State-of-the Art Low Salinity Waterflooding for Enhanced Oil Recovery

Dang, Cuong Thanh Quy; Nghiem, Long X.; Chen, Zhangxin; Nguyen, Quoc P.; Nguyen, Ngoc Thi Bich

doi:10.2118/165903-ms

Cited by 27 publications

(24 citation statements)

References 49 publications

(30 reference statements)

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“…The oil recovery factor was found to increase by about 20 % of the OOIP in low salinity WAG 1:2 as compared to high salinity WAG 1:2 which are in line with the results obtained by Dang et al (2013). High salinity CO2-WAG flooding experiments, using CC (33 cm long) and 20 % of PV of CO 2 divided into two cycles for different CO2-WAG ratios of 1:1, 2:1, and 1:2 at reservoir pressure of 3,200 psia and 250°F were conducted first.…”

Section: High-and Low-salinity Co2-wag Performancesupporting

confidence: 90%

“…On the other hand, the secondary recovery of water flooding decreases with the increase of injection brine salinity in the experiments with Cottonwood Creek crude oil. Dang et al (2013) conducted a reservoir simulation on LSW CO 2 four cycles WAG 1:1 and reported a 9 % increase of the OOIP recovery by LSW over high salinity water. To our knowledge very limited work has been reported in the literature that covers the influence of injection brine salinity on CO 2 WAG process and additional work is needed.…”

Section: Introductionmentioning

confidence: 99%

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Experimental investigation of the effect of injection water salinity on the displacement efficiency of miscible carbon dioxide WAG flooding in a selected carbonate reservoir

Zekri

Al-Attar

Alfarisi³

et al. 2015

J Petrol Explor Prod Technol

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The effect of injection brine salinity on the displacement efficiency of low water salinity flooding was investigated using sea water at 35,000 ppm, and two field injection waters, namely, Um-Eradhuma (UER) at 171,585 ppm and simsima (SIM) at 243,155 ppm. The salinity of the employed waters was varied from original salinity to 1,000 ppm and used in the displacement of oil in selected core samples. The results of this set of experiments revealed that UER salinity of 5,000 ppm is the optimum system for the candidate reservoir. UER original water and its optimum water were then used in this project as the high and low salinity waters in the CO 2 -WAG flooding experiments. Displacement efficiencies were evaluated under three injection modes: carbon dioxide WAG miscible flooding (CO 2 -WAG, 1:1, 2:1, and 1:2), continuous CO 2 injection, and waterflood. The WAG performance parameters, such as secondary and tertiary displacement efficiencies, CO 2 flood utilization factor, and CO 2 performance during different WAG flood cycles were determined. To insure miscibility condition between the injected gas and the employed oil, all of the flooding experiments were conducted at 3,200 psia (which is 300 psia above the minimum miscibility pressure of CO 2 and used oil) and 250°F. Experimental results indicated that core length is a critical parameter in determining the optimum WAG process, and that a minimum core length of 29 cm is required to insure the generation of miscibility before breakthrough in CO2-WAG flooding experiments. On the other hand, core length had no effect on the performance of the low salinity flooding experiments. Using single core flooding low salinity CO 2 -WAG of 1:2 flooding produced an improvement in the displacement efficiency of 29 % over the high salinity system. Also, composite core flooding experiments showed that the high salinity CO 2 -2:1 WAG achieved a displacement efficiency of 98 %. These results indicate that achieving miscibility at the reservoir conditions is the dominant mechanism and that low salinity will have no major effect on the displacement efficiency of CO 2 -Miscible WAG flooding. Results also indicate that oil recovery during different CO2-WAG cycles is a function of WAG ratios.

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Section: High-and Low-salinity Co2-wag Performancesupporting

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Experimental investigation of the effect of injection water salinity on the displacement efficiency of miscible carbon dioxide WAG flooding in a selected carbonate reservoir

Zekri

Al-Attar

Alfarisi³

et al. 2015

J Petrol Explor Prod Technol

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“…It has been experimentally found that the low salinity brine has a significant effect on the shape and the end points of the relative permeability curves (Webb et al, 2004;Kulkarni and Rao, 2005;Rivet, 2009;Fjelde et al, 2012), resulting in a lower water relative permeability and higher oil relative permeability. The mechanisms of wettability alteration due to ion exchange and geochemical reactions have been successfully implemented in a compositional simulator for modeling of LSW (Dang et al, 2013b). Excellent agreements between simulation results and important measurements from coreflood experiments and pilot observations were obtained with this modeling approach (Dang et al, 2013a).…”

Section: Introductionmentioning

confidence: 86%

“…Several mechanisms have been proposed during the last two decades including fines migration, wettability alteration, multi-component ionic exchange (MIE), saponification, pH modification, and electrical double layer effects. Dang et al (2013b) provided a critical review and discussion of these mechanisms. Among the proposed hypotheses, wettability alteration towards increased water wetness during LSW is the widely accepted cause for enhanced oil recovery.…”

Section: Introductionmentioning

confidence: 99%

“…These positive results would encourage extending LSW and CO 2 LSWAG into heavy oil reservoirs in addition to light/medium oil reservoirs at this moment. Dang et al (2013b) evaluated the potential of the novel concept of CO 2 LSWAG injection under CO 2 miscible displacement conditions using a 1D linear model. From their simulation results, CO 2 LSWAG has the highest oil recovery factor compared to CO 2 HSWAG, pure CO 2 flood, and LSW.…”

Section: Introductionmentioning

confidence: 99%

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CO2 Low Salinity Water Alternating Gas: A New Promising Approach for Enhanced Oil Recovery

Dang

Nghiem²,

Chen

et al. 2014

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It has been recognized that there are significant advantages on combining low salinity waterflooding (LSW) with other enhanced oil recovery (EOR) techniques such as polymer or low tension surfactant flooding. This paper proposes a novel concept of low salinity water-alternating-CO 2 (CO 2 LSWAG) injection under CO 2 miscible displacement conditions. While LSW is an emerging EOR method based on alteration of wettability from oil-wet to water-wet conditions, WAG is a proven method for improving gas flooding performance by controlling the gas mobility. Therefore, LSWAG injection promotes the synergy of the mechanisms underlying these methods (i.e., ion-exchange, wettability alteration, and CO 2 miscible displacement and mobility control) that further enhances oil recovery and overcomes the late production problem frequently encountered in the conventional WAG. These features are demonstrated in this work based on a field case study. To investigate the advantages of CO 2 LSWAG, a comprehensive ion exchange model associated with geochemical processes has been developed and coupled to the multi-phase multi-component flow equations in an equation-of-state compositional simulator. Laboratory core flood simulations of different CO 2 LSWAG schemes are conducted to understand the combined effects of solubility of CO 2 in brine, dissolution of carbonate minerals, ion exchange, and wettability alteration. CO 2 LSWAG performance is then evaluated on a field scale through an innovative workflow that includes geological modeling, multiphase multi component reservoir flow modeling and process optimization. The simulation results indicate that CO 2 LSWAG has the highest oil recovery compared to conventional high salinity waterflood, high salinity WAG, and low salinity waterflood. A number of geological realizations are generated to assess the geological uncertainty effect, in particular clay distribution uncertainties, on CO 2 LSWAG efficiency. Finally, CO 2 LSWAG injection strategies are optimized by identifying key WAG parameters. The proposed workflow demonstrates the synergy between CO 2 WAG and LSW. Built in a robust reservoir simulator, it serves as a powerful tool for screening, design, optimization, and uncertainty assessment of the process performance from laboratory to and field scales. CO 2 LSWAG is a promising EOR technique as it not only combines the benefits of CO 2 injection and low salinity water floods but also promotes the synergy between these processes through the interactions between geochemical reactions associated with CO 2 injection, ion exchange process, and wettability alteration. This paper demonstrates the merits of this process through modeling, optimization and uncertainty assessment. IntroductionThe modification of the injected brine composition could improve the oil recovery factor of conventional waterflooding up to 38% (Web et al., 2004), leading to a new concept of optimal injection brine composition for waterflooding. Other than using high salinity reservoir water

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