Numerical Simulation for Fracture Propagation in Elastoplastic Formations

Ya-fei, HU; Zhao, Jin; Cao, Liyuan; Zhao, Jinzhou; Li, Junshi; Wu, Zhonghua; Hou, Jianfeng

doi:10.1155/2021/6680023

Cited by 3 publications

(3 citation statements)

References 40 publications

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“…Although the net pressure of the fracture propagation can be well fitted by the apparent fracture toughness model, the fracture geometry cannot be evaluated accurately [231]. Therefore, not only the crack propagation criterion considering the plastic deformation needs to be used, but also elastoplastic constitutive models characterizing the stress-strain relationship should be used to simulate the rock deformation, such as Drucker-Prager criterion [232,233], the Mohr-Coulomb criterion [234], and the Cambridge model [24,235]. Simulation results confirm that the fracture propagation pressure and fracture width are increased by the formation plasticity, and these also cause the fracture closure pressure to be lower than the minimum horizontal stress [236].…”

Section: Hydraulic Fracturing Simulation Methods Considering Rock Pla...mentioning

confidence: 99%

A Review of the Hydraulic Fracturing in Ductile Reservoirs: Theory, Simulation, and Experiment

Zhu

Han

et al. 2022

Processes

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The bottom-hole pressure of hydraulic fracturing in ductile reservoirs is much higher than that of the hydraulic fracturing simulation, and the fracture toughness inferred from the field data is 1–3 orders of magnitude higher than that measured in the laboratory. The rock apparent fracture toughness increases with the increase in the confining pressure. Excluding the influence of the fluid viscosity and the fluid lag on the apparent fracture toughness, the fracture process zone (FPZ) at the fracture tip can explain the orders of magnitude of difference in the apparent fracture toughness between the laboratory and the field. The fracture tip is passivated by plastic deformation, forming a wide and short hydraulic fracture. However, the size of the FPZ obtained in the laboratory is in the order of centimeters to decimeters, while an FPZ of 10 m magnitude is speculated in the field. The FPZ size is affected by the rock property, grain size, pore fluid, temperature, loading rate, and loading configuration. It is found that the FPZ has a size effect that tends to disappear when the rock specimen size reaches the scale of meters. However, this cannot fully explain the experience of hydraulic fracturing practice. The hydraulic fracturing behavior is also affected by the relation between the fracture toughness and the fracture length. The fracture behavior of type II and mixed type for the ductile rock is poorly understood. At present, the apparent fracture toughness model and the cohesive zone model (CZM) are the most suitable criteria for the fracture propagation in ductile reservoirs, but they cannot fully characterize the influence of the rock plastic deformation on the hydraulic fracturing. The elastic-plastic constitutive model needs to be used to characterize the stress–strain behavior in the hydraulic fracturing simulation, and the fracture propagation criteria suitable for ductile reservoirs also need to be developed.

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Section: Hydraulic Fracturing Simulation Methods Considering Rock Pla...mentioning

confidence: 99%

A Review of the Hydraulic Fracturing in Ductile Reservoirs: Theory, Simulation, and Experiment

Zhu

Han

et al. 2022

Processes

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“…Shimizu et al used the DDM to study the effects of fluid viscosity and particle size distribution on HF cracking initiation and propagation based on the cemented particle model (BPM) [43,44]. Zhang Fengshou et al simulated the coupling behavior between HF and NF based on the mixed discrete continuum method [45][46][47][48][49][50]. Chen established the model of fracture turning during propagation based on the theory of fracture mechanics [51].…”

Section: Introductionmentioning

confidence: 99%

Study on the Influence of Perforating Parameters on the Flow Rate and Stress Distribution of Multi-Fracture Competitive Propagation

Zhao,

Wang

et al. 2024

Processes

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It is of great significance to investigate the flow rate and stress distribution of multi-fracture propagation for the optimization of perforation parameters and fracture parameters. Considering the coupling of rock deformation, fracture direction and fluid flow in multi-fracture scenarios, a mathematical model and solution program for the flow and stress distribution of multiple fractures are established, and the analytical model is used for comparison and verification. The effects of perforation cluster number, cluster spacing, perforation diameter on fracture extension trajectory, fracture width, flow rate of each fracture and stress field are studied by the model. The results show that, as the number of perforating clusters increases, the inner fracture is inhibited more severely with less width, length and flow distribution, as well as lower bottom hole pressure. With the increase in cluster spacing, the stress interference between whole fractures is weakened and the flow distribution of the inner fracture is increased with lower bottom hole pressure. With the decrease in perforation diameter, the inhibition effect of inside fractures is weakened, while the inhibition effect of outside fractures, the flow distribution of inside fractures and the bottom hole pressure are increased. The uniform propagation of multiple fractures can be promoted by decreasing the perforation clusters’ number and perforation diameter or increasing fracture spacing.

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“…In recent years, energy shortages, and environmental problems have become the focus of world attention 1 . With the rising energy consumption, natural gas hydrate has become increasingly important in both environmental and energy supply issues.…”

Section: Introductionmentioning

confidence: 99%

Experimental study on the effect of PVP, NaCl and EG on the methane hydrates formation and dissociation kinetics

Shen,

Zhao,

Zhou

et al. 2024

Sci Rep

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The problem of hydrate plug, low efficiency of hydrate dissociation and short production time in hydrate exploitation processes have significantly hindered the commercial viability of gas hydrate extraction. This study investigated the inhibitory effects of ethylene glycol (EG), EG + polyvinyl pyrrolidone (PVP), and EG + PVP + sodium chloride (NaCl) on methane hydrate formation through experiment. The hydrate inhibitory performance is evaluated by using differential of pressure curve, the amount of hydrate, and pressure drop values, and the effects of different temperatures, pressures, inhibitors, and injection time on hydrate dissociation are further studied. The experiment results indicate that the rank of inhibitors combination in terms of effectiveness is 5%EG + 0.5 wt%PVP + 3 wt%Nacl > 10%EG + 1 wt%PVP > 30% EG. At low-temperature conditions, 30% EG exhibits good inhibition of hydrate synthesis but poor dissociation efficiency. As temperature increases, the hydrates dissociation rate with 30% EG also increases. For the combination inhibitor system of EG, PVP, and NaCl, PVP will reduce the dissociation efficiency of hydrates, while EG and Nacl will improve the hydrate dissociation performance. For low production pressure, it is found that 10% EG + 10% NaCl have a good promotion effect on hydrate dissociation, whereas under high production pressure, 20% EG + 10% NaCl is more effective. Furthermore, injecting the inhibitors earlier enhances the dissociation of hydrates more effectively.

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Numerical Simulation for Fracture Propagation in Elastoplastic Formations

Cited by 3 publications

References 40 publications

A Review of the Hydraulic Fracturing in Ductile Reservoirs: Theory, Simulation, and Experiment

A Review of the Hydraulic Fracturing in Ductile Reservoirs: Theory, Simulation, and Experiment

Study on the Influence of Perforating Parameters on the Flow Rate and Stress Distribution of Multi-Fracture Competitive Propagation

Experimental study on the effect of PVP, NaCl and EG on the methane hydrates formation and dissociation kinetics

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