Microprocessor computerized pressure/temperature/time down-hole recorder
AssigneeOtis Engineering Corporation
InventorOliver W. McCracken
Life of this patent
Estimating the term…
Abstract
A down-hole temperature, pressure and time measuring and digital data storage tool, utilizing self-contained microprocessor-based data taking and data reduction, with power conservation realized by processor controlled powering of data transducers only during sample periods and control of the rate at which samples are taken as an inverse function of dynamically calculated data rate of change. Data storage is effected only for data samples representing a significant change in data magnitude as established by a processor program-defined significant-data criteria.
Claims21
The method of storing data versus time down-hole in a well bore from a self-contained tool comprising temperature and pressure transducers, a pressure transducer reference bridge, a power source, and an associated microprocessor computer;
- comprising the steps of:
- (1) initiating a preselected program-defined initial time-out period,
- (2) upon completion of said preselected initial time-out period, initiating via said microprocessor, a time-multiplexed analog read-out sample of each of said transducers and reference bridge,
- (3) converting each said analog output sample to a digital format and storing same in a register of said microprocessor,
- (4) determining the differential between each instant stored sample and the next preceding like sample and storing those instant samples effecting a differential with absolute value exceeding a least count value in RAM storage means,
- (5) storing a time tag associated with each sample stored in step (4),
- (6) computing the data rate of change from successive pairs of samples,
- (7) adjusting a next successive time-out period as an inverse function of each next preceding data rate of change computation;
- and
- (8) repeating steps (2) through (7), above.
In a down-hole measured parameter recorder of the type employing analog-to-digital conversion of analog signal outputs from periodically sampled transducers and subsequent storage of digital data in solid state memory;
- first comparing means for comparing each transducer output sample with a next previously stored sample, second comparing means for comparing the absolute value of the output from said first comparing means with a reference value, and control means, responsive to the output of said second comparing means, to effect writing into memory only those samples having magnitudes at least as great as said reference value.
In a temperature, pressure and time recorder instrument, including storage means for storing periodically-taken samples of pressure and temperature;
- means responsive to said samples to calculate the rate of change of magnitude thereof, and means responsive to the absolute value of said calculated rate of change to alter the rate at which samples are taken as a direct function of said rate of change of magnitude.
In a variable parameter timing recorder instrument, including storage means for storing periodically-taken samples of at least one variable parameter;
- means responsive to said samples to calculate the rate of change of magnitude thereof, and means responsive to the absolute value of said calculated rate of change to alter the rate at which samples are taken as a function of said rate of change of magnitude.
The method of storing data versus time down-hole in a well bore from a self-contained tool comprising parameter sensing transducer means, a power source, and an associated microprocessor computer;
- comprising the steps of:
- (1) initiating via said microprocessor, an analog read-out sample of said transducer means,
- (2) converting each said analog output sample to a digital format and storing same in a register of said microprocessor,
- (3) determining the differential between each instant stored sample and the next preceding sample and storing those instant samples effecting a differential with absolute value exceeding a least count value in RAM storage means,
- (4) storing a time tag associated with each sample stored in step (3),
- (5) computing the data rate of change from said samples,
- (6) adjusting the rate of taking said samples as a direct function of said data rate of change;
- and
- (7) repeating steps (1) through (6), above.
Dependencies are inferred from the claim text.