A new inorganic sealing material used for gas extraction borehole

The quality of borehole sealing has significant influence on the gas extraction. Inorganic sealing material has the advantages of low cost, multiple functions and high performance; therefore, it has been widely used in many fields. In the paper, the single factor experiment was conducted on the new inorganic sealing material, and the effect of the polymer and the expansive agent on the properties of the new inorganic seal material was studied, on the basis of which such three factors as polymer-to-cement weight ratio, dosage of dispersant, and dosage of the expansive were used as the research object of the orthogonal experiment; the flexural strength, compressive strength and expansion coefficient were used as the evaluation indicators to analyze the effect of such three factors on the properties of the inorganic material. The results of the research show that the final proportion of the new inorganic sealing material is: 1.2% dosage of dispersant, 6% polymer-to-cement weight ratio, and 0.1% dosage of expansion agent. The water cement ratio exerts great influence on the mechanical properties of the material; the higher the water cement ratio is, the lower the compressive strength and the flexural strength are. Furthermore, the water cement ratio also has significant influence on the fluidity of the slurry; the water cement ratio is determined to be 1.5:1. According to the aforesaid proportion, the sealing performance test was conducted on the new inorganic sealing material, and the comparison was made with the Portland cement material. The results of the test show that the time required for the air space to restore from the initial pressure value to the atmospheric pressure value is much greater than that needed for the cement material, so the sealing performance of the inorganic sealing material is much better than that of the Portland cement materials. It is of practical significance to develop the new inorganic seal material, which can improve the quality of sealing, increase the gas extraction rate and reduce the mine gas accidents.