SEALING MEMBER FOR DISINTEGRATING DOWNHOLE TOOL, DOWNHOLE TOOL AND WINZE EXCAVATION METHOD

摘要

PROBLEM TO BE SOLVED: To provide a sealing member capable of facilitating a winze process by reliably sealing a fluid between a downhole tool and a casing under various mining conditions, and capable of desirably designing to removal the sealing member and ensure a flow path thereof, and capable of cost saving and step reduction in winze excavation.SOLUTION: The sealing member for downhole tool is formed of a high polymer material including a material which has disintegrating property by 5 pts.mass or more relative to a high polymer material of 100 pts.mass. Preferably, the reduction ratio of mass or 50% strain compressive stress after being immersed in a water of 150°C for 24 hours is 5% or more; or the mass reduction ratio after being immersed in a water of 150°C for 72 hours is 5-100%; or the flexural modulus at hardness A60-D80/23°C is 0.005-10 GPa; or the sealing member maintains a stable state under a dry environment and/or capable of being decomposed in a fluid of 66°C or more; or the tensile fracture strain is 50% or more; the compressive stress is 10 MPa or more; and the compression failure strain is 50% at 66°C. There are also provided a downhole tool such as a winze excavation plug and a winze excavation method.