Effects of fracturing parameters on fracture network evolution during multicluster fracturing in a heterogeneous reservoir

Zhang, Haoyu; Chen, Junbin; Gong, Diguang; Liu, Huanmei; Ouyang, Wen

doi:10.1016/j.compgeo.2023.105474

Cited by 6 publications

(2 citation statements)

References 52 publications

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“…The total loss coefficient consists of friction loss and directional loss terms, which is written as C l = f L D h where f is the friction factor, L is the length of the well, D h is the wetted perimeter, which is expressed as D h = 4 A / P .…”

Section: Model and Methodologymentioning

confidence: 99%

Multiwell Fracturing Characteristic in Layered Heterogeneous Formation and the Optimization of Stimulated Reservoir Volume

Ke,

Wang,

et al. 2024

Energy Fuels

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Hydraulic fracturing within multiwell pads is considered an effective technique for enhancing the recovery of oil/gas resources, but the fracture propagation behaviors have not been fully understood, typically considering the layered heterogeneous construction and intricate stress interference effects. This work establishes a multiwell fracturing model based on the threedimensional displacement and pore pressure coupled cohesive method to precisely characterize the propagation and morphology features of the hydraulic fracture. The flow behavior in the well follows the Bernoulli equation, and the fluid distribution at each perforation point is automatically regulated with the fluid pipe element. The fracturing model is validated with the analytical solution for the penny-shaped fracture. Various fracturing scenarios, including the spatial relations of wells and clusters and the geological conditions are thoroughly revealed. The results demonstrate that the layered formation significantly influences the stress interference between wells and clusters and thus alters the fracture propagation. It can be observed that the intercluster stress interference is weakened when confined within the layered formation, where the fractures grow uniformly along the lateral direction even with a small cluster spacing. When the wells are located at different layers, three typical propagation modes are summarized as lateral propagation, penetration, and aggregation, depending on the in situ stress, rock strength, and fracture energy of different layers in the formation. Meanwhile, optimization of the well pattern is discussed from the perspective of the fracture area to achieve the maximization of the stimulated reservoir volume (SRV). These insights are helpful for the design and implementation of multiwell fracturing technology in tight formation with layered heterogeneous construction.

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Section: Model and Methodologymentioning

confidence: 99%

Multiwell Fracturing Characteristic in Layered Heterogeneous Formation and the Optimization of Stimulated Reservoir Volume

Ke,

Wang,

et al. 2024

Energy Fuels

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“…As the fracture initiates, the fluid within the fracture generates a flow field and the original seepage field in the rock changes. The Reynold’s equation for fluid flow is satisfied: ∂ w ∂ t + ∇ q + ( q t + q b ) = Q ( t ) δ ( x ) where Q ( t ) is the injection amount of fracturing fluid, m 3 /s, and t is time, s.…”

Section: Mathematical Modelmentioning

confidence: 99%

Influence of Engineering Parameters on Fracture Vertical Propagation in Deep Shale Reservoir: A Numerical Study Based on FEM

Zhang,

Liao,

et al. 2024

ACS Omega

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The geometry of hydraulic fractures in deep shale facies is significantly affected by the longitudinal inhomogeneity of rock physical properties and stresses. Numerous studies have been conducted on the influence of the longitudinal inhomogeneity of rocks on fracture morphology. However, there is still a lack of research that simultaneously considers the reservoir dip, bedding plane interface, and longitudinal inhomogeneity of the reservoir. To fill this gap, a three-dimensional (3D) numerical model of multireservoir hydraulic fracturing, which takes into account the bedding plane interface, was developed using the finite element method (FEM). The Drucker−Prager elastic-plasticity criterion was incorporated to accurately represent the plasticity of deep shale. The research revealed the influence of the formation dip angle on fracture morphology. Additionally, the perforation layer position and pump rate were optimized based on the actual geological parameters in North Jiangsu shale reservoir. The study findings indicate that reservoir fractures with a formation dip are easily detected by the interface. However, it is not necessarily true that the larger the formation dip, the easier it is for fluids to enter the interface. Fracturing from high-strength and stress reservoirs to lower reservoirs promotes the propagation of fracture height and the connectivity of multiple reservoirs. On the other hand, fractures initiated from low-strength and stress reservoirs tend to be confined to adjacent reservoirs more easily. The pump rate significantly affects the vertical propagation of fractures. At high interface strength, fractures with pump rate below 2.4 m 3 /min can only propagate at the perforation layer. The limited fracture height in shale reservoirs is likely due to substantial energy consumption by the fracturing fluid at the bedding plane interface. These studies offer theoretical guidance for understanding the vertical propagation of fractures in a deep multilayer reservoir.

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Research on the factors influencing the width of hydraulic fractures through layers

Liang,

Wang,

Luo

et al. 2024

J Petrol Explor Prod Technol

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The method of segmented hydraulic fracturing in the coal seam roof has proven to be an efficient technique for coalbed methane exploitation. However, the behavior of hydraulic fractures in multilayer formations with significant differences in mechanical properties is still unclear. This paper studied the variation in hydraulic fracture width at the coal-rock interface by employing experimental method with a true triaxial hydraulic fracturing experimental system and numerical simulation method. Results revealed that the hydraulic fracture more likely to expanded along the coal-rock interface instead of break through it with the small horizontal stress difference and low flow rate injection condition. And improving the injection flow rate lager than a critical value, the hydraulic fracture tends to break through the coal-rock interface. Hydraulic fractures in both mudstone and coal beds exhibited a trend of increasing and then decreasing of fracture width at the interface. Since the strength of the coal seam was lower compared to that of the mudstone, maintaining high pressure was no longer necessary when the hydraulic fracture crossed the interface and entered the coal seam, leading to a reduction in fracture width within the mudstone. During the later stages of fracturing, the entry of proppant into the coal seam became challenging, resulting in a phenomenon characterized by excessive fluid but insufficient sand. The time required for the fracture width to traverse the proppant was found to be inversely proportional to the difference in horizontal ground stress and the flow rate of the fracturing fluid. And it was directly proportional to the modulus of elasticity, permeability of the coal seam, and interface strength. The interface strength has the greatest influence on the width of hydraulic fractures. In conclusion, this study provides valuable insights into the behavior of hydraulic fractures in multilayer formations with varying mechanical properties. The findings contribute to a better understanding of the factors affecting hydraulic fracture width within coal seams, which can ultimately enhance the efficiency of coalbed methane exploitation.

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Effects of fracturing parameters on fracture network evolution during multicluster fracturing in a heterogeneous reservoir

Cited by 6 publications

References 52 publications

Multiwell Fracturing Characteristic in Layered Heterogeneous Formation and the Optimization of Stimulated Reservoir Volume

Multiwell Fracturing Characteristic in Layered Heterogeneous Formation and the Optimization of Stimulated Reservoir Volume

Influence of Engineering Parameters on Fracture Vertical Propagation in Deep Shale Reservoir: A Numerical Study Based on FEM

Research on the factors influencing the width of hydraulic fractures through layers

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