Patent ID: 7382686
Filing Date: 2008-06-03
Classification: E21B

Abstract:
1. A pressure pulse generator for use in transmitting pressure signals to surface in a fluid-based drilling system, said generator being arranged in use in the path of a pressurized fluid to operate a drilling assembly and being capable of being actuated to generate pressure signals in such fluid for transmission to surface pressure monitoring equipment, in which the pulse generator comprises: a housing positionable in the path of the supply of pressurized fluid, said housing having an inlet anangement for admitting a portion of the fluid to the interior of the housing, and an outlet arrangement for discharging fluid from the interior of the housing for supply of the drilling assembly; a control element slidably mounted in the housing for movement between an open and a closed position with respect to said inlet anangement, said control element being operative to generate a pressure pulse in the supply of pressure fluid when the control element takes-up the closed position; a control passage extending through the control elements and closable by a pilot valve element arranged to be exposed to the pressure of the fluid in the passage; and an actuator coupled with the valve element and operative, when the pressure generator is activated to generate a pressure signal, to move the valve element to a position closing said passage and thereby to cause movement of the control element towards the closed position; in which the coupling between the actuator and the valve element includes a yieldable biasing element which provides control of the amplitude of the pressure signals produced by the generator.