Hydraulic Fracturing Experiments in the Great Northern Coal Seam

Abstract

Two field-scale hydraulic fracturing experiments were performed in vertical boreholes on the lease of Munmorah Colliery located south of Newcastle, NSW. The treatments fractured the 3-metre thick, 220-metre deep Great Northern coal seam and were designed to provide a direct comparison between a borate-crosslinked gel and a water treatment. The fracture geometries were mapped during mining of the coal seam. Geologic mapping disclosed a well-defined coal face cleat and systematic full-seam joints perpendicular to bedding and trending NW. The vertical hydraulic fractures extended along the joint and face cleat direction. Evidence that an early slurry stage of fine mesh proppant acted to block off one of two competing parallel fractures was found at one of the mineback sites. Introduction Two hydraulic fracture experiments were conducted in the Great Northern Coal seam on the lease of Munmorah Colliery located south of Newcastle in New South Wales, Australia. P. 361^

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“…Jeffrey et al 7 studied the influence of bedding, face cleats and joints on the fracture geometry. Gu et al 8 proposed an interfacial slip model based on the displacement discontinuity method.…”

“…Taking an example of Shuping landslide, Wang et al 6 found that the deformation of Shuping landslide corresponds to the Three Gorges reservoir fluctuations, especially, the deformation of the landslide is more active during periods of declining reservoir levels. Continuous rainfall also triggers the failure of slope, because the strength of the sliding zone is reduced by water infiltration 7 . Besides, Burda et al 8 proposed that the climate change induces reactivation of landslide.…”