Propagation law of hydraulic fractures during multi-staged horizontal well fracturing in a tight reservoir

Liu, Naizhen; Zhang, Zhaopeng; Zou, Yushi; Ma, Xinfang; Zhang, Yinuo

doi:10.1016/s1876-3804(18)30116-2

Cited by 47 publications

(24 citation statements)

References 17 publications

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“…The cyclic pumping method is worth investigating in the initiation and propagation of multiple fractures. Other researchers [29][30][31] have also carried out experimental studies.…”

Section: Of 21mentioning

confidence: 99%

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Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

Wang

Yang

et al. 2021

Energies

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Competitive propagation of fractures initiated from multiple perforation clusters is universal in hydraulic fracturing of unconventional reservoirs, which largely influences stimulation. However, the propagation mechanism of multi-fractures has not been fully revealed for the lack of a targeted laboratory observation. In this study, a physical simulation experiment system was developed for investigating the initiation and propagation of multi-cluster hydraulic fractures. Different from the traditional hydro-fracking test system, the new one was equipped with a multi-channel shunting module and a strain monitoring system, which could guarantee the full fracture extension at each perforation clusters and measure the internal deformation of specimens, respectively. Several groups of true tri-axial fracturing tests were performed, considering the factors of in situ stress, cluster spacing, pumping rate, and bedding structures. The results showed that initiation of multi-cluster hydraulic fractures within one stage could be simultaneous or successive according to the difference of the breakdown pressure and fracturing fluid injection. For simultaneous initiation, the breakdown pressure of the subsequent fracture was lower than or equal to the value of the previous fracture. Multiple fractures tended to attract and merge. For successive initiation, the breakdown pressures of fractures were gradually increasing. The subsequent fracture tended to intersect with or deviated from the previous fracture. Multiple fractures interaction was aggravated by the decrease of horizontal stress difference, bedding number and cluster spacing, and weakened by the increase of pump rate. The propagation area of multiple fractures increased with the pump rate, decreased with the cluster spacing. The strain response characteristics corresponded with the initiation and propagation of fracture, which was conducive to understanding the process of the fracturing. The test results provide a basis for optimum design of hydraulic fracturing.

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“…The cyclic pumping method is worth investigating in the initiation and propagation of multiple fractures. Other researchers [29][30][31] have also carried out experimental studies.…”

Section: Of 21mentioning

confidence: 99%

“…However, the formation of multiple fractures is random. After improving the fracturing system, the formation of multiple fractures is so common that the interaction between fractures can be studied [27,30]. For multi-stage fracturing in the laboratory, the fracturing sequence is fixed.…”

Section: Multiple Fractures Interactionmentioning

confidence: 99%

Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

Wang

Yang

et al. 2021

Energies

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“…Liu et al [20] revealed the mechanism of casing deformation problems, established a semianalytical model for calculating induced stress along the fault caused by hydraulic fracture, and discussed the effects of fluid pressure, dip angle of fault, scale of fluid stimulated area, and the friction coefficient of fault slippage. Liu et al [21] established a novel laboratory simulation method for modeling multistaged fracturing in a horizontal well based on a true triaxial hydraulic fracturing simulation system, and the effects of net pressure in hydraulic fracture, stage spacing, perforation parameter, horizontal stress bias, and well cementation quality on the propagation geometry of multiple fractures in a tight sandstone formation were studied. Wasantha et al [22] discussed fracture containment behavior under varying in situ stress conditions for single-staged and multistaged fracturing using a fully coupled hydromechanical model.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Study and Numerical Simulation Research on the Effect of Coal‐Rock Interface on Multistaged Fracturing in the Roof of Outburst Coal Seam

Zhai

Tang

2021

Shock and Vibration

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Multistaged fracturing in the roof of outburst coal seam is an efficient and creative technology for coalbed methane (CBM) drainage, which can effectively improve the permeability of coal seam. To reveal its mechanism of permeability enhancement, the effect of coal-rock interface on multistaged fracturing in the roof of outburst coal seam was simulated and discussed in this paper. Firstly, the lithological difference between outburst coal seam and roof was compared, and the concept and significance of multistaged fracturing in the roof of outburst coal seam were explained. Then, the mechanical conditions of multiple fractures in the roof traversing coal-rock interface were analyzed. The effects of mechanical parameters on multiple fractures were numerically simulated. The results indicated that fracturing borehole in adjacent rocks of outburst coal seam is much easier to drill and maintain gas drainage. Considering gas drainage efficiency and avoiding being blocked by coal fines, multistaged fracturing borehole is generally drilled in the stable rock stratum of roof. Whether the multiple fractures in the roof can traverse coal-rock interface is related to mechanical parameters of coal and rock, friction factor of coal-rock interface, angle between horizontal profile and coal-rock interface, cementing strength of coal-rock interface, minimum horizontal stress, and other factors. Higher fracturing fluid pressure contributes to propagating from the reservoir with low elastic modulus to the one with high elastic modulus for hydraulic fracture. Hydraulic fracture is more likely to propagate in the rock stratum with high brittleness index. The research results can improve multistaged fracturing theory and provide technological support for field test.

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“…With the development of unconventional oil and gas reservoirs and the advancement of technology, directional wells, horizontal wells, and multistage fracturing technology are combined to increase the drainage area of the reservoir, hence to improve oil recovery and economic benefits. Currently, multistage fracturing is the main stimulation technology for unconventional resources; the principle of which is to enlarge the oil and gas discharge area by forming dense transverse fractures that are perpendicular to the wellbore [1][2][3][4]. However, due to the limited area of offshore plat-forms, high equipment operating costs, and high operational safety risks, it is difficult to apply mature onshore staged fracturing technologies to offshore oilfields.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of Hydraulic Fracture Propagation Behavior during Multistage Fracturing in a Directional Well

Jin

Guo²,

Qiu³

et al. 2021

Geofluids

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Due to the limited space of offshore platform, it is unable to implement large-scale multistage hydraulic fracturing for the horizontal well in Lufeng offshore oilfield. Thus, multistage hydraulic fracturing technology in directional well was researched essentially to solve this problem. Modeling of fracture propagation during multistage fracturing in the directional and horizontal wells in artificial cores was carried out based on a true triaxial hydraulic fracturing simulation experiment system. The effects of horizontal stress difference, stage spacing, perforation depth, and well deviation angle on multifracture propagation were investigated in detail. Through the comparative analysis of the characteristics of postfrac rock and pressure curves, the following conclusions were obtained: (1) multistage fracturing in horizontal wells is conducive to create multiple transverse fractures. Under relatively high horizontal stress difference coefficient (1.0) and small stage spacing conditions, fractures tend to deflect and merge due to the strong stress interference among multiple stages. As a consequence, the initiation pressure for the subsequent stages increases by more than 8%, whereas in large stage spacing conditions, the interference is relatively lower, resulting in the relatively straight fractures. (2) Deepening perforation holes can reduce the initiation pressure and reduce the stress interference among stages. (3) When the projection trace of directional wellbore on horizontal plane is consistent with the direction of the minimum horizontal principal stress, fractures intersecting the wellbore obliquely are easily formed by multistage fracturing. With the decrease of well deviation angle, the angle between fracture surface and wellbore axis decreases, which is not conducive to the uniform distribution of multiple fractures. (4) When there is a certain angle between the projection trace of directional wellbore on horizontal plane and the direction of minimum horizontal principal stress, the growth of multiple fractures is extremely ununiform and the fracture paths are obviously tortuous.

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Propagation law of hydraulic fractures during multi-staged horizontal well fracturing in a tight reservoir

Cited by 47 publications

References 17 publications

Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

Experimental Study on the Initiation and Propagation of Multi-Cluster Hydraulic Fractures within One Stage in Horizontal Wells

Theoretical Study and Numerical Simulation Research on the Effect of Coal‐Rock Interface on Multistaged Fracturing in the Roof of Outburst Coal Seam

Experimental Study of Hydraulic Fracture Propagation Behavior during Multistage Fracturing in a Directional Well

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