US3821696A
Expired / Lapsed
US
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Downhole data generator for logging while drilling system
Assignee: ExxonMobil Oil Corp
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Filing: 1973-03-13
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Granted: 1974-06-28
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Expires: 1993-03-13
Abstract
Abstract A logging-while-drilling system includes a downhole digital data generator. A multiplexer applies analog signals representing sensed downhole conditions to an analog-to-digital converter. The digital bits are stored in the analog-to-digital converter while a programmed switching means sequentially switches each of the parallel bits to a single output to convert the parallel bits to a serial-by-bit signal. An encoder responds to the serial-by-bit signal to control the speed of a rotor in the transmitter to produce a phase encoded sonic signal in the drilling liquid in the well being investigated. A stable source of high frequency clock pulses is used to generate all of the required timing clock pulses with high resolution. In order to do this, serial frequency dividers count down the basic clock pulse to produce sonic pulses, bit clock pulses, word clock pulses and frame clock pulses.
Inventors
- 👤 J Harrell
- 👤 B Patton
- 👤 B Ballard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 17:01
CPC Classifications
E; E21; E21B; E21B47/00; E21B47/12; E21B47/14; E21B47/18; E21B47/20
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
301 words
In a logging-while-drilling system for transmitting downhole measured conditions to the surface of the earth during the drilling of a well utilizing a flowing drilling liquid, said system being of the type including: an acoustic generator having a movable member which when driven at a constant speed produces in the liquid a continuous acoustic wave signal having a first phase state and having a frequency proportional to the speed of movement of said movable member, a plurality of transducers for sensing downhole conditions and for generating analog signals representative of said conditions, an encoder, and driving means for said member responsive to the output of said encoder, an improved digital data generator comprising: an analog-to-digital converter for converting said analog signals to digital words including a plurality of parallel bits each represented by two states ''''0'''' and ''''1,'''' multiplexing means for sequentially applying said analog signals to said analog-to-digital converter, a parallel to serial converter for sequentially switching each of said parallel bits to a single output to convert said parallel bits to a serial-by-bit signal, said serial-by-bit signal being applied to said encoder which transmits digital words in response thereto, a stable source of high frequency clock pulses, and first, second and third frequency divider means responsive to said clock pulses for respectively producing sonic clock pulses, bit clock pulses and word clock pulses, said sonic clock pulses being applied to said encoder to produce said acoustic signal with constant frequency and phase state, said bit clock pulses being applied to said switching means which sequentially switches each of said parallel bits to a single output in response to said bit clock pulses, and said word clock pulses being applied to said multiplexing means which sequentially applies said analog signals to analog-to-digital converter in response to said word clock pulses.
Claim 2
Dependent Claim
301 words
In a logging-while-drilling system for transmitting downhole measured conditions to the surface of the earth during the drilling of a well utilizing a flowing drilling liquid, said system being of the type including: an acoustic generator having a movable member which when driven at a constant speed produces in the liquid a continuous acoustic wave signal having a first phase state and having a frequency proportional to the speed of movement of said movable member, a plurality of transducers for sensing downhole conditions and for generating analog signals representative of said conditions, an encoder, and driving means for said member responsive to the output of said encoder, an improved digital data generator comprising: an analog-to-digital converter for converting said analog signals to digital words including a plurality of parallel bits each represented by two states ''''0'''' and ''''1,'''' multiplexing means for sequentially applying said analog signals to said analog-to-digital converter, a parallel to serial converter for sequentially switching each of said parallel bits to a single output to convert said parallel bits to a serial-by-bit signal, said serial-by-bit signal being applied to said encoder which transmits digital words in response thereto, a stable source of high frequency clock pulses, and first, second and third frequency divider means responsive to said clock pulses for respectively producing sonic clock pulses, bit clock pulses and word clock pulses, said sonic clock pulses being applied to said encoder to produce said acoustic signal with constant frequency and phase state, said bit clock pulses being applied to said switching means which sequentially switches each of said parallel bits to a single output in response to said bit clock pulses, and said word clock pulses being applied to said multiplexing means which sequentially applies said analog signals to analog-to-digital converter in response to said word clock pulses.
Claim 3
Dependent Claim
66 words
The system recited in claim 1 wherein said second divider is a programmable synchronous divider having means for changing the number of sonic clock pulses per bit so that the number of sonic cycles per bit can be increased, thus lengthening the time interval of each bit, as the signal-to-noise ratio of said sonic signal decreases with increasing depth of said acoustic generator in said well.
Claim 4
Dependent Claim
45 words
The system recited in claim 1 wherein said first, second and third frequency dividers are connected in series, said frequency dividers each being adjustable to allow independent adjustment of the sonic frequency, the time interval of each bit and the number of bits per word.
Claim 5
Dependent Claim
73 words
The system recited in claim 1 wherein said multiplexing means includes a multiplexer programmer having a plurality of settable stages, said word clock pulses being applied to said programmer to sequentially set said stages, the outputs of said stages being used to sequentially apply said analog signals to said analog-to-digital converter, the output of the last stage producing a frame clock pulse indicating the completion of conversion of each of said analog signals.
Claim 6
Dependent Claim
33 words
The system recited in claim 4 wherein the number of settable stages is adjustable to allow independent adjustment of the number of words per frame. adjustment of the number of words per frame.
Claim 7
Dependent Claim
32 words
The system recited in claim 4 further comprising: a sync generator for generating a sync word applied to said encoder, said frame clock pulse being applied to actuate said sync word generator.
Claim 8
Dependent Claim
116 words
The system of claim 6 further comprising: a complement generator, the output of said word generator being applied to said complement generator, a sync gate, the outputs of said sync word generator and said complement generator being applied to said sync gate, and a sync word flip-flop, said frame clock pulses being applied to said sync word flip-flop to toggle it, the outputs of said flip-flop being applied to enable said sync gate to pass either said sync word or the complement of said word to said encoder so that said sync word is applied to said encoder after certain frames and the complement of said sync word is applied to said encoder after alternate frames.
Claim 9
Dependent Claim
38 words
The system recited in claim 7 wherein the output of said sync word flip-flop is applied to said sync word generator so that the state of said flip-flop is included as the parity bit in each sync signal.
Claim 10
Dependent Claim
82 words
The system recited in claim 6 further comprising: a parallel-serial programmer having a plurality of settable stages, said bit clock pulses being applied to said programmer to sequentially set said stages, the outputs of said stages being applied to said parallel to serial converter to sequentially switch each of said parallel bits to a single output, the outputs of said stages being also applied to each sync word generator to sequentially switch the bits of each sync word to said single output.
Claim 11
Dependent Claim
80 words
The system recited in claim 1 further including a parity generator for generating a parity bit for each digital word comprising: a flip-flop re-set by said word clock pulses, said serial-by-bit signal being applied to said flip-flop to toggle said flip-flop in response to one state of said serial-by-bit signal, the output of said flip-flop being applied to said switching means so that the state of said flip-flop is included as the parity bit in said serial by bit signal.
Claim 12
Dependent Claim
54 words
The system recited in claim 12 further comprising: a parallel-serial programmer having a plurality of settable stages, said bit clock pulses being applied to said programmer to sequentially set said stages, the outputs of said stages being applied to said switching means to sequentially switch each of said parallel bits to a single output.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-06-27 | 1977-12-27 | 1978-06-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-06-27 | 1981-12-27 | 1982-06-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-06-27 | 1985-12-27 | 1986-06-28 | $7700.00 | Window Closed / Lapsed |