Investigation of salinity and ion effects on low salinity water flooding efficiency in a tight sandstone reservoir

Liu, Guangfeng; Fan, Jun; Ge, Lizhen; Zhang, Qingjiu; Chen, Xiaoming; Fan, Zhixing; Wang, Juntao

doi:10.1016/j.egyr.2023.01.098

Cited by 20 publications

(14 citation statements)

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“…The impacts of brine salinity on the wettabilities of rock surfaces have been emphasized in previous research. ,− It is well-known that varying the concentration and type of reservoir brine significantly affects the wetting characteristics of the rock surface in the oil/brine environment. ,, Therefore, the effects of increasing salinity (0.0 to 0.3 M) on the wettabilities of the SA- (10 –2 mol/L) and 100 mg/L MB-aged Khewra sandstone samples are revealed by the CA measurements in Figure . Here, it can be seen that the CA values increase with the increase in salt concentration, which is consistent with the results of previous studies. ,,,, However, the degree of change in the CA value is lower in the MB-aged samples than in the SA-aged ones. This confirms the effectiveness of MB in decreasing the hydrophobicity of the SA-contaminated Khewra sandstone samples, thereby increasing their hydrocarbon potential.…”

Section: Resultssupporting

confidence: 92%

“…The effect of increasing salinity on the wettability of the rock surface can be attributed to the screening effect due to the brine-induced surface charge, which may become positive at higher salt concentrations, thereby nullifying the original negative surface charge of the sandstone. , This, in turn, decreases the interactions between the rock surface and water, thereby increasing the attraction between the oil and the rock surface to favor the oil-wet behavior. For example, Pan et al reported that the zeta potential of a shale sample surface increased when CaCl 2 and NaCl were introduced into the system due to the surface adsorption of divalent ions, thus resulting in a positive charge.…”

Section: Resultsmentioning

confidence: 99%

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Impact of Methylene Blue on Enhancing the Hydrocarbon Potential of Early Cambrian Khewra Sandstone Formation from the Potwar Basin, Pakistan

Ali,

Shar,

Yekeen

et al. 2023

ACS Omega

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Significant amounts of hydrocarbon resources are left behind after primary and secondary recovery processes, necessitating the application of enhanced oil recovery (EOR) techniques for improving the recovery of trapped oil from subsurface formations. In this respect, the wettability of the rock is crucial in assessing the recovery and sweep efficiency of trapped oil. The subsurface reservoirs are inherently contaminated with organic acids, which renders them hydrophobic. Recent research has revealed the significant impacts of nanofluids, surfactants, and methyl orange on altering the wettability of organic-acid-contaminated subsurface formations into the water-wet state. This suggests that the toxic dye methylene blue (MB), which is presently disposed of in huge quantities and contaminates subsurface waters, could be used in EOR. However, the mechanisms behind hydrocarbon recovery using MB solution for attaining hydrophilic conditions are not fully understood. Therefore, the present work examines the impacts of MB on the wettability reversal of organic-acid-contaminated Khewra sandstone samples (obtained from the outcrop in the Potwar Basin, Pakistan) under the downhole temperature and pressure conditions. The sandstone samples are prepared by aging with 10 –2 mol/L stearic acid and subsequently treated with various amounts of aqueous MB (10–100 mg/L) for 1 week. Contact angle measurements are then conducted under various physio-thermal conditions (0.1–20 MPa, 25–50 °C, and salinities of 0.1–0.3 M). The results indicate that the Khewra sandstone samples become hydrophobic in the presence of organic acid and under increased pressure, temperature, and salinity. However, the wettability changes from oil-wet to preferentially water-wet in the presence of various MB solutions, thus highlighting the favorable effects of MB on EOR from the Khewra sandstone formation. Moreover, the most significant change in wettability is observed for the Khewra sandstone sample that was aged using 100 mg/L MB. These results suggest that injecting MB into deep underground Khewra sandstone reservoirs may produce more residual hydrocarbons.

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Section: Resultssupporting

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Impact of Methylene Blue on Enhancing the Hydrocarbon Potential of Early Cambrian Khewra Sandstone Formation from the Potwar Basin, Pakistan

Ali,

Shar,

Yekeen

et al. 2023

ACS Omega

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“…In unconventional reservoirs, due to the micron- to nanometer-scale pores, the change of wettability and other interfacial properties can significantly influence the capillary pressure . As the reservoir core is a micron-scale pore network system, increasing the water film thickness caused some of the flow channels in the pore throat structure to decrease in size . This phenomenon strengthens the capillary force, resulting in the discharge of crude oil from the pore space and the reduction of the residual oil content …”

Section: Resultsmentioning

confidence: 99%

“…38 This phenomenon strengthens the capillary force, resulting in the discharge of crude oil from the pore space and the reduction of the residual oil content. 38 3.3.2. Wettability Characteristics.…”

Section: Wettabilitymentioning

confidence: 99%

Experimental Study on the Mechanism and Law of Low-Salinity Water Flooding for Enhanced Oil Recovery in Tight Sandstone Reservoirs

Fan,

Liu,

et al. 2024

ACS Omega

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Currently, research surrounding low-salinity water flooding predominantly focuses on medium-to high-permeability sandstone reservoirs. Nevertheless, further investigation is necessary to implement this technique with regard to tight sandstone reservoirs. The present study comprises a series of experiments conducted on the crude oil and core of the Ordos Chang 6 reservoir to investigate the influence of ionic composition on low-salinity water flooding in tight oil reservoirs. The change in wettability on the rock surface was analyzed by using the contact angle experiment. The change in recovery rate was analyzed using a core displacement experiment. The reaction between rock fluids was analyzed using an ion chromatography experiment. Additionally, a nuclear magnetic resonance (NMR) experiment was used to analyze the mobilization law of crude oil and the change in wettability on the scale of the rock core. This led to a comprehensive discussion of the law and mechanism of enhancing the recovery rate via low-salinity water flooding from various perspectives. Experiments show that low-salinity water flooding is an effective technique for enhancing recovery in tight sandstone reservoirs. Altering the ionic composition of injected water can improve the water wettability of the rock surface and enhance recovery. Decreasing the mass concentration of Ca 2+ or increasing the mass concentration of SO 4 2− can prompt the ion-exchange reaction on the rock surface and detachment of polar components from the surface. Consequently, the wettability of the rock surface strengthens, augmenting the recovery process. Nuclear magnetic resonance experiments evidence that low-salinity water injection, with ion adjustment, significantly alters the interactions between the rock and fluid in tight sandstone reservoirs. As a result, the T 2 signal amplitude decreases significantly, residual oil saturation reduces considerably, and the hydrophilic nature of the rock surface increases.

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“…The development of conventional reservoirs cannot meet the current growing oil demand. Unconventional oil resources with high temperature, high salt, low permeability, and heterogeneity have been taken as the focus of development. − Due to the complex reservoir conditions, a variety of effective oil recovery methods have been developed for enhanced oil recovery (EOR). − Among them, chemical flooding has received significant attention in tertiary oil recovery. − At present, various types of surfactants are widely used in oil fields, including anionic surfactants, cationic surfactants, nonionic surfactants, and zwitterionic surfactants. − However, each surfactant has its limitations in application. Therefore, the development of surfactants with high surface activity and good environmental tolerance will be an important research direction. − …”

Section: Introductionmentioning

confidence: 99%

Properties and Aggregation Behavior of Gemini Surfactants for Heavy Oil Recovery in High Temperature and Salinity Conditions

Wang,

Zheng,

Shi

et al. 2023

Energy Fuels

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In this paper, the thermal stability of the surfactant CEA-n molecules with different structures was determined by thermal gravimetric analysis. The aggregation behavior in aqueous solution was studied by dynamic light scattering and transmission electron microscopy (TEM). The interfacial behavior, emulsification performance, and heavy oil universality of the surfactants under high temperature and high salinity conditions were evaluated by interfacial tension (IFT), viscosity reduction rate (VRR), and multiple light scattering. Also, microscopic oil displacement experiments were performed to investigate the oil displacement mechanism of the surfactant. Results indicated that the surfactant molecules had good thermal stability. The initial decomposition temperature (T i ) of surfactants CEA-n was greater than 280 °C. The average hydrodynamic radius (R h ) of the surfactant CEA-2 system after aging was larger than that of the unaged system, and the aggregation of CEA-2 molecules was promoted by the addition of NaCl. Moreover, the IFT of surfactant CEA-2 had a small change with the increase of aging temperature (100−300 °C), which could be maintained on the order of 10 −1 mN/m. And the VRR of the surfactants was higher than 95.0%, showing good emulsifying and viscosity reduction effects. Although the turbiscan stability index (TSI) value of the oil LD2-1 emulsion system was the lowest and had the best emulsion stability, the VRR between the surfactant and oil NB35-2 could reach more than 99.0%, indicating that CEA-2 had good heavy oil universality. Furthermore, the sand-pack flooding experiments were also carried out to confirm the great potential of the Gemini surfactant systems for heavy oil recovery.

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Investigation of salinity and ion effects on low salinity water flooding efficiency in a tight sandstone reservoir

Cited by 20 publications

References 50 publications

Impact of Methylene Blue on Enhancing the Hydrocarbon Potential of Early Cambrian Khewra Sandstone Formation from the Potwar Basin, Pakistan

Impact of Methylene Blue on Enhancing the Hydrocarbon Potential of Early Cambrian Khewra Sandstone Formation from the Potwar Basin, Pakistan

Experimental Study on the Mechanism and Law of Low-Salinity Water Flooding for Enhanced Oil Recovery in Tight Sandstone Reservoirs

Properties and Aggregation Behavior of Gemini Surfactants for Heavy Oil Recovery in High Temperature and Salinity Conditions

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