Shifting The Focus To An Optimal Oil Recovery Strategy. Dr. John D.M. Belgrave, Belgrave Oil And Gas Corp. 13th International Oil And Gas Conference & Exhibition, Delhi, India...
The applicability of EOR technologies depends, very broadly, on two factors: the API gravity of the oils and the depth of the reservoirs. In reality, these are related to the proper technical selection parameters oil viscosity and the reservoir pressure, respectively.
Shallow reservoirs with heavy and extra heavy oils are the best disposed to steam injection processes. Intermediate and deep reservoirs with oils above 30 oAPI are the ones best adapted to miscible CO2 injection. Other miscible processes with N2, HC gases and flue gases require reservoirs deeper than 5,000 feet. Polymer and other chemical processes are limited mostly by temperature and salinity, usually intermediate depth reservoirs with oils in the range of 15-30 oAPI. In situ combustion has no depth restriction, but reservoirs with mobile oil and significant dip have produced recovery factors from 50%-90% of the original oil in place.
The key to expanding the use of the technically proven EOR processes is the reduction of implementation costs and mitigation of environmental impact. Economics of EOR projects are significantly improved when the use of existing wells and associated facilities, is maximized.