Halliburton Company

Smith International, Inc.

Develco, Inc.

Charles D Barron

Patrick E Dailey

Wallace R Gardner

Louis H Rorden

Felix Kuus

The present invention discloses an MWD system which permits an indirect measurement of the wellbore inclination angle at the drill bit, in situations where it is difficult or expensive to measure that angle directly. The system includes a first inclinometer included as part of a conventional directional sensor, which is located in the bottomhole assembly a relatively large distance above the bit. The first inclinometer provides a measure of the inclination angle .alpha. at point A. The system also includes a second inclinometer, which is provided closer to the drill bit to provide a measure of the inclination angle .beta. at point B. The inclination angles .alpha. and .beta. are used, together with bottomhole assembly configuration information, and other information relating to drilling tendencies, to determine with a reasonable degree of accuracy the inclination angle .theta. of the wellbore at the bit.

System and method for indirectly determining inclination at the bit

A poppet and orifice mud pulser assembly is disclosed for use in an MWD system. The mud pulser is capable of generating pressure pulses in the column of drilling mud of various amplitudes to increase the data rate of the mud pulse telemetry system. The mud pulser includes a piston assembly that positions the poppet with respect to the orifice. The piston assembly comprises part of a by-pass conduit which defines a mud flow path around the orifice. Mud flow in the piston assembly generates a force tending to shut the poppet, because the surface area of the piston A.sub.2 is greater than the surface area of the poppet A.sub.1. Mud flow through the conduit (and thus through the piston) tends to force the poppet into a closed position because the force on the piston is greater than the force on the poppet, because of the greater surface area of the piston. A pilot valve is provided to enable and disable flow through the conduit, thus allowing the poppet to open and close. Other amplitude level signals are generated by permitting the poppet to partially open through the implementation of a plurality of parallel pressure relief valves, each of which is set with a different pressure relief value. The pressure relief valves are selected by an associated selector valve. Selection of a pressure relief valve prevents pressure within the piston from exceeding the pressure relief valve, which causes the poppet to partially open, thereby changing the pressure pulse amplitude generated. Alternatively, a motor operated pressure control valve may be used to vary the amplitude of the pressure pulse, thereby permitting the generation of waveforms of any shape.

Mud operated pulser

The short hop communication link includes a sensor module positioned downhole from a motor in a well. The module includes sensors that monitor operational, directional and environmental parameters downhole and provide an electrical data signal indicative thereof. Sensors may also be positioned in the drill bit for obtaining parameters related to the bit, and communicating data signals reflecting the sensed parameters to the sensor module. The sensor module includes a transceiver, with an annular anrenna, for transmitting electromagnetic sensor data signals to a point above the motor. A control module, which also includes a transceiver with an annular antenna, is located above the motor, and receives the electromagnetic signals from the sensor module reflecting the sensed parameters. In addition, the control module is capable of transmitting command signals to the sensor module requesting data regarding desired parameters. The command module connects to a host module which orchestrates all measurement-while-drilling components downhole. The host module connects to a mud pulser for transmitting desired data to the surface for real-time processing. The sensor module is strategically placed within a removable, interchangeable sub below the motor, or alternatively, within an extended driveshaft of the motor, while the sensor antenna is located on an exterior shoulder of the sub or driveshaft. The sensor module and an associated battery pack reside within a pressure container which forms part of a current return path from the sensor antenna to the circuitry within the sensor module.

Short hop communication link for downhole MWD system

Apparatus and method are disclosed for feeding a cablehead assembly into the side of a drill string. The cablehead is passed through a low angle side entrance in a side entry sub into the drill string. A cartridge assembly is seated in the side entrance around the cable to prevent pressure loss through the entry port. The cable is clamped to the outside of the sub to lock the cable in place. The cartridge assembly is thereafter tightened about the cable to seal against pressure loss. A cover plate is secured to the outside of the sub adjacent to the entry port to prevent expulsion of the cartridge.

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Kingwood, TX, United States of America

Charles D Barron