Numerical study of the influence of seepage force on the stress field around a vertical wellbore

Zhou, Desheng; Wang, Haiyang; He, Zexuan; Liu, Yafei; Liu, Shun; Ma, Xianlin; Cai, Wei; Bao, Jin

doi:10.1080/19942060.2020.1835733

Cited by 7 publications

(4 citation statements)

References 28 publications

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“…4,5 In the field of petroleum engineering, it has been established that when the injected fluid flows into the porous media, it exerts a SF on the rock skeleton in the direction of flow, driven by the pore pressure gradient. 6 Some scholars have demonstrated that the fluid pressure gradient can introduce SF and modify the stress state of the reservoir using sandbox simulation experiments. 7,8 Rozhko et al 9 studied the interaction between fluid overpressure gradient and failure patterns in rocks.…”

Section: Introductionmentioning

confidence: 99%

“…The drag force of the flowing fluid exerting on the rock particles in the unit volume of rock‐soil under the action of the hydraulic gradient is defined as the SF 4,5 . In the field of petroleum engineering, it has been established that when the injected fluid flows into the porous media, it exerts a SF on the rock skeleton in the direction of flow, driven by the pore pressure gradient 6 . Some scholars have demonstrated that the fluid pressure gradient can introduce SF and modify the stress state of the reservoir using sandbox simulation experiments 7,8 .…”

Section: Introductionmentioning

confidence: 99%

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Mechanistic study on the effect of seepage force on hydraulic fracture initiation

Wang,

Zhou

2024

Fatigue Fract Eng Mat Struct

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The flow of fracturing fluid through rock pores generates a seepage force (SF) that disrupts the existing stress equilibrium and significantly affects rock deformation and failure. Despite its impact, the effect of SF on hydraulic fracture (HF) initiation has yet to be fully understood. In this study, a mechanistic model of SF's impact on fracture initiation was established through analysis of the force balance on a microscopic element. Using the finite difference method, a transient hydro‐mechanical model was developed to simulate fluid seepage‐induced stress distribution and pore pressure variation around a wellbore. Model results were validated through comparison with an analytical solution of pore pressure. The influence of SF on fracture initiation was investigated by conducting simulations with various wellbore pressurization rates and fracturing fluid viscosities. The results showed that fluid viscosity and pressurization rate have a significant impact on fracture initiation pressure (FIP) and SF‐induced circumferential stress. A larger SF‐induced circumferential stress and a lower FIP were observed when the viscosity and pressurization rate were smaller. A higher Biot coefficient results in stronger SF and reduced FIP. The theoretical mechanical model of seepage force established in this paper can provide crucial theoretical support for understanding the mechanism of fracture initiation and propagation, as well as for optimizing the effectiveness of hydraulic fracturing construction.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mechanistic study on the effect of seepage force on hydraulic fracture initiation

Wang,

Zhou

2024

Fatigue Fract Eng Mat Struct

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“…Analyzing the nuanced processes involved in crack initiation and propagation is crucial in tailoring hydraulic fracturing strategies, ultimately influencing the success and efficiency of well stimulation endeavors. Therefore, a comprehensive investigation into the intricacies of fracture nucleation and propagation is essential for advancing the state of the art in hydraulic fracturing construction design [3][4][5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Research on Fluid–Solid Coupling Mechanism around Openhole Wellbore under Transient Seepage Conditions

Liu,

Zhou,

et al. 2024

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Hydraulic fracturing is one of the most important enhanced oil recovery technologies currently used to develop unconventional oil and gas reservoirs. During hydraulic fracture initiation, fluid seeps into the reservoir rocks surrounding the wellbore, inducing rock deformation and changes in the stress field. Analyzing the fluid–solid coupling mechanism around the wellbore is crucial to the construction design of fracturing technologies such as pulse fracturing and supercritical carbon dioxide fracturing. In this study, a new transient fluid–solid coupling model, capable of simulating the pore pressure field and effective stress field around the wellbore, was established based on the Biot consolidation theory combined with the finite difference method. The numerical results are in excellent agreement with the analytical solutions, indicating the reliability of the model and the stability of the computational approach. Using this model, the influence of seepage parameters and reservoir properties on the fluid–solid coupling around the open-hole wellbore was investigated. The simulation results demonstrate that, during wellbore pressurization, significant changes occur in the pore pressure field and effective stress field near the wellbore. The fluid–solid coupling effect around the wellbore returns to its initial state when the distance exceeds four times the radius away from the wellbore. As the fluid viscosity and wellbore pressurization rate decrease, the pore pressure field and effective circumferential stress (ECS) field around the wellbore become stronger. Adjusting the fluid viscosity and wellbore pressurization rate can control the effect of seepage forces on the rock skeleton during wellbore fluid injection. For the same injection conditions, rocks with q higher Young’s modulus and Poisson’s ratio exhibit stronger pore pressure fields and ECS fields near the wellbore. This model furnishes a dependable numerical framework for examining the fluid–solid coupling mechanism surrounding the open-hole wellbore in the initiation phase of hydraulic fractures.

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“…With the large-scale development of unconventional low-permeability oil and gas reservoirs, staged fracturing technology for horizontal wells has become one of the main reservoir stimulation technologies at present (Wang et al, 2021;Zhou et al, 2020). It is of great significance to study the fracture initiation and propagation law of volume fracturing in horizontal wells and analyze the interaction between hydraulic fractures and natural fractures for predicting the fracture network shape and optimizing the design of hydraulic fracturing construction plans.…”

Section: Introductionmentioning

confidence: 99%

Research on the propagation mechanism of hydraulic fractures in infill horizontal wells

et al. 2022

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In recent years, infill horizontal well technology has been used to develop oil and gas in the remaining oil areas of unconventional low-permeability reservoirs. However, the initial fractures in parent wells will affect the hydraulic fractures formed by fracturing infilling horizontal wells. The interaction mechanisms between initial fractures and artificial fractures in infill horizontal wells are still unclear. Combined with the boundary element method and the maximum circumferential tensile stress criterion, a numerical model of hydraulic fracturing that can simulate the evolution of fracture trajectory and stress field was established. The analytical solution of the hydraulic fracture-induced stress field was used to verify the accuracy of the model. Using this model, propagation of hydraulic fractures in infill horizontal wells under different conditions was analyzed. Simulation results show that both the fracture spacing and well spacing have a significant impact on the propagation trajectory of hydraulic fractures in infill horizontal wells. The shorter the fracture spacing and well spacing is, the stronger the inter-fracture stress interference between the initial fractures and hydraulic fractures is. Reasonable fracture spacing and well spacing can enhance the induced stress field and form a complex fracture network in the reservoir. Too small well spacing may cause artificial fractures to communicate with initial fractures, thereby reducing hydraulic fracturing efficiency and limiting the stimulation volume of the reservoir.

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Numerical study of the influence of seepage force on the stress field around a vertical wellbore

Cited by 7 publications

References 28 publications

Mechanistic study on the effect of seepage force on hydraulic fracture initiation

Mechanistic study on the effect of seepage force on hydraulic fracture initiation

Research on Fluid–Solid Coupling Mechanism around Openhole Wellbore under Transient Seepage Conditions

Research on the propagation mechanism of hydraulic fractures in infill horizontal wells

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