Study On Roof Control Technology Of Working Face Under The Influence Of Waste Oil Casing

Coal and oil and gas resources overlap region,the oil buried deep,lead to oil well throughout the coal measures strata,and abandoned oil well casing damage to the roof deformation,changed the original roof mechanical state.At present,CH4,H2S and other poisonous and harmful gases in the well seriously exceed the standard,partly because of the diffusion of them into coal-bearing strata,especially through the old damaged casing.So the waste oil casing under the influence of the structure characteristics of overlying rock strata,mobile destruction rules,support load,overlapping area roof control of resources to provide theoretical basis,and provide important basis for oil and gas diffusion in coal measures strata.In this paper,the influence of the abandoned oil casing on the roof of the working face is studied.Research shows:1 Through mechanics analysis and calculation of oil casing increases the shear resistance of the rock and soil mass,slightly increased the internal friction Angle of surrounding rock,sleeve anchor solid cohesive force increased by 91.5 MPa,the elastic modulus of 16884 MPa,poisson’s ratio of 0.274.Therefore,the bearing capacity,mechanical properties and mechanical parameters of rock mass are changed,and the stability of rock mass is improved.2 Through the presence of casing two physical analog simulation experiment contrast,because of the influence of the casing,face first he step distance increase 18 m,average period to step pressure increases from 6.93 m,support working resistance increases when the 1698 mpa,and to pressure strength increases,higher pressure area expanded 10～30 m,the peak stress increases around 10 mpa,overburden subsidence in different layers have different degree is reduced,especially in the casing in the sink.3 Through the state of numerical simulation experiment,the influence of casing increased average period to pressure step 5 m or so,basic roof subsidence reduce 0.5 cm,have increased pressure zone in expanding 10～30 m,the peak stress increases around 10 mpa,a maximum of 60 mpa,overburden deformation damage amount is reduced,and the casing stress concentration around the more obvious,the result is similar to physical analog simulation experiment.4 because of the influence of the horse out 31 Wells,the roof support working resistance when near the oil well is bigger than the other side,the side of the weighting interval and the support working resistance also as well as decreases with the increasing of the distance,the bracket rear overhang intermittent phenomenon.According to the measured results of the observation results,the measured results of the support load are 8162.34KN～9287.34 KN,and the zy1010/22/45d hydraulic supports used in the working face can meet the control requirements of the roof.