EOR Screening and Potential Applications on the Norwegian Continental Shelf (NCS)

Abstract

Enhanced oil recovery (EOR) projects have moved down the industry's priority list given the present oversupply of world crude oil and resulting low oil prices. However, this is the right time for the industry to evaluate options for injecting new life into some of the brown fields on the Norwegian continental shelf (NCS). Inspite of the current market challenges, EOR application in offshore oil fields remains a promising option for increasing the oil production on the NCS. The size of the targeted offshore oil fields is generally large and their proven original oil in place (OOIP) can be sufficiently large to overcome the high cost required for re-development. This means that a large amount of oil remaining on the NCS could potentially be recovered using EOR processes. In this work, the main objective was to screen some selected oil fields on NCS for possible EOR processes based on present-day reservoir data. The work was carried out in the National IOR Center based on published reservoir data on the selected fields. As a result, available reservoir information for the selected fields were limited. In addition, there were significant differences in the quality of field data supporting the viability of the various EOR processes considered. However, a fast evaluation of various EOR processes based on a simulation screening tool, SWORD proved to be very useful and assisted in providing an assessment of recovery strategies and EOR methods applicable for the selected fields. The EOR processes screened included hydrocarbon gas, CO2, surfactant, polymer and a combined surfactant/polymer process. The screening criteria for the EOR processes were based on six quantitative reservoir data namely density and viscosity of reservoir oil, and properties such as depth, temperature, porosity and permeability of the formations. The applicability of the different EOR methods and recovery strategies at different reservoir properties and conditions were evaluated based on existing information published on the selected fields and knowledge collected from a suite of successful EOR projects around the world. Results based on simulations indicate that the estimates of potential EOR incremental oil recovery compared to water flooding for the screened fields can be quite significant. However, key project development including realistic laboratory experiments and reservoir simulations needs to be performed to evaluate the EOR processes in detail. In addition, implementation and environmental issues, and additional cost elements must be weighed equally with oil recovery forecasts in any EOR ranking process.