Co-Optimizing Enhanced Oil Recovery and CO₂ Storage by Simultaneous Water and CO₂ Injection

Abstract

This paper presents a numerical simulation study to investigate whether simultaneous water and gas (SWAG) injection can co-optimize CO 2 storage and enhanced oil recovery. Compositional displacements in a three-dimensional, layered reservoir model are modeled to examine different injection scenarios for maximizing oil recovery and CO 2 storage capacity. The effects of various CO 2 -water ratios and different miscibility conditions on sweep efficiency, incremental oil recovery and CO 2 storage capacity are investigated. Compositional changes of oil and gas phases, in the presence of mobile water in immiscible, near miscible or miscible SWAG injection are examined. Simulation results show that SWAG injection can enhance oil recovery compared to waterflooding and continuous CO 2 injection by 6 to 21% the original oil in place. The optimum gas fraction in injection fluid increases as miscibility develops. When CO 2 is injected simultaneously with water, 30-60% of injected CO 2 can be stored with optimum injection ratios depending on the miscibility condition. On the contrary, in continuous gas injection, both oil recovery and CO 2 storage capacity increase with miscibility. The simulation results also reveal that, for the reservoir studied, near miscible SWAG injection yields the highest oil recovery and storage efficiency in shortest operating duration.

Analytical solution of Buckley-Leverett equation for gas flooding including the effect of miscibility with constant-pressure boundary

“…For its remarkable achievement in oil recovery and storage capacity for the greenhouse gases, the gas flooding technology has been attracting more and more concern and discussion among the EOR methods (Kamali and Cinar, 2014;Zhao et al, 2016). The gas injection is divided into two categories, consisting of hydrocarbon gas injection, such as natural gas and produced gas, and non-hydrocarbon gas injection, such as CO 2 , N 2 and flue gas.…”

Experimental evaluation of carbonated waterflooding: A practical process for enhanced oil recovery and geological CO2 storage

“…Likewise, if the objective is to maximize CO 2 storage, w 2 = 1. As there are various tax systems for CO 2 sequestration in different countries, the weighting factors should be chosen based on the revenue produced by both oil recovery and CO 2 storage …”

“…As regards the storage aspect of a CO 2 EOR process, in order to quantify the percentage of injected CO 2 which is efficiently stored in a petroleum reservoir, a number of definitions, such as the ratio of the volume of CO 2 stored in the reservoir to the pore volume (PV) of the reservoir, or the mass of CO 2 stored in a reservoir over the total capacity of reservoir for CO 2 storage, have been proposed. 33,34 For a more accurate estimation of the fraction of the CO 2 stored in the porous media, a more practical storage factor which uses the amount of injected CO 2 instead of the total capacity of CO 2 in the reservoir, is applied in the present study. The formula pertaining to the widely accepted term of retention within the oil and gas industry is shown as follows: 35…”

“…As there are various tax systems for CO 2 sequestration in different countries, the weighting factors should be chosen based on the revenue produced by both oil recovery and CO 2 storage. 34 Many studies in laboratory scale have been conducted on CWF. Steffens 18 performed coreflooding experiments using Bentheimer sandstone and n-hexadecane with periods of injection and no injection.…”

Optimal Well Positioning under Geological Uncertainty by Equalizing the Arrival Time

“…The principal reason of using water flooding for oil reservoirs is to increase oil production rates and, ultimately, oil recovery (Kamali and Cinar, 2014). Oil recovery by natural forces of a reservoir is mostly low.…”