Full text loading...
-
Discerning In Situ Performance of an EOR Agent in the Midst of Geological Uncertainty
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, IOR 2015 - 18th European Symposium on Improved Oil Recovery, Apr 2015, cp-445-00031
- ISBN: 978-94-6282-141-5
Abstract
An enhanced-oil-recovery pilot test has multiple goals, among them to verify the properties of the EOR agent in situ. Given the complexity of EOR processes and the inherent uncertainty in the reservoir description, it is a challenge to discern the properties of the EOR agent in situ. We present a simple case study to illustrate this challenge: a polymer EOR process in a 2D layer-cake reservoir. The intended polymer design value is 21 cp in situ but we allow it might be ¼ that intended in the simulations. We test whether the signals of this difference at injection and production wells would be statistically significant in the midst of the geological uncertainty. We compare the deviation caused by loss of polymer viscosity to the scatter caused by the geological uncertainty at the 95% confidence level. Among the signals considered, the rate of rise in injection pressure with polymer injection and maximum injection pressure in the injector give the most reliable indications of whether a polymer viscosity was maintained in situ. Arrival time of the oil bank, minimum oil cut before oil bank arrival and polymer breakthrough time also give a statistically significant indication.