Abstract: 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.

Abstract: 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.

Abstract: An articulated downhole surveying instrument and method for measuring parameters of a wellbore includes one or more laterally flexible coupling sections. The laterally flexible coupling sections are rigid in axial tension and axial compression, and are smaller in cross-section than the surveying instrument housing. A separate housing is used for each component of the surveying instrument, and each component housing is interconnected with the laterally flexible coupling. One or more flexible spacer bars are also provided. The spacer bars and coupling sections enable the assembly to be passed through a short-radius angle wellbore with greatly reduced risk of sticking or hanging up.

Abstract: 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.