Mechanism of hydraulic fracture vertical propagation in deep shale formation based on elastic–plastic model

Liao, Songze; Hu, Jinghong; Zhang, Yuan

doi:10.1016/j.engfracmech.2023.109806

Cited by 11 publications

(2 citation statements)

References 31 publications

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“…The effectiveness of hydraulic fracturing in shale reservoirs depends on many factors, − such as mineral fraction content, stratigraphy, and natural fractures. Among these factors, the mineral fraction content plays a key role in determining the properties of a shale reservoir and the hydraulic fracture extension.…”

Section: Introductionmentioning

confidence: 99%

Study on the Fracture Extension Pattern of Shale Reservoir Fracturing under the Influence of Mineral Content

Sun,

Hou,

Liang

et al. 2024

ACS Omega

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This study aimed to investigate the effect of the microstructure of shale on fracture initiation and extension during hydraulic fracturing. The Longmaxi Formation shale reservoir in the Sichuan Basin was considered as the research object; its structure was modeled from a microscopic perspective, and a zero-thickness cohesive unit was embedded within the solid unit. Numerical simulations were performed to study the effect of mineral content on the microextension of the hydraulic fracture, extension behavior, and evolution law of shale. The results showed that changes in the mineral content resulted in changes in the forces between molecules within the minerals, which, in turn, affected the shale's brittleness. The percentages of brittle mineral content in the Long I, II, and III reservoir sections are 60.37, 47.60, and 53.56%, respectively. The fracture initiation pressures of the three reservoirs were 29.22, 31.42, and 30.22 MPa, respectively, and a linear correlation was found between the fracture initiation pressures and the brittle mineral contents of the reservoir sections. An increase in the reservoirs' percentage of brittle mineral content facilitated the fracture initiation, with a corresponding gradual decrease in the resistance to fracture initiation. The pore pressures of the fractures in the three reservoirs after fracture initiation were 0.90, 1.18, and 1.00 MPa, respectively. The larger the percentage of brittle minerals was, the lower was the fracture pore pressure. The greater the length, number, area, and width of the cracks were, the more likely they were to form longer and wider cracks. Hence, reservoirs with a high percentage of brittle minerals should be prioritized as the target formations for hydraulic fracturing operations. The results of this study reveal how the mineral content affects the extension of microscopic hydraulic fractures in shale reservoirs. As such, this work can provide a theoretical basis for rationally selecting a hydraulic fracturing operation layer in shale gas reservoirs.

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Section: Introductionmentioning

confidence: 99%

Study on the Fracture Extension Pattern of Shale Reservoir Fracturing under the Influence of Mineral Content

Sun,

Hou,

Liang

et al. 2024

ACS Omega

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“…In practice, propped hydraulic fractures are under various closure pressure conditions; proppant compaction deformation and proppant embedment occur simultaneously in the hydraulic fractures. , In addition to pure elastic deformation, elastic-plastic and pure plastic deformations of proppants successively occur with the increase of closure pressure, leading to further compaction deformation and embedment. , Thus, both pure elastic, elastic-plastic, and pure plastic embedment and compaction deformation of the proppants should be precisely characterized and their effects on fracture permeability and conductivity should be investigated. For instance, Wang et al investigated the effects of proppant embedment on fracture permeability and well production through the lattice Boltzmann method (LBM), and they found that the proppant embedment significantly decreases the permeability.…”

Section: Introductionmentioning

confidence: 99%

Rod-Shaped Proppant Conductivity of a Hydraulic Fracture Considering Elastic-Plastic Deformation and Embedment: An Analytical Model

Tang,

Kang,

Zhao

et al. 2024

Energy Fuels

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Hydraulic fracturing with a proppant is widely employed to create fracture networks and enhance the conductivity of unconventional oil and gas reservoirs. However, the proppant conductivity tends to decrease due to the increasing closure pressure and temperature during long-term production. Hence, it is of great significance to quantitatively characterize the effects of thermal expansion and mechanical behaviors of proppant deformation and embedment on hydraulic fracture conductivity. In this paper, an analytical model is proposed for revealing physical relations between rod-shaped proppant conductivity and various impacting factors, and the model is validated against available experimental data. Results show that with increasing closure pressure and temperature, the rod-shaped proppant experiences pure elastic, elastic-plastic, pure plastic deformation, and linear thermal expansion, which leads to a declining proppant conductivity. Effects of critical parameters on the proppant deformation and proppant conductivity evolution are also investigated. Specifically, the proppant conductivity shows a positive relationship with the proppant aspect ratio. It is also found that with increasing closure pressure, the proppant conductivity variation can be divided into five stages. This model provides insights into the proppant deformation, embedment, and productivity, by which suggestions can be offered to optimize the parameter design in the hydraulic fracturing process, helping to realize the efficient extraction of unconventional oil and gas reservoirs.

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Interference Behaviour between Bedding Planes and Hydraulic Fractures and Its Influence on the Complex Fracture Network in Shale

Li,

Yang,

et al. 2024

Rock Mech Rock Eng

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Mechanism of hydraulic fracture vertical propagation in deep shale formation based on elastic–plastic model

Cited by 11 publications

References 31 publications

Study on the Fracture Extension Pattern of Shale Reservoir Fracturing under the Influence of Mineral Content

Study on the Fracture Extension Pattern of Shale Reservoir Fracturing under the Influence of Mineral Content

Rod-Shaped Proppant Conductivity of a Hydraulic Fracture Considering Elastic-Plastic Deformation and Embedment: An Analytical Model

Interference Behaviour between Bedding Planes and Hydraulic Fractures and Its Influence on the Complex Fracture Network in Shale

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