Research on key technology of L type coalbed methane well drilling through goaf
With the large-scale mining of coal mines,a large area of goaf crushing zone has been formed in most coal mines.However,due to the existence of goaf,there are great difficulties in underground construction and surface pre-pumping of coalbed methane.As a result,conventional drilling technology cannot pass through the goaf for pre-extraction of coal in the lower group.Therefore,this paper aims to overcome the technical problems such as coalbed methane pre-pumping in the lower coal group.Through in-depth analysis of the geological characteristics and existing drilling technical problems in the goaf of Sihe Coal Mine,a new directional drilling technology through goaf was developed,which solved the technical problems that the goaf compaction cannot achieve efficient development of coal-bed methane horizontal wells due to overburden in goaf,and the technology was applied to the underground test.The results show that the fourth spudding deep structure can effectively solve the problem of difficult extraction of coalbed methane in the lower goaf.The use of extended multi-head gas screw,nitrogen injection drilling technology and wireless magnetic measuring while drilling instrument can improve the the working torque of the screw,enhance the rock breaking ability,and improve the accuracy of horizontal drilling well;opti-mize the maximum wellbore curvature and trajectory profile to ensure the drilling quality and encounter rate of the coal seam horizontal section.After comparing the theoretical analysis with the final construction results on site,there is no significant error and it can be widely used.
coalbed methane wellthrough goafpneumatic screwdrilling system
万方数据
维普
