... ABSTRACT Cleats play a crucial role in the propagation of fractures during coalbed hydraulic fracturing. However, current numerical methods still suffer from significant drawbacks in terms of computational efficiency and fracture trajectory prediction. In this study, we used the displacement...

...., cleats and bedding planes) as input data for the 3DEC model are estimated based on the results of the laboratory tests and field observations. The DFNs explicitly generated the coal seam that was poorly or well cleated, indicating the different spacing between cleat apertures using the probability...

... of freezing were carried out. The test results show that the shear strength, tensile strength and Mode-I fracture toughness significantly increase after freezing treatment. The freezing-assisted hydraulic fractures extend along the maximum horizontal principal stress, instead of along the cleats orientation...

... ABSTRACT: The fracture development of the coal cleat along with its significant anisotropy of mechanical properties, low mechanical strength and fragile features make it difficult to prepare rock samples for mechanical experiments. And thus the conventional profile prediction method of sand...

... matrix swelling strain, mechanical compression induced strain, and cleat volume strain induced cleat compressibility. Based on transversely isotropic assumption, the proposed model can effectively describe the anisotropy characteristics strain evolution of coal by involving geomechanics parameters...

... fracture length predictions within 9% of measured values by microseismic monitoring in the target block. This paper may provide theoretical guidance for the optimization of CBM reservoir hydraulic fracturing operations with high-rank coal rock. Artificial Intelligence coal seam gas face cleat...

... of hydraulic fracture propagation around horizontal well in coal seam is unpredictable because of the developed coal cleats. To clarify fracture initiation and propagation mechanism, PFC2D is introduced in this paper to build a discrete element model with coal cleats of coal seam considering the effect of coal...

..., the results of the unconfined compressive test do not agree with the strength models of the classical strength formula because the strengths at certain orientations of cleats appear much higher than the estimation by the classical solution. The influence of non-persistent cleats on coal strength is, thus...

... ABSTRACT: Coal pillar bumps involve the sudden expulsion of coal and rock into the mine opening. Cleating is a type of joint system unique to coal seams. Cleat systems differ from adjacent joint systems in that they are pervasive throughout the coal seam, and are much more tightly spaced than...

... Abstract: This study presents the development and application of a fully coupled numerical model that integrates different flow regimes and the generation of coal fines. The Scanning Electron Microscopy (SEM) was employed to obtain coal cleat geometry at the micro-scale. Based on the real...

... Abstract: True tri-axial test system was deployed for directional well fracturing simulation experiments of coal outcrops, and an ingenious method of proppant adding during fracturing was performed in laboratory. Subsequently, the influence of in-situ stress, azimuth, cleats and proppant...

... in the latter case, injected nitrogen reduces the partial pressure of methane in coalbed, flushing it out from the cleat system and resulting in desorption of methane from the sorption sites. However, the former option is more attractive since it not only enhances the recovery of methane, but also offers...

... reservoir geomechanics Wellbore Design treatment pressure hydraulic fracturing drillstem/well testing wellbore integrity Upstream Oil & Gas cleat high treatment pressure coal pore pressure buildup specimen in-situ stress stress condition pore pressure experiment pressure...

..., Colo. ABSTRACT: Systematic fracture (face cleat) strikes in Upper Cretaceous Fruitland Formation coal (San Juan Basin, Colorado and New Mexico) delineate two domains of regional extent that are separated by a boundary of variable cleat orientation near the Colorado-New Mexico border. South...

... structural geology outcrop eastern kentucky metals & mining weathered joint shale Upstream Oil & Gas roadcut cleat stress relief joint stress relief Kentucky preferred direction sandstone diagram surface contour joint trend Parallel highwall perpendicular Rock Mechanics...

... planes of symmetry - bedding, major cleat (face) and minor cleat (butt) [2-4]. A typical element of such a coal seam is shown in Fig. 1, where the x, y, and z axes correspond to the major cleat, minor cleat and bedding directions. In terms of on-axis stress components (in the x-y-z reference system...