Classification Method and Application of Rock Fracture Ability by Supercritical CO2 Blasting

Zhu, Xiaoyan; Jia, Jianhong; Cai, Zhongwei

doi:10.1155/2022/7973016

Cited by 2 publications

(3 citation statements)

References 20 publications

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“…Based on some simple and easily measurable indicators of rock mass, engineering rock mass classification connects geological conditions and rock mechanical properties to comprehensively judge the quality of rock mass, reveal the possible rock mechanics problems, and provide parameters and basis for design and construction [1][2][3][4][5][6]. Köken [1] analyzed different rock characteristics based on various mineralogical, physical, and mechanical aggregate properties using AHP method.…”

Section: Introductionmentioning

confidence: 99%

“…Köken [1] analyzed different rock characteristics based on various mineralogical, physical, and mechanical aggregate properties using AHP method. Zhu [2] determined the level of rock mass fracturing by rock density, rock tensile strength, rock wave impedance, and rock mass integrity coefficient, based on that, the rock mass on Tibet Highway are divided into grade II, grade III, and grade IV. Chen [3] proposed an analytic hierarchy process (AHP) method based on confidence indexes.…”

Section: Introductionmentioning

confidence: 99%

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Comparison of different scale indicators and verification of rock mass classification

Hong,

Zhou,

et al. 2024

Eng. Res. Express

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The basic principle of fuzzy comprehensive evaluation is introduced, and different scales of determining indicator weights using Analytic Hierarchy Process (AHP) are summarized and organized. The inspection indicators for evaluating the quality of the judgment matrix are provided. Taking the underground station of a planned intercity railway as the engineering background, a comparative study is conducted on the advantages and disadvantages of the indicator judgment matrix and the comprehensive evaluation results about a n scale, 10/10 ∼ 18/2 scale, 9/9 ∼ 9/1 scale, 1 ∼ 9 scale. The results show that the consistency of the judgment matrix constructed by 1–9 scale is poor and may lead to incorrect evaluation results. The consistency of judgment matrix constructed by a n scale is optimal and the fuzzy comprehensive evaluation results are the closest to the actual situation. It can provide useful guidance for the classification work of surrounding rocks in underground engineering projects.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Comparison of different scale indicators and verification of rock mass classification

Hong,

Zhou,

et al. 2024

Eng. Res. Express

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“…Priors implemented comprehensive investigations on the borehole pressure evolution [19][20][21][22] , explosion energy [22,23] , shock wave [24,25] and fracture propagation [26][27][28][29] of CO2 blasting fracturing experimentally and numerically. Field tests indicate that the quantity of gas extraction from a single borehole controlled by fracturing increased by about 4 times in the initial 8 hours after CO 2 blasting [30] .…”

Section: Introductionmentioning

confidence: 99%

Laboratory Study of Supercritical CO2 Shock Fracturing in Hot Dry Rock: The Utilization of CO2 in Geothermal Stimulation

Xiaoguang¹,

Wu²,

Zou³

et al. 2023

Preprint

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Carbon dioxide (CO 2 ) has great utilization potential in the exploitation of deep geothermal resources, especially hot dry rock (HDR). As a clean and renewable resource, HDR geothermal presents a promising prospect in meeting the growing demand for energy and achieving low-carbon solutions. To address the challenges posed in HDR development, such as large water consumption, simple fracture pattern and corresponding fast thermal breakthrough of Enhanced Geothermal System (EGS), a novel non-aqueous stimulation method which combines the advantages of supercritical CO2 (SC) fracturing and dynamic shock effect is proposed and investigated in this paper, i.e. supercritical carbon dioxide shock (SCS) fracturing. To determine its stimulation performance in HDR, we performed controllable lab-scale SCS fracturing experiments on high-temperature granites subjected to true tri-axial stresses. By comparing with conventional water fracturing and SC-CO 2 fracturing, the fracture initiation behavior and stimulation performance of SCS fracturing were investigated quantitatively based on CT scanning and reinjection tests, with respect to fracture morphology and conductivity. Effects of critical parameters were analyzed as well, such as shock pressure, in-situ stress and rock temperature. Results indicate that the breakdown pressure of granite is 24.2~57.5% lower than the shock pressure during SCS fracturing, and it decreases with increasing rock temperature. SCS fracturing could create complex fracture network with more interconnected branches and larger seepage spaces. The volume, area and width of fractures by SCS fracturing are 545.3%, 98.4% and 126.3% higher than those of water fracturing, respectively. The fracture conductivity is 3.4~7.0 times and 4.5~21.2 times higher, as compared to water fracturing and SC fracturing. As the rock temperature increases, both the tortuosity and conductivity of fractures improve dramatically, which benefits to extend the flow path of working medium and enhance the heat transfer performance. In-situ stress plays a relatively weak role in controlling fracture propagation of SCS fracturing. At horizontal stress difference coefficient of 0.14~0.60, the fracture propagation behaves more randomly in direction, contributing to forming complex fractures with multi-branches. Higher shock pressure conduces to the stimulation performance enhancement of SCS fracturing, improving the complexity and connectivity of fracture networks, and promote the fracture to get rid of the control of insitu stress in EGS. The key findings are expected to provide a novel insight into developing HDR geothermal in a more environmentally and more efficient way, and achieving CO 2 utilization and storage.

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Classification Method and Application of Rock Fracture Ability by Supercritical CO2 Blasting

Cited by 2 publications

References 20 publications

Comparison of different scale indicators and verification of rock mass classification

Comparison of different scale indicators and verification of rock mass classification

Laboratory Study of Supercritical CO2 Shock Fracturing in Hot Dry Rock: The Utilization of CO2 in Geothermal Stimulation

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