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Effect of Borehole Radial Pore Pressure Gradient on the Initiation and Propagation of Sandstone Hydraulic Fractures
The initial pore pressure gradient along the borehole radial direction affects the initiation and instability of a hydraulic crack tip and its...
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Effect of damage zone around borehole on carbon dioxide injection promoted gas extraction in soft and low-permeability coal seam
Injecting external CO 2 into soft and low-permeability coal seams can improve CH 4 extacctinn efficiency, and also benefit in CO 2 sequestration....
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A New Method for Determining the Sealing Depth of Extraction Borehole Based on the Constant-Pressure Gas Injection and its Applications
Coalbed methane is a risk of coal mining safety while being an important energy source, and gas extraction is the most effective treatment method....
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Synchronous Inversion of Coal Seam Gas Pressure and Permeability Based on a Dual Porosity/Dual Permeability Model and Surrogate Optimization Algorithm
Rapid and accurate acquisition of permeability and gas pressure is crucial for gas development and disaster prevention in coal mines. However, these...
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Analysis on borehole stability of gas drilling with complete stress–strain and thermal stress theory
In conventional mud drilling, sufficient drilling fluid density is required to maintain wellbore stability. However, in gas drilling, the support...
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Modeling of borehole washout effects and gas hydrate-filled fractures using NGHP-02 downhole data in Krishna Godavari offshore basin, India
The purpose of this study is to look into the effects of borehole washouts on log measurements and the resulting error in predicting gas hydrate...
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Rapid In-Situ Stress Measurement in Vertical Borehole Based on Borehole Diametrical Deformation Analysis
In-situ stress measurement is an important prerequisite for underground engineering excavation design and surrounding rock stability analysis....
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Modeling of Coalbed Gas Pressure/Content Identification Using Image Analysis
Coalbed gas pressure and content are fundamental parameters for mine gas recovery and disaster prevention. In response to the lengthy measurement...
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Quantitative Assessment of Coal Seam Permeability Improvement Around an Enlarged Borehole in Gas Extraction Engineering: A Method for Field Application
AbstractUnderstanding the permeability distribution is an important basis for the design of hydraulic strengthened gas extraction. However, the...
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Progressive Initiation Phenomenon of Radial and Axial Cracks of the Borehole During Rock Hydraulic Fracturing
Hard roof control is a technical problem that restricts the safe and efficient coal mine production. Hydraulic fracturing is an effective technical...
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Gas Extraction Mechanism and Effect of Ultra-High-Pressure Hydraulic Slotting Technology: a Case Study in Renlou Coal Mine
Ultra-high-pressure hydraulic slotting technology is an effective method to realize pressure relief and permeability enhancement of a single coal...
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A comprehensive review of deep borehole heat exchangers (DBHEs): subsurface modelling studies and applications
Deep borehole heat exchangers (DBHEs) with depths exceeding 500 m have been researched comprehensively in the literature, focusing on both...
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Zonal Seepage in Coal Seams Generated by Hydraulic Fracturing Under Gas Pressure Attenuation: Characteristics and Affecting Factors
Hydraulic fracturing causes the fracture zone phenomenon in a coal seam. The effectiveness of coalbed methane (CBM) extraction is determined by the...
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Selecting the Optimal Borehole Drilling Pattern for Methane Drainage in Underground Coal Mining: A Case Study in Iran
The emission of gas from the coal seams is one of the most important issues during the underground coal mining operation. Each year, coal gas...
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Water Content Effect on Borehole Breakout in Hard Rock and Its Interpretation: An Experimental Study
Borehole breakout is an important geological phenomenon that provides a significant reference for the estimation of the direction and magnitude of in...
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Fully Coupled Anisotropic Porothermoelasticity Modeling for Inclined Borehole in Shale Formations
Existing porothermoelastic models assume that shale is isotropic and disregard material anisotropy. When material anisotropy is considered, the...
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Acoustic Emission Crustal Stress Experiment Based on Borehole Wall Electrical Imaging
Core orientation parameters is calculated by using the electrical imaging data of borehole wall, and the sampling and calculation methods of acoustic...
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Evolution of Permeability and Gas Seepage in Deep Coal Under 3D Stress
More and more gas extraction in deep coal seam is conducted under extreme geological conditions. The coal permeability determines the efficiency of...
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Research on Cementing Technology in Narrow Gaps at Changqing Gas Field
As a typical “three-lows” characteristic of low permeability, low pressure, and low abundance, the Changqing gas field has been developed from...
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Field investigation of multi-stage pulse hydraulic fracturing for improving permeability of coal seam in directional long borehole in underground coal mines
Directional long borehole has been promoted in underground coal mines. However, the hydraulic fracturing technology based on directional long...
