Multi-fractured stimulation technique of hydraulic fracturing assisted by radial slim holes

Guo, Tiankui; Gong, Facheng; Shen, Lin; Qu, Zhanqing; Qi, Ning; Tao, Wang

doi:10.1016/j.petrol.2018.11.064

Cited by 23 publications

(6 citation statements)

References 27 publications

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“…Fracturing. The existing study shows that the geostress of multiradial borehole is the superimposition of that of single radial borehole [27]. Thus, the fracture propagation mechanism in the horizontal dual-radial borehole is studied to represent the multiradial boreholes in this paper.…”

Section: Fracture Morphology Of Multiradial Boreholementioning

confidence: 99%

Research and Application of Radial Borehole Fracturing Based on Numerical Simulation

2019

Geofluids

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The radial borehole fracturing technology has been applied in a certain number of oilfields with good results being achieved. However, the morphology and variation of fracture still require further study. In this paper, the reservoir model based on formation fluid-solid coupling equation is established with the extended finite element method (XFEM) in ABAQUS, and the fracture morphologies in the single-radial borehole, vertical multiradial borehole, and horizontal multiradial borehole are simulated and analyzed with criteria of maximum principal stress and maximum energy release rate as the damage mechanism. Moreover, the accuracy of numerical simulation results is verified with the large-scale true 3D physical simulation experiment. The results show that the induced stress field along the radial borehole during fracturing is the root cause of fracture directional propagation along the radial borehole whose effective guidance distance reaches 40 m. The vertical multiradial borehole can effectively enhance fracture directional propagation and is capable of reducing fracture initiation pressure. In the horizontal multiradial borehole, the major fracture propagating along each radial borehole is formed in the remote-borehole area, and the secondary fracture connecting the neighboring radial boreholes is formed in the near-borehole zone. Coordination of major and secondary fractures can effectively increase the drainage area and reduce the flow resistance in the near-borehole zone. Based on the research on fracture morphology of multiradial borehole fracturing, the scheme of radial borehole arrangement is optimized and verified through numerical simulation of deliverability. The final optimum borehole arrangement scheme is the intersectional angle of 45°between four orthogonal radial boreholes and horizontal maximum principal stress.

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Section: Fracture Morphology Of Multiradial Boreholementioning

confidence: 99%

Research and Application of Radial Borehole Fracturing Based on Numerical Simulation

2019

Geofluids

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“…Protective layer exploitation can effectively reduce stress and improve permeability under the condition of multiple coal seams (Cheng et al, 2018;Jia et al, 2022;Fang et al, 2021;Fang et al, 2022;Niu et al, 2021;Ma et al, 2021). Hydraulic measures, gas fracturing, and other measures are adopted to improve the permeability of coal seams and the efficiency of gas pre-extraction in single lowpermeability coal seams (Lu et al, 2017;Xue et al, 2017;Feng and Shi, 2019;Guo et al, 2019;Lu et al, 2021). Hydraulic flushing in borehole has been widely applied to realize permeability improvement and rapid elimination of coal and gas outbursts in soft coal seams with low permeability (Feng et al, 2017;Li, 2019;Chen et al, 2020;Cao et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Research and application of pressure relief and permeability improvement in high gas outburst mines by directional drilling and hydraulic jet

Chen

Zhang

et al. 2023

Front. Earth Sci.

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Efficient gas extraction technology is an important topic for low permeability and high gas outburst coal seam. Based on the engineering background of Hudi Coal Mine with the soft and hard coal seams and the existing hydraulic permeability enhancement technology, a new construction process to improve coal seam permeability was proposed to effectively reduce coal seam gas content and the risk of coal and gas outburst. In this measure, the roadway in floor was replaced with a directional main borehole, directional branch boreholes were used to replace crossing holes, and soft coal was mined along soft sub layers via the directional drilling machine and directional hydraulic jet. Main boreholes are drilled parallel to the seam in the coal seam floor, and branch boreholes are drilled through the floor and coal seam. The numerical simulation was used to study the permeability improvement effect of different mining diameters by the proposed measure. The result showed that, as the mining diameter increased from 2 m to 4 m, the average influence diameter of coal seam porosity increased from 15.44 m to 19.65 m, and the average influence diameter of the permeability increased from 15.75 m to 20.07 m, which is three times the influence range of the ordinary borehole. The application of the proposed measure and its supporting equipment was carried out under the special coal seam and gas conditions of Hudi Coal Mine. Results show that the soft coal was mined efficiently along the soft sub layer using the main borehole, branch boreholes, and directional hydraulic jet. Compared the traditional hydraulic flushing in the borehole with the ordinary drilling machine, the average speed of mining soft sub layers increased from 0.5 t/h to 3.6 t/h, the equivalent mining diameter of soft sub layers increased from 1.2 m to 7.6 m, and the average flow of gas extraction increased from 0.41 m3/d to 6.25 m3/d. The conclusions obtained in this study can provide a reference for coal mine gas extraction with similar coal seam conditions.

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“…Hydraulic fracturing enhancement technology is a main measure to increase production of conventional and unconventional oil and gas wells. [8][9][10][11][12] Various hydraulic fracturing technologies are also used in underground coal mines for coal seam penetration enhancement. [13][14][15][16] Coal seam hydraulic fracturing involves injecting high-pressure fluid into the coal seam through fracturing holes.…”

Section: Introductionmentioning

confidence: 99%

Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam

Liangwei

2021

Energy Science & Engineering

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Multi-fractured stimulation technique of hydraulic fracturing assisted by radial slim holes

Cited by 23 publications

References 27 publications

Research and Application of Radial Borehole Fracturing Based on Numerical Simulation

Research and Application of Radial Borehole Fracturing Based on Numerical Simulation

Research and application of pressure relief and permeability improvement in high gas outburst mines by directional drilling and hydraulic jet

Variation law of roof stress and permeability enhancement effect of repeated hydraulic fracturing in low‐permeability coal seam

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