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Research And Application Of Large Diameter Directional Drilling In Fracture Zone Of High Gas Fully Mechanized Mining Face

Posted on:2024-01-22Degree:MasterType:Thesis
Country:ChinaCandidate:Z X GongFull Text:PDF
GTID:2531307118488604Subject:Mining engineering
Abstract/Summary:PDF Full Text Request
In view of the problems such as long layout period and large engineering quantity of high pumping roadway,which seriously affect the mining and replacement of working face,taking 1305 working face of Licun Coal Mine,Lu ’an Group as the engineering background,the paper systematically studies and applies the largediameter directional drilling and mining technology in crack zone with the characteristics of short construction period and strong flexibility.The method of theoretical analysis,numerical simulation and field measurement is adopted.The evolution law of overburden rock fracture,gas extraction mechanism of large diameter directional drilling in fracture zone,reasonable layout parameters of large diameter directional drilling in fracture zone and applicability of large diameter directional drilling in fracture zone were analyzed,and the following results were obtained:(1)The evolution characteristics of overlying rock fissure in high gas fully mechanized mining face are analyzed.Based on the geological production conditions of 1305 working face in Licun Coal Mine,the UDEC numerical calculation model was established,and the evolution characteristics of overburden fracture,stress and displacement under different advancing distances were analyzed,and the easy extraction range of goaf gas was determined.Based on the fractional source prediction method,the gas gushing quantity of fully mechanized mining face is predicted,and the equipment supporting conditions of large diameter directional drilling in fracture zone are analyzed.(2)The principle of gas extraction by large diameter directional drilling in fracture zone is analyzed.The radial seepage model of borehole gas extraction is established,and the key influencing factors of borehole gas extraction and their relationship with gas extraction effect are determined.Based on the distribution law of gas flow field in goaf under different extraction methods,the influence range of extraction under different extraction measures is analyzed.(3)The reasonable layout parameters of large diameter directional drilling in fracture zone are studied.By using orthogonal analysis method,the upper corner gas concentration as the index,the sensitivity analysis of the layout parameters of gas extraction in the large diameter directional borehole in the fracture zone was carried out,and the sensitivity order of the layout parameters was obtained.The reasonable layout parameters of gas extraction in the large diameter directional borehole in the fracture zone were determined,and the gas extraction effect was compared with that in the high drainage roadway.The feasibility of large diameter directional drilling in fracture zone for gas extraction in goaf is improved.(4)A multi-attribute and multi-objective applicability evaluation model for gas extraction by large diameter directional drilling in fractured zone is established.Based on the distribution characteristics of discrete random variables,a Monte Carlo-Analytic Hierarchy process simulation test was designed to optimize the weights of traditional analytic hierarchy process index and scheme layer,and the applicability of large-diameter directional drilling gas extraction in fractured zone was quantitatively evaluated.The research results have been successfully applied in the 1305 working face of Licun Coal mine.The gas extraction rate of large-diameter directional drilling in fractured zone is more than 30%,and the average gas concentration in the upper corner of the working face is 0.32%,which is equivalent to the effect of high pumping under similar conditions.However,it saves cost and time limit,and solves the problem of tight connection between mining and excavation in the working face.It can provide reference for the research and application of large diameter directional drilling in fracture zone under similar conditions.There are 59 figures,32 tables and 81 references in this thesis.
Keywords/Search Tags:High gas, fracture zone, large diameter directional drilling, gas extraction
PDF Full Text Request
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