Development and application of high-performance drilling hole protection materials.

Area of Science:

• Materials Science
• Geotechnical Engineering
• Environmental Science

Background:

• Borehole instability and collapse critically impair gas extraction efficiency.
• Effective borehole protection is vital for maintaining stable extraction channels and maximizing gas recovery.
• Development of advanced, sustainable materials is needed for robust borehole reinforcement.

Purpose of the Study:

• To engineer an environmentally friendly borehole protection material with high strength, permeability, and controllable setting time.
• To propose a synergistic borehole protection technology integrating in-hole screen protection and grouting reinforcement.
• To validate the material properties and the efficacy of the proposed protection technology through laboratory and field tests.

Main Methods:

• Preparation of a composite protein foaming agent from hydrolyzed human hair residue.
• Utilization of pulverized coal as a sustainable mineral admixture, replacing fly ash.
• Optimization of grouting material composition (water-cement ratio, material ratios, foaming agent content) via orthogonal tests.
• Characterization of foam concrete properties: compressive strength, permeability, porosity, setting time, and fluidity.
• Verification of on-site construction feasibility through dynamic curing characteristics experiments.
• Implementation and testing of the synergistic protection technology in industrial field applications.

Main Results:

• Optimal foam performance achieved using 2 g/L sodium laureth sulfate (SLS) and 0.3% calcium stearate.
• Pulverized coal incorporation enhanced concrete strength and durability while reducing environmental impact and carbon emissions.
• Optimized material (0.7:1 water-cement ratio, 25 ml foam, 30 g pulverized coal, 5 g silica fume, 0.2 g polypropylene) exhibited 13.665 MPa compressive strength, 2.12 MD permeability, 22.019% porosity, and a 401-418 min setting time.
• Fluidity of 320 mm confirmed suitability for field application.
• Industrial tests demonstrated the effectiveness of the synergistic protection technology in preventing borehole wall instability and collapse.

Conclusions:

• The developed foam concrete, utilizing waste materials like human hair and pulverized coal, offers a high-strength, high-permeability, and eco-friendly solution for borehole protection.
• The synergistic protection technology, combining internal screen reinforcement with external grouting, effectively enhances borehole stability and ensures unobstructed gas extraction pathways.
• This approach significantly improves gas extraction efficiency and wellbore integrity, offering a sustainable alternative to conventional methods.