Baker Hughes Corporation

Exploration Logging, Inc.

Ronald A Hall

Larry Wayne Thompson

Richard A Meador

Edward S Mumby

James E Meisner

The present invention is directed to an improved logging apparatus. The logging apparatus includes transmitters, receivers, and a controller member. The controller member is utilized to selectively energize the transmitters to generate an interrogation signal. The receivers are utilized to obtain measurements of the interrogation signal. The controller member can be utilized to substantially simultaneously process the recorded samples--such as by mathematically combining a plurality of measurements in order to obtain a measure of an attribute value which relates to at least one of the wellbore and surrounding formation.

Well logging system arranged for stable, high-sensitivity reception of

A logging-while-drilling system is disclosed which includes a pair of receiving antenna disposed between upper and lower transmitting antenna. The upper and lower transmitting antenna are energized successively to generate an electromagnetic wave which propagates through the formation surrounding the borehole. The amplitude attenuation and phase shift of the electromagnetic wave between the receiving antenna is measured. Measurements from both the upper and lower transmitting antenna can be combined to eliminate by cancellation system error components. In order to further improve the performance of the logging-while-drilling system, separate and dedicated driver circuits are provided proximate each transmitter. In addition, reference signals which are utilized to coordinate and synchronize the operation of the various components of the logging-while-drilling system are provided at frequencies which are substantially different from the interrogation frequency of the electromagnetic interrogation signal.

Method and apparatus for logging-while-drilling with improved

A well logging apparatus and method for measuring the resistivity of the formation surrounding a borehole is disclosed. The invention provides two transmitting antennas arranged around a housing means or drill collar in spaced relation from one another. A transmitting circuit alternately supplies an oscillating drive signal to each transmitting antenna with a sufficiently high frequency such that one and then the other of the transmitting antennas radiates an electromagnetic wave signal which propagates through the formation. Two receiving antennas are located equally spaced between the transmitting antennas to produce pick-up signals from the electromagnetic wave propagating through the formation. Each receiving antenna includes a single turn coil connected in series with a capacitor to provide a reduced impedance circuit to resonate in the frequency region embracing the oscillating drive signal. Receive antenna circuitry responsive to induced alternating current in the coil produces a signal indicative of the formation parameter under study. The method of positioning two series resonant single turn receiving antennas tuned to the oscillating drive frequency and alternately coupling an electrical drive signal to a pair of transmitters spaced equally on each side of the receiving antennas allows receiving signals which are self-cancelling for system induced effects.

High sensitivity well logging system having dual transmitter antennas

In an apparatus for measuring equipment depth in a well, the movement of wire rope used to raise and lower the equipment is measured by proximity sensors located adjacent the wire rope and spaced along the direction of movement of the wire rope. The signals from the proximity sensors caused by the spiral windings of the wire rope are employed to determine the length and direction of movement of the wire rope. The invention may be employed to measure movement of wire rope in other applications, such as in elevators or with cages in mine shafts that are supported by wire rope.

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Sacramento, CA, United States of America

Ronald A Hall