Strategies for Creating Prescribed Hydraulic Fractures in Cave Mining

He, Qingyuan; Oh, Joung

doi:10.1007/s00603-016-1141-7

Cited by 37 publications

(28 citation statements)

References 66 publications

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“…These factors measure how the PHF re-orientates from its preferred propagation direction and determine the PHF effectiveness in generating an additional joint set. He et al [17] concluded that PHFs in cases with the same differential stress magnitudes reach similar propagation distances. He et al [32] found that the differential stress σ 1 − σ 3 has a limited impact on PHF propagation if the PHF borehole is placed on the σ 2 − σ 3 plane.…”

Section: Prescribed Hydraulic Fractures Dimensional Analysismentioning

confidence: 99%

“…ND applications to regular shaped HFs attempt to relate the applied fluid pressure and HF dimensions to the influencing factors. For PHFs that focus on fracture re-orientation trajectories [17], the established dimensionless relation is unable to project the PHF propagation path. Important dependent and independent factors involved in prescribed hydraulic fracturing are listed in Table 4 and differ from those in Table 3.…”

Section: Dimensional Analysis Applied To Hydraulic Fracturingmentioning

confidence: 99%

“…He et al [17] simulated prescribed hydraulic fracturing and studied the effects of various factors on their trajectories with the assumption that the PHF borehole lies on the σ 2 − σ 3 plane (Figure 2). In Figure 2, four dependent factors are used to quantify PHF re-orientation distances, including the vertical (L vu ) and horizontal (L hu ) propagation lengths of the PHF upper strand and the vertical (L vl ) and horizontal (L hl ) propagation lengths of the PHF lower strand.…”

Section: Prescribed Hydraulic Fractures Dimensional Analysismentioning

confidence: 99%

“…While the proposed approaches were proven feasible theoretically with numerical modelling [17], no proof of these concepts has been given in the field. The field trial is a direct way to prove newly developed theoretical concepts.…”

Section: Introductionmentioning

confidence: 99%

“…He et al [17] found that material homogeneity does not influence the feasibility of prescribed hydraulic fracturing (i.e., whether if the PHF succeeds in connecting the pre-located fractures) but has an impact on the PHF re-orientation trajectory. Liu et al [60] noted that the homogeneity index m [54] value for a typical rock material is about 2.…”

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confidence: 99%

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Application of Dimensional Analysis to Project Laboratory Scale Numerical Modelling Prescribed Hydraulic Fracturing Results to Field Scales

et al. 2018

Energies

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Abstract:Hydraulic fracturing has been applied in the cave mining industry with the purpose of re-creating an orebody rock mass condition that is suitable for caving. Prescribed hydraulic fracturing was proposed in a previous study as a supplement to the conventional hydraulic fracturing strategy. In this paper; dimensional analysis is used to project laboratory scale numerical modelling results to field scales in order to study the applicability of creating prescribed hydraulic fractures (PHFs) under field conditions. The results indicate that field scale PHFs are feasible if the stress shadows of the pre-located fractures are properly utilized. Water can be used to create the pre-located fractures that induce the local stress change in a low differential stress state; and the use of more proppants and a shorter pre-located fracture spacing lead to PHFs propagating more quickly towards the pre-located fractures. For field condition having high differential stresses, more viscous fluid must be used to create the pre-located fractures in order to enhance the stress shadows. In this case, a shorter pre-located fracture spacing does not necessarily result in the re-orientation of PHFs towards the pre-located fractures and may even lead to unsatisfactory pre-conditioning. A sufficiently high pre-located fracture net pressure to the differential stress ratio (close to 0.5) is the prerequisite for creating PHFs.

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Section: Prescribed Hydraulic Fractures Dimensional Analysismentioning

confidence: 99%

Section: Dimensional Analysis Applied To Hydraulic Fracturingmentioning

confidence: 99%

Section: Prescribed Hydraulic Fractures Dimensional Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

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Application of Dimensional Analysis to Project Laboratory Scale Numerical Modelling Prescribed Hydraulic Fracturing Results to Field Scales

et al. 2018

Energies

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Numerical simulation of directional fracturing by shaped charge blasting

Meng

Chen

Bai

et al. 2020

Energy Science & Engineering

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Longwall mining has been widely applied in China in the recent decades. Safety hazards frequently happen at longwall mining working faces with hard roof conditions. This is one of the main challenges for underground mining, especially for most coal mines in Shanxi province in China. 1 Hard roofs have characteristics of high tensile strength and large thickness. They normally have poor caveability and few existing rock joints. 2 With the working face advancing, the hanging roof area increases gradually, resulting in the hanging roof of this opening room reaching area up to 8000 m 2 . The roof material is strong but brittle that causes it to cave suddenly once ground pressure reaches a threshold value. And this sudden failure causes the pressure to greatly exceed the capacity of the hydraulic roof supports. The sudden caving can cause spall of coal bodies,

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An Experimental Study on the Mechanical Properties and Expansion Characteristics of a Novel Self-Swelling Cartridge for Rock Breakage

Hou

et al. 2020

Rock Mech Rock Eng

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Strategies for Creating Prescribed Hydraulic Fractures in Cave Mining

Cited by 37 publications

References 66 publications

Application of Dimensional Analysis to Project Laboratory Scale Numerical Modelling Prescribed Hydraulic Fracturing Results to Field Scales

Application of Dimensional Analysis to Project Laboratory Scale Numerical Modelling Prescribed Hydraulic Fracturing Results to Field Scales

Numerical simulation of directional fracturing by shaped charge blasting

An Experimental Study on the Mechanical Properties and Expansion Characteristics of a Novel Self-Swelling Cartridge for Rock Breakage

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