Abstract: 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.

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: A drilling instrument adapted to be positioned in a conduit for the flow of mud. The instrument has a passage sealing a fluid from the mud. Means is responsive to energy derived from the mud for causing the sealed fluid to flow. An electrical generator derives energy from the flowing fluid to provide electrical energy.

Abstract: A mud pulser for mud flow in a conduit. A fluid reservoir operates when positioned in the flow of mud for imparting energy from the mud to separate fluid in the reservoir. A hydraulically operated valve is inserted in the flow of mud displaced from the fluid reservoir and includes an actuation chamber for the separate fluid. A fluid operated control valve is coupled between the fluid reservoir and the actuation chamber. An electrically controllable valve is coupled between the fluid reservoir and a control port for the control valve. The electrically controllable valve is operative in response to a first electrical signal applied thereto for providing communication in the separate fluid between the fluid reservoir and the control port to thereby allow an energy transfer in the fluid between the mud flow and the control port. The electrically controllable valve is also operative in response to a second electrical signal for blocking fluid communication between the fluid reservoir and the control port.

Abstract: A threaded connection is subject in use after assembly to a load of specified magnitude in a selected direction along the thread axis. As so loaded, the basically constant pitch threads are uniformly stressed. The load faces of the threads on at least one of the members are defined, in the unstressed condition, to have a lead which varies from a constant lead by an amount which, at any given location along the threads, is equal to the amount of net relative deflection of the threaded members along the axis at such location in response to the application to the members of the load of specified magnitude.The design considerations pertinent to such a connection are set forth in the context of the presently preferred embodiment of the connection.