Study of the Interaction of a Packing Device with a Coal Seam at Interval Hydraulic Fracturing

The technological scheme of the interval hydrodynamic influence on the coal seam is considered. The design of a double-sided packer is presented, the results of laboratory tests to determine the axial movement of the seals during the interval fracturing are shown. The numerical scheme based on the Finite Element Method has been developed for calculating the stress-strain state of a rock in the vicinity of a well, loaded by internal pressure through packer seals. The pressure acting on the contacts between the seals and the well is calculated, the stress distribution in the geomaterial is investigated.

RISK REDUCTION ESTIMATION FOR UNDERGROUND MINING OF GAS-CONTAINED COAL SEAMS WHILE USING THE HYDRAULIC FRACTURING

In the paper, influence of hydraulic fracturing parameters on filtration resistance of system of parallel holes during preliminary degassing of coal seam loaded with strata pressure is considered. Results of comparative analysis of degassing rates of coal seam while using holes without hydraulic fracturing and holes with non-directed or plural interval hydraulic fracturing of various orientation are represented. Estimation of influence of fracturing of different types on risk reduction of underground mining of gas-contained coal seams is given. Obtained results allow to estimate perspective of application of present modifications of hydraulic fracturing technology at coal mines.

Stimulation of Gas Emission Processes in Boreholes Using Interval Hydraulic Fracturing in Borehole Local Parts

Due to limited scope of degassing activities and insufficient efficiency of degassing schemes in many methane-rich Russian coal mines there is a gas barrier which prevents miners from achieving high speed at developing mine workings and high working face loads. For that reason there is a strange situation in coal-mining industry when technical capabilities of coal-face operation equipment working on gently sloping coal seams exceed ultimate face load in relation to gas factor several times. The authors prove the efficiency of using coal seam interval hydraulic fracturing for gas drainage stimulation. They consider the established coal seam gas drainage methods. The authors developed the process flowchart for coal seam hydraulic fracturing implementation and suggested using equipment for taking measures aimed at gas drainage stimulation.