Drill pipe capable of transmitting high-bandwidth data from downhole sensors and surface control signals back to those sensors has been developed and successfully tested. The system incorporates a high-speed data cable that runs the length of each joint and downhole tool. The cable terminates at induction coils that are installed in protecting grooves machined in the secondary torque shoulders of doubleshoulder tool joints at each end of the pipe. The coils are recessed in ferrite troughs that focus the magnetic field. The system is virtually transparent to standard rig procedures and offers robust, reliable operation.The paper provides background data on prior work relating to telemetry drill pipe and contrasts the results of these efforts with the new system. The new system has successfully demonstrated data transmission rates of up to 2,000,000 bits/sec. Current mud pulse telemetry is limited to 8 to 10 bits/sec. Electromagnetic technology provides data rates of up to 100 bits/sec, but suffers from hole depth and formation related electric impedance limitations. Full realization of system benefits requires further development of additional drill stem components with highspeed telemetry capabilities including HWDP, collars, jars and top drive subs. A top drive sub that incorporates the telemetry design has been successfully manufactured and tested and is described in the paper. Development efforts relating to other drill stem components are also detailed. The system has been tested in a laboratory environment and in test wells. Results of these tests along with plans for field-testing in actual drilling environments are presented.Telemetry drill pipe can improve well and field productivity by providing more complete, real-time logging information and reduce drilling time and costs and enhance well control by providing real-time downhole drilling data and early kick detection.

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TX 75083-3836, U.S.A., fax 01-972-952-9435. AbstractAn advanced 9e-inch high-temperature turbodrill has been developed that uses a gear box to increase the turbodrill torque to 7,800 ft-lbs and reduce the speed to 80 rpm, making it ideal for use with roller and PDC bits in hard rocks. The high torque output eliminates stalling problems associated with high-speed turbodrills, making these turbodrills easier to run in the field. In laboratory tests, this turbodrill drilled a 12¼-inch hole in granite at 96 ft/hr, while in the field it drilled at rates of 207 ft/hr compared to 76 ft/hr for rotary drilling. The turbodrill will operate at temperatures up to 400EF, making it ideal for horizontal drilling in deep, hot gas, and geothermal wells

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An oblique circular arc representation for wellbore trajecories, a geometric analysis termed the sectional method, is presented. This approach permits projected line segments to be functions of the dogleg angle and to be related to usually measured displacements between survey stations. The advantages of this analysis are: a solution for the dogleg angle and a method of survey interpretation, the sectional method; a procedure for exact interpolation of true vertical depth, azimuth, and inclination between survey stations; a basis of solution for a computer program which provides course correction information during a turn to a target. The program provides a solution summary for a course correction from various survey stations in a well to any planned target. As a result, an optimum course correction or “minimum plugback depth” can be quickly determined. Once the desired kickoff point is selected, the program provides an exact solution of true vertical depth, azimuth, inclination, and toolface angle for every 100 of correction course length. The latter result provides a dramatic improvement in existing technology because all measurements used to control the correction run are now based on a center of turn rather than the arbitrary reference used in the typical ouija board solution; and because the solution is exact, such variables as effective toolface angle can better be evaluated and precisely corrected resulting in the smoothest possible turn with minimum doglegs.