Research on the Negative Pressure Distribution Law and Application within In-seam Borehole

In order to thoroughly explore the variation law of negative pressure along the length of in-seam boreholes, a negative pressure distribution formula within in-seam boreholes was derived through coupling a gas flow model in the coal mass surrounding the borehole and a gas flow model inside the borehole. Field tests were conducted to measure the negative pressure values at different depths within the boreholes, thereby obtaining the negative pressure distribution law and verifying the feasibility of the theoretical model. By applying the negative pressure distribution law, a novel gas extraction technology that alters the negative pressure distribution within the boreholes was proposed, and its superiority under certain applicable conditions was validated, providing references and guidance for the design of in-seam gas extraction.