Method and Apparatus for Improving the Efficiency of a Positive Displacement Motor for Drilling and Oil or Gas Well

摘要

A method and apparatus for improving the efficiency of a drill string that includes drilling pipe, a dump valve, a positive displacement motor and a rotary drill bit driven by the motor utilize a dump valve that does not depend upon a pressure loss to maintain the dump valve in a position which closes communication between the drilling string and the annulus between the drilling string and the well bore or casing. The dump valve includes a flow sleeve that is axially moved to close outlet passages to the annulus by the flow of fluid through the outlet passages rather than a pressure drop across the flow sleeve.

主权项

1. A dump valve for use with a positive displacement motor in a drill string comprising:
a housing having an inlet and an outlet;an axially movable flow sleeve positioned within the housing and forming with the housing an annular space in communication with pressure exterior to the valve;
the flow sleeve including a flow passage therethrough; one or more outlet passages formed in the housing extending between an interior portion of the housing and an exterior portion of the housing; and the flow sleeve being shiftable from a first open position to allow fluid flow through the one or more outlet passage(s) to a second position blocking the flow of fluid to the outlet passages.