EOR Miscible gas injection

Abstract

Across company’s portfolio of technological projects an especial place is reserved for gas technologies and miscible flooding is one of them. It allows to increase current production and overall recovery factor but also helps utilize light gas components which otherwise would be flamed or sold without extra value. The oil field under consideration includes several oil rim reservoirs. The main consideration behind its development strategy was to use all available resources as efficient as possible. The gas plant is designed to produce stabilized NGL from associated gas and mix it with oil to gain extra value from increased volume and lightness. Lean gas is injected into gas caps. The other product is C₂-C₄ which could be sold with lean gas or put to good use and be injected in oil rim to displace oil in a miscible way. At the beginning PVT model was designed and MME was evaluated. Having results from actual lab experiments and compositional simulation software available optimal composition of injection fluids and pressure regimes were investigated. Reservoirs were ranked and most prominent chosen. Current and planned patterns of oilfields were studied for best injector location. Integrated models were built to monitor and predict produced and injected gas compositions and volumes. In addition they allowed watching for bottle-necks in production network, cryogenic plant, gas facilities and calculation of recycling volume.