GB2512960A - Downhole data transmission system - Google Patents
Downhole data transmission system Download PDFInfo
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- GB2512960A GB2512960A GB1317671.4A GB201317671A GB2512960A GB 2512960 A GB2512960 A GB 2512960A GB 201317671 A GB201317671 A GB 201317671A GB 2512960 A GB2512960 A GB 2512960A
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- data transmission
- downhole
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- receiving unit
- surface receiving
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- 230000005540 biological transmission Effects 0.000 title claims abstract description 106
- 238000000034 method Methods 0.000 claims abstract description 32
- 238000005259 measurement Methods 0.000 claims abstract description 11
- 238000003909 pattern recognition Methods 0.000 claims abstract description 10
- 238000004458 analytical method Methods 0.000 claims abstract description 8
- 238000004590 computer program Methods 0.000 claims description 9
- 230000004044 response Effects 0.000 claims description 7
- 230000011664 signaling Effects 0.000 claims description 4
- 239000004020 conductor Substances 0.000 claims description 3
- 238000011065 in-situ storage Methods 0.000 description 4
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000003247 decreasing effect Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000011900 installation process Methods 0.000 description 2
- 238000012512 characterization method Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000007405 data analysis Methods 0.000 description 1
- 238000013075 data extraction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B47/00—Survey of boreholes or wells
- E21B47/12—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling
- E21B47/13—Means for transmitting measuring-signals or control signals from the well to the surface, or from the surface to the well, e.g. for logging while drilling by electromagnetic energy, e.g. radio frequency
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
- G01V1/00—Seismology; Seismic or acoustic prospecting or detecting
- G01V1/40—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging
- G01V1/44—Seismology; Seismic or acoustic prospecting or detecting specially adapted for well-logging using generators and receivers in the same well
- G01V1/48—Processing data
- G01V1/50—Analysing data
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F2218/00—Aspects of pattern recognition specially adapted for signal processing
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Remote Sensing (AREA)
- Geophysics (AREA)
- Environmental & Geological Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Fluid Mechanics (AREA)
- Geochemistry & Mineralogy (AREA)
- General Physics & Mathematics (AREA)
- Electromagnetism (AREA)
- Theoretical Computer Science (AREA)
- Computer Vision & Pattern Recognition (AREA)
- Acoustics & Sound (AREA)
- Arrangements For Transmission Of Measured Signals (AREA)
Abstract
A downhole data transmission system comprises a downhole tool 10 arranged to measure at least one downhole characteristic, and a telemetry cartridge 12 associated with the tool 10. The system also comprises a data transmission cable 16, and a surface receiving unit 14. The data transmission cable 16 is arranged to transmit data from the telemetry cartridge 12 to the surface receiving unit 14 via an electrical signal being sent along the data transmission cable. The surface receiving unit 14 comprises a pattern recognition device configured to receive and analyse the signal transmitted from the telemetry cartridge 12 to the surface receiving unit 14. Also claimed is a method of converting a downhole measurement to a digital signal and transmitting it to the surface and comparing the signal to one or more stored signals. There is also claimed a method of sending first and second downhole signals to the surface along a cable where a surface unit records the first and second signals.
Description
Downhole Data Transmission System
Field of the Invention
The present invention concerns a downhole data transmission system. More particularly, but not exclusively, this invention concerns a downhole data transmission system and method of data transmission for use in transmittIng data relating to oil and gas well cased-hole and production logging.
Background of the Invention
It is desirable to be able to monitor the production data of oil and gas wells, and log the data to provide a record of the well production. Such information can be obtained by deploying into a well a range of downhole senscrs, the sensors measuring one or more production related parameters. The data is then transmitted from the location of the downhole tool to a surface station, where the data may be recorded and monitored. The data is typically transmitted digitally along an armoured logging' data transmission cable containing a single or multiple electrical conductors. Due to the nature of the logging cable (capacitance, varying resistance as the cable spools into and out of the well) it can be difficult to transmit data at any reasonable speed, Typically a logging cable is a number of kilometres long, and a data transmission signal can deteriorate between the downhole tool and the surface station to such an extent that the signal is not readable or errors in data reading are experienced at the surface station. The transmission characteristics of a logging cable may depend upon one or mote of the overall cable length, the spooled cable length, , the materials from which the cable is manufactured, the temperature rating and the chemical environment in which the cable is intended to be deployed.
The present Invention seeks to mitigate the above-mentioned problems. Alternatively or additionally, the present invention seeks to provide an Improved downhole data transmission system and method of downhole data transmission.
Summary of the Invention
The present invention provides, according to a first aspect, a downhole data transmission system comprising: a downhole tool arranged to measure at least one downhole parameter, a telemetry cartridge associated with the downhole tool, a data transmission cable over which data is to be transmitted, and a surface receiving unit, the data transmission cable being arranged to transmit data from the telemetry cartridge to the surface receiving unit via an electrical signal being sent along the data transmission cable, wherein the surface receiving unit comprises a pattern recognition device configured to receive and analyse the signal transmitted from the telemetry cartridge to the surface receiving unit.
The data transmission cable may comprise a logging' cable, for example an armoured logging' data transmission cable. The cable may comprise a singie or plurality of electrical conductors. Throughout the specification the terms data transmission cable and logging cable may be used interchangeably.
The downhole parameter being measured may be any one of flow, temperature, pressure, casing ID, casing metal loss or any other downhole characteristic it is desired to monitor.
Data un-related to downhole parameters may also be transmitted to the surface (downhole tool physical orientation, head voltage measurement etc.).
Each well installation will have individual characteristics which may influence the signal deterioration of the data transmission system, along with the characteristics of the data transmission system itself which influence the signal deterioration. The downhoie data transmission system may be arranged to allow the system to be characterised for any particular set of in situ conditions.
If the logging cable is constructed as an outer (conducting) armoured section encasing a single isolated central core then the telemetry data signai may be superimposed onto the power iine.
If a single digital 1 (electrical pulse) is transmitted by the telemetry cartridge with a certain length of cable run into a well, the 1 will be received at the surface receiving unit as a characteristic signal shape superimposed onto the baseline signal. If a second 1 is transmitted immediately after the first 1, the signal arriving at the surface receiving unit will have a different, but still specific characteristic shape or pattern. The shape or pattern will include the characteristic of the second 1 (later in time) but also still some of the first 1 transmitted. If the second bit transmitted was a 0, the signal shape would be different, but still characteristic of a 1 followed by a 0. A third bit sent as either a 0 or a 1 will again add to the characteristic of the signal pattern being received by the surface receiving unit. In principle, the shape of the signal being received by the surface receiving unit is influenced by many preceding bits transmitted by the telemetry cartridge.
The pattern recognition device is configured to analyse the signal received by the surface receiving unit by comparing the signal received to a series of stored signal patterns. The pattern recognition device may comprise a computer processing unit and a memory unit. The computer processing unit may be configured to analyse the signal received by the surface receiving unit. The computer processing unit may comprise one or more of a digital signal
processor, a field-programmable gate array, or
microprocessor unit. The memory unit may store one or more signal patterns, each pattern corresponding to a particular data signal that may be transmitted by the telemetry cartridge. Each of the stored signal patterns may represent a particular series of data bits being transmitted by the telemetry cartridge. The surface receiving unit may comprise a signal modelling unit associated with the pattern recognition device. The signal modelling unit may comprise a computer processing unit. The modelling unit may be configured to output one or more predicted signal values in response to an input of received signal values.
In one embodiment of the invention, the thirty two previous bits of data (l's or 0's) transmitted by the telerr.etry cartridge may affect the shape or pattern of the current data bit being received by the surface receiving device. Bits of data that were transmitted more than thirty two bits away from the present bit of data may be too far in the past to have any significant influence on the surface signal relating to the present bit of data. The number of bits of data which need to be taken into account by the surface receiving unit may be determined experimentally.
If the thirty two previous bits of data have been correctly identified, the signal modelling unit may be able to provide a model of the signal that will be received if the next bit transmitted is a 1, and a model of the signal that will be received if the next bit transmitted is a 0.
The pattern recognition device may compare the signal being received to the model values as calculated by the signal modelling unit and thereby correctly identify the bit value despite severe distortion of the signal during propagation along the data transmission cable.
In order to provide an accurate signal modelling unit, the downhole data transmission system may be configured to undertake a real-time characterisation (or learning) of the data transmission line when the system is in situ, and before recording downhole measurements. Arranging the apparatus in such a way allows the data transmission system to be used in many different environmental conditions, and allows the data transmission system to adjust for any particular line characteristics that affect the data transmission fidelity.
The apparatus according to the invention allows for high speed transmission of data via the downhole data transmission system. The speed of data transmission is preferably over 50kbps, and more preferable allows data transmission of up to, or greater than, 200 kbps. The data transmission cable may be an armoured electrical cable. The data transmission cable may be greater than 100Cm long, and may be geater than 800Cm long.
The present invention provides, according to a second aspect, a method of transmitting downhoie measurement data from a downhole measuring device to a surface receiving unit, comprising the steps of: obtaining downhoie measurement data using the downhole measuring device, converting the downhole measurement data into a digital signal, transmitting the digital signal to the surface receiving unit via a data transmission cable, the surface receiving unit analysing the signal received at the surface receiving unit by comparing the signal to one or more stored signal patterns.
The digital signal may be an alternate mark inversion signal. The skilled person will appreciate that alternative signal configurations may be used without departing from the scope of the invention.
The present invention provides, according to a third aspect, a method calibrating a downhole data transmission system, the method comprising the steps of: sending a first signal from a downhole telemetry cartridge to a surface receiving unit via a data transmission cable, the surface receiving unit recording the characteristics of the first signal as received at the surface receiving unit, sending a second, different, signal from the downhole telemetry cartridge to the surface receiving unit via the data transmission cable, the surface receiving unit recording the characteristics of the second signal as received at the surface receiving unit.
The method of calibration may comprise repeating the step of sending additional, different, signals from the downhole telemetry cartridge to the surface receiving unit, and the surface receiving unit recording the characteristics of the signal received at the surface receiving unit. The method of calibration may include repeating the signalling and recording step a plurality of times, such that the signal receiving unit has recorded all of the possible signals that may be sent to it from the downhole telemetry cartridge. The repetition of the signalling and recording step may be done at least as many times as it is thought a previously transmitted bit affects the received signal of a presently transmitted bit. For example, if Is believed Lhat the 30 previously transmitted bits affect the received signal of a presently transmitted bit, the repetition of the signalling and receiving step may be repeated at least 30 times. The number of repetitions may be many more than this.
The signal receiving unit may compile a model from the calibration data obtained by the repetition of the steps identified above. In use, a downhole data transmission system, calibrated as above, may compare the signals being received by the signal receiving unit to the model constructed using the calibration data. The signal receiving unit may compare the signal being received from the data transmission cable to the model constructed using the calibration data to determine the signal, or series of signals, that have been sent by the downhole telemetry cartridge.
Advantageously, aspects of the invention provide a downhole data transmission system which allows high speed transmission of data along a data cable wherein the data may be accurately read at the surface receiving unit. The system may be configured to automatically "learn" the in situ data transmission characteristics via an automatic installation process. The automatic installation process may include one or more of a routine to determine the maximum permissible data rate, and a calibration routine to learn the transmission characteristics of the cable.
According to a fourth aspect the invention provides a computer program including a set of instructions for a downhole data transmission system, the set of instructions arranged to instruct the downhole data transmission system to transmit downhole measurement data according to the method as described above.
According to a fifth aspect, the invention provides a computer program including a set of instructions for a downhole data transmission system, the set of instructions arranged to configure the downhole data transmission system according to the method as described above.
The downhole data transmission systems according to the fourth and fifth aspects of the invention may be the downhole data transmission system according to the first aspect of the invention.
The computer programs of the fourth and fifth aspect of the invention may comprise computer readable media on which the computer program is installed.
It will of course be appreciated that features described In relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the invention may incorporate any of the features described with reference to the apparatus of the invention and vice versa.
Description of the Drawings
Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: Figure 1 shows a schematic view of a downhole data transmission system according to a first embodiment of the invention; Figure 2 shows a method of determining the maximum data transmission rate of a data transmission cable; Figure 3 shows a pulse emitted and received during the learning phase; Figure 4 shows a plurality of pulses emitted and received during the learning phase; Figure 5 shows the pulse pattern that will be received when all zeros are being emitted; and -10 -Figure 6 shows a typical pulse pattern received during operation of the downhole data transmission system.
Detailed Description
According to one aspect, the invention provides a downhole data transmission system, for oil and gas downhole logging tools. The downhole data transmission system is represented schematically in figure 1. The data is transmitted from a downhole tool 10, via the telemetry cartridge 12, to a surface "panel" or surface receiving unit 14. The data is transmitted along an armoured data transmission cable 16 as a series of electrical pulses. The data transmission cable 16 is an electrical cable with an aggressive low-pass filter characteristic. The downhole data transmission system is adaptable to provide low error-rate data transmission regardless of the differing data transmission characteristics of the data transmission cable due to overall cable length, spooled cable length, cable stretch and cable manufacturer/type. The cable length may, for example, be 8,00Gm long.
The data transmission from the telemetry cartridge 12 to the surface receiving unit 14 is a digital signal which has been modulated using Alternate Mark Inversion (M'JI) modulation. The skilled person will appreciate that alternative modulation schemes may be utilised. In short, AMI modulation transmits l's by alternate positive and negative pulses (marks) and 0's are transmitted as no pulses. The positive and negative pulses are of the same magnitude and duration. An example of an AMI modulated -11 -signal is shown in figure 5, where the lower two sections of the graph show the positive pulses (lowest section) and negative pulses (middle section) respectively. The bits are transmitted at the data rate. The data transmission cable 16 has an aggressive low-pass characteristic, and so the pulses are "stretched" to extend over a number of bits.
If the signal receiving unit receives a single pulse, there may be several bit times before the received signal reaches the maximal value;, and some bit times later a signal of the opposite polarity is received before the signal decays. An example of a single pulse transmission is shown in figure 6. When multiple bits of data are transmitted, the signal received by the signal receiving unit 14 is the sum of time shifted waveforms, each waveform corresponding to a single pulse. The data extraction method used by the signal receiving unit uses a model of the single pulse response of the data transmission cable 16 and reconstructs the cable response by summing together a number of these pulse responses using the data previously extracted. The signal received by the surface receIving unit 14 is then examined with the model generated signal, and compared to how the model would respond to a variety of signal possibilities. The signal which is derived with this process which results in the smallest error between the model values and actual cable data is used as the decoded value. The decoded value is then added to the array of previous data bits received by the signal receiving unit, and is used to derive the expected line value at the next bit time, and the process repeated.
Going into detail regarding the model construction, the model is operated over 30 bits. A test pattern consisting -12 -of alternative positive and negative pulses with a large gap between them, for example 64 bits, is sent by the telemetry cartridge 12 across the data transmission cable 16 to the surface receiving unit 14. The surface receiving unit 14 oversamples the signal and the response to the pulse is extracted. The oversampled model pulse is then examined to determine where the best discrimination is achieved for a range of data patterns. Once this pqint has been determined, the model is re-sampled, from the captured data set, at the bit rate. The amplitude ratio between positive and negative pulses is also determined by data analysis in order to correct for any driver differences.
In order to extract data from the signal received at the surface receiving unit, the signal is sampled at five times the data rate. Using the last 30 decoded values, an expected value for the line may be generated by multiplying these values by the model values and summing, as a skilled person will recognise, in a similar way to finite impulse response filtering. The signal value is then compared to the model output and the difference determines the value of the next decoded bit by determining whether the difference is greater than a predetermined threshold. As the received pulse has quite a slow rise time, there is an offset of approximately two bit times between the decoded data and the signal data. At the same time, the error between the model and the centre sample point is determined and compared to the errors of the two adjacent sample points. The errors are filtered and allow the sampling to phase adjust to correct for timing difference between the downhole and surface systems. The data, once extracted, may be -13 -transmitted via an asynchronous serial stream to a further device.
During the model learning phase, the frequency of the transmitted bit rate is measured by counting the number of learn pulses (N) over approximately half a second and also measuring the time taken for these N pulses to an accuracy of 2ps. Knowing the length of the learning pulse in bit times allows for an accurate determination of the bit frequency to be determined, relative to the signal receiving unit clock.
The downhole data transmission system may determine the maximum data rate at which data may accurately be transmitted when the system is initialised. Figure 2 sets out the process of determining the maximum data rate for the downhole data transmission system when in situ. The system begins the process at step 100, when it is decided to determine the maximum data rate. The maximum data rate may be determined during the system start up, if the system starts to receive a number of signal errors, at the prompting of a user, and/or if the system detects that the cable characteristics have changed (with the possibility that a higher data rate may be used). The data rate is set to an initial value 102. The system undergoes a characteristic "learning phase" 104. P1 known set of data is transmitted by the telemetry cartridge 12. The interpretation of the data received at the surface receiving unit is checked 106 for errors against the set of data which it is known was transmitted by the telemetry cartridge. If the received data includes errors, the data rate is reduced by 10 kbps 108 and the characteristic learning phase repeaced. If the received data does not include any errors, -14 -the data rate may be increased by 10 kbps 110. If the signal received at the signal receiving unit continues to show no errors, the data rate is increased by a further 10 kbps. If the data does show an error at the increased data rate, the data rate is decreased 114 and the system re-learns the data transmission characteristics. The data transmission system is then configured to transmit data at the maximum permissible data rate, where errors will not occur due to the transmission speed. It should be noted that the data rate can be increased or decreased by any step size, higher or lower than 10 kbps, in this process.
The principle behind the learning phase of the downhole data transmission system is illustrated in figure 3. Figure 3 shows a single pulse as transmitted by the telemetry cartridge and as received by the signal receiving unit. The pulse 300 emitted by the telemetry cartridge Is a single square pulse as illustrated. The pulse 302 shows the signal received by the surface receiving unit, where it can clearly be seen that the pulse has been stretched and distorted.
The model operates over 30 bits, as represented by the broken lines on the graph.
Figure 4 shows a downhole data learning pattern, where in this case, three pulses are emitted by the telemetry cartridge. The pulse shape received by the signal receiving unit is similar for both positive and negative pulses, with the signals simply appearing inverted to each other. The pulses emitted in the learning pattern are separated by 64 bits between pulses in order to ensure that the steady state' signal condition is reached.
Figure 5 shows a start-up signal that is received at the surface receiving unit, where a series of zeros are -15 -transmitted. It will be seen that every 1 bits a 1 pulse is transmitted and the skilled person will recognise this is standard when using an alternate mark inversion signal in order to retain signal accuracy. The top line represents the signal received at the surface, and the two pulse patterns underneath represent the downhole data pulses, negative and positive respectively.
Figure 6 shows a typical data transmission pattern emitted by the telemetry cartridge and received by the surface receiving unit. The top line represents the waveform that is received by the surface signal receiving unit, and the two pulse patterns underneath represent the downhole data pulses, negative and positive respectively, which make up the data signal. The signal receiving unit is able to analyse the signal that is received and compare it to the waveforms received during the learning phase of the data transmission process. By comparing the received waveforms to the stored waveforms, the signal receiving unit is able to accurately predict the data signal that was originally transmitted from the telemetry cartridge.
The signal receiving unit may comprise a computer processing unit and a memory unit. The computer processing unit may be configured to run a number of computer programs which cause the downhole data transmission system to undertake the various method steps described above. The computer processing unit may comprise a computer readable/writable medium on which a computer program is stored. The computer program may include commands which cause the downhole data transmission system to undertake the method steps as described herein. The memory unit may be utilised by the signal receiving unit to store the waveforms -16 -learned during the learning phase of the data transmission method. The surface receiving unit may send the data received from the telemetry cartridge to external devices, such transmission may be wireless or over the internet or a network.
Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein.
Where in the foregoing description, integers or
elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and nay therefore be absent, in other embodiments.
Claims (20)
- -17 -Claims 1. A downhole data transmission system comprising: a downhole tool arranged to measure at least one downhole characteristic, a telemetry cartridge associated with the downhole tool, a data transmission cable, and a surface receiving unit, the data transmission cable being arranged to transmit data from the telemetry cartridge to the surface receiving unit via an electrical signal being sent along the data transmission cable, wherein the surface receiving unit comprises a pattern recognition device configured to receive and analyse the signal transmitted from the telemetry cartridge to the surface receiving unit.
- 2. A downhole data transmission system, wherein the data transmission cable comprises an armoured logging cable.
- 3. A downhole data transmission system, wherein the data transmission cable comprises at least one electrical conductor.
- 4. A downhole data transmission system according to any of claims 1 to 3, wherein the pattern recognition device is configured to analyse the signal received by the surface receiving unit by comparing the signal received by the surface receiving unit to a series of stored signal patterns.-18 -
- 5. A downhole data transmission system according to any preceding claim, wherein the pattern recognition device comprises a computer processing unit and a memory unit.
- 6. A downhole data transmission system according to claim 5, wherein the computer processing unit is configured to analyse the signal received by the surface receiving unit.
- 7. A downhole data transmission system according to claim or 6, wherein the memory unit is arranged to store one or more signal patterns, each pattern corresponding to a particular data signal that may be transmitted by the telemetry cartridge.
- 8. A downhole data transmission system according to any preceding claim, wherein the surface receiving unit comprises a signal modelling unit associated with the pattern recognition device.
- 9. A downhole data transmission system according to claim 8, wherein the signal modelling unit comprises a computer processing unit.
- 10. A downhole data transmission system according to claim 8 or 9, wherein the modelling unit is configured to output one or more predicted signal values in response to an input of received signal values.-19 -
- 11. A method of transmitting downhole measurement data from a downhole measuring device to a surface receiving unit, comprising the steps of: obtaining downhole measurement data using the downhole measuring device, converting the downhole measurement data into a digital signal, tiTansmitting the digital signal to the surface receiving unit via a data transmission cable, the surface receiving unit analysing the signal received at the surface receiving unit by comparing the signal to one or more stored signal patterns.
- 12. A method according to claim 11, wherein the digital signal is an alternate mark inversion signal.
- 13. A method of calibrating a downhole data transmission system, the method comprising the steps of: sending a first signal from a downhole telemetry cartridge to a surface receiving unit via a data transmission cable, the surface receiving unit recording the characteristics of the first signal as received at the surface receiving unit, sending a second, different, signal from the downhole telemetry cartridge to the surface receiving unit via the data transmission cable, the surface receiving unit recording the characteristics of the second signal as received at the surface receiving unit.-20 -
- 14. A method according to claim 13, comprising repeating the step of sending additional, different, signals from the downhole telemetry cartridge to the surface receiving unit, and the surface receiving unit recording the characteristics of the signal received at the surface receiving unit.
- 15. A method according to claim 13 or 14, comprising repeating the signalling and recording tep a plurality Qf times, such that the signal receiving unit has recorded all of the possible signals that may be sent to it from the downhole telemetry carbridge.
- 16. A method according to any of claims 13 to 15, including the step of the surface receiving unit compiling a model from the calibration data obtained by the repetition of the steps identified above.
- 17. A computer program including a set of instructions for a downhole data transmission system, the set of instructions arranged to instruct the downhole data transmission system to transmit downhole measurement data according to the method as claimed in claim 11.
- 18. A computer program including a set of instructions for downhole data transmission system, the set of instructions arranged to configure the downhole data transmission system according to the method as claimed in claim 13.
- 19. A method of downhole data transmission substantially as herein described with reference to any of Figs. 1 to 6 of the accompanying drawings.-21 -
- 20. A downhole data transmission system substantially as herein described with reference to any of Figs. 1 to 6 of the accompanying drawings.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1317671.4A GB2512960B (en) | 2013-10-07 | 2013-10-07 | Downhole data transmission system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB1317671.4A GB2512960B (en) | 2013-10-07 | 2013-10-07 | Downhole data transmission system |
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| Publication Number | Publication Date |
|---|---|
| GB201317671D0 GB201317671D0 (en) | 2013-11-20 |
| GB2512960A true GB2512960A (en) | 2014-10-15 |
| GB2512960B GB2512960B (en) | 2020-06-03 |
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| GB1317671.4A Expired - Fee Related GB2512960B (en) | 2013-10-07 | 2013-10-07 | Downhole data transmission system |
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| CN114459904B (en) * | 2022-04-08 | 2022-06-24 | 深圳市微特精密科技股份有限公司 | Data line quality comprehensive testing device |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4355310A (en) * | 1977-02-03 | 1982-10-19 | Schlumberger Technology Corporation | Well logging communication system |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4216536A (en) * | 1978-10-10 | 1980-08-05 | Exploration Logging, Inc. | Transmitting well logging data |
| US20090146836A1 (en) * | 2007-12-11 | 2009-06-11 | Schlumberger Technology Corporation | Methods and apparatus to configure drill string communications |
| US8860416B2 (en) * | 2009-10-05 | 2014-10-14 | Halliburton Energy Services, Inc. | Downhole sensing in borehole environments |
| WO2013074093A1 (en) * | 2011-11-15 | 2013-05-23 | Philip Edmund Fox | Modeling passage of a tool through a well |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4355310A (en) * | 1977-02-03 | 1982-10-19 | Schlumberger Technology Corporation | Well logging communication system |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2512960B (en) | 2020-06-03 |
| GB201317671D0 (en) | 2013-11-20 |
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| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20221007 |