Theoretical study on fracture initiation in deep perforated wells with considering wellbore deformation

Ren, Lan; Jiang, Hao; Zhao, Jinzhou; Lin, Rungtai; Wang, Zhenhua; Xu, Yizhuang

doi:10.1016/j.petrol.2022.110141

Cited by 5 publications

(3 citation statements)

References 27 publications

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“…Although this approach partially alleviated the issue of uneven steam injection, its complex process hindered widespread application. – Subsequently, technologies such as segmented perforation completion, variable density perforation completion, and central tubing completion were developed. However, these techniques had limited control over steam injection or reservoir steam absorption profiles, making it difficult to ensure sufficient uniformity in the steam absorption profile. – Later on, a commonly employed approach involved the utilization of steam flow control methods, relying on specially designed steam control valves to achieve uniform steam injection. – In 2014, Liu developed adjustable steam control valves and the corresponding retrieval tools to address the issue of nonadjustability of steam valves in horizontal wells. This innovation led to the establishment of a more refined process for achieving a uniform steam injection in horizontal wells.…”

Section: Introductionmentioning

confidence: 99%

“…However, these techniques had limited control over steam injection or reservoir steam absorption profiles, making it difficult to ensure sufficient uniformity in the steam absorption profile. 16 – 19 Later on, a commonly employed approach involved the utilization of steam flow control methods, relying on specially designed steam control valves to achieve uniform steam injection. 20 – 22 In 2014, Liu 23 developed adjustable steam control valves and the corresponding retrieval tools to address the issue of nonadjustability of steam valves in horizontal wells.…”

Section: Introductionmentioning

confidence: 99%

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New Design Method of a Supersonic Steam Injection Nozzle and Its Numerical Simulation Verification

Wang,

Pang,

Tian

et al. 2023

ACS Omega

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Steam huff-n-puff in horizontal wells often had limitations, such as uneven steam injection and low reservoir utilization. To improve steam injection efficiency, a new method for designing a supersonic nozzle was proposed based on the principles of aerodynamics and thermodynamics. The nozzle featured a tapering section, a throat, and a diverging section. The best geometric shape of the tapering section was the Witoszynski curve. A set of nozzle size designs were established, and the size parameters were optimized. The results showed that the nozzle could inject steam into the formation at supersonic speed and it had the characteristics of constant flow rate and uniform development of the steam chamber. According to the steam Reynolds number and the good aggregation distribution characteristics of the size design model, three sequential nozzles of 3.0, 5.0, and 6.5 mm were formed based on the throat. When the throat diameter was 5.0 mm, the tapering length was 4.3 mm, the diverging length was 5.5 mm, the throat length was 3.0 mm, the inlet diameter was 9.8 mm, and the outlet diameter was 6.2 mm. Numerical simulations indicated that the pressure drop loss during steam huff-n-puff injection in horizontal wells was within 10%. It was of great significance to establish the nozzle size design model of the steam injection effect of horizontal wells.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

New Design Method of a Supersonic Steam Injection Nozzle and Its Numerical Simulation Verification

Wang,

Pang,

Tian

et al. 2023

ACS Omega

View full text Add to dashboard Cite

show abstract

“…For the CSCTC problem, many scholars have conducted studies and obtained meaningful conclusions, but due to the complexity of the compression-shear failure problem, there are still many issues. At present, there are more studies on the rupture and extension law of hydraulic main fractures [18], but there are fewer studies on the opening and expansion law under which MNC form on the wall of the main fracture and on the horizontal section during the formation of the main fracture. However, this targeted research is critical to the formation of fracture networks.…”

Section: Introductionmentioning

confidence: 99%

Analytical Investigation on the Shear Propagation Mechanism of Multi-Cracks in Brittle Tight Rocks under Compressive and Shear Loading Conditions

Luo

et al. 2023

Processes

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There is abundant shale oil in the ocean and on land. Due to the tight lithology of the reservoir, volume fracturing technology is needed to improve the oil and gas productivity. It is very important to study the expansion law of multiple natural fractures in rock masses and its influencing factors in the process of volume fracturing for the formation of fracture networks. Based on the theory of online elastic fracture mechanics, the calculation method of the stress intensity factor at the end of any I–II composite fracture is established by using effective shear stress and considering the influence of T-stress. The calculation model of the stress intensity factor of any fracture on the main fracture wall or the horizontal section of the main fracture wall is established according to the concrete stress conditions in the process of hydraulic fracturing. Based on the principle of stress superposition, the combined interference stress calculation model of fracture ends is established for the case of multiple penetrating cracks in infinite-plane rock masses. Based on the theory of shear failure and plane strain, a model of the initiation direction and condition of natural cracks on the horizontal section of the main fracture wall and both sides of the main fracture in brittle rock is established when there are many coaxial natural cracks under the action of remote site stress and water pressure on the fracture surface. According to the simulation results, on the main fracture wall, when σH > σv > σh or σH > σh > σv, when the crack angle (CA) is within a certain range and multiple natural cracks (MNC) exist, the required pressure for shear failure decreases. When the fracture angle exceeds a certain size, the required pressure increases. When there are MNC in the horizontal or perpendicular sections of the rock mass on both sides of the main fracture, the required net pressure for shear failure decreases within a certain CA range. When the CA exceeds a certain range, it increases or remains basically unchanged. On the whole, the presence of MNC reduces the net pressure for shear failure, which is conducive to the formation of fracture networks.

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Prediction of Fracture Initiation Pressure for Slotting-Directional Hydraulic Fracturing Based on the Anisotropy of Coal

Zheng

et al. 2023

Journal of Energy Resources Technology

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The precise estimation of fracture initiation pressure is crucial for the effective implementation of slotting-directional hydraulic fracturing methods in coal seams. Nonetheless, current models fail to account for the impact of the morphology of the slotted borehole and the anisotropy of coal. To address this issue, a three-dimensional model was created in this study, which simplified the slotted borehole as an elliptical medium and the coal as an orthotropic medium. Laboratory experiments were conducted to validate the model, and the findings regarding the changes in fracture initiation pressure and deflection angle due to various factors were presented. The calculated outcomes of the proposed model align with the observed pattern of the experimental results, and the numerical discrepancy falls within the acceptable range of 7%, showcasing the precision of the proposed model. A rise in the horizontal stress difference and a decrease in the depth of the slots will result in an elevation of the fracture initiation pressure and deflection angle. Additionally, the slotting angle will impact the distribution pattern of the fracture initiation pressure and deflection angle, underscoring the significance of these factors in the hydraulic fracturing of slotted boreholes.

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Theoretical study on fracture initiation in deep perforated wells with considering wellbore deformation

Cited by 5 publications

References 27 publications

New Design Method of a Supersonic Steam Injection Nozzle and Its Numerical Simulation Verification

New Design Method of a Supersonic Steam Injection Nozzle and Its Numerical Simulation Verification

Analytical Investigation on the Shear Propagation Mechanism of Multi-Cracks in Brittle Tight Rocks under Compressive and Shear Loading Conditions

Prediction of Fracture Initiation Pressure for Slotting-Directional Hydraulic Fracturing Based on the Anisotropy of Coal

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