Patent ID: 6237701
Filing Date: 2001-05-29
Classification: E21B

Abstract:
Apparatus for generating a suction pressure pulse in a borehole in which a pressurized fluid is being circulated, comprising:(a) a valve having an inlet port, an outlet port, and a drain port, the inlet port of said valve being adapted to couple to a conduit through which the pressurized fluid is conveyed down into the borehole, said valve including a first member that is actuated by the pressurized fluid to cycle between an open state and at least a partially closed state, said first member, while in the at least partially closed state, at least partially interrupting a flow of the pressurized fluid through the outlet port so that at least a portion of said flow of the pressurized fluid is redirected within the valve without completely interrupting the flow of the pressurized fluid into the inlet port, the pressurized fluid that was redirected within the valve when the first member was last in the at least partially closed state subsequently flowing through the drain port and back up the borehole; and(b) a high velocity flow course coupled in fluid communication with the outlet port of the valve and having an inlet and an outlet, said suction pressure pulse being generated when the first member is in the at least partially closed state by substantially reducing the flow of the pressurized fluid through the high velocity flow course.