Development of the Impermeable Membranes Using Directional Hydraulic Fracturing

Shilova, Tatjana; Patutin, A. V.; Rybalkin, L. A.; Serdyukov, S. V.; Hutornoy, Vladimir

doi:10.1016/j.proeng.2017.05.212

Cited by 7 publications

(3 citation statements)

References 2 publications

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“…The main research areas of the mine modification of the method are associated with improving the safety of underground operations. When mining coal seams, HF is used to increase the efficiency of the production of methane from coal by increasing the gas recovery [12][13][14] and creating impervious protective screens in the rock mass near mine workings [15,16]. In the case of the extraction of coal seams by longwall mining, hydraulic fracturing is applied for the controlled roof's collapse to prevent it from hanging [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Hydraulic Fracture Propagation Near the Cavity in a Poroelastic Media

2021

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In this paper, we investigate the problem of the propagation of hydraulic fractures in a poroelastic medium that has a circular cavity. The research was conducted using the extended finite element method (XFEM) implemented in the ABAQUS software package. The problem was considered in a plane formulation. The initial crack was oriented parallel to the surface of the cavity. It was shown that the path of the hydraulic fracture depends strongly on the hydrostatic stress in the medium and the distance between the crack and the cavity. We studied the influences of the poroelastic parameters, such as permeability and the Biot coefficient, on the propagation of cracks. It was shown that the cracks were less curved when the coupled problem of poroelasticity was considered. The features of fluid pressure changes inside the fracture and at the opening of the mouth were studied. It was shown that the fluid pressure in the fracture during injection was minimally sensitive to the state of the stress in the medium, to the position of the initial crack, and to the poroelastic parameters. The solution to the problem in this setting can be used to simulate hydraulic fracturing close to mine workings during a controlled roof’s collapse to prevent it from hanging, and the formation of impervious screens to reduce airflow from the mine to degassing boreholes through the rock, for example.

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Section: Introductionmentioning

confidence: 99%

Hydraulic Fracture Propagation Near the Cavity in a Poroelastic Media

2021

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“…Hydraulic fracturing cannot control the direction and boundary of fracturing in the complexity of coal seam. Although a great number of researches on directional fracturing technology have been studied by many experts and scholars, hydraulic fracturing is easy to cause stress concentration in coal body, which leads to coal and gas outburst . Hydraulic flushing can enlarge borehole diameter by flushing coal body with high‐pressure water jet, which is equivalent to large diameter borehole, and the larger the borehole diameter is, the larger the pressure relief range of the borehole and the permeability of the coal around the borehole are .…”

Section: Introductionmentioning

confidence: 99%

A new cross‐borehole hydraulic caving technique in the coal seam with a soft layer for preventing coal and gas outbursts during coal roadway excavation

Qin

Wei

Lou

et al. 2020

Energy Science & Engineering

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Predrainage of gas by cross‐boreholes is an important method to prevent coal and gas outbursts in the process of a coal roadway excavation. Limitations of technologies and poor effects of preventing coal and gas outbursts occur in the coal seam with a soft layer. In this study, a new hydraulic caving technology for cross‐boreholes has been proposed to solve this problem. A CT equipment was used to observe the development of coal fissures around cross‐boreholes in the coal seam with a soft layer. The plastic zone range and permeability distribution of ordinary hydraulic slotting technologies and the new hydraulic caving technology also were compared by numerical simulation. The field test of hydraulic caving was taken in the Xuehu Mine (China). The results show that the fracture development degree of soft coal is greater than that of hard coal at the same distance from cross‐boreholes. The fracture development degree in the plastic zone is greater than that in the elastic zone. The hydraulic caving technique can achieve the same effect as the ordinary hydraulic slotting with less workload. The mass of coal discharged from a cross‐borehole was 1.15 t/m and the average methane concentration of single drainage borehole increased by 1.09‐4.1 times, and the average methane extraction amount of single drainage borehole increased by 6.06 times. Elimination of coal and gas outburst had been completed after 110 days of extraction in the area of hydraulic caving, and Q and S values are lower than the critical value during roadway excavation. It is conclusion that hydraulic caving technique can effectively improve the permeability and rapidly eliminate coal and gas outburst in the coal seam with a soft layer.

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“…In the past decades, significant research has been focused on the mechanism of hydraulic fracture initiation and propagation [10,13,33,[36][37][38][39][40][41][42][43][44][45]. Theoretically, in intact rocks or rocks with few natural macro-fractures, it is well accepted that the initial hydraulic fractures are roughly perpendicular to the direction of minimum principal stress.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Hydraulic Fracture Propagation in Coal Seams with Discontinuous Natural Fracture Networks

Wang

2018

Processes

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To investigate the mechanism of hydraulic fracture propagation in coal seams with discontinuous natural fractures, an innovative finite element meshing scheme for modeling hydraulic fracturing was proposed. Hydraulic fracture propagation and interaction with discontinuous natural fracture networks in coal seams were modeled based on the cohesive element method. The hydraulic fracture network characteristics, the growth process of the secondary hydraulic fractures, the pore pressure distribution and the variation of bottomhole pressure were analyzed. The improved cohesive element method, which considers the leak-off and seepage behaviors of fracturing liquid, is capable of modeling hydraulic fracturing in naturally fractured formations. The results indicate that under high stress difference conditions, the hydraulic fracture network is spindle-shaped, and shows a multi-level branch structure. The ratio of secondary fracture total length to main fracture total length was 2.11~3.62, suggesting that the secondary fractures are an important part of the hydraulic fracture network in coal seams. In deep coal seams, the break pressure of discontinuous natural fractures mainly depends on the in-situ stress field and the direction of natural fractures. The mechanism of hydraulic fracture propagation in deep coal seams is significantly different from that in hard and tight rock layers.

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Development of the Impermeable Membranes Using Directional Hydraulic Fracturing

Cited by 7 publications

References 2 publications

Hydraulic Fracture Propagation Near the Cavity in a Poroelastic Media

Hydraulic Fracture Propagation Near the Cavity in a Poroelastic Media

A new cross‐borehole hydraulic caving technique in the coal seam with a soft layer for preventing coal and gas outbursts during coal roadway excavation

Numerical Simulation of Hydraulic Fracture Propagation in Coal Seams with Discontinuous Natural Fracture Networks

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