Abstract: A variable length data packet in a seismic system includes a fixed-length data portion and a variable-length data portion, the amount of data in the variable-length portion depending on the number of active channels. The data packet identifies the number channels which are in operation in the system, which may be the same or fewer than the number of installed channels. This signals the central recorder as to the length of the block of data in the data packet which includes seismic data. This feature permits the scaling of the system to accommodate varying numbers of channels, without reconfiguring the system. In another aspect, a method of sending data in a data system having a plurality of installed channels includes the steps of determining the number of active channels; assembling a packet of data comprising a fixed-length field and a variable-length field, the number of data bytes in the variable-length field being a function of the number of active channels; and sending the packet of data.

Abstract: A connector for fiber optics provides a means for eliminating a receiver in a redundant communications channel. The connector receives at least two optical fibers in side-by-side contact and positions the optical fibers in close proximity but not abutting contact with a photo detector imbedded in the connector. The connector further provides a method and a system for redundant data communications.

Abstract: A technique and a system provide control and monitoring of devices external to a marine seismic streamer by segmenting the conductor to which the external devices are coupled. The module which connects sections of the seismic data telemetry cable is modified to include a switch. The switch is controlled by a command signal on the seismic data telemetry cable to segment the twisted pair bus into a plurality of dedicated busses, each dedicated to a subset of the external devices, such as one or two such devices. In this way, the external devices can be communicated with in parallel, rather than in series as in conventional systems.

Abstract: In a marine seismic data acquisition system, a plurality of seismic data transmission paths are utilized to conduct seismic data to a central recording unit from seismic data acquisition modules positioned along the length of cable. Signals from a plurality of data acquisition modules are applied to each of the transmission paths. Data acquisition modules which apply seismic signals to a given transmission path may be spaced and substantially uniform distances along the length of the cable and may be interspersed with data acquisition modules which apply seismic data to each of the other transmission paths. The operation of the data acquisition modules is synchronized by means of a signal transmitted continually from a central recording unit. Each section of the cable includes a plurality of remote units distributed along the cable section for detecting seismic signal.

Abstract: Monitoring the torque applied by the rotary table to the drill string and the RPM of the drill string is provided. An intermediate adapter is positioned between the drill Kelly and the rotary table. A strain gauge is attached to the intermediate adapter to measure torsional deformation and provide an indication of rotary torque. Transmission of torque data is accomplished by radio frequency transmission utilizing a transmitter on the intermediate adapter. A receiver is mounted to the side of the drill rig floor to receive and demodulate the torque signal. The intermediate adapter is rotating at the same rate as the drill string. Detection of the revolutions utilizing the changing R.F. field strength is accomplished at the edge of the drill rig platform or elsewhere with a stationary sensor which doubles as the torque receiver. A highly directional torque transmitter antenna mounted on the adapter is used with the major lobe lying parallel to the rig floor and perpendicular to the pipe.

Abstract: The pumping rate of an oil well pump or other recurring event is determined by providing a force sensor, such as an accelerometer, and a transmitter arranged in a housing adapted to be affixed to the pump piston rod or drive train which move in a vertical plane. As the piston rod or drive train moves, the sensor measures gravitational and centrifugal forces, the former providing a sinousoidally varying sensor output having a period equal to the rotational or reciprocal period of the piston rod or drive train. The transmitter is a battery-powered R.F. device which is activated once each stroke or revolution by an amplifier-detector coupled to the output of the force sensor. A one-shot multivibrator is used to transmit a short burst during the on-time and such burst may be modulated for better noise rejection by the receiver. The receiver is located remote from the sensor/transmitter package and comprises an R.F. detector, amplifier and, if required, a demodulator.