Oil recovery by low-salinity polymer flooding in carbonate oil reservoirs

Lee, Yeonkyeong; Lee, Won Suk; Jang, Young Ho; Sung, Wonmo

doi:10.1016/j.petrol.2019.106211

Cited by 63 publications

(19 citation statements)

References 32 publications

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“…The limitations of standalone PF can be overcome by combining it with EW or LSW, and this has been given the term 'hybrid engineered water polymer flooding' (EWPF). The effectiveness of EWPF in carbonates has been proven by various experimental [61][62][63][64][65] and numerical modeling [66][67][68][69] studies. EWPF provided incremental recovery of 10% OOIP from carbonate cores in experiments by Al Sofi et al [70].…”

Section: Introductionmentioning

confidence: 99%

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

et al. 2021

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Several studies have shown the synergetic benefits of combining various chemical enhanced oil recovery (CEOR) methods with engineered waterflooding (EWF) in both sandstones and carbonate formations. This paper compares the capillary desaturation tendency of various hybrid combinations of engineered water (EW) and CEOR methods with their conventional counterparts. Several coreflood experiments were conducted, including EW-surfactant flooding (EWSF), EW-polymer flooding (EWPF), EW-alkali-surfactant flooding (EWASF), EW-surfactant-polymer flooding (EWSPF), and EW-alkali-surfactant-polymer flooding (EWASP). Capillary numbers (Nc) and corresponding residual oil saturation (Sor) for each scenario are compared with capillary desaturation curves (CDC) of conventional CEOR methods from the literature. The results indicate that hybrid EW–CEOR methods have higher capillary desaturation tendency compared to conventional methods. The capillary numbers obtained by standalone polymer flooding (PF) are usually in the range from 10−6 to 10−5, which are not sufficient to cause a significant reduction in Sor. However, the hybrid EW-polymer flooding approach considerably reduced the Sor for the same Nc values, proving the effectiveness of the investigated method. The hybrid EWASP flooding caused the highest reduction in Sor (23%) against Nc values of 8 × 10−2, while conventional ASP flooding reduced the Sor for relatively higher Nc values (3 × 10−3 to 8 × 10−1). Overall, the hybrid methods are 30–70% more efficient in terms of recovering residual oil, compared to standalone EWF and CEOR methods. This can be attributed to the combination of different mechanisms such as wettability modification by EW, ultralow interfacial tension by alkali and surfactant, reduced surfactant adsorption by alkali addition, and favorable mobility ratio by polymer. Based on the promising results, these hybrid techniques can be effectively implemented to carbonate formations with harsh reservoir conditions such as high salinity and high temperature.

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Section: Introductionmentioning

confidence: 99%

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

et al. 2021

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“…Additionally, Lee et al [ 185 ] performed experiments on carbonate core-samples, using low salinity with ionic adjustments followed by polymer flooding. The residual oil saturation (S

) value was considerably decreased by using low-salinity polymer (LSP) flooding compared to conventional high salinity water flooding and engineered water flooding.…”

Section: Experimental Laboratory Studiesmentioning

confidence: 99%

“…The residual oil saturation (S

) value was considerably decreased by using low-salinity polymer (LSP) flooding compared to conventional high salinity water flooding and engineered water flooding. All designed injection water (IW) solutions (i.e., IW-1: pH 7, 1000 ppm SO

, IW-2: pH 7, 4000 ppm SO

, IW-3: pH 4, 4000 ppm SO

, IW-4: pH 7, 100 ppm Ca

, IW-5: pH 7, 1000 ppm Ca

, and IW-6: pH 4, 1000 ppm Ca

) reduced the S

value; however, the neutral low salinity water containing only SO

ions gave the lowest Sor value [ 185 ].…”

Section: Experimental Laboratory Studiesmentioning

confidence: 99%

Updated Perceptions on Polymer-Based Enhanced Oil Recovery toward High-Temperature High-Salinity Tolerance for Successful Field Applications in Carbonate Reservoirs

2022

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The aging of the existing reservoirs makes the hydrocarbon extraction shift toward newer reserves, and harsh conditioned carbonates, which possess high temperature and high salinity (HTHS). Conventional polymer-flooding fails in these HTHS carbonates, due to precipitation, viscosity loss, and polymer adsorption. Therefore, to counteract these challenges, novel polymer-based cEOR alternatives employ optimized polymers, polymer–surfactant, and alkali–surfactant–polymer solutions along with hybrid methods, which have shown a potential to target the residual or remaining oils in carbonates. Consequently, we investigate novel polymers, viz., ATBS, Scleroglucan, NVP-based polymers, and hydrophobic associative polymers, along with bio-polymers. These selected polymers have shown low shear sensitivity, low adsorption, and robust thermal/salinity tolerance. Additionally, adding an alkali-surfactant to polymer solution produces a synergy effect of improved mobility control, wettability alteration, and interfacial-tension reduction. Thus, enhancing the displacement and sweep efficiencies. Moreover, low-salinity water can precondition high-salinity reservoirs before polymer flooding (hybrid method), to decrease polymer adsorption and viscosity loss. Thus, this paper is a reference for novel polymers, and their hybrid techniques, to improve polymer-based cEOR field applications under HTHS conditions in carbonates. Additionally, the recommendations can assist in project designs with reasonable costs and minimal environmental impact. The implication of this work will aid in supplementing the oil and gas energy sector growth, making a positive contribution to the Middle Eastern economy.

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“…Polymer flooding technology is representative of the tertiary oil recovery stage. Through the application of polymer flooding, more supporting techniques can be studied to improve the sweep volume of the injection agent and the recovery factor of the tertiary oil recovery stage [15,16]. In China, in-situ combustion experiments were carried out in Xinjiang, Yumen, Shengli and Fuyu oilfields from 1958 to 1976.…”

Section: Research Statusmentioning

confidence: 99%

Numerical Simulation Study of Heavy Oil Production by Using In-Situ Combustion

2019

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An in-situ combustion method is an effective method to enhance oil recovery with high economic recovery rate, low risk, fast promotion and application speed. Currently, in-situ combustion technique is regarded as the last feasible thermal recovery technology to replace steam injection in the exploitation of bitumen sands and heavy oil reservoirs. However, the oil-discharging mechanism during the in-situ combustion process is still not clearly understood. In this paper, the in-situ combustion process has been numerically simulated based on the Du 66 block. The effect of production parameters (huff and puff rounds, air injection speed, and air injection temperature) and geological parameters (bottom water thickness, stratigraphic layering, permeability ratio, and formation thickness) on the heavy oil recovery have been comprehensively analyzed. Results show that the flooding efficiency is positively correlated with the thickness of the bottom water, and negatively correlated with the formation heterogeneity. There exist optimum values for the oil layer thickness, huff and puff rounds, and air injection speed. And the effect of air injection temperature is not significant. The results of this paper can contribute to the understanding of mechanisms during in-situ combustion and the better production design for heavy oil reservoirs.

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Oil recovery by low-salinity polymer flooding in carbonate oil reservoirs

Cited by 63 publications

References 32 publications

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

Capillary Desaturation Tendency of Hybrid Engineered Water-Based Chemical Enhanced Oil Recovery Methods

Updated Perceptions on Polymer-Based Enhanced Oil Recovery toward High-Temperature High-Salinity Tolerance for Successful Field Applications in Carbonate Reservoirs

Numerical Simulation Study of Heavy Oil Production by Using In-Situ Combustion

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