WAG Process Optimization in the Rangely CO2 Miscible Flood

Attanucci, Vincent; Aslesen, K.S.; Hejl, K.A.; Wright, Charles Alan

doi:10.2118/26622-ms

Cited by 36 publications

(9 citation statements)

References 10 publications

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“…The improved gas handling and oil recovery have been reported for SWAG injection at Siri field (Berg et al 2002 andQuale et al 2000), the Joffre Viking (Stephenson et al 1993) CO 2 miscible flood and SWAG emulation at the Rangely CO 2 miscible flood (Attanucci et al 1993). Pilot tests performed on Kuparuk River Field in Alaska Stoisits et al 1995) have also demonstrated the feasibility of SWAG injection.…”

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confidence: 86%

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

2008

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We present results of high-pressure micromodel visualizations of pore-scale fluid distribution and displacement mechanisms during the recovery of residual oil by nearmiscible hydrocarbon gas and SWAG (simultaneous water and gas) injection under conditions of very low gas-oil IFT (interfacial tension), negligible gravity forces and water-wet porous medium. We demonstrate that a significant amount of residual oil left behind after waterflooding can be recovered by both near-miscible gas and SWAG injection. In particular, we show that in both processes, the recovery of the contacted residual oil continues behind the main gas front and ultimately all of the oil that can be contacted by the gas will be recovered. This oil is recovered by a microscopic mechanism, which is strongly linked to the low IFT between the oil and gas and to the perfect spreading of the oil over water, both of which occur as the critical point of the gas-oil system is approached. Ultimate oil recovery by near-miscible SWAG injection was as high as near-miscible gas injection with SWAG injection using much less gas compared to gas injection. Comparison of the results of SWAG experiments with two different gas fractional flow values (SWAG ratio) of 0.5 and 0.2 shows that fractional flow of the near-miscible gas injected simultaneously with water is not a crucial factor for ultimate oil recovery. This makes SWAG injection an attractive IOR (improved oil recovery) process especially for reservoirs, where continuous and high-rate gas injection is not possible (e.g. due to supply constraint).

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confidence: 86%

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

2008

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“…The feasibility of CO 2 injection for either light or heavy oil recovery has been shown by various laboratory investigations. − Several field trials have also shown a considerable increase in oil production after CO 2 injection. − In light oil systems, miscibility between CO 2 and the oil is usually a target, and it is often achievable by increasing reservoir pressure or enriching the injection fluid . However, in the case of medium or heavy oil reservoirs, the decrease in the interfacial tension (IFT) is not as significant as that in the light oil systems, and the contact between the oil and CO 2 would remain immiscible .…”

Section: Introductionmentioning

confidence: 99%

Investigation of Low-Density CO₂ Injection for Enhanced Oil Recovery

Seyyedsar

Farzaneh

Sohrabi

2017

Ind. Eng. Chem. Res.

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The density of the CO2-rich phase in a reservoir would play a crucial role in the performance of an enahcned oil recovery (EOR) scheme. Many oil reservoirs are located in deep formations; hence, they have high temperatures. Moreover, the pressure of reservoirs decreases because of natural depletion. Under the conditions of those reservoirs, CO2 would be a low-density gas. A series of coreflood experiments were performed to evaluate the potential of low-density CO2 EOR. The experiments are intermittent CO2 injection, continuous tertiary and secondary CO2 injection, and water alternating CO2 injection followed by the coinjection of a surfactant and CO2. The same oil and gas were mixed to prepare live oil for all the experiments. The initial rate of oil recovery during secondary waterflood was high, but the efficiency of the process decreased after the breakthrough. Three pore volumes (PVs) of secondary CO2 injection resulted in the recovery of around 50% of the initial oil in place, which was 27% higher than the oil recovered during 1 PV of water injection. It was also observed that CO2 injection can improve the recovery factor after waterflood. However, the performance of tertiary CO2 injection is reduced because of the presence of water in pore spaces, which likely makes the oil less accessible to CO2. Waterflood after a period of CO2 injection recovered 20% of initial oil in place mainly because of the dissolution of CO2 in the oil and the resultant oil viscosity reduction. The impact of the rate of CO2 injection on the efficiency of oil recovery was investigated, and it appears that the dissolution of CO2 in the oil is the main mechanism of enhanced recovery. The reduction of oil viscosity as a result of the dissolution of CO2 in the oil as well as the low density of CO2 improved the effect of gravity drainage on oil production. In addition, it was observed that the mechanism of solution gas drive plays an important role in the process of oil recovery. The analysis of the physical properties of the core effluent reveals that CO2 can also improve the quality of produced oil compared to that of the original oil in the rock. The results of this study provide experimental evidence of the potential of low-density CO2 EOR.

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“…Water blocking may become a severe effect in water-wet reservoirs during carbon dioxide (CO 2 ) flooding. As a consequence of water blocking, during the processes of conventional CO 2 injection, continuous/slug CO 2 injection, simultaneous water and gas injection (SWAG), and water alternating gas injection (WAG), , a considerable amount of the residual oil is hindered from being contacted by the injected CO 2 . Such a continuous water phase, which is the water-blocking effect, greatly reduces the microscopic displacement efficiency. − To eliminate the water-blocking effect in CO 2 injection, active carbonated water is applied as a preflush prior to a CO 2 flood …”

Section: Introductionmentioning

confidence: 99%

Mass Transfer of CO₂ in a Carbonated Water–Oil System at High Pressures

Shu

Dong

Chen

2016

Ind. Eng. Chem. Res.

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In this paper, CO2 diffusion coefficients in a carbonate water–oil system are determined by measuring the pressure buildup in the closed water–oil system experimentally and modeling the pressure change mathematically. The mathematical method of investigating one-dimensional, time-dependent heat conduction in a composite medium is adopted to solve the mass transfer problem between two liquid phases. The model is combined with well-designed trial-and-error method to determine diffusion coefficients of CO2 in both water and oil phases at the same time. The model considers a moving interface between carbonated water and oil as well as variations of interface concentrations of CO2 in these two phases, which more effectively conforms to reality. Results show that the pressure buildup during the diffusion process resulted from the increased density and swelling of the oil phase. The diffusion coefficient of CO2 in the water phase plays a major role in the interphase mass transfer process.

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WAG Process Optimization in the Rangely CO2 Miscible Flood

Cited by 36 publications

References 10 publications

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

Investigation of Low-Density CO₂ Injection for Enhanced Oil Recovery

Mass Transfer of CO₂ in a Carbonated Water–Oil System at High Pressures

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WAG Process Optimization in the Rangely CO2 Miscible Flood

Cited by 36 publications

References 10 publications

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

Visualisation of Residual Oil Recovery by Near-miscible Gas and SWAG Injection Using High-pressure Micromodels

Investigation of Low-Density CO2 Injection for Enhanced Oil Recovery

Mass Transfer of CO2 in a Carbonated Water–Oil System at High Pressures

Contact Info

Product

Resources

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Investigation of Low-Density CO₂ Injection for Enhanced Oil Recovery

Mass Transfer of CO₂ in a Carbonated Water–Oil System at High Pressures