Numerical simulation on near-wellbore temporary plugging and diverting during refracturing using XFEM-Based CZM

Wang, Bo; Zhou, Fujian; Wang, Daobing; Liang, Tianbo; Lou, Yuan; Jia, Hu

doi:10.1016/j.jngse.2018.05.009

Cited by 78 publications

(25 citation statements)

References 27 publications

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“…The viscous zone model (CZM) was established based on extended finite element method (XFEM) to simulate the process of plugging and flow diversion. The model has been verified by test results [19]. Numerical simulation method seems to be useful for identifying the refracturing fracture propagation.…”

Section: Introductionmentioning

confidence: 89%

Study on Fracture Morphological Characteristics of Refracturing for Longmaxi Shale Formation

et al. 2020

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Refracturing technology has become an important means for the regeneration of old wells reconstruction. It is of great significance to understand the formation mechanism of hydraulic fracturing fracture for the design of hydraulic fracturing. In order to accurately evaluate and improve fracturing volume after refracturing, it is necessary to understand the mechanism of refracturing fracture in shale formation. In this paper, a true triaxial refracturing test method was established. A series of large-scale true triaxial fracturing experiments were carried out to characterize the refracturing fracture initiation and propagation. The results show that for shale reservoirs with weak bedding planes and natural fractures, hydraulic fracturing can not only form the main fracturing fracture, which is perpendicular to horizontal minimum principal stress, but it can also open weak bedding plane or natural fractures. The characteristics of fracturing pump curve indicated that the evolution of fracturing fractures, including initiation and propagation and communication of multiple fractures. The violent fluctuation of fracturing pump pressure curve indicates that the sample has undergone multiple fracturing fractures. The result of refracturing shows that initial fracturing fracture channels can be effectively closed by temporary plugging. The refracturing breakdown pressure is generally slightly higher than that of initial fracturing. After temporary plugging, under the influence of stress induced by the initial fracturing fracture, the propagation path of the refracturing fracture is deviated. When the new fracturing fracture communicates with the initial fracturing fracture, the original fracturing fracture can continue to expand and extend, increasing the range of the fracturing modifications. The refracturing test results was shown that for shale reservoir with simple initial fracturing fractures, the complexity fracturing fracture can be increased by refracturing after temporary plugging initial fractures. The effect of refracturing is not obvious for the reservoir with complex initial fracturing fractures. This research results can provide a reliable basis for optimizing refracturing design in shale gas reservoir.

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Section: Introductionmentioning

confidence: 89%

Study on Fracture Morphological Characteristics of Refracturing for Longmaxi Shale Formation

et al. 2020

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“…This can be explained by the fact that the hydraulic fracture with a larger deflection angle can expand far away from the initial perforation. As a result, a larger stimulated reservoir area is formed, and a better fracturing effect is obtained (Wang et al, 2018a). Therefore, the deflection angle can be selected to measure the deflection degree of hydraulic fractures under different working conditions and used to analyse the engineering effect of directional perforation hydraulic fracturing.…”

Section: Deflection Angle Of Hydraulic Fracturesmentioning

confidence: 99%

“…The model was used to study the influence of perforation azimuth, perforation length and perforation phase angle on the initiation and expansion of hydraulic fractures (Chen et al, 2017). A fluid-solid coupling model of the steering fracture was established by Wang Xiaolong et al The effects of the fluid injection parameters, such as the injection rate and the viscosity of the fracturing fluid, on the deflection propagation of hydraulic fractures were simulated (Wang et al, 2018a(Wang et al, , 2018b. The concept of the deflection angle of hydraulic fractures was proposed by Wang et al to quantitatively analyse the steering effect of hydraulic fractures (Dong and Tang, 2019;Wang et al, 2018a).…”

Section: Introductionmentioning

confidence: 99%

Quantitative evaluation indexes of the spatial steering effect of directional perforation hydraulic fractures

2021

Energy Exploration & Exploitation

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To better evaluate the spatial steering effect of directional perforation hydraulic fractures, evaluation indexes for the spatial steering effect are first proposed in this paper. Then, these indexes are used to quantitatively evaluate existing physical experimental results. Finally, with the help of RFPA2D-Flow software, the influence of perforation length and azimuth on the spatial steering process of hydraulic fracture are quantitatively analysed using four evaluation indexes. It is shown by the results that the spatial deflection trajectory, deflection distance, deflection angle and initiation pressure of hydraulic fractures can be used as quantitative evaluation indexes for the spatial steering effect of hydraulic fractures. The deflection paths of directional perforation hydraulic fractures are basically the same. They all gradually deflect to the maximum horizontal principal stress direction from the perforation hole and finally represent a double-wing bending fracture. The deflection distance, deflection angle and initiation pressure of hydraulic fractures increase gradually with increasing perforation azimuth, and the sensitivity of the deflection angle to the perforation azimuth of hydraulic fractures also increases. With increasing perforation length, the deflection distance of hydraulic fractures increases gradually. However, the deflection angle and initiation pressure decrease gradually, as does the sensitivity.

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“…However, the boundary element method cannot deal with problems with reservoir heterogeneity, which limits its application in the field. The finite element method with the cohesive force model can solve the problem of multi-cluster fracture propagation in the heterogenous reservoir with a moderate computation cost, and thus also being widely used in hydraulic fracturing simulations [14][15][16] . Wang et al extended the finite element method with the cohesive zone model (CZM), and conducted a comprehensive study that showed the impact of primary fractures on the secondary fractures in different scenarios; however, the dynamic distribution of fracturing fluid and proppants among multiple fractures were ignored [15] .…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Multi-Cluster Fracture Propagation In Horizontal Wells With Limited-Entry Designs

Guo

Liu

et al. 2021

Preprint

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The effective propagation of multi-cluster fractures in horizontal wells is the key to the development of unconventional reservoirs. Due to the influence of pressure drops at perforating holes and the stress shadow effect, it is difficult to predict the fracturing fluid distribution and fracture dimensions in a fracturing stage. In this paper, a two-dimensional fluid-solid coupling model for simultaneous propagation of multiple fractures is established, and fluid distributions and dimensions of multiple fractures are studied with respect to different perforation designs. The model combines the User Amplitude Curve Subroutine (UAMP) in ABAQUS and the cohesive zone model (CZM) to calculate the perforating friction, fluid distribution and fracture propagation behaviors. After the accuracy of this model is verified by the analytical solution, a group of simulation is conducted to compare fracture propagations when the conventional limited-entry method (CLE) and extreme limited-entry method (less than 5 perforations per cluster, XLE) are used. Simulation results show that the edge and sub-central fractures in CLE cases almost get all the fluid and effectively propagate; central fractures receive little fluid and hardly propagate. In XLE cases, the fluid distribution of each fracture is relatively uniform, but the fracture lengths within one fracturing stage is still uneven; however, only reducing numbers or radii of perforation holes cannot achieve the uniform fracture propagation, where diverters might be further needed. Findings of this study provide a reference for the perforation optimization of multi-cluster horizontal wells in the field.

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Numerical simulation on near-wellbore temporary plugging and diverting during refracturing using XFEM-Based CZM

Cited by 78 publications

References 27 publications

Study on Fracture Morphological Characteristics of Refracturing for Longmaxi Shale Formation

Study on Fracture Morphological Characteristics of Refracturing for Longmaxi Shale Formation

Quantitative evaluation indexes of the spatial steering effect of directional perforation hydraulic fractures

Numerical Simulation of Multi-Cluster Fracture Propagation In Horizontal Wells With Limited-Entry Designs

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