Influences of formation water invasion on the wellbore temperature and pressure in supercritical CO 2 drilling

Wang, Haizhu; Shen, Zhonghou; Li, Gensheng

doi:10.1016/s1876-3804(11)60039-6

Cited by 17 publications

(5 citation statements)

References 6 publications

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“…88 This characteristic of SC-CO 2 helps reduce damage near the wellbore and decreases the skin factor, thereby reducing the oil and gas flow resistance. Haizhu et al 89 prepared a mathematical model based on the special physical properties (density, viscosity, thermal conductivity, heat capacity, etc.) of supercritical CO 2 to study the influence of formation water invasion on the distribution of temperature and pressure in the wellbore during SC-CO 2 drilling.…”

Section: Sc-co 2 -Based Drillingmentioning

confidence: 99%

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

et al. 2022

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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...

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Section: Sc-co 2 -Based Drillingmentioning

confidence: 99%

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

et al. 2022

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“…EGS could be considered as economical development only when the injection capacity reaches 50 kg/s [16] . In addition, taking CO 2 as the substitution of conventional waterbased fracturing fluid can not only eliminate the environmental risks mentioned above, but achieve CO 2 utilization and storage, providing a potential decarbonization solution [17,18] .…”

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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“…The physical properties of the mixture were calculated by the Pen-Robinson Equations of State (hereinafter referred to as EoS). Wang [43] combined the Span-Wagner model [44], Fenghour model [45], and Vesovic model [46] with the quasisteady temperature equation and the steady mass and momentum equations to analyze the wellbore temperature and pressure distribution in a vertical well during supercritical CO 2 drilling. Dou [47] applied a similar method to simulate the wellbore temperature field of the CO 2 flooding process and compared it with the measured data to verify the accuracy of the model.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on Wellbore Temperature Prediction during the CO2 Fracturing in Horizontal Wells

Lyu

Zhang

et al. 2021

Sustainability

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A novel model is established to predict the temperature field in the horizontal wellbore during CO2 fracturing. The pressure work and viscous dissipation are considered, and the transient energy, mass and momentum equations as well as the CO2 physical properties are solved fully coupled. The model passes the convergence test and is verified through a comparison using the COMSOL software. Then, a sensitivity analysis is performed to study the effects of the treating parameters. Results illustrate that the relationship between the injection rate and the stable bottom-hole temperature (hereinafter referred to as BHT) is non-monotonic, which is different from the hydraulic fracturing. The existence of the horizontal section will increase the BHT at 2 m3/min condition but reduce the BHT at 10 m3/min condition. The problem of high wellbore friction can be alleviated through tube size enhancement, and the ultimate injection rate allowed increased from 2.7 m3/min to 29.6 m3/min when the tube diameter increased from 50.3 mm to 100.3 mm. Additionally, the open-hole completion method of the horizontal section can increase the BHT to 2.7 °C but reduce the near formation temperature to 24.5 °C compared with the casing completion method.

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Influences of formation water invasion on the wellbore temperature and pressure in supercritical CO 2 drilling

Cited by 17 publications

References 6 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

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

Numerical Investigation on Wellbore Temperature Prediction during the CO2 Fracturing in Horizontal Wells

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Influences of formation water invasion on the wellbore temperature and pressure in supercritical CO 2 drilling

Cited by 17 publications

References 6 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

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

Numerical Investigation on Wellbore Temperature Prediction during the CO2 Fracturing in Horizontal Wells

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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