Influences of subcritical and supercritical CO2 treatment on the pore structure characteristics of marine and terrestrial shales

Pan, Yi; Hui, Dong; Luo, Pingya; Zhang, Yan; Zhang, Lu; Sun, Lijun

doi:10.1016/j.jcou.2018.09.016

Cited by 92 publications

(54 citation statements)

References 71 publications

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“…These interactions trigger dissolution, precipitation, and migration of fine clay grains, which can open or close the pore throats [148]. On the one hand, studies have revealed an increase of total porosity and connective porosity upon CO 2 exposure [140,142,144]; on the other hand, a decrease of porosity and connective porosity/matrix permeability was also reported [140,142,145,146,[148][149][150]. The increase in pore volume may be related to the decrease in capillary threshold pressure [144].…”

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 97%

“…It is also important to recall the different states of CO 2 while talking about the interactions between CO 2 and shale. Pan et al [140] showed that supercritical CO 2 has a significantly greater effect on shale than subcritical CO 2 . The effects of CO 2 -brine-shale interactions on porosity, permeability, pore size, and surface area have been reported by several experimental studies [141][142][143][144][145][146][147].…”

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

“…Wu et al [145] explained that this reduction in permeability was dependent on permeability's initial value in shale and the effective stress. Pan et al [140] investigated a broad range of pore structure parameter changes under sub and supercritical CO 2 exposure. It is difficult to highlight a single parameter behind the mechanism that decreases or increases the total porosity, pore diameter/width, and connective porosity under CO 2 exposure (especially supercritical CO 2 ).…”

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

“…It is difficult to highlight a single parameter behind the mechanism that decreases or increases the total porosity, pore diameter/width, and connective porosity under CO 2 exposure (especially supercritical CO 2 ). Dissolution and adsorption-induced expansion are the two most important mechanisms able to alter the pore structure during the interactions between subcritical CO 2 and shales, but these mechanisms may play different roles in pore structure modification [140]. On the one hand, geochemical reactions dissolve and destroy the internal structures of minerals, leading to nanopore enlargement; on the other hand, adsorption-induced expansion leads to volumetric changes, which may alter the pore structure and ultimately narrow the pores [145,146,152].…”

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

“…However, if the swelling stress exceeds the rock strength, it may destroy the sealing capacity [155]. Pan et al [140] noticed a difference in the changes of pore structures for marine and terrestrial sediments and concluded that more complicated geochemical reactions may exist between shale and CO 2 . Moreover, the presence of organic carbon, and its maturity, may affect pore structure modification [156,157].…”

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

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Micro- and Macroscale Consequences of Interactions between CO2 and Shale Rocks

et al. 2020

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In carbon storage activities, and in shale oil and gas extraction (SOGE) with carbon dioxide (CO2) as stimulation fluid, CO2 comes into contact with shale rock and its pore fluid. As a reactive fluid, the injected CO2 displays a large potential to modify the shale’s chemical, physical, and mechanical properties, which need to be well studied and documented. The state of the art on shale–CO2 interactions published in several review articles does not exhaust all aspects of these interactions, such as changes in the mechanical, petrophysical, or petrochemical properties of shales. This review paper presents a characterization of shale rocks and reviews their possible interaction mechanisms with different phases of CO2. The effects of these interactions on petrophysical, chemical and mechanical properties are highlighted. In addition, a novel experimental approach is presented, developed and used by our team to investigate mechanical properties by exposing shale to different saturation fluids under controlled temperatures and pressures, without modifying the test exposure conditions prior to mechanical and acoustic measurements. This paper also underlines the major knowledge gaps that need to be filled in order to improve the safety and efficiency of SOGE and CO2 storage.

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Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 97%

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

Section: Effect Of Co 2 On Petrophysical Parameters Of Shalementioning

confidence: 99%

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Micro- and Macroscale Consequences of Interactions between CO2 and Shale Rocks

et al. 2020

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Applied techniques for residual oil recovery from source rocks: A review of current challenges and possible developments

Abdulkareem

Padmanabhan

2020

Can J Chem Eng

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Depleted fossil fuel resources have led to an investigation of other promising alternatives such as renewable and unconventional energy sources. Shale formations have limited permeability. Therefore, several extraction techniques have been applied to improve residual oil recovery and production. In this work, the techniques applied above ground to extract the organic fractions from oil/gas shale are discussed. Studies related to compositional fractionation, ultrasonic-assisted, microwave-assisted, supercritical fluids, and surface retorting techniques have been conducted systematically in approximately 150 scholarly articles over the past 10 years. The impacts of each technique as well as the drawbacks and challenges are highlighted in this paper. The fractionation techniques are sufficient in general; however, they are time consuming as they include several stages and use a considerable amount of solvents. Ultrasonic and microwave techniques are highly reliant on formation transparency linked to the organic fraction heterogeneous distribution. The surface retorting method, which is highly efficient with up to 90% recovery, for example, the Galoter and Paraho methods, is still dependent on shale particulate size, generates a massive amount of spent shale as waste, and is prominently emissive. Therefore, assessments that can be used to overcome existing drawbacks are considered. This can provide practical insight about these techniques to overcome limitations and concerns in terms of efficiency, cost, environmental issues, and reliability features. The work highlights the dominant extraction techniques for further development.

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Chemomechanical effects of oxidizer‐CO₂ systems upon hydraulically fractured unconventional source rock

Hull

Abousleiman

2021

Can J Chem Eng

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Carbon dioxide (CO2) as supercritical (scCO2) or foamed (CO2‐Foam) fluid has been tested many times as a fracturing fluid, though it has not yet proven viable. Many challenges have been identified with scCO2 as a fracturing fluid, including poor additive solubility, low viscosity, and limited accessibility. However, CO2 is known to adsorb to organic matter (OM) and displace methane (i.e., enhanced coal bed methane [ECBM] operations), or to mobilize oil as in tertiary enhanced oil recovery. In this study we augment the efficacy of the kerogen control fluid (KCF) for stimulating unconventional rock formations by alternating aqueous oxidizing fracturing fluid with CO2 injection or by combining oxidizers directly with CO2 as a new additive. To this end, KCF‐CO2 tests were designed to treat OM and extend the depth of permeability enhancement. We report the first attempt to combine oxidizer with CO2 in the presence of source shale rocks at elevated temperature and pressure. Scanning electron microscopy imaging of the treated shale sample surfaces demonstrate potential porosity and permeability enhancement, though some mineral and organic deposits are also observed, which may prove to be detrimental. Meanwhile, alternating water‐based KCF with CO2 provides a potential improvement to the KCF as predicted by early lab results on OM. The KCF‐CO2 concept has no equivalent to date in unconventional hydraulic fracturing operations. This technology will contribute to reducing the footprint of anthropogenic CO2 and enhancing its permanent sequestration in unconventional stimulated reservoirs, compliant with our global clean energy initiative of carbon capture, utilization, and storage.

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Influences of subcritical and supercritical CO2 treatment on the pore structure characteristics of marine and terrestrial shales

Cited by 92 publications

References 71 publications

Micro- and Macroscale Consequences of Interactions between CO2 and Shale Rocks

Micro- and Macroscale Consequences of Interactions between CO2 and Shale Rocks

Applied techniques for residual oil recovery from source rocks: A review of current challenges and possible developments

Chemomechanical effects of oxidizer‐CO₂ systems upon hydraulically fractured unconventional source rock

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Influences of subcritical and supercritical CO2 treatment on the pore structure characteristics of marine and terrestrial shales

Cited by 92 publications

References 71 publications

Micro- and Macroscale Consequences of Interactions between CO2 and Shale Rocks

Micro- and Macroscale Consequences of Interactions between CO2 and Shale Rocks

Applied techniques for residual oil recovery from source rocks: A review of current challenges and possible developments

Chemomechanical effects of oxidizer‐CO2 systems upon hydraulically fractured unconventional source rock

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Product

Resources

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Chemomechanical effects of oxidizer‐CO₂ systems upon hydraulically fractured unconventional source rock