Effects and Mechanisms of Acidic Crude Oil–Aqueous Solution Interaction in Low-Salinity Waterflooding

Chai, Rukuan; Liu, Yuetian; He, Yuting; Cai, Mingjun; Zhang, Jialiang; Liu, Feifei; Xue, Liang

doi:10.1021/acs.energyfuels.1c00654

Cited by 10 publications

(11 citation statements)

References 62 publications

(178 reference statements)

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“…SDBS desorption was enhancing through the substitute adsorption of Na in the LSW. This is well agreed with Chai et al [37], who addressed that the ionic composition has a great influence on crude oil-aqueous solution interaction, so the reduction of Na in the aqueous phase further improves the effectiveness of desorbed SDBS on the crude oil-aqueous interface. The Na desorption in LSW-SDBS-LSW however affects the effectiveness of SDBS in the post-flush.…”

Section: Chemistry Of Effluent and Iftsupporting

confidence: 89%

Enhancing surfactant desorption through low salinity water post-flush during Enhanced Oil Recovery

Ngo

Sasaki

et al. 2021

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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Low Salinity Water (LSW) incorporates in surfactant Enhanced Oil Recovery (EOR) as a pre-flush is a common practice aiming to reduce the formation salinity, which affects surfactant adsorption. However, in a field implementation, the adsorption of surfactant is unavoidable, so creating a scheme that detaches the trapped surfactant is equally essential. In this study, LSW was a candidate to enhance the desorption of surfactant. LSW solely formulated from NaCl (1 wt.%), Sodium Dodecylbenzene Sulfonate (SDBS) was chosen as the primary surfactant at its critical micelle concentration (CMC, 0.1 wt.%). It found that injecting LSW as post-flush achieved up to 71.7% of SDBS desorption that lower interfacial tension against oil (31.06° API) to 1.3 mN/m hence bring the total Recovery Factor (RF) to 56.1%. It was 4.9% higher than when LSW injecting as pre-flush and 5.2% greater than conventional surfactant flooding (without LSW). Chemical analysis unveiled salinity reduction induces Na+ ion adsorption substitution onto pore surface resulting in an increment in surfactant desorption. The study was further conducted in a numerical simulation upon history matched with core-flood data reported previously. By introducing LSW in post-flush after SDBS injection, up to 5.6% RF increased in comparison to other schemes. The proposed scheme resolved the problems of adsorbed surfactant after EOR, and further improve the economic viability of surfactant EOR.

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Section: Chemistry Of Effluent and Iftsupporting

confidence: 89%

Enhancing surfactant desorption through low salinity water post-flush during Enhanced Oil Recovery

Ngo

Sasaki

et al. 2021

Oil Gas Sci. Technol. – Rev. IFP Energies nouvelles

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show abstract

“…Chai et al' results revealed that Mg 2+ and Ca 2+ both had positive effects on EOR, while SO 4 2− showed no positive effect through adjusting crude oil−aqueous solution interactions in low salinity waterflooding. 121 Other important results related with water modification of carbonate came form Zhang et al's research. They consider that reactivity of the surface of biogenic chalk is much higher than for recrystallized limestone.…”

Section: Potential Ions Modifying the Wettability Of Carbonatementioning

confidence: 98%

“…In addition, it is noted that the mechanism is strongly dependent on temperature, in which temperature has a great influence on dehydration of Mg 2+ and Ca 2+ , and Mg 2+ became much more reactive in eqs and . Chai et al’ results revealed that Mg 2+ and Ca 2+ both had positive effects on EOR, while SO 4 2– showed no positive effect through adjusting crude oil–aqueous solution interactions in low salinity waterflooding …”

Section: Potential Ions Modifying the Wettability Of Carbonatementioning

confidence: 99%

Review on Underlying Mechanisms of Low Salinity Waterflooding: Comparisons between Sandstone and Carbonate

et al. 2022

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Low salinity effects (LSE) improved recovery could be obtained by reducing salinity and/or modifying the specific ions of injected brines. Low salinity waterflooding (LSW) is described as a certain low-cost and eco-friendly oil recovery technique, when referring the enhanced oil recovery (EOR) potential by laboratory observations and field pilots in recent decades. Various underlying mechanisms behind LSE were proposed, including saponification, multi-ionic exchange (MIE), electric double-layer (EDL) expansion, fines migration, salt in effect, osmotic effect, and so on. However, first, to our best knowledge, there is not yet a certain mechanism recognized by all experts. Second, LSE mechanisms of sandstones were always taken for granted to be applied directly to carbonates, without considering discrepancies in mineral compositions and pore structures. Third, spontaneous imbibition performances were usually concluded as the indication of wettability alteration, without considering the straightforward effects on imbibition caused by low salinity brine. Review results reveal LSE necessary conditions and influences. Necessary conditions should be satisfied to trigger LSE, including oil phase with polar components, connate water, injected brine key ions composition and low salinity, clay minerals, and initial wettability without the best performance. Their sole or mutual interactions influence LSE functions. Mechanisms could be classified into two types: solid–liquid and liquid–liquid. These (e.g., EDL expansion, MIE, fines migration) caused by solid–liquid could be attributed to wettability alteration, while microdispersion, osmosis effect, and snap-off belong to liquid–liquid interfacial factor. Sandstones mainly consist of quartz and clay, initially tending to behave as initial water wetness, while carbonates mainly consist of calcium carbonate or magnesium carbonate, mainly behaving as initial oil-wet. Therefore, LSE in carbonates are contributed to by mechanisms related with wettability alteration, while LSE in sandstones are mainly related to other factors. The findings of this study can help with better understanding of LSE and speeding up our further endeavors to explore its potential in EOR.

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“…Much of the prior research has proven fluid–rock interaction as the primary consideration for improving oil recovery. The fluid–fluid interactions on low salinity effect have recently received more attention. − Chai et al have shown the relation between the ionic composition of the injected brines and oil recovery through coreflooding experiments . Some research has found relations between oil recovery improvement and an increase in interfacial elasticity. − For instance, Garcia-Olvera et al demonstrated that low salinity brine made a more elastic interfacial film with crude oils.…”

Section: Introductionmentioning

confidence: 99%

“…25−27 Chai et al have shown the relation between the ionic composition of the injected brines and oil recovery through coreflooding experiments. 28 Some research has found relations between oil recovery improvement and an increase in interfacial elasticity. 29−31 For instance, Garcia-Olvera et al 31 demonstrated that low salinity brine made a more elastic interfacial film with crude oils.…”

Section: Introductionmentioning

confidence: 99%

Direct Insight into the Cause and Time Evaluation of Spontaneous Emulsification of Water in Crude Oil during Low Salinity Waterflooding Using Microfluidic Model

Beyranvand

Rostami

2022

Energy Fuels

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In prior research, the formation of emulsions has been proposed as an effective mechanism to enhance the recovery during the injection of low salinity water (LSW) from different points of view, such as improving the mobility ratio, changing the wettability, and swelling the oil layer adhered to the rock surface. The spontaneous emulsification process and its causes are still an unclear area of LSW studies. To study the formation of the emulsion as an active mechanism in the LSW injection, it is necessary to pay attention to the time required to form these emulsions spontaneously and places prone to their formation. In addition to the visual investigation of the spontaneous formation of emulsions, the current study also aimed at evaluating the time required for their spontaneous formation and identifying the main drive force to form these microsized dispersions. To this end, water-in-oil emulsions were prepared naturally without the use of surfactants to simulate spontaneous emulsification. Also, stability analysis by droplet size measurement was used as an observational criterion to evaluate different brines’ tendencies to form expected in situ emulsions in a porous medium. However, for visual investigation of emulsification in porous media, glass micromodels were used. The stability analysis results showed that the increase in the emulsions’ instability occurred with the increase of the ionic strength of the aqueous phase. In the micromodel experiments, the spontaneous emulsification was confirmed when low salinity water was injected. Moreover, the micromodel experiments revealed that the emulsions did not start to form immediately but formed within a week and reached a maximum approximately after 10 days. It can be concluded that the oil layer can act as a semipermeable layer and water inverse micelles enter the oil layer by diffusion. The rate of emulsion formation is controlled by diffusion induced by the osmosis imbalance condition in LSW injection.

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Effects and Mechanisms of Acidic Crude Oil–Aqueous Solution Interaction in Low-Salinity Waterflooding

Cited by 10 publications

References 62 publications

Enhancing surfactant desorption through low salinity water post-flush during Enhanced Oil Recovery

Enhancing surfactant desorption through low salinity water post-flush during Enhanced Oil Recovery

Review on Underlying Mechanisms of Low Salinity Waterflooding: Comparisons between Sandstone and Carbonate

Direct Insight into the Cause and Time Evaluation of Spontaneous Emulsification of Water in Crude Oil during Low Salinity Waterflooding Using Microfluidic Model

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