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Study and Application of a New Casing Protection Technology for Long-Term Gas Extraction in Deep Coal Seams
Hao Li1,2,3, Junqi Cui1,2,3, Peng Lu1,2,3
1School of Safety Science and Engineering, Henan Polytechnic University, Jiaozuo 454003, China.
ACS Omega
|March 30, 2026
Summary
A novel high-strength extraction pipe (HSEP) with internal support enhances borehole stability in deep coal seams. This improved pipe design significantly boosts gas extraction efficiency and longevity compared to traditional extraction pipes (TEP).
Area of Science:
- Mining Engineering
- Materials Science
- Geotechnical Engineering
Background:
- Borehole instability in deep coal seams causes extraction pipe failure.
- Traditional extraction pipes (TEP) deform and rupture under compressive stress, reducing gas extraction efficiency.
Purpose of the Study:
- To develop and validate a high-strength extraction pipe (HSEP) with an internal support structure.
- To improve the long-term gas extraction efficiency and structural integrity of extraction pipes in deep coal seams.
Main Methods:
- Theoretical analysis and numerical simulation to determine structural parameters.
- Quasi-static compression tests to analyze compressive performance and deformation.
- Underground field industrial trials to validate HSEP performance.
Main Results:
- HSEP compressive strength increases with decreasing radial compression angle, reaching 1.15 times the load capacity of TEP.
- Internal support creates chambers exhibiting stage-wise failure, prolonging plastic deformation.
- Field trials showed significantly superior gas extraction in HSEP (39% concentration) vs. TEP (16% concentration) after 92 days.
Conclusions:
- The HSEP design effectively addresses borehole instability and pipe failure in deep coal seams.
- The HSEP demonstrates enhanced compressive strength and prolonged plastic deformation stages.
- Industrial trials confirm the HSEP's superior long-term gas extraction performance.
