CN211692449U

CN211692449U - Single core cable transmission device of high-reliability self-adaptation rate adjustment

Info

Publication number: CN211692449U
Application number: CN201922316276.1U
Authority: CN
Inventors: 黄松涛; 王德平; 车行; 候勇慧; 陈小安
Original assignee: China Institute of Radio Wave Propagation CETC 22 Research Institute
Current assignee: China Institute of Radio Wave Propagation CETC 22 Research Institute
Priority date: 2019-12-21
Filing date: 2019-12-21
Publication date: 2020-10-16
Anticipated expiration: 2029-12-21

Abstract

The utility model discloses a single core cable transmission device of high reliable self-adaptation speed adjustment, the device is including underground part and ground part, underground part is including power signal isolation module and keep apart command interface circuit and data drive circuit that the module electricity is connected with power signal, data drive circuit is direct to be connected with the codec MCU electricity, command interface circuit then is connected with the codec MCU electricity through command shaping filter circuit, the codec MCU is connected with bus management MCU electricity. The utility model discloses a single core cable transmission device of high reliable self-adaptation speed adjustment and data transmission method thereof has following advantage: (1) the coding is simple and is easy to realize in high-temperature and high-pressure environment; (2) the system reliability is high by adopting a spread spectrum mode; (3) the CCSK coding mode is automatically switched according to the channel characteristic and the error code characteristic, and the matching is easy; (4) the system has high transmission rate and meets the requirements of production logging.

Description

Single core cable transmission device of high-reliability self-adaptation rate adjustment

Technical Field

The utility model belongs to single core cable transmission device field, in particular to single core cable transmission device of a high reliable self-adaptation speed adjustment in this field.

Background

The existing single-core cable transmission system mainly comprises a WTC series, a 3508 series, a sondex series and an OFDM series, and the following table shows a parameter list and an application scene of the existing single-core cable transmission system.

With the increase of logging projects and the development of testing technologies, the combined logging modes are more and more, the downhole data volume is larger and larger, and the traditional WTCs and 3508 gradually exit the history stage. The current mainstream production logging system at home and abroad is a Sondex system, a cable bus adopts AMI coding modes of 50kbps, 100kbps and 200kbps, and an instrument bus adopts an AMI coding mode of 500 kbps; and because the domestic cable characteristics are poor, the transmission rate of a cable bus of the Sondex series or the logging system similar to the Sondex series is 50kbps at most.

With the development of the OFDM technology and the application of the OFDM technology in an open hole well logging system, a single-core cable OFDM transmission system is gradually developed by domestic mainstream enterprises and universities, and the transmission rate can reach 350kbps on a single-core cable, but the transmission rate which can be used stably and reliably is about 100 kbps. Fig. 1 shows a system block diagram of a single-core cable OFDM transmission system in China at present, the system adopts a half-duplex mode, downlink command data adopts AMI coding, and uplink logging data adopts OFDM modulation. The system can automatically distribute the coded bits on each subcarrier of the OFDM according to the cable characteristics, thereby achieving the purpose of adaptive matching.

Fig. 2 shows a schematic block diagram of a single-core cable OFDM transmission system, and as can be seen from fig. 2, the single-core cable OFDM transmission system is complex in composition, the downhole part is composed of two parts, namely, a man code decoding part and an OFDM modulation part, and the man code decoding part mainly completes interpretation and forwarding of downlink commands and controls the actions of downhole tools; OFDM modulation mainly completes coding transmission of uplink data, FPGA and DSP with rich resources are needed to complete channel coding, QAM mapping and IFFT conversion, a DA (digital-to-analog) converter with high speed is needed to be added in order to convert digital signals into waveform signals capable of being transmitted in a single-core cable, and the devices are difficult to meet the application under the high-temperature environment of 175 ℃ underground, so the problem is solved by adopting a thermos bottle technology in the underground part of a single-core cable OFDM transmission system. The ground part mainly comprises a man code encoder and an OFDM demodulator, wherein the man code encoder mainly completes baseband encoding of downlink data; the OFDM demodulator mainly completes the demodulation work of uplink data, the implementation of the demodulator is complex, the FPGA and the ARM with rich resources are used for completing the work of AD acquisition control, equalization processing, signal synchronization, FFT conversion, QAM demodulation, RS decoding and the like, and the hardware cost is high.

The prior art solves the problems of reliability and field matching to a certain extent, but has higher complexity and is not suitable for being applied to production logging, and the main problems thereof are as follows:

(1) the outer diameter of the production logging instrument is limited, in order to ensure that the logging instrument can reach a measurement section through the annular space of an oil pipe and a sleeve, the outer diameter of the annular logging instrument is generally phi 28mm or phi 26mm, the width of a circuit board in the instrument is generally 16mm, and a plurality of processors cannot be applied to the annular logging instrument. The OFDM transmission needs an FPGA or a DSP chip with rich resources, a rapid DA chip and a high-power driving chip, and the sizes of the chips cannot meet the requirements of producing logging instruments.

(2) In order to ensure that a logging instrument can smoothly reach a measuring point to complete a measuring task, and in order to ensure construction safety and construction efficiency, the length of a production logging instrument is strictly limited, and a thermos bottle technology needs a long upper and lower heat absorbent and a sealing structure, so that the thermos bottle is not suitable for application in production logging. The single core cable OFDM technology cannot safely and reliably operate for a long time in a high temperature environment of 175 °.

(3) The underground encoder of Sondex series products or products like Sondex series products has simple structure and is easy to realize in high-temperature environment, but the underground encoder has larger difficulty in field matching and low adaptability to cables and is greatly influenced by well site environment, and stable and reliable transmission cannot be ensured.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a single core cable transmission device of high reliable self-adaptation speed adjustment is provided exactly.

The utility model adopts the following technical scheme:

a high-reliability single-core cable transmission device with self-adaptive rate adjustment is improved in that: the device comprises an underground part and a ground part, wherein the underground part comprises a power signal isolation module, a command interface circuit and a data driving circuit, the command interface circuit and the data driving circuit are electrically connected with the power signal isolation module, the data driving circuit is directly and electrically connected with a coding and decoding MCU (microprogrammed control unit), the command interface circuit is electrically connected with the coding and decoding MCU through a command shaping filter circuit, the coding and decoding MCU is electrically connected with a bus management MCU, the bus management MCU is electrically connected with the bus driving circuit and a data acquisition circuit, and the data acquisition circuit is electrically connected with a well temperature sensor, a pressure sensor and a GR probe through a sensor driving and analog processing circuit; the ground part comprises a power supply signal isolation module which is electrically connected with the logging computer sequentially through a program control gain amplification module, an anti-aliasing filtering module, an AD acquisition module and a processor, and the processor is also electrically connected with the power supply signal isolation module through an issued command coding module and an issued command driving module; the power supply signal isolation modules of the underground part and the ground part are electrically connected through a single-core cable.

Furthermore, the coding and decoding MCU and the bus management MCU are integrated on a 210-DEG high-temperature chip sm470r1b1m-ht, and sm470r1b1m-ht is packaged by a CQFP of 10mm by 10 mm.

Furthermore, a ground case of the ground part comprises a signal preprocessing card and a communication acquisition card, the case adopts a 1U standard case form, and a rear panel comprises a depth wiring lead-in, a tension or magnetic mark wiring lead-in, a logging cable lead-in, two paths of direct current power line lead-ins, a 1 path of alternating current power line lead-in and a case power supply line lead-in.

In a data transmission method using the above transmission apparatus, the improvement comprising: the data exchange between the ground and the underground is completed by adopting a frequency division full duplex mode, the downlink data adopts an AMI coding mode of 300bps, and the uplink data adopts a CCSK + AMI coding mode of 108 kbps; the processing flow of the underground encoder is to output an input waveform after sequentially carrying out chip division, CCSK encoding, AMI encoding and signal driving on input information, the decoding flow of the ground CCSK is to carry out low-pass filtering on AD acquisition signals, remove signals after high-frequency components, send the signals into a time domain equalization filter for equalization processing, carry out mean value down-sampling on the processed data, filter out base line jitter, reduce the operand of synchronous extraction, carry out related judgment on the signals after synchronization, the related judgment is composed of CCSK correlators, the decoding information sequence and the spread spectrum sequence are related one by one, and the maximum value of the comparative correlators is used as decoding output.

The utility model has the advantages that:

the utility model discloses a single core cable transmission device of high reliable self-adaptation speed adjustment and data transmission method thereof has following advantage: (1) the coding is simple and is easy to realize in high-temperature and high-pressure environment; (2) the system reliability is high by adopting a spread spectrum mode; (3) the CCSK coding mode is automatically switched according to the channel characteristic and the error code characteristic, and the matching is easy; (4) the system has high transmission rate and meets the requirements of production logging.

Drawings

FIG. 1 is a block diagram of a single cable OFDM transmission system;

FIG. 2 is a functional block diagram of a single cable OFDM transmission system;

FIG. 3 is a schematic block diagram of a downhole portion of the device;

FIG. 4 is a schematic diagram of the structure of a portion of the downhole tool;

FIG. 5 is a functional block diagram of a ground portion;

FIG. 6 is a layout view of a front panel of the floor chassis;

FIG. 7 is a layout view of the rear panel of the floor chassis;

FIG. 8 is a process flow diagram of a downhole encoder;

FIG. 9 is a CCSK decoding flow diagram;

fig. 10 is a functional block diagram of a correlation decision.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

CCSK is a multi-system non-orthogonal coding spread spectrum technology, and compared with the traditional Direct Sequence Spread Spectrum (DSSS), the CCSK also has the characteristics of low interception-low detection and excellent error code performance, but the spectrum utilization rate is higher, the hardware implementation is simpler, and the calculated amount is smaller. CCSK is widely used in the data modulation module of Joint Tactical Information Distribution System (JTIDS) of the united states high-speed line-of-sight tactical data Link 16.

The CCSK coding technology which is applied to the military field for a long time is introduced into the single-core cable transmission device, and the problems that the system is difficult to connect and the communication reliability is low are solved. Fig. 3 shows a schematic block diagram of the downhole portion of the present embodiment. The device adopts a frequency division full duplex mode to complete data exchange between the ground and the underground, the downlink data adopts an AMI coding mode of 300bps, and the uplink data adopts a CCSK + AMI coding mode of 108 kbps. Data coding and bus management are completed by adopting a 210-degree high-temperature chip sm470r1b1m-ht in the well, and the sm470r1b1m-ht is packaged by adopting a CQFP (quantum well programmable) of 10mm by 10mm, so that the size requirement of the circuit board in the well can be met. The underground data driving circuit is simple, and the temperature index characteristic of the system is ensured by adopting a high-temperature operational amplifier and a high-temperature resistor capacitor. The structure and appearance of the downhole tool in the embodiment are shown in FIG. 4.

The device parameters of the embodiment are as follows: 1) the communication mode is as follows: frequency division full duplex; 2) and (3) an encoding mode: uplink 108Kbps CCSK + AMI and downlink 300bps AMI; 3) temperature index: 175 ℃ for 2 h; 4) instrument external diameter: 26 mm; 5) length of the instrument: 966 mm; 6) width of the circuit board: 18 mm; 7) cable joint: a single core cable; 8) bus interface: a single core bus; 9) bus mode: a 500KbpsAMI bus; 10) a measurement channel: cable pressure, well temperature, pressure, magnetic positioning, GR; 11) cable head supply voltage: 70-210 VDC; 12) supply voltage of downhole instruments: 18 VDC.

Fig. 5 shows a block diagram of the ground portion processing of the present invention. The ground part mainly comprises two parts of uplink data decoding and command issuing coding. The method comprises the following steps that uplink data transmitted by a cable firstly enter a power supply signal isolation module, the influence of a power supply signal is removed, and the influence of a downlink signal is removed by using a frequency-selecting transformer; and then the signals are sent to a program control gain amplification module for program control gain amplification, then anti-aliasing filtering and high-speed AD acquisition are carried out, the AD acquired data are sent to a processor for digital equalization, frame synchronization and CCSK decoding, and after the decoding is finished, the data are sent to a logging computer for protocol processing and analysis. Fig. 6 and 7 show the front and rear panel structure layout of the floor chassis of the present invention. The ground case mainly comprises two cards, namely a signal preprocessing card and a communication acquisition card, wherein the signal preprocessing card mainly completes the analog processing of uplink signals, the communication acquisition card mainly completes the data acquisition and data decoding, and the case adopts a 1U standard case form and can be conveniently arranged on a frame. The rear panel is mainly used for wiring introduction and is divided into deep wiring introduction (DEPTH), tension/magnetic mark wiring introduction (TENS/MAG), logging CABLE line introduction (CABLE), two-way direct current POWER line introduction (DC1 and DC2), 1-way alternating current POWER line introduction (AC) and case POWER supply line introduction (POWER).

In this embodiment, CCSK coding uses coding schemes in (1,1), (2,4), (3,8), (4,16), (5,32), and (6,64)6, where (1,1) indicates no spreading, and (2,4) indicates 2-spreading-4, i.e., the transmitting end uses a 4-bit spreading code to represent 2-bit effective transmission information. The spreading code formats are shown in the following table:

the CCSK (3,8) spread spectrum is taken as an example to explain the CCSK coding method: spreading code 00111010 is a₀a₁a₂a₃a₄a₅a₆a₇It is shown that the spreading code uses cyclic shift to represent the 8-state of the original sequence, and the corresponding relationship is shown in the following table:

original information	Information after spreading
		000	a₀a₁a₂a₃a₄a₅a₆a₇
001	a₁a₂a₃a₄a₅a₆a₇a₀
		010	a₂a₃a₄a₅a₆a₇a₀a₁
011	a₃a₄a₅a₆a₇a₀a₁a₂
		100	a₄a₅a₆a₇a₀a₁a₂a₃
101	a₅a₆a₇a₀a₁a₂a₃a₄
		110	a₆a₇a₀a₁a₂a₃a₄a₅
111	a₇a₀a₁a₂a₃a₄a₅a₆

FIG. 8 shows a process flow of a downhole encoder. Dividing chips by input information of the underground bus according to a coding mode determined by channel conditions, if the channel conditions are good, selecting not to spread spectrum, and not carrying out chip division and CCSK coding on the system; if the signal condition is poor, encoding is carried out according to the fastest rate which can be transmitted by a channel, if a (5,32) encoding mode is selected, input information is divided into one chip per 5 bits to carry out CCSK encoding, 32-bit information output by the CCSK encoding is subjected to AMI encoding, the influence of length 0 on symbol synchronization of a receiving end is considered when a spreading sequence is generated, so that the spreading sequence is not 0, the influence of excessive direct current components of AMI encoding on system timing is avoided, signals after the AMI encoding are sent to an analog circuit to be subjected to signal driving, and a signal waveform suitable for being transmitted on a cable is formed. Therefore, the CCSK coding mode is simple, hardware implementation is easy, compared with a single-core cable OFDM system, QAM mapping and IFFT conversion are not needed, DA conversion is not needed, hardware complexity is greatly reduced, and the CCSK coding mode is suitable for being used on small-diameter instruments in a high-temperature and high-pressure environment.

Fig. 9 shows a flow chart of terrestrial CCSK decoding. The AD acquisition signal is sent to a digital signal processor for low-pass filtering, the signal with high-frequency components removed is sent to a time domain equalization filter for equalization processing, the processed data is subjected to mean value down-sampling, baseline jitter is filtered, the operand of synchronous extraction is reduced, the signal after synchronization is subjected to correlation judgment, the correlation judgment consists of CCSK correlators, a decoding information sequence and a spreading sequence are correlated one by one, the maximum value of the correlators is compared to be used as decoding output, and a correlation judgment principle block diagram is shown in figure 10. And the related judgment abandons the selection of the traditional AMI decoding judgment threshold, the output of the correlator is compared, and the label corresponding to the correlator with the maximum output value is the decoding output.

Further, it should be noted that: the self-adaptive rate adjustment in the embodiment means that the data transmission rate can be automatically adjusted according to a single-core cable channel, so that the reliability of data transmission is ensured; the single-core cable is a cable commonly used in production logging and provided with a cable core and cable armoring at the periphery, is used for supplying power to an underground instrument and is a channel for transmitting data between the underground instrument and a ground system. The present invention can also be implemented by replacing the spreading code sequence or by changing part of the device parameters.

In the embodiment, the technical problems of low transmission rate, high system error rate, difficult field connection and the like of a single-core logging cable transmission system are solved by introducing a CCSK (cyclic Code Shift keying) cyclic Shift coding technology. The encoding mode of the CCSK of the underground instrument can be automatically adjusted according to the cable characteristics, so that the purpose of adaptive matching is achieved; in addition, the method has simple coding, low underground complexity and easy high-temperature realization, and is particularly suitable for a high-temperature (175 DEG) and high-pressure (100Mpa) single-core cable transmission system.

Claims

1. The utility model provides a single core cable transmission device of high reliable self-adaptation rate adjustment which characterized in that: the device comprises an underground part and a ground part, wherein the underground part comprises a power signal isolation module, a command interface circuit and a data driving circuit, the command interface circuit and the data driving circuit are electrically connected with the power signal isolation module, the data driving circuit is directly and electrically connected with a coding and decoding MCU (microprogrammed control unit), the command interface circuit is electrically connected with the coding and decoding MCU through a command shaping filter circuit, the coding and decoding MCU is electrically connected with a bus management MCU, the bus management MCU is electrically connected with the bus driving circuit and a data acquisition circuit, and the data acquisition circuit is electrically connected with a well temperature sensor, a pressure sensor and a GR probe through a sensor driving and analog processing circuit; the ground part comprises a power supply signal isolation module which is electrically connected with the logging computer sequentially through a program control gain amplification module, an anti-aliasing filtering module, an AD acquisition module and a processor, and the processor is also electrically connected with the power supply signal isolation module through an issued command coding module and an issued command driving module; the power supply signal isolation modules of the underground part and the ground part are electrically connected through a single-core cable.

2. The highly reliable adaptive rate adjusting single conductor cable transmission device of claim 1, wherein: the coding and decoding MCU and the bus management MCU are integrated on a 210-degree high-temperature chip sm470r1b1m-ht, and sm470r1b1m-ht is packaged by a CQFP of 10mm by 10 mm.

3. The highly reliable adaptive rate adjusting single conductor cable transmission device of claim 1, wherein: the ground case of the ground part comprises a signal preprocessing card and a communication acquisition card, the case adopts a 1U standard case form, and the rear panel comprises a depth wiring lead-in, a tension or magnetic mark wiring lead-in, a logging cable lead-in, two paths of direct current power line lead-ins, a 1 path of alternating current power line lead-in and a case power supply line lead-in.