Monitoring IOR/EOR Onshore with Frequent Time-Lapse Seismic - Status and Survey Adaptations for the Middle East

Abstract

IOR/EOR stimulation is a complex process that requires frequent areal monitoring to optimize recovery. On-demand seismic surveys are a suitable solution if cost, quality, environmental, and efficiency conditions are met. In this paper, we discuss the state of the art. We show that frequent buried seismic has the necessary quality and was able to add value to steam injection operations at a heavy oil field in Canada. However, in its current form, buried seismic is too expensive and intrusive. That is why, for future deployments, we seek cost and footprint reductions through judicious reduction of survey frequency (from days to weeks or months apart) and novel survey designs such as a buried cross-spread with Distributed Acoustic Sensing (DAS) receivers and movable subsurface sources. We are in the process of maturing the buried cross-spread solution. Its application to some extreme settings found in the Middle East (deep reservoirs with weak seismic expression under thick and complex overburden) is expected to be challenging. A promising alternative already available is 4D VSP with DAS in multiple wells. This solution requires sufficient surface access, fiber optic cables in wells, and skillful seismic processing.

Processing of multi‐well offset vertical seismic profile data acquired with distributed acoustic sensors and surface orbital vibrators: Stage 3 of the CO2CRC Otway Project case study

“…Continuous borehole-based seismic monitoring with fixed receivers and sources can provide excellent data quality and rich 4D information (Cotton et al, 2013;Berron et al, 2015). Furthermore, distributed acoustic sensing (DAS) has been increasingly used to overcome the limitations of conventional point receiver arrays that include durability of the equipment, high cost of operations, disruption to local activities and real-estate conflict in boreholes (Parker et al, 2014;Hornman et al, 2015;Mateeva et al, 2016;Hartog, 2017;Correa, 2018). Deployment of surface orbital vibrators (SOVs) as permanent sources (Freifeld et al, 2016) has the potential to enable continuous seismic acquisition with improved data repeatability (Kasahara et al, 2013).…”