Combination of a chemical blend with CO2 huff-n-puff for enhanced oil recovery in oil shales

Zeng, Tongzhou; Miller, Chammi; Mohanty, Kishore K.

doi:10.1016/j.petrol.2020.107546

Cited by 29 publications

(15 citation statements)

References 17 publications

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“…In this work, our goal was to determine whether CO 2 -dissolved surfactants can alter the wettability of shale and whether that alteration leads to an increased oil recovery in unconventional formations when compared to CO 2 alone. To the best of our knowledge, this work represents the first time that surfactants have been dissolved directly in CO 2 to increase shale oil extraction via wettability alteration. − Others have added surfactants to the aqueous phase during surfactant-alternating CO 2 gas (SAG) injection in shale, presoaked cores in aqueous surfactant solutions before CO 2 injection, , coinjected aqueous surfactant solutions with CO 2 to produce foams, used ethanol as a cosolvent to dissolve ionic and nonionic surfactants in CO 2 , − or used high concentrations of CO 2 -soluble surfactants (0.5 wt %) to reduce CO 2 –oil IFT . In our current study, no water, brine, or cosolvent is introduced to the shale during the huff-n-puff process; only the injection of a CO 2 -surfactant solution is considered.…”

Section: Introductionmentioning

confidence: 99%

Dissolving Nonionic Surfactants in CO₂ to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

et al. 2022

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CO2 injection is a promising method for enhanced oil recovery (EOR) in unconventional shale reservoirs. In this work, we postulate that CO2 EOR may be improved by the dissolution of surfactants into CO2. Although CO2 is a relatively good solvent for oil, we show that CO2 and Eagle Ford oil are immiscible at compositions above 70 wt % CO2, even at pressures as high as 62 MPa. The presence of a CO2–oil interface at reservoir conditions indicates that the addition of a surfactant has the potential to improve oil recoveryvia wettability alteration from oil-wet to CO2-wet, CO2–oil interfacial tension (IFT) reduction, or both. Three nonionic surfactants (branched tridecyl ethoxylate Indorama SURFONIC TDA-9, branched nonylphenol ethoxylate Indorama SURFONIC N-100, and linear dodecyl ethoxylate Indorama SURFONIC L12-6) were evaluated for CO2-solubility, shale wettability alteration, effect on CO2–oil IFT, ability to generate CO2–oil foams, and ability to increase oil extraction from Eagle Ford, Mancos, and Bakken shale cores. Each surfactant dissolved in CO2 up to 1 wt % at pressures and temperatures commensurate with CO2 EOR. CO2-dissolved surfactants did not significantly affect CO2–oil IFT or generate CO2–oil foams, but they did induce a dramatic change in the contact angle of an oil droplet on an oil-aged shale chip in CO2 from strongly oil-wet (11°) toward intermediate CO2–oil wettability (82°) (at 80 °C, 27.6 MPa). The branched tridecyl ethoxylated surfactant, SURFONIC TDA-9, afforded the highest oil recovery in core soaking experiments75%, compared to 71% by pure CO2. Analysis of oil extracts by gas chromatography revealed that heavier oil components were produced when the surfactant was added to CO2. These results indicate that CO2-dissolved surfactants may increase oil recovery from shale by wettability alteration from oil-wet toward CO2-wet.

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Section: Introductionmentioning

confidence: 99%

Dissolving Nonionic Surfactants in CO₂ to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

et al. 2022

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“…Increasing energy demands make fine-grained sedimentary rocks become the active research field of petroleum exploration. − Specifically, the uptick in crude oil production in North America is mostly from shale oil. However, due to extremely low permeabilities and the need for hydraulic fracturing to stimulate oil from nanoscale shale matrixes, , the current shale oil recovery rate is less than 10%. − The current low oil recovery rate is strongly affected by shale pore structures and components including organic matter (OM) and minerals …”

Section: Introductionmentioning

confidence: 99%

Role of Organic Matter, Mineral, and Rock Fabric in the Full-Scale Pore and Fracture Network Development in the Mixed Lacustrine Source Rock System

et al. 2022

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The mixed deposition constitutes the external clastic, intrabasinal, and pyroclastic components in both marine and lacustrine environments. The finegrained mixed lacustrine source rocks are rich in organic matter and present good unconventional energy resources. However, the mixed lacustrine source rock systems have extremely low permeabilities and need hydraulic fracturing to stimulate oil from the complex nanoscale matrix. The role of rock fabric, organic matter, and mineral compositions in full-scale pore structures is still unclear, especially for the source rock from a mixed sedimentary environment. This restricts sweet spot identification. Here, we use three groups of Permian Lucaogou source rock samples with fine laminated, thick laminated, and massive rock fabric to investigate the relationship between rock fabric, organic matter, and pore structure using a combination of mineralogy, organic geochemistry, low-pressure nitrogen adsorption, micro-CT, and mercury injection capillary pressure data. The results indicate that the Lucaogou source rocks mainly contain type I and type II kerogen and show good to excellent hydrocarbon generation potential. The source rock was deposited in a mixed environment with high contents of carbonate and less siliceous minerals, showing good frackability. The mineralogy-based ternary classification shows that the source rock mainly belongs to high total organic carbon (TOC > 4%) mixed carbonate mudstone and high TOC mixed mudstone. For mixed lacustrine source rock, the full-scale pore-fracture distribution shows that the average percentage values of pore volume for micropores (<10 nm), transitional pores (10−100 nm), mesopores (100−1000 nm), and macropores (fracture) (>1000 nm) are 11.14, 21.62, 10.77, and 56.47%, respectively. However, the average percentage values of pore surface area for the abovementioned pores are 62.45, 30.45, 5.47, and 1.63%, respectively. Both quartz and terrigenous clast present a weak-medium unimodal correlation with the TOC content. Both terrigenous clast and clay minerals control the source rock hydrocarbon generation potential. The carbonate and terrigenous clast mineral content play a significant role in micropores and transitional pores, while the clay mineral presents a negative impact on macropore development. The effect of rock fabric on shale oil potential is negligible compared with organic matter abundance. Shales with thick parallel laminae and medium TOC (2% < TOC < 4%) possess favorable shale oil potential.

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“…At the present time, CO 2 -enhanced oil recovery technology is widely used in many oil-field projects. 1 However, the produced fluid contains much CO 2 , 2 so it is critical to improve the gas-liquid separation process in the separator at the first station. In this respect, the flow characteristics of the CO 2 -containing oil-water fluid mixture in the separator are complicated by the solubility of CO 2 in the liquid phase.…”

Section: Introductionmentioning

confidence: 99%

“…Computational fluid dynamics (CFD) is an important tool for analyzing the complex flow state in separators, and for the improvement of devices. At the present time, CO 2 ‐enhanced oil recovery technology is widely used in many oil‐field projects 1 . However, the produced fluid contains much CO 2 , 2 so it is critical to improve the gas–liquid separation process in the separator at the first station.…”

Section: Introductionmentioning

confidence: 99%

Numerical simulation on gas–liquid separation characteristics in a GLCC‐horizontal combined separator

Zhang

2022

Energy Science & Engineering

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Currently, computational fluid dynamics has become the primary method for analyzing the fluid flow state inside the machine. Herein, the Ansys Fluent software is used to design a more effective oil‐field device, namely, a gas–liquid cylindrical cyclone (GLCC)‐horizontal combined separator. The characteristics of gas–liquid mixed flow, fluid turbulence intensity, and phase volume fraction distribution are analyzed, and the factors affecting the gas–liquid separation efficiency are evaluated under various working conditions. The results show that low gas–liquid separation efficiencies are obtained at inlet liquid ratios (liquid proportion in fluid) of both 30% and 70% in GLCC. After the fluid enters the separator, the maximum level of turbulence in the collision area increases from 2.458 to 3.033 m2/s2 as the inlet liquid ratio is increased from 30% to 70%, with the generation of oil–water and gas–liquid stratification at the back. Furthermore, the maximum gas holdup in the liquid outlet increases from 7% to 12% to 25% as the liquid ratio is increased from 30% to 50% to 70%. With throttling at a liquid ratio of 70%, the maximum gas holdup is again close to 14%.

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Combination of a chemical blend with CO2 huff-n-puff for enhanced oil recovery in oil shales

Cited by 29 publications

References 17 publications

Dissolving Nonionic Surfactants in CO₂ to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

Dissolving Nonionic Surfactants in CO₂ to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

Role of Organic Matter, Mineral, and Rock Fabric in the Full-Scale Pore and Fracture Network Development in the Mixed Lacustrine Source Rock System

Numerical simulation on gas–liquid separation characteristics in a GLCC‐horizontal combined separator

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Combination of a chemical blend with CO2 huff-n-puff for enhanced oil recovery in oil shales

Cited by 29 publications

References 17 publications

Dissolving Nonionic Surfactants in CO2 to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

Dissolving Nonionic Surfactants in CO2 to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

Role of Organic Matter, Mineral, and Rock Fabric in the Full-Scale Pore and Fracture Network Development in the Mixed Lacustrine Source Rock System

Numerical simulation on gas–liquid separation characteristics in a GLCC‐horizontal combined separator

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Product

Resources

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Dissolving Nonionic Surfactants in CO₂ to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration

Dissolving Nonionic Surfactants in CO₂ to Improve Oil Recovery in Unconventional Reservoirs via Wettability Alteration