Research And Application Of Thickened Expansion Slurry Sealing Technology For Gas Extraction Borehole

Coal is the main energy of China,gas as coal associated products,not only the major coal mine disaster and pollution sources,it is a valuable non-renewable energy.Underground drilling gas drainage is a critical technique of the coal mine gas collection and prevention of gas accidents.The quality of the drilling seal directly determines the effect of gas extraction and a successful sealing process can guarantee the long and efficient pumping of the drilling gas.Therefore,it is of great significance to carry out research on drilling sealing materials,technology and equipment.First,the sealing mechanism of drilling is analyzed based on the fluid seal theory of mechanical industry in this paper.Point out that the failure of the drilling seal is due to the presence of the leak channel,through the study of the drilling mechanism.Drilling leak channel mainly includes the following three kinds: leakage channel caused by roadway relief,air leakage channel caused by drilling broken zone,sealing material cracks leak.The most important task is to avoid sealing material forming a fissure.Secondly,a high-performance cement-based composite expansion material had been developed,which expansion ratio of up to 1.4.A set of sealing equipment was developed for the material properties,including the single bag and pneumatic grouting device.On the basis of new materials and equipment,the traditional sealing technology was improved,and a new thickening slurry sealing technology was developed.The ground simulation drilling test showed good results.Finally,the technology was conducted industrial test in Huainan Zhu Jidong mine which include two aspects: the thickened expansion slurry sealing technology and "two sealing and one grouting" method with the new material.Comparison of new technology and old technology shows that: in the study period of 30 days,the concentration of borehole for original technology decreased to below 10% after 30 days,and borehole for the new technology has maintained a high concentration of more than 60% extraction.The application of new technology increases the average extraction concentration of single hole by 50% and prolongs the effective extraction period.The sealing effect of the new process and mixing process is almost equal,which shows that the sealing material can't meet the requirements of drilling sealing,which is the fundamental reason for poor sealing effect of the test coal mine.The application of the single capsule sealing method simplifies the construction steps,improves the sealing efficiency,and reduces the sealing cost.