Coding - and transmission system for the drilling mud pulse - remote transmission of the drilling tool end face by a helicoidal guide angle data

摘要

Orthogonal indicia of orientation of a drilling tool 22 at the end of a drill string 18 within a borehole 12 are measured by a pair of sensors at intervals of a first frequency. Pressure pulses indicative of the tool face angle are generated in the mud flow passing along the drill string 18 by means of a mud flow valve in response to each measurement, and the pressure pulses are sensed at the surface in the vicinity of the well head 28 so that the tool face angle data can be obtained and used by the drilling operator. When the drilling tool 22 requires rapid reorientation following the addition of a section of drill pipe to the drill string 18, the reduction in the pressure of the mud flow due to the interruption of the mud flow necessitated by such addition is sensed by a mud pressure sensor. The sensor in turn provides a transmission rate selector signal which changes the interval of tool face angle measurement from the first frequency to a second, higher frequency, with the result that a more rapid updating of tool face angle is possible for reorientating the drilling tool 22 following addition of a drill pipe section. IMAGE