Evaluation of CO2 injection in Gullfaks field, segment K1-K2 in Statfjord formation to improve oil recovery - simulation study

Abstract

Carbon dioxide is one of the vital substances, which caused the greenhouse effect. This phenomenon results in a higher average temperature of earth and leads to many environment problems. The amount of CO2 emission tends to increase dramatically in each year. According to this situation, many ways to reduce the amount of CO2 are studied and developed. One of the efficient ways is to use CO2 for increase oil recovery, with this method not only CO2 is disposed in the subsurface but also amount of produced oil is increased, which leads to higher revenue of the project. CO2 has been proven for a decade to be a good candidate for increase oil recovery. Since the density of CO2 is higher than Methane, which is the major composition of normal injected gas so gravity segregation is reduced. Moreover, CO2 has higher viscosity than Methane so viscous fingering is reduced and the displacement becomes more stable. CO2 injection can also reduce the MMP of the reservoir which makes the miscible displacement easy to be achieved. CO2 can be used with water to enhanced oil production. This can be classified into: continuous injection, WAG injection and Hybrid injection. The compositional fluid description is used in the simulation calculation. The EOS of Peng and Robinson is used for the whole simulation.

In Norway, there are many sources of CO2 however the amount of CO2 emission is not much enough for using in the CO2 injection project. Nevertheless, one of the sources, which is Statoil Mongstad represents a good candidate since it located near the interested reservoir and the amount is high enough to be used for CO2 injection. There are some supplemental expenditures in CO2 injection compare to the normal injected gas case these are: capture cost, compression cost and the pipeline transportation cost. The additional revenue from increased oil by CO2 injection should be higher than the investment so that the CO2 injection would be accepted to be done.