Energy Characteristics of Seismic Waves on Cardox Blasting Tube

Cui, Xuejiao; Ke, Bo; Yu, Songtao; Li, Ping; Zhao, Mintao

doi:10.1155/2021/9919764

Cited by 2 publications

(2 citation statements)

References 25 publications

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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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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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“…In summary, even though extensive studies on the ground vibration characteristics induced by drilling and blasting excavation and the vibration energy caused by liquid CO 2 phase-changing technique in rock engineering have been conducted experimentally and numerically. There is still a lack of investigations on dynamic responses of ground vibration, including blasting vibration propagation and attenuation law [9,[22][23][24]. On this basis, the purpose of this paper is to study the ground vibration characteristics during the liquid CO 2 rock fracturing process by performing on-site tests and numerical simulations.…”

Section: Introductionmentioning

confidence: 99%

Study on ground vibration characteristics induced by liquid CO2 blasting technique in bench excavation

Ruan¹,

Pan²,

Wang³

et al. 2022

J. vibroeng.

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The liquid CO2 phase change fracturing technique has been widely applied in rock engineering for a long time. However, the ground vibration characteristics in bench excavation have not been well demonstrated. In this study, the particle velocities, main frequencies, and displacements of rock induced by liquid CO2 blasting are investigated based on field tests and numerical simulations. Firstly, three field tests of bench excavation using DM83-1.4 type liquid CO2 storage tube were implemented in a specific highway slope project, in which the TC-4850 N vibration monitors were installed at horizontal distances of 4.2 m, 10.6 m, 20.3 m and 32.2 m from the detonation source to detect the rock vibration velocity and frequency. Subsequently, by employing the dynamic finite element program LS-DYNA, a three-dimensional numerical model was established, and then the particle velocities and displacements were analyzed and discussed. The research results indicate that the peak particle velocity (PPV) decays with distance in an exponential pattern, that is, the PPV decays rapidly in the near zone of the blasting source, and it decays more slowly in the far zone. At the position of 20.3 m in the horizontal distance and 15.8 m in elevation, an elevation amplification effect appears with an amplification factor of 1.12. Moreover, the vibration frequency generated by the liquid CO2 phase change fracturing technique is in the range of 0-80 Hz, which is much smaller than that induced by explosive blasting. The main frequency in the near-field of the blasting source is dominated by the radial frequency (Fr), while the vertical frequency (Fv) is dominant in the far-field. The attenuation law of displacement is generally consistent with the vibration velocity, and the difference between radial and tangential displacement increases gradually with distance.

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Energy Characteristics of Seismic Waves on Cardox Blasting Tube

Cited by 2 publications

References 25 publications

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

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

Study on ground vibration characteristics induced by liquid CO2 blasting technique in bench excavation

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