Halliburton Company

Gilbert H Forehand

Michael J Lynch

Richard L Duncan

Stephen E Tilghman

Jack C Penn

Billy W White

Ronald E Dant

Charles F VanBerg, Jr

Charles D Donaghe

Terry O Anderson

J Mark Richardson

Ronnie J Buchanan

John E Haley, Jr

Timothy D Rice

C Lynden Lee

An intelligent automatic gain stabilization method and apparatus for a radiation detection instrument automatically locate the position of a predetermined characteristic within an energy spectrum, automatically determine whether the characteristic is properly located, and automatically provide gain adjustment to the output of the radiation detection instrument to maintain measurement accuracy of the system.

Intelligent automatic gain stabilization for radiation detection

A self-contained downhole apparatus for being lowered into an oil or gas well to internally record samples of at least one environmental condition comprises three body sections linearly and releasably interconnected. One of the body sections is a selected one of a plurality of transducer housing sections. The selected transducer housing section is mechanically and electrically connected to a second body section containing microcomputer-operated signal processing circuitry. The third body section contains a power supply.

Self-contained downhole gauge system

A temperature to frequency converter includes two temperature detectors having an electrical characteristic, such as resistance, that varies proportionally with sensed temperature. These devices are connected into an oscillator circuit that provides an electrical signal output having a frequency inversely proportional to sensed temperature. An amplitude control feedback loop connected to the oscillator circuit maintains the amplitude of the output signal constant.

Temperature to frequency converter

A self-contained memory gauge includes either semiconductor or magnetic core memory for retaining downhole information related to sampled parameters, such as borehole temperature and pressure. A microprocessor-based computer manages the power utilization by independently and selectably energizing and de-energizing different sections of the gauge. The magnetic core memory is tested for operability, and the addressing of the magnetic core memory is adjusted in accordance with any inoperable memory locations. Samples of the monitored environmental conditions can be taken at variable rates dependent upon software monitoring of the condition, the remaining battery life and the remaining memory capacity and in response to hardware monitored pressure changes. Each sample can be taken to a selectable resolution. A watchdog circuit monitors the microprocessor to insure that it is operating within a preselected time limit. Further, resolution counters (282) and (284), in association with multiplexer (280), provide selectable timing signals.

Self-containing downhole gauge system

In an oil well instrumentation system, the downhole sensor system is controlled by a computer which is powered-on only during sampling movement. An independent circuit, continuously powered, detects significant sensor rate-of-change values whereby the computer-sampling equipment is powered-on. A self-contained memory gauge includes either semiconductor or magnetic core memory for retaining downhole information related to sampled parameters, such as borehole temperature and pressure. A microprocessor-based computer manages the power utilization by independently and selectably energizing and deenergizing different sections of the gauge. The magnetic core memory is tested for operability, and the addressing of the magnetic core memory is adjusted in accordance with any inoperable memory locations. Samples of the monitored environmental conditions can be taken at variable rates dependent upon software monitoring of the condition, the remaining battery life and the remaining memory capacity and in response to hardware monitored pressure changes. Each sample can be taken to a selectable resolution. A watchdog circuit monitors the microprocessor to insure that it is operating within a preselected time limit.

An apparatus for monitoring the operation of a railroad train includes two on-board units which collect and utilize data for ultimate transfer to a portable unit which can be carried onto and off of the railroad train. One of these on-board units operates under microcomputer control to compute speed, acceleration/deceleration, and distance traveled data and to store such computred data for subsequent transfer to the portable unit. The other on-board unit acquires additional data under separate microcomputer control. This data acquisition retrieves either binary or analog data, or both, and stores it in the acquiring on-board unit for later transfer to a separate memory in the other on-board unit for subsequent transfer to the portable unit. Power failure detection circuits are also implemented to insure the microcomputers are initiated in respective determinate states.

Data collection apparatus and train monitoring system

A load, such as a control circuit for a DC/DC converter, is initially operated by an initial load powering voltage developed by a power consuming regulator until another voltage, such as the DC/DC converter's output voltage derived from an input voltage used by the voltage regulator to establish the initial load powering voltage, reaches a predetermined level. A switching control circuit initially allows the regulator to operate and connects its output to the load. The switching control circuit, however, responds to the other voltage so that when this other voltage reaches the predetermined magnitude, the switching control circuit prevents the regulator from further operating and thus from further dissipating energy. The switching control circuit then connects the other voltage to power the load. The switching control circuit is designed so that it dissipates less energy than the regulator when the switching control circuit disables the regulator and allows the other voltage to power the load.

Apparatus for conserving power in operating a load

The power-conversing apparatus includes a plurality of independently energizable electrical circuits used in receiving electrical signals from a transducer which senses an environmental condition, in processing the electrical signals, and in storing information related to the detected environmental condition. The apparatus further includes a power control circuit for continuously providing electrical power to at least one of the electrical circuits and for independently switchably providing electrical power to selectable ones of at least two others of the separately energizable circuits.

Power-conserving self-contained downhole gauge system

An analog-to-digital conversion technique utilizes an oscillator which provides a primary oscillating signal that drives a counter and that generates a derived signal having a frequency less than the primary signal. The derived signal is integrated for use in comparing against the threshold voltage defining the analog signal to be converted. The comparison of the integrated and the threshold signals provides a pulse width modulated signal which is related to the primary signal. The pulse width modulated signal gates the counter for generating a count at the rate established by the primary signal. This output can be communicated to a microcomputer or other device.

Apparatus and method for interfacing a transducer

A physical condition in a well bore is sampled and information taken from the sample is recorded by a method of conserving electrical energy in performing such sampling and recording. The method sequentially energizes and de-energizes a plurality of different electrical circuits within the downhole apparatus with which the physical condition is detected and in which the information is recorded. The method determines when the next sample is to be taken and, depending upon how much time remains until the next sample, de-energizes the apparatus to conserve energy.

Method of sampling and recording information pertaining to a physical

The method for controlling the rate at which a downhole logging tool samples and records a detected condition obtains three samples of the condition at three consecutive sample times and computes a prediction value for the n-th sample from the first three samples. The method compares the actual n-th sample with the predicted value and records the (n- 1)-th sample if the variance between the predicted and actual values is outside a predetermined threshold or difference. The sample rate is changed if the actual values of the samples remain within the predicted value's preselected range for more than a preselected number of samples. The sample rate interval is also increased if the battery life or memory capacity decrease below predetermined thresholds. The sample rate interval is decreased to its shortest interval if a pressure change above a predetermined threshold is detected.

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Duncan, OK, United States of America

Gilbert H Forehand