Multi-angle analysis of the mechanism of polymer materials to improve the sealing quality of boreholes

ABSTRACT

The quality of borehole sealing is closely related to the sealing materials. As a kind of sealing material, how polymer materials improve the sealing quality has not been deeply analyzed. This paper based on the analyses of the dynamic contact state between polymer material and borehole wall, taking borehole, polymer material and their contact surface as the research object, this paper analyzes the changes of air leakage channel after sealing, the internal particles of foaming material, and the structure characteristics of contact surface. From multi-angle to obtain the sealing mechanism of polymer material. The results are: (1) the reduction rate D equation of the air leakage channel is derived. It positively relates to the expansion support force of sealing material. (2) Polymer materials could reduce the stress and deformation of coal surrounding borehole by 2.3 ~ 4.5% and 15.2% ~ 19.9% respectively, to narrow the air leakage range outside the hole. (3) The unusual structure of polymer foam particles can be well bonded and fixed with the borehole wall, improve the borehole stability, and reduce the air leakage inside the hole. (4) Polymer sealing material can maintain an average gas concentration of 44.90% within 60 days, not less than 30%, and ensure the extraction effect.

KEYWORDS:

• Polymer material
• sealing quality
• contact state
• air leakage channel
• gas concentration

Acknowledgments

The research was supported by the National Natural Science Foundation of China (Project No. 51874315). Meanwhile, we are very grateful to the editor and anonymous reviewers for their very valuable comments which improve this paper significantly.

Disclosure statement

No potential conflict of interest was reported by the author(s).

List of symbols

Table