A Novel Thief Zone Identification Method by Interwell Connectivity for Offshore Unconsolidated Sandstone Reservoir

Pore structure will change greatly and ultimately form thief zones after a long-term water flooding procedure for unconsolidated sandstone reservoir. However, there is lack of fast and accurate identification method for thief zones. We develop an new method based on interwell connectivity to solve this problem. As compared to conventional water flooding simulation by Eclipse, using interwell connectivity can save computation time more than 50 times and shows good agreement with history data (with less than 8% in error). The present method has been validated by comparing with in-site tracer test results and available results from reservoir engineering methodology. This method has then been applied in an actual offshore oilfield S and successfully identifies 25 interwell connection units and 45 units as thief zones and channeling paths (that are for pores classified in between normal pores and thief zone) in total, which plays a vital role in follow-up oilfield overall profile control and oil displacement design procedure.