The coal permeability is an important parameter in mine methane control and coal bed methane (CBM) exploitation, which determines the practicability of methane extraction. Permeability prediction in deep coal seam plays a significant role in evaluating the practicability of CBM exploitation. The coal permeability depends on the coal fractures controlled by strata stress, gas pressure, and strat...

We report flow-through experiments on a natural fracture in novaculite under moderate effective stresses (∼1.4 MPa) and temperatures (20–120 °C) to examine the effect on flow and transport characteristics. The efflux of fluid and dissolved minerals were measured throughout the 3150-h experiment. After the experiment the fracture was imaged by X-ray CT, impregnated with Wood's metal, and a cast ...

BACKGROUND There is a large amount of information regarding risk factors for fifth metatarsal stress fractures; however, there are few studies involving large numbers of subjects. This study aimed to compare the static foot alignment and distribution of foot pressure of athletes with and without a history of fifth metatarsal stress fractures. METHODS The study participants comprised 335 colle...

Based on the analysis of seepage mechanism of fracturing wells in low permeability reservoir, this paper establishes the capacity model of the vertical fractured well production under the factors of Start-up pressure gradient, pressure sensitive effect and the artificial fracture length. The numerical simulation is compiled and software calculates the capacity model by using numerical simulatio...

Abstract Hydraulic fracturing and permeability enhancement are effective methods to improve low-permeability coal seams. However, few studies focused on increase permeability, there no suitable prediction for engineering applications. In this work, PFC2D software was used simulate seam hydraulic fracturing. The results were in a coupled mathematical model of the interaction between deformation ...

Radial drilling-fracturing, the combination of hydraulic fracturing and radial borehole, is a technology that can guide fractures to directionally propagate efficiently develop low permeability reservoir. In this paper, an analytical model two boreholes (a basic research unit) established predict fracture initiation pressure (FIP) from one particular borehole interference between when guided by...

Permeable feed zones in geothermal wells are commonly identified using well profiles of temperature, pressure and fluid velocity measured at different injection rates during well completion testing and heat-up. While this data gives some indication of the depth and relative strength of the feed zones it does not give any information on the nature of the permeability in those zones, be it primar...

We present 2D dynamic rupture models of the 2011 Tohoku-Oki earthquake based on linear slip-weakening friction. We use different types of available observations to constrain our model parameters. The distribution of stress drop is determined by the final slip distribution from slip inversions. As three groups of along-dip slip distribution are suggested by different slip inversions, we present ...

*Correspondence: Sonja L. Philipp, Department of Structural Geology and Geodynamics, Geoscience Centre, University of Göttingen, Goldschmidtstrasse 3, D-37077 Göttingen, Germany e-mail: sonja.philipp@ geo.uni-goettingen.de Fractures generated by internal fluid pressure, for example, dykes, mineral veins, many joints and man-made hydraulic fractures, are referred to as hydrofractures. Together w...