AU2020103125A4 - Bus transmission method while drilling - Google Patents
Bus transmission method while drilling Download PDFInfo
- Publication number
- AU2020103125A4 AU2020103125A4 AU2020103125A AU2020103125A AU2020103125A4 AU 2020103125 A4 AU2020103125 A4 AU 2020103125A4 AU 2020103125 A AU2020103125 A AU 2020103125A AU 2020103125 A AU2020103125 A AU 2020103125A AU 2020103125 A4 AU2020103125 A4 AU 2020103125A4
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- AU
- Australia
- Prior art keywords
- double
- instrument
- bus
- wire
- core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Ceased
Links
- 230000005540 biological transmission Effects 0.000 title claims abstract description 35
- 238000005553 drilling Methods 0.000 title claims abstract description 29
- 238000000034 method Methods 0.000 title abstract description 6
- 238000004891 communication Methods 0.000 abstract description 9
- 238000010586 diagram Methods 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 238000003384 imaging method Methods 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000012545 processing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 238000013500 data storage Methods 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- 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
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/023—Arrangements for connecting cables or wirelines to downhole devices
-
- 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
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B11/00—Communication cables or conductors
- H01B11/02—Cables with twisted pairs or quads
- H01B11/06—Cables with twisted pairs or quads with means for reducing effects of electromagnetic or electrostatic disturbances, e.g. screens
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01B—CABLES; CONDUCTORS; INSULATORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING OR DIELECTRIC PROPERTIES
- H01B7/00—Insulated conductors or cables characterised by their form
- H01B7/04—Flexible cables, conductors, or cords, e.g. trailing cables
- H01B7/046—Flexible cables, conductors, or cords, e.g. trailing cables attached to objects sunk in bore holes, e.g. well drilling means, well pumps
-
- 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
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/003—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings with electrically conducting or insulating means
-
- 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
- E21B44/00—Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B15/00—Suppression or limitation of noise or interference
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Geology (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geophysics (AREA)
- Remote Sensing (AREA)
- Electromagnetism (AREA)
- Mechanical Engineering (AREA)
- Cable Transmission Systems, Equalization Of Radio And Reduction Of Echo (AREA)
Abstract
The invention relates to the technical field of downhole instruments, in particular to a bus
transmission method while drilling, which comprises a plurality of instruments and a double
wire transmission system, wherein the instruments are connected to the double-wire
transmission system; and the interface part of the instrument is connected with the double-wire
transmission system through a double-core wire or a single-core wire. The invention is a
double-wire transmission bus system while drilling, which reduces or shields the influence of
external environment on the bus system and greatly increases the signal-to-noise ratio of the
system so that the stability and reliability of the bus system can be ensured.
1 /3
Upper bus Control unit Lower bus
Communication Communication Communication Communication
module module module module
Figure 1
Instrument A Instrument B Instrument C Instrument D
Figure 2
Instrument A Instrument B Instrument C Instrument D
Coaxial Wire
Coaxial wire Shell ground Shell ground
Figure 3
Description
1 /3
Upper bus Control unit Lower bus
Communication Communication Communication Communication module module module module
Figure 1
Instrument A Instrument B Instrument C Instrument D
Figure 2
Instrument A Instrument B Instrument C Instrument D
Coaxial Wire
Shell ground Coaxial wire Shell ground
Figure 3
Bus transmission method while drilling
[01] The invention relates to the technical field of downhole instruments, in particular to a double-wire transmission bus system while drilling, which reduces or shields the influence of external environment on a bus system and greatly increases the signal-to-noise ratio of the system so that the stability and reliability of the bus system can be ensured.
[02] Placing the logging tool near the drill bit and drilling while obtaining various in stratum about the stratum is logging while drilling (LWD). In particular to horizontal well drilling, the trajectory of the drill bit is adjusted in a timely manner by adoption of the measured drilling parameters and stratum parameters, so that the drill bit to drill along the direction of the target layer can be ensured. The stratum parameters obtained by logging while drilling are closest to the original state of the stratum, which are more valuable than those from the ordinary cable logging. In addition to the conventional stratum parameters logging, such as resistivity, acoustic velocity, neutron porosity, density, and some imaging logging, the logging while drilling instruments also measure drilling parameters such as bit pressure, torque, rotation speed, annular pressure, temperature, chemical composition and the like.
[03] The while drilling system consists of a data acquisition and processing system on the ground and downhole instruments, and the downhole bus system is a core component of the logging while drilling system, which is mainly responsible for monitoring and managing the bus communication transmission of the downhole instruments, completing real-time data acquisition and data storage, monitoring the bus voltage/current, managing the clock of the downhole instrument and the like. The downhole bus system is as shown in FIG. 1.
[04] The bus system comprises an upper bus and a lower bus, the lower bus is including various instruments of logging while drilling represented by an instrument A, an instrument B and an instrument C, while the upper bus is including measurement instruments while drilling(MWD) used for measuring azimuth in stratum and various drilling parameters.
[05] In the drilling process of the drill bit, the environment is harsh, the temperature is very high, the pressure is extremely large, and the vibration is exactly strong. Due to the restrictions of downhole environment and instrument assembly on the ground, at present, the downhole instrument buses in China and abroad almost adopt a single-wire core serial bus structure, i.e., the instrument shell is used as the bus system reference ground to realize two functions of bus signal transmission and bus power supply simultaneously through a single-wier in the instrument and connection interface, as shown in FIG. 2.
[06] The downhole single-wire core bus mode of the while-drilling system is greatly influenced by the drilling environment, and external interference is directly coupled to the bus, so that the signal-to-noise ratio of a signal on the bus is low, the bit error rate is high, and the stability of the system is reduced. Moreover, the distributed parameters of the bus reduce the bus transmission rate. For some imaging instruments with large data volume, due to a packet of data and a low signal-to-noise ratio, the whole packet of data must be abandoned at the same time and cannot be used normally, which has great influence on the system.
[07] The invention aims to overcome the defects of the prior art and provides a double-wire transmission bus while drilling system, which reduces or shields the influence of external environment on the bus system and greatly increases the signal to-noise ratio of the system so that the stability and reliability of the bus system can be ensured.
[08] In order to achieve the above purpose, the invention adopts the following technical scheme that the double-wire transmission bus while drilling system comprises a plurality of instruments and a double-wire transmission system, wherein the instruments are connected to the double-wire transmission system, and the interface part of the instrument is connected with the double-wire core transmission system through a double-wire core wire or a single-core wire.
[09] And when the interface part of the instrument is connected with the double wire transmission system through the double-core wire, wherein the double-core wire is a double-core coaxial structure or a double-core and twisted-pair structure.
[010] The double-core coaxial structure or the double-core and twisted-pair structure uses the shell of the instruments as shielding layer.
[011] When the interface part of the instrument is connected with the double-wire transmission system through a single core wire, the inside of the instrument adopts twisted-pair structure.
[012] At the interface of two adjacent sides, the single-wire core and the shell are connected by a common mode inductor.
[013] The invention has the beneficial effects that the instrument shell is adopted as the shielding layer, and due to the natural shielding effect of the instrument shell, the signal on the bus is ensured to be hardly influenced by the external environment, so that the signal-to-noise ratio of the bus is greatly improved, and the bit error rate is reduced.
[014] FIG. 1 is a schematic diagram of a conventional downhole bus system.
[015] FIG. 2 is a schematic diagram of a single-core bus structure while drilling.
[016] FIG. 3 is a schematic diagram of double-core coaxial.
[017] FIG. 4 is a schematic diagram of a double-core and twisted-pair structure.
[018] FIG. 5 is a schematic diagram of a single-core and twisted-pair structure.
[019] FIG. 6 is a schematic diagram of the interface of FIG 5.
[020] FIG. 7 is a schematic diagram of a single-core bus termination signal voltage.
[021] FIG.8 is a double-wire bus transmission terminal signal.
[022] In order to make the purpose, technical scheme and advantages of the invention to be clearer and more understandable, the invention will be described in further detail with reference to the attached drawings and specific embodiments. It should be understood that the specific embodiments described herein are only illustrative of the invention and are not to be construed as limitation of the invention.
[023] In order to reduce the influence of the external environment on the bus, the invention proposes a double-wire transmission bus while drilling system. It is necessary to ensure that there are two wires passing through the internal of the instrument. The method is classified into two cases: the first case is that the double-core wire connection is realized at instrument interface part; and the second case is that only single-core wire connection is implemented at instrument interface part. When the double-core wire connection is partly realized at the interface part of instrument, a double-core coaxial structure as shown in FIG.3 or the double-core and twisted-pair structure as shown in FIG.4 can be introduced.
[024] As shown in FIGS.3 and 4, the double-core coaxial structure and the double-core and twisted-pair structure both take the instrument shell as a shielding layer, and due to the natural shielding effect of the instrument shell, the signal on the bus is ensured to be hardly influenced by the external environment, so that the signal to-noise ratio of the bus is greatly improved, and the error rate is reduced.
[025] As shown in FIG. 5, when the interface part of the instrument is connected with the double-wire transmission system through a single-core wire, a twisted-pair structure is also required to be adopted in the internal of the instrument, and the power supply of the instrument on two adjacent sides and the ground are respectively connected to the single-core wire and the shell through common mode inductors at the positions of the interfaces, namely, as shown in FIG. 6.
[026] It should be noted that since the double-wire transmission bus while drilling system of the invention comprises a plurality of instruments and a double-wire transmission as shown in FIGS. 2 to 5, in order to better distinguish, a plurality of instruments are represented by instrument A, instrument B, instrument C, and instrument D, and the shell of the instrument serves as a bus reference ground.
[027] The shielding effect is obvious under the condition of double-core wire connection, and when the interface of the instruments is connected with the double wire transmission system through a single-core wire, the internal of the instrument adopts the single-core and twisted-pair structure. The single-core and twisted-pair structure is analyzed below to explain the reason why the conventional single-core and single-wire structure such as that shown in FIG.2 is preferred. The common mode inductor of the single-core and twisted-pair structure has a certain isolation effect on the shell, meanwhile, the common mode inductor has no impedance effect on useful signals, the signals can pass through without obstruction, and the external interference is blocked; and the distributed inductance of the bus is greatly reduced by the twisted pair, so that the capability of the bus transmission rate is greatly increased.
[028] As shown in FIG. 7, assuming that the external environment has a white noise signal with amplitude of 0.6V and the signal transmitted on the bus is a square wave signal with amplitude of 1V and 100 kHz, the signal obtained at the receiving end is as shown in FIG. 7.
[029] It can be seen that the signal received by the terminal has larger noise, the signal-to-noise ratio is not ideal, and the ideal signal recovery can be obtained by signal processing circuits such as a Schmidt comparator and the like. Because of the limited anti-interference ability of bus system, the bit error rate is larger.
[030] As shown in FIG.8, double-wire bus transmission is introduced, that is, a twisted-pair is adopted to penetrate through the internal of an instrument while drilling, Because the common mode inductor is used for electrical connection at an interface, signals on the bus can be smoothly passed through, and external noise interference can be greatly suppressed. Assuming a common mode inductance of 0.1mH, the terminal signal is as shown in FIG. 8 under the condition that other parameters remain unchanged.
It can be seen that the signal-to-noise ratio of the terminal signal transmitted by adoption of the double-wire bus has been greatly improved. Due to the action of the twisted-pair, the current of the bus flowing through the shell is greatly reduced, which greatly reduces the influence of the bus current on the logging instrument while drilling.
[031] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention may be embodied in many other forms, in keeping with the broad principles and the spirit of the invention described herein.
[032] The present invention and the described embodiments specifically include the best method known to the applicant of performing the invention. The present invention and the described preferred embodiments specifically include at least one feature that is industrially applicable
Claims (5)
1. A double-wire transmission bus while drilling system, which is characterized in that it comprises a plurality of instruments and a double-wire transmission system, wherein the instruments are all connected to the double-wire transmission system, and an interface part of the instrument is connected to the double-wire transmission system through a double-core wire or a single-core wire.
2. The double-wire transmission bus while drilling system according to claim 1 is characterized in that when the interface part of the instrument is connected to the double-wire transmission system through a double-core wire, the double-core wire is a double-core coaxial structure or a double-core and twisted-pair structure.
3. The double-wire transmission bus system according to claim 2 is characterized in that the double-core coaxial structure or the double-core and twisted-pair structure uses the shell of the instruments as shielding layer.
4. The double-wire transmission bus system according to claim 3 is characterized in that when the interface part of the instrument is connected to the double-wire transmission system through a single-core wire, the internal of the instrument adopts a single-core and twisted-pair structure.
5. The double-wire transmission bus system according to claim 4 is characterized in that at the interface of two adjacent sides, the single-core wire and the shell are connected by a common mode inductor..
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2020103125A AU2020103125A4 (en) | 2020-10-30 | 2020-10-30 | Bus transmission method while drilling |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2020103125A AU2020103125A4 (en) | 2020-10-30 | 2020-10-30 | Bus transmission method while drilling |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2020103125A4 true AU2020103125A4 (en) | 2021-01-07 |
Family
ID=74041694
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2020103125A Ceased AU2020103125A4 (en) | 2020-10-30 | 2020-10-30 | Bus transmission method while drilling |
Country Status (1)
| Country | Link |
|---|---|
| AU (1) | AU2020103125A4 (en) |
-
2020
- 2020-10-30 AU AU2020103125A patent/AU2020103125A4/en not_active Ceased
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| FGI | Letters patent sealed or granted (innovation patent) | ||
| MK22 | Patent ceased section 143a(d), or expired - non payment of renewal fee or expiry |