Research on mechanical properties of wireline drill pipes for geological ultra-deep holes

Abstract:

wireline coring drill pipe for geological ultra-deep hole is structurally different from the API oil drill pipe; thus their mechanical properties cannot be determined by the relevant formulas of API oil drill pipe directly. In view of the lack of theoretical basis and calculation method, this paper analyzes the stress of the double shoulder drill pipe joint for geological ultra-deep hole, carries out the theoretical research on the calculation of tensile load and torsional load for the tool joint, and develops the theoretical calculation model of the wireline coring drill pipe’s mechanical properties. Through the finite element analysis and property test, the mechanical properties of the H-5000 drill pipe are determined, and the accuracy of the calculation method is verified. The proposals for improving the drill pipe structure and the next research direction are put forward, which provide technical support for deployment of the high-performance thin-wall wireline coring drill pipe in the 5000m geological core drilling works.

Key words:ultra-deep hole; core drilling; wireline coring drilling pipe; double shoulder; mechanical properties; make-up torque