Patent ID: 7646310
Filing Date: 2010-01-12
Classification: E21B,G01V

Abstract:
1. A system for communicating downhole information through a wellbore to a surface location comprising: a drill bit; a drilling sub; a BHA interconnected between the drill string and the drilling sub; a valve means for providing a flow restriction to fluid passing through the wellbore, said valve means comprising a float valve mounted in said drilling sub suitable for controlling a flow of drilling mud in said wellbore; a sensor means positioned in the wellbore for sensing a downhole condition in the wellbore; an actuator means cooperative with the valve means for moving said valve means between at least two positions in timed relation to the downhole condition sensed by the sensor means; and a detector means positioned at the surface location and cooperative with the fluid passing in the wellbore for providing a measurement value at the surface location correlative to time between changes of pressure of the fluid in the wellbore, said valve means and actuator means being positioned within said drilling sub.