Hydraulic fracturing model featuring initiation beyond the wellbore wall for directional well in coal bed

Li, Yuwei; Jia, Dechang; Wang, Meng; Liu, Jia; Fu, Chunkai; Yang, Xianyou; Ai, Chi

doi:10.1088/1742-2132/13/4/536

Cited by 23 publications

(9 citation statements)

References 18 publications

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“…According to existing research, many natural cleats and joints exist in coal seams [29,30]. These cleats and joints are vertically distributed in the coal seam and form a stereo network [31,32], as shown in Figure 1. According to the microscopic damage mechanics theory of micro-cracks, the continuous impact of the water jet on the coal rock causes stress concentration and crack initiation around the cleat tip in the coal.…”

Section: Optimization Of Borehole Anglesmentioning

confidence: 99%

Analysis of Application Parameters of Hydraulic Slotting Technology in Jointed Coal Reservoirs

Zuo

Wang

et al. 2019

Applied Sciences

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Hydraulic slotting technology is typically used in coal mines to enhance permeability and prevent gas outbursts. Because a coal seam contains many cleats and joints, this study investigated the influence of conventional application parameters on the hydraulic slotting effect by numerical simulation and experimental testing. The cleats in the coal generated stress concentration and initiated with the water jet impact, which promoted the formation of a complex fracture network. The optimized arrangement included angles with an inclination of 20–45° between the borehole and the coal seam strike. The water jet pressure and rotation speed determined the shape of the slot. A high water jet pressure and low rotation speed promoted the formation of cracks at the end of the slot and strengthened the permeability-enhancing effect. Coal fragments could more easily peel off from the sides of the seam and block the borehole. The high water pressure and low rotation speed application parameters were optimized without blocking the borehole. Results obtained by field application revealed that the gas extraction flow after optimization was 1.3 times that of conventional hydraulic slotting. An appropriate angle between the cleats and borehole can more effectively increase the permeability of the coal seam and results in higher gas drainage flow. The results of this study can be useful as guidelines for field applications of hydraulic slotting technology.

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Section: Optimization Of Borehole Anglesmentioning

confidence: 99%

Analysis of Application Parameters of Hydraulic Slotting Technology in Jointed Coal Reservoirs

Zuo

Wang

et al. 2019

Applied Sciences

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“…At present, the deformation and failure characteristics of the rock mass of the mine floor of seams have been studied by many both Chinese and international academics and practitioners, so a large volume of research results have been obtained (Li et al 2013;Feng et al 2016;Li et al 2016;Zhu and Zhang 2018). As a result, many research methods for determining the characteristics of failure of the mine floor have been proposed, which can be primarily grouped into field measurements (Zhang et al 2006;Kang et al 2010;Xu et al 2012;Huang et al 2014Huang et al , 2018Yin et al 2016;Zhao et al 2016), laboratory experiments Liu et al 2015;Sun et al 2017;Zhu et al 2017; and analytical calculations (Wang et al 2009;Yu et al 2009;Song et al 2016;Yin et al 2016;Cheng et al 2018;Su and Wei 2018;.…”

Section: Introductionmentioning

confidence: 99%

Experimental investigation on mining-induced strain and failure characteristics of rock masses of mine floor

Zeng

Huang

et al. 2020

Geomatics, Natural Hazards and Risk

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“…Hydraulic fracturing is the primary means of stimulating CBM wells and has been widely used in exploration of coalbed methane [1][2][3][4][5][6][7][8][9]. The fractures produced by hydraulic fracturing can communicate with natural fractures in the coal seam [10][11][12], enhance the connectivity between natural fractures, greatly improve the permeability of coal reservoir [9], and have a very significant effect of increasing production [13,14].…”

Section: Introductionmentioning

confidence: 99%

The Calculation of Coal Rock Fracture Conductivity with Different Arrangements of Proppants

Meng

Rui

et al. 2018

Geofluids

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An accurate evaluation of coal rock fracture conductivity is an important prerequisite for predicting the productivity of CBM wells. Coal rock is soft and fragile, with low elastic modulus and high Poisson ratio. In the process of fracturing flowback, the contact deformation between proppant and fracture wall will affect the fracture conductivity when the proppant is embedded in the coal rock; thus the calculation method of plate fracture conductivity is no longer suitable for the evaluation of coal rock. Based on the contact deformation theory of elastic mechanics, a method for calculating contact deformation of proppant in fracture is proposed. Considering the effect of the deformation and embedded depth of proppant and the tortuosity of pore flow channel between proppant particles on fracture conductivity, a model for calculating fracture conductivity of coal rock fractures under three kinds of proppant arrangement (Model 4-1, Model 3-1, and Model 2-1) is established. Comparison of calculation results of theoretical model and experiments confirmed that the arrangement of proppant in coal rock fracture is closest to Model 3-1, and the influence of mechanical parameters of coal rock and proppant on fracture conductivity is calculated and analyzed by this theoretical model. The study shows that the coal rock fracture conductivity is affected little by Poisson’s ratio of coal rock and proppant, which is greatly influenced by the elastic modulus of them, and the effect of particle size of proppant is especially significant.

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Hydraulic fracturing model featuring initiation beyond the wellbore wall for directional well in coal bed

Cited by 23 publications

References 18 publications

Analysis of Application Parameters of Hydraulic Slotting Technology in Jointed Coal Reservoirs

Analysis of Application Parameters of Hydraulic Slotting Technology in Jointed Coal Reservoirs

Experimental investigation on mining-induced strain and failure characteristics of rock masses of mine floor

The Calculation of Coal Rock Fracture Conductivity with Different Arrangements of Proppants

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