Heavy-Oil-Recovery Enhancement With Choline Chloride/Ethylene Glycol-Based Deep Eutectic Solvent

Summary Because of increasing energy demand, unconventional resources such as heavy oil are being explored and recovered. Enhanced-oil-recovery (EOR) methods such as surfactants and polymer flooding must be optimized and new chemicals must be designed to produce more oil. This paper introduces a new deep eutectic solvent (DES) that is based on choline chloride/ethylene glycol for EOR. As preliminary investigations revealed, different concentrations of DES solutions in brine (0 to 100 vol%) were characterized by measuring density, viscosity, conductivity, surface tension, and refractive index at different temperatures (25 to 55°C). Then, the effects of the DES/brine solutions on emulsification with oil phase, wettability alteration, oil/solvent interfacial tension (IFT), formation damage, and tertiary heavy-oil recovery were studied. Potential of the DES solution on enhancing heavy-oil recovery was explored by use of coreflood experiments. This was performed at reservoir condition (pressure = 1,200 psi, temperature = 45 to 80°C) with Berea sandstone core samples and fluids from the field of interest (formation brine and crude oil). An increase in IFT rather than a decrease was observed between the DES/brine solution and the oil. The spontaneous-water-imbibition tests suggested that a decrease in oil-wetness led to an increase in oil production. Approximately 52% of residual oil after waterflooding was recovered with the DES from the coreflooding. The results show an increase in oil recovery with reservoir temperature (6, 13, and 16% on the basis of initial oil in place at 45, 60 and 80°C, respectively). The interaction of the DES with the core materials did not lead to formation damage, as demonstrated by the permeability measurements of the DES/brine solution before and after injection. Viscous forces and wettability alteration were found to be the dominant mechanisms for the tertiary oil-recovery enhancement.

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Reconsideration of Steam Additives to Improve Heavy-Oil Recovery Efficiency: Can New Generation Chemicals Be a Solution for Steam-Induced Unfavorable Wettability Alteration?

Energy & Fuels ◽

10.1021/acs.energyfuels.0c01406 ◽

2020 ◽

Vol 34 (7) ◽

pp. 8283-8300 ◽

Cited By ~ 1

Author(s):

Randy Agra Pratama ◽

Tayfun Babadagli

Keyword(s):

Oil Recovery ◽

Heavy Oil ◽

Wettability Alteration ◽

Recovery Efficiency ◽

Heavy Oil Recovery ◽

New Generation

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Low Salinity Hot Water Injection With Addition of Nanoparticles for Enhancing Heavy Oil Recovery

Journal of Energy Resources Technology ◽

10.1115/1.4042238 ◽

2019 ◽

Vol 141 (7) ◽

Cited By ~ 8

Author(s):

Yanan Ding ◽

Sixu Zheng ◽

Xiaoyan Meng ◽

Daoyong Yang

Keyword(s):

Thermal Energy ◽

Oil Recovery ◽

Heavy Oil ◽

Water Injection ◽

Operating Conditions ◽

Hot Water ◽

Wettability Alteration ◽

Heavy Oil Recovery ◽

Oil Saturation ◽

Low Salinity

In this study, a novel technique of low salinity hot water (LSHW) injection with addition of nanoparticles has been developed to examine the synergistic effects of thermal energy, low salinity water (LSW) flooding, and nanoparticles for enhancing heavy oil recovery, while optimizing the operating parameters for such a hybrid enhanced oil recovery (EOR) method. Experimentally, one-dimensional displacement experiments under different temperatures (17 °C, 45 °C, and 70 °C) and pressures (about 2000–4700 kPa) have been performed, while two types of nanoparticles (i.e., SiO2 and Al2O3) are, respectively, examined as the additive in the LSW. The performance of LSW injection with and without nanoparticles at various temperatures is evaluated, allowing optimization of the timing to initiate LSW injection. The corresponding initial oil saturation, production rate, water cut, ultimate oil recovery, and residual oil saturation profile after each flooding process are continuously monitored and measured under various operating conditions. Compared to conventional water injection, the LSW injection is found to effectively improve heavy oil recovery by 2.4–7.2% as an EOR technique in the presence of nanoparticles. Also, the addition of nanoparticles into the LSHW can promote synergistic effect of thermal energy, wettability alteration, and reduction of interfacial tension (IFT), which improves displacement efficiency and thus enhances oil recovery. It has been experimentally demonstrated that such LSHW injection with the addition of nanoparticles can be optimized to greatly improve oil recovery up to 40.2% in heavy oil reservoirs with low energy consumption. Theoretically, numerical simulation for the different flooding scenarios has been performed to capture the underlying recovery mechanisms by history matching the experimental measurements. It is observed from the tuned relative permeability curves that both LSW and the addition of nanoparticles in LSW are capable of altering the sand surface to more water wet, which confirms wettability alteration as an important EOR mechanism for the application of LSW and nanoparticles in heavy oil recovery in addition to IFT reduction.

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Synergistic Effect of Nanofluids and Surfactants on Heavy Oil Recovery and Oil-Wet Calcite Wettability

Nanomaterials ◽

10.3390/nano11071849 ◽

2021 ◽

Vol 11 (7) ◽

pp. 1849

Author(s):

Jinjian Hou ◽

Lingyu Sun

Keyword(s):

Synergistic Effect ◽

Oil Recovery ◽

Heavy Oil ◽

Interaction Force ◽

Hot Water ◽

Wettability Alteration ◽

Heavy Oil Recovery ◽

Optimal Salinity ◽

Synergistic Mechanism ◽

Enhance Oil Recovery

In recent years, unconventional oils have shown a huge potential for exploitation. Abundant reserves of carbonate asphalt rocks with a high oil content have been found; however, heavy oil and carbonate minerals have a high interaction force, which makes oil-solid separation difficult when using traditional methods. Although previous studies have used nanofluids or surfactant alone to enhance oil recovery, the minerals were sandstones. For carbonate asphalt rocks, there is little research on the synergistic effect of nanofluids and surfactants on heavy oil recovery by hot-water-based extraction. In this study, we used nanofluids and surfactants to enhance oil recovery from carbonate asphalt rocks synergistically based on the HWBE process. In order to explore the synergistic mechanism, the alterations of wettability due to the use of nanofluids and surfactants were studied. Nanofluids alone could render the oil-wet calcite surface hydrophilic, and the resulting increase in hydrophilicity of calcite surfaces treated with different nanofluids followed the order of SiO2 > MgO > TiO2 > ZrO2 > γ-Al2O3. The concentration, salinity, and temperature of nanofluids influenced the oil-wet calcite wettability, and for SiO2 nanofluids, the optimal nanofluid concentration was 0.2 wt%; the optimal salinity was 3 wt%; and the contact angle decreased as the temperature increased. Furthermore, the use of surfactants alone made the oil-wet calcite surface more hydrophilic, according to the following order: sophorolipid (45.9°) > CTAB (49°) > rhamnolipid (53.4°) > TX-100 (58.4°) > SDS (67.5°). The elemental analysis along with AFM and SEM characterization showed that nanoparticles were adsorbed onto the mineral surface, resulting in greater hydrophilicity of the oil-wet calcite surface, and the roughness was related to the wettability. Surfactant molecules could aid in the release of heavy oil from the calcite surface, which exposes the uncovered calcite surface to its surroundings; additionally, some surfactants adsorbed onto the oil-wet calcite surface, and the combined role made the oil-wet calcite surface hydrophilic. In conclusion, the study showed that hybrid nanofluids showed a better effect on wettability alteration, and the use of nanofluids and surfactants together resulted in synergistic alteration of oil-wet calcite surface wettability.

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Microbial enhanced heavy oil recovery through biodegradation using fungal extracellular enzymes from Aspergillus spp.

10.21203/rs.2.19561/v2 ◽

2020 ◽

Author(s):

Junhui Zhang ◽

Hui Gao ◽

Hangxian Lai ◽

Shibin Hu ◽

Quanhong Xue

Keyword(s):

Enhanced Oil Recovery ◽

Oil Recovery ◽

Heavy Oil ◽

Energy Demand ◽

Extracellular Enzymes ◽

Substantial Contribution ◽

Good Growth ◽

Heavy Oil Recovery ◽

Mineral Salts ◽

Enzyme Preparations

Abstract Background: The progressive depletion of light crude oils has led to increased focus on efficient exploitation of heavy oil reserves to meet energy demand. Microbial enhanced oil recovery makes a substantial contribution to the recovery of heavy oils; however, most methods use bacteria, with less attention paid to the potential of fungi. In this study, we investigated the efficiency of fungal extracellular enzymes in biotransformation and biodegradation of heavy oil fractions into light compounds and the feasibility of the use of such enzyme preparations in enhanced oil recovery. Results: Two fungal strains of Aspergillus spp., isolated from bitumen samples, showed good growth on plates of mineral salts medium with heavy oil as the sole carbon source. The fungal extracellular enzymes, with dehydrogenase and catechol 2,3-dioxygenase activities, exhibited the ability to biodegrade heavy oil. The biodegradation process was coupled with abundant production of gases, mainly CO 2 and H 2 . Gas chromatography analysis revealed a significant redistribution of n -alkanes in the heavy oil after treatment with fungal enzyme preparations, which resulted in an increase in individual n -alkanes. The viscosity of the heavy oil was decreased 66.33% by fungal enzymatic degradation. Conclusions: These results demonstrate the potential of fungal extracellular enzymes from Aspergillus spp. for applications in enhanced heavy oil recovery, including biotransformation of heavy to lighter crude oil and byproduct biogas formation.

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