Mechanism of CO2 enhanced oil recovery in shale reservoirs

Li, Haibo; Yang, Zhengming; Li, Ruishan; Zhou, Tiyao; Guo, Honglian; Liu, Xuewei; Dai, Yi-Xin; Hu, Zhen-Guo; Meng, Huan

doi:10.1016/j.petsci.2021.09.040

Cited by 51 publications

(19 citation statements)

References 47 publications

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“…The numerical modeling of CO 2 -EOR in Bakken shale by Mahzari et al [18], as well as the five-step recovery process proposed by Hawthorne et al [19], supports the use of EOR through diffusion (driven by concentration gradient). The experiments by Li et al [20] on shales from the Jianghan oilfield, Jianghan Basin, also indicated the preferential tendency of CO 2 to recover lighter hydrocarbon, which can be caused by the above mechanism.…”

Section: Introductionmentioning

confidence: 93%

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

et al. 2022

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The recovery factor in unconventional reservoirs is typically 5-10%, with extensive hydraulic fracturing and infill drilling to maintain the production rate. Concurrently, the rush towards decarbonization is opening up new possibilities for CO2 utilization, enhanced oil recovery (EOR) being one example. CO2-EOR in unconventional reservoirs presents an opportunity for both financial gain through improved recovery factors, as well as reducing the carbon footprint of the produced oil. In this work, we examine the CO2-EOR potential in 4 organic-rich shale samples from the Canadian Bakken Formation. A number of characterization tests alongside CO2 extraction experiments were performed to gain insight into the controlling factors of CO2-EOR in these ultra-tight formations. The results show CO2 can penetrate the tight rock matrix and recover a substantial amount of hydrocarbon. Concentration gradient driven diffusion is the dominant form of recovery.

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Section: Introductionmentioning

confidence: 93%

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

et al. 2022

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“…Gas injection can effectively solve the shortcomings of water injection development and has become an important means to enhance oil recovery in the world. At present, the gas injection media mainly include CO 2 , N 2 , air, hydrocarbon gas, and flue gas. − Compared with other injection gases, CO 2 has the advantages of being easily miscible with crude oil, having a low miscible pressure, promoting volume expansion of crude oil, reducing crude oil viscosity, reducing oil–water interfacial tension, improving crude oil flow characteristics, and forming dissolved gas flooding. , In addition, the weak acidity of CO 2 dissolved in water can play a role in acidizing plugging to a certain extent. CO 2 flooding can enhance oil recovery by 7–18% .…”

Section: Introductionmentioning

confidence: 99%

“… 1 − 5 Compared with other injection gases, CO 2 has the advantages of being easily miscible with crude oil, having a low miscible pressure, promoting volume expansion of crude oil, reducing crude oil viscosity, reducing oil–water interfacial tension, improving crude oil flow characteristics, and forming dissolved gas flooding. 6 , 7 In addition, the weak acidity of CO 2 dissolved in water can play a role in acidizing plugging to a certain extent. CO 2 flooding can enhance oil recovery by 7–18%.…”

Section: Introductionmentioning

confidence: 99%

Solubility Variation and Prediction Model of CO₂ in Water-Bearing Crude Oil

Zhang

Guan

et al. 2022

ACS Omega

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The solubility of CO2 in water-bearing crude oil is of great significance for the calculation of crude oil reserves, the development of CO2-EOR (CO2-enhanced oil recovery), CO2-CCUS (carbon capture, utilization, and storage), and CO2 assisted steam huff-and-puff technology, and the optimization of the design of CO2 for heavy oil pipeline transportation. In order to determine the variation of the solubility of water-bearing crude oil by injecting CO2 into the formation, taking the Upper Wuerhe Formation reservoir in the 53 East Block as an example, the study of the dissolution characteristics of CO2 in water-bearing crude oil at different temperature and pressure conditions was carried out by using a high-temperature and high-pressure reaction kettle. At the same time, a new solubility prediction model of CO2 in water-bearing crude oil was proposed based on the existing solubility prediction models. The results show that, under the same water cut, the solubility of CO2 in water-bearing crude oil decreases with the increase of temperature and decreases with the decrease of pressure. At the same time, the solubility of CO2 in water-bearing crude oil is more sensitive to pressure. At the same temperature, the solubility of CO2 in water-bearing crude oil decreases with the increase of water cut, and the higher the pressure, the greater the effect of water cut on the solubility of CO2 in water-bearing crude oil. The newly established combined prediction model of CO2 solubility in water-bearing crude oil is convenient for calculation and has a wide range of applications. The average relative error is only 9.5%, which can meet the requirements of engineering calculation accuracy.

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“…Various research methods and testing methods are for microscopic pore-throat characteristics of reservoirs, − among which the NMR T 2 spectrum can quantitatively reflect rock pore throat structure and fluid occurrence state. − Scholars take shale reservoirs − and tight sandstone reservoirs − as research objects, and studies have been carried out by using NMR technology to analyze the distribution of pore throats, the occurrence of movable fluids, the oil displacement mechanism of reservoirs, and the distribution of remaining oil. Wei et al, Chen et al, and Li et al used low-field NMR technology to quantitatively characterize the microscopic oil displacement mechanism of low-permeability sandstone, tight sandstone, and shale under different injection media. Li et al, Huang et al, and Dou et al used low-field NMR technology to quantitatively characterize the microscopic pore throat damage mechanism of low-permeability sandstone, tight sandstone, and shale under different development methods.…”

Section: Introductionmentioning

confidence: 99%

Influence of Sand Production Damage in Unconsolidated Sandstone Reservoirs on Pore Structure Characteristics and Oil Recovery at the Microscopic Scale

Luo²,

Yu³

et al. 2022

ACS Omega

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Unconsolidated sandstone reservoirs have low rock strength and are easily damaged by sand production. To evaluate the effect of the microscopic pore system on the degree of recovery and sand production damage, five typical unconsolidated sandstone core samples were selected. The nuclear magnetic resonance T 2 spectrum of the water-flooding experiments was used to analyze the oil displacement mechanism and sand production damage of the pore throat structure, and the control mechanism of the injection parameters was used to evaluate the recovery and sand production damage degree. The results showed that the recovery of the unconsolidated sandstone core samples was the highest when the injection volume was 6 PV, and the overall pore throat recovery increased from 14.37 to 48.72%. The recovery and sand production damage increased with increasing injection pressure. The overall pore throat recovery was the highest when the pressure was 20 MPa (48.42%), and the sand production damage index was the maximum when the pressure was 25 MPa (19.98%). Under a lower injection pressure, sand production damage mainly originates from loose sand. The main target of loose sand production damage is a smaller pore throat, and the sand production index increases slowly. The recovery increased with the pressure and increased relatively quickly. Under a higher injection pressure, sand production damage mainly comes from loose sand and skeleton sand, causing damage to both smaller and larger pore throats. The sand production damage is positively correlated with injection pressure. The recovery slows down with an increase in pressure or even decreases.

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Mechanism of CO2 enhanced oil recovery in shale reservoirs

Cited by 51 publications

References 47 publications

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

Solubility Variation and Prediction Model of CO₂ in Water-Bearing Crude Oil

Influence of Sand Production Damage in Unconsolidated Sandstone Reservoirs on Pore Structure Characteristics and Oil Recovery at the Microscopic Scale

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Mechanism of CO2 enhanced oil recovery in shale reservoirs

Cited by 51 publications

References 47 publications

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

CO2-Enhanced Oil Recovery Mechanism in Canadian Bakken Shale

Solubility Variation and Prediction Model of CO2 in Water-Bearing Crude Oil

Influence of Sand Production Damage in Unconsolidated Sandstone Reservoirs on Pore Structure Characteristics and Oil Recovery at the Microscopic Scale

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Solubility Variation and Prediction Model of CO₂ in Water-Bearing Crude Oil