Abstract

The oil production performance has been a vital key performance indicator to assess the oil reservoir in oil industry. It can be either naturally production which strongly depends on gas expansion energy, or artificially production which depends on external energies such as waterflooding and enhanced oil recovery methods “EOR”. EOR methods depend on the reservoir conditions as well as rock and fluid properties. Based on EOR applications, gas injection has been considered the common method in oil industry in order to increase oil production performance and decrease the environmental pollution.
In this paper, a simulation model is created to mimic a lab scale, and its dimensions are 61 cm length, 16.2 cm width and 5 cm thickness. For fluid and rock properties, brine is an aqueous phase, and n-Decane and light crude oil are used as oleic phase, furthermore, the rock is assumed homogeneous and water wet porous media. Using commercial software, several gas injection methods are applied in order to increase oil production performance, and those depend on miscibility levels, stage of gas injection and injection schemes.
The oil production performance strongly depends on the viscosity ratio between displaced and displacing fluids. For miscibility factor, fully miscible gas injection has highest oil production performance rather than immiscible and near miscible gas injections. For gas injection schemes, simultaneous water and miscible gas injection scheme is the optimum scheme to produce more oil with less gas consumption. Finally, gas injection at secondary stage is more achievable rather than gas injection at tertiary stage in order to improve macroscopic and microscopic sweep efficiencies.