Hydro-mechanical properties of a low-clay shale with supercritical CO2 imbibition

Lyu, Qiao; Wang, Kaixi; Wanniarachchi, W.A.M.; Hu, Chenger; Shi, Jinyan

doi:10.1007/s40948-020-00200-x

Cited by 15 publications

(6 citation statements)

References 43 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The variations in the strength characteristics for samples with different adsorption time revealed similar change trends with the bedding orientation angle. The effect of SC-CO 2 imbibition for 30 days on the triaxial compressive strength of low-clay samples was investigated by Lyu et al 191 They observed increase in the axial stresses with increasing confining pressures with or without SC-CO 2 saturation. However, axial stresses of samples with the same confining pressure revealed losses in strength and rigidity, because of SC-CO 2 imbibition.…”

Section: Influence Of Sc-co 2 On Shale Petrophysics Geomechanics and ...mentioning

confidence: 99%

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

et al. 2022

View full text Add to dashboard Cite

Hydraulic fracturing has transformed the international energy landscape by becoming the go-to method for the exploitation of natural gas from unconventional shale reservoirs. However, in the recent years, the search for an alternative method of shale-gas exploration has intensified, because of various problems (e.g., contamination of ground and surface water, overexploitation of precious water resources, air pollution, etc.) associated with the usage of water-based fracturing techniques. The use of CO2 for shale gas exploitation has emerged as a better alternative to aqueous-based gas exploration techniques. CO2 when injected into deep shale reservoirs, transitions into supercritical CO2 (SC-CO2) when temperature and pressure condition exceeds the critical point, i.e., 31.1 °C and 7.38 MPa. In this paper, we comprehensively review the impact of SC-CO2 on shale gas reservoirs during the different stages of shale-gas exploration, i.e., (i) drilling, which involves the superiority of SC-CO2 over water-based drilling fluids, in terms of achieving under-balanced well condition, higher rates of penetration, and resistance to formation damage; (ii) fracturing, which involves factors affecting the tortuosity of fractures created by SC-CO2 fracturing, breakdown pressure, and proppant-carrying capacity; and (iii) injection, which involves the twin-headed benefit of enhanced recovery due to CO2/CH4 competitive adsorption and geological sequestration, CO2 vs CH4 excess sorption as a function of pressure, etc. Several research works have indicated discrepancies on how SC-CO2 impacts different shale properties. Some studies show low-pressure N2-gas-adsorption-derived surface area and total pore volume to be increasing with SC-CO2 imbibition, while others show a decreasing trend for the same. Similarly, for some shales, the quartz content, along with the clay mineral contents, decreased as the exposure to SC-CO2 increased, while in some other studies, with similar long-term exposure to SC-CO2, the quartz content was observed to increase along with the decrease in clay content and vice versa. Essentially, the increased exposure to SC-CO2 results in the dissolution of primary porous structures and fractures, and reformation of newer porous structure and conduits in shales. Nonetheless, these changes in the mineralogy weaken the microstructure of the rock bringing significant changes in the mechanical properties of the shales with implications on the wellbore stability and fracturing efficiency. The mechanical properties such as uniaxial compressive strength (UCS), Young’s modulus, and tensile strength decrease as the SC-CO2 saturation period increases. However, some studies have shown factors like bedding angle and phase-state of CO2 having varying effect on the strength behavior of the shales. Moreover, changes in the structure of shales caused by the creation of fractures and the reduction of their strength can also pose major risks, because of potential leakage of CO2 through these created pathways. How these processes would i...

show abstract

Section: Influence Of Sc-co 2 On Shale Petrophysics Geomechanics and ...mentioning

confidence: 99%

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Actually, the variation of the mechanical parameters of shale rock relating to CO 2 soaking has been widely studied. According to published data, three groups of shale rock’s mechanical parameters under different soaking times were collected, as shown in Table . − It is shown that both the elastic modulus and Poisson’s ratio decline with the increment of CO 2 soaking time. However, the parameters of internal friction angle and cohesion rarely vary with CO 2 soaking .…”

Section: Numerical Simulation Of Hydraulic Fracturing After Co2 Soakingmentioning

confidence: 99%

“…According to published data, three groups of shale rock’s mechanical parameters under different soaking times were collected, as shown in Table . − It is shown that both the elastic modulus and Poisson’s ratio decline with the increment of CO 2 soaking time. However, the parameters of internal friction angle and cohesion rarely vary with CO 2 soaking . Thus, the varied elastic modulus and Poisson’s ratio were arranged for the numerical model in different scenarios, while the internal friction angle and cohesion remain constant.…”

Section: Numerical Simulation Of Hydraulic Fracturing After Co2 Soakingmentioning

confidence: 99%

Numerical Simulation Study on the Effect of Preinjected CO₂ on the Hydraulic Fracturing Behavior of Shale Oil Reservoirs

Yu,

Ding,

Wang

et al. 2024

ACS Omega

View full text Add to dashboard Cite

Due to the low permeability and apparent mechanical anisotropy of shale reservoirs, shale oil production highly depends on the performance of hydraulic fracturing of the tight reservoir. Pre-injection of CO 2 before hydraulic fracturing treatment has been proven beneficial to enhance shale oil production. A comprehensive understanding of the effect of changes in the properties of shale reservoirs after preinjected CO 2 on the hydraulic fracturing behavior of shale reservoirs is essential to improve the stimulated reservoir volume (SRV) of shale oil reservoirs. In this study, comprehensive evaluating parameters were proposed to specify the variation of mechanical properties of shale rock at different soaking times of CO 2 based on published testing parameters of shale. Accordingly, a threedimensional (3D) numerical model was established and three groups of horizontal well fracturing cases with different cluster spacings were conducted based on the adaptive FE−DE method to simulate and compare the hydraulic fracturing behavior in the reservoirs with different mechanical properties. We established a quantitative relationship between the alterations in reservoir properties and the stimulated reservoir volume. The results indicate that both the brittleness and conductivity properties of shale rock are dramatically improved as the increment of soaking time of CO 2 . It is beneficial to improve the SRV, and the initiation pressure is reduced with the increment of soaking time of CO 2 . However, as the stress shadow effect is involved in the horizontal well fracturing, the complexity of the hydrofracturing crack is significantly enhanced to restrain the development of hydrofracturing crack. When the cluster spacing is larger, the stress shadow effect is weakened, and the weakening effect of CO 2 soaking on reservoir is more obvious.

show abstract

“…On one hand, the organic content in kerogen can be extracted by CO 2 , converting micropores in kerogen to meso- or macropores. In addition, the carbonic acid dissolves minerals to form secondary dissolution pores, converting micropores in inorganic matter into meso- or macropores. − On the other hand, the dissolved mineral ions can react with carbonic acid, generating precipitates on the pore surface to reduce the pore size. The precipitated particles can also migrate to block the pore throat .…”

Section: Co2-induced Mineralization and Its Influences On Shale Prope...mentioning

confidence: 99%

Minireview of Microscopic CO₂ Interactions with Fluids and Minerals in Shale: Advances and Outlook

et al. 2023

View full text Add to dashboard Cite

Shale is featured by nanometer pores and ultralow permeability. Enhancing shale oil recovery after primary production is challenging as a result of the low injectivity of water. CO 2 could be a promising injection fluid to enhance shale oil recovery for its high mobility in porous media and mixability with hydrocarbons. Fluid behaviors in the nanometer pores of shale reservoirs deviate from those in the micrometer pores of conventional reservoirs. The previous understanding of CO 2 displacement and sequestration in conventional reservoirs is not completely applicable to shale reservoirs. In this review, we analyzed research advances in CO 2 interactions with reservoir fluids and shale rocks at the microscopic level. We delineated recent progress in interpreting phase behavior, mass transfer of the CO 2 −oil system confined in nanometer pores, and reshaping of CO 2 -induced mineralization in shale porous media. We also discussed limitations and future directions for studying CO 2 injection in shale reservoirs, from the experimental scope, theoretical analysis, and field application.

show abstract

Hydro-mechanical properties of a low-clay shale with supercritical CO2 imbibition

Cited by 15 publications

References 43 publications

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Numerical Simulation Study on the Effect of Preinjected CO₂ on the Hydraulic Fracturing Behavior of Shale Oil Reservoirs

Minireview of Microscopic CO₂ Interactions with Fluids and Minerals in Shale: Advances and Outlook

Contact Info

Product

Resources

About

Hydro-mechanical properties of a low-clay shale with supercritical CO2 imbibition

Cited by 15 publications

References 43 publications

Impact of Supercritical CO2 on Shale Reservoirs and Its Implication for CO2 Sequestration

Impact of Supercritical CO2 on Shale Reservoirs and Its Implication for CO2 Sequestration

Numerical Simulation Study on the Effect of Preinjected CO2 on the Hydraulic Fracturing Behavior of Shale Oil Reservoirs

Minireview of Microscopic CO2 Interactions with Fluids and Minerals in Shale: Advances and Outlook

Contact Info

Product

Resources

About

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Impact of Supercritical CO₂ on Shale Reservoirs and Its Implication for CO₂ Sequestration

Numerical Simulation Study on the Effect of Preinjected CO₂ on the Hydraulic Fracturing Behavior of Shale Oil Reservoirs

Minireview of Microscopic CO₂ Interactions with Fluids and Minerals in Shale: Advances and Outlook