CN214174637U

CN214174637U - Borehole three-component seismic data acquisition system

Info

Publication number: CN214174637U
Application number: CN202023180793.XU
Authority: CN
Inventors: 张俊杰; 杨泓渊; 田入运; 张怀柱
Original assignee: Jilin University
Current assignee: Jilin University
Priority date: 2020-12-25
Filing date: 2020-12-25
Publication date: 2021-09-10
Anticipated expiration: 2030-12-25

Abstract

The utility model belongs to a geophysical exploration data acquisition system, in particular to a borehole three-component seismic data acquisition system, which comprises an acquisition subsystem and a communication subsystem, wherein the acquisition subsystem is positioned in a borehole for acquiring seismic data, and the information acquired by the acquisition subsystem is communicated with a ground control center through the communication subsystem; the communication subsystem comprises a modulation unit connected with the acquisition subsystem, and the modulation unit is connected with a demodulation unit through an analog signal transmission unit and connected with a PC (personal computer) end. The transmission rate is improved and errors caused by noise interference are reduced.

Description

Borehole three-component seismic data acquisition system

Technical Field

The utility model belongs to geophysical exploration data acquisition system, especially a three-component seismic data acquisition system in well.

Background

Currently, there are data showing that the reserves of medium and high permeability oil and gas fields in our country are much smaller than those of low permeability oil and gas fields. Therefore, the exploitation of low permeability fields is becoming the focus of field development research. At present, the hydraulic fracturing technology is a main technical means for low-permeability oil and gas field exploitation, and the method for monitoring the hydraulic fracturing process is the most effective method for monitoring microseismic. The microseism monitoring mainly comprises two modes of in-well monitoring and ground monitoring, and compared with ground monitoring, the seismic data acquired in the well has the advantages of high signal-to-noise ratio, high resolution of effective waves and strong vertical resolution capability. Therefore, the seismic signal acquisition is carried out by using the data acquisition equipment in the well, and the reliability and the exploration effect of the final result can be guaranteed. Meanwhile, the well acquisition system also puts requirements on long distance and high speed for the transmission system. At present, wired communication mainly depends on two media, namely optical fiber and cable, and although the bottleneck problem of data transmission is solved by the application of optical fiber communication in some fields, the high temperature resistance, the tensile resistance and the maintainability of the optical cable are all inferior to those of the cable. Therefore, at present, cable communication is still the main communication means for signal transmission in a well, and how to improve the transmission rate of the cable is still the problem to be solved.

Therefore, the research on the borehole three-component seismic data acquisition system with high-speed cable communication is of great significance.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a three-component seismic data collection system in well is provided, promoted transmission rate and reduced the error that noise interference brought.

The utility model discloses a realize like this, a three-component seismic data collection system in well, this system includes:

the system comprises an acquisition subsystem and a communication subsystem, wherein the acquisition subsystem is positioned in a well to acquire seismic data, and the information acquired by the acquisition subsystem is communicated with a ground control center through the communication subsystem; the communication subsystem comprises a modulation unit connected with the acquisition subsystem, and the modulation unit is connected with a demodulation unit through an analog signal transmission unit and connected with a PC (personal computer) end.

Furthermore, the acquisition subsystem comprises a three-component detector, an analog signal preprocessing module, a main control module, an ADC (analog to digital converter) sampling and calibrating circuit module, a clock synchronization module and a power circuit module, wherein the main control module is a minimum system which is built by taking STM32 as a core, the clock synchronization module is connected with the main control module through an RS485 data line to ensure the synchronous acquisition of the system, and the power circuit module adopts a 12V power supply to supply power to the system through converting voltage by a DC-DC conversion unit; the three-component wave detector is sequentially connected with the analog signal preprocessing module and the ADC sampling and calibrating circuit module and is connected with the main control module through the SPI interface, and the clock synchronization module is arranged on the ground.

Furthermore, a bidirectional transient voltage suppression tube is added to the front end of the signal input of the analog signal preprocessing module, and the bidirectional transient voltage suppression tube comprises a Butterworth low-pass filter circuit for filtering.

Further, the AD sampling and checking circuit module: sampling is carried out by adopting a 32-bit analog-to-digital converter ADS1282, and when a monitoring pin of the 32-bit analog-to-digital converter ADS1282 is at a low level, data are output to a main control module from an SDO port of the 32-bit analog-to-digital converter ADS 1282. A 32-bit analog-to-digital converter ADS1282 is connected as a calibration circuit through a DAC1282 chip.

Further, the main control module adopts an STM32F4 series product STM32F407ZFT 6.

Furthermore, the analog transmission unit comprises two transformers and a logging cable between the two transformers, one transformer is connected with the modulation unit, the other transformer is connected with the demodulation unit, the modulation unit is converted into an analog signal through the DAC, the analog signal is coupled to the logging cable through the transformer for transmission, and the analog signal is restored into a digital signal through a completely symmetrical reverse process after being transmitted to the other end of the cable.

Compared with the prior art, the utility model, beneficial effect lies in, this novel use 32 high accuracy ADS1282 to guarantee seismic data's high accuracy collection as the collection unit of core. Meanwhile, a ground GPS time service unit is adopted to communicate with an in-well acquisition unit through RS485, so that synchronous data acquisition is guaranteed, and accurate time information is granted. And finally, data transmission is carried out after data modulation, so that the transmission rate is improved, and errors caused by noise interference are reduced.

Drawings

FIG. 1 is a block diagram of the overall architecture of a three-component seismic acquisition system in a well;

FIG. 2 is a block diagram of an acquisition subsystem;

wherein. The system comprises a main control module 1, an analog signal preprocessing module 2, an ADC sampling and calibrating circuit module 3, a clock synchronization module 4, a power circuit module 5 and a cache module 6;

fig. 3 is a block diagram of a communication subsystem architecture.

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.

Referring to fig. 1, an in-well three-component seismic data acquisition system, the system comprising:

Referring to fig. 2, the acquisition subsystem comprises a three-component detector, an analog signal preprocessing module, a main control module, an ADC sampling and calibration circuit module, a clock synchronization module and a power circuit module, wherein the main control module is a minimum system built by taking STM32 as a core, the clock synchronization module is connected with the main control module through an RS485 data line to ensure synchronous acquisition of the system, and the power circuit module adopts a 12V power supply to supply power to the system through voltage conversion of a DC-DC conversion unit; the three-component wave detector is sequentially connected with the analog signal preprocessing module and the ADC sampling and calibrating circuit module and is connected with the main control module through the SPI interface.

The analog signal preprocessing module adopts a bidirectional transient voltage suppression tube added at the front end of signal input for forming an overvoltage and current protection circuit. Meanwhile, a Butterworth low-pass filter circuit is added to filter the original signal to enhance the signal-to-noise ratio of the signal and improve the anti-interference capability of the system.

AD sampling and checking circuit module: sampling is carried out by adopting a 32-bit analog-to-digital converter ADS1282, and when a monitoring pin of the 32-bit analog-to-digital converter ADS1282 is at a low level, data are output to a main control module from an SDO port of the 32-bit analog-to-digital converter ADS 1282. A 32-bit analog-to-digital converter ADS1282 is connected as a calibration circuit through a DAC1282 chip. The DAC1282 chip generates sine wave test signals, detects the data acquisition function and related index parameters of the system, and switches through the analog switch after self-checking is completed to start acquiring seismic signals. The seismic signals after signal processing are sampled by a high-precision 32-bit analog-to-digital converter ADS1282 special for seismic exploration. The chip is internally provided with a programmable gain amplifier and can be matched and connected with a detector to the maximum extent. Meanwhile, the sampling rates of 250SPS, 500SPS, 1000SPS, 2000SPS and 4000SPS can be selected according to requirements. The system adopts a continuous sampling mode, is communicated with the main control module through the SPI interface, and outputs data to the main control module through the SDO interface when the monitoring pin is at a low level. Meanwhile, a DAC1282 chip is used for building a calibration circuit of the ADC, so that verification and test signals are provided for the ADC chip, and the influence of the problems of zero drift, gain deviation and the like caused by temperature and device aging is reduced.

The main control module adopts STM32F4 series products STM32F407ZFT 6.

As shown in fig. 3, the analog transmission unit includes two transformers and a logging cable between the two transformers, one transformer is connected to the modulation unit, the other transformer is connected to the demodulation unit, the modulation unit is converted into an analog signal by the DAC, and the analog signal is coupled to the logging cable through the transformer for transmission, and is restored to a digital signal again through a completely symmetrical reverse process after being transmitted to the other end of the cable.

As shown in fig. 3, the communication system includes a modulation unit, an analog transmission unit, and a demodulation unit. The seismic data are firstly processed by the modulation unit and then transmitted to the demodulation unit through the cable, and the data are recovered by the PC end after being recovered, so that the whole data recovery process is completed.

A modulation unit: the seismic data acquired by the acquisition system enter the FPGA module in the form of binary data stream, and form a data signal to be transmitted after modulation and coding.

An analog transmission unit: the data after code modulation is firstly converted into analog signals through a DAC conversion module, then is subjected to filtering processing and power amplification, and finally is coupled to a logging cable through a transformer for transmission. After being transmitted to the other end of the cable, the signal is recovered into a digital signal again through a completely symmetrical reverse process.

A modulation unit: after receiving the data, the ground receiving end performs deinterleaving, decoding and descrambling after passing through the ADC conversion module, and finally recovers the data. The PC end is connected through the internet access for communication, and data is recycled to complete the whole data acquisition and recycling process.

And a clock synchronization module arranged on the ground is connected with the in-well acquisition subsystem through an RS485 data line. The clock synchronization module comprises three independent acquisition channels, so that the acquisition channels can acquire seismic data synchronously, data acquisition time nodes can be recorded accurately, and accurate time information can be provided conveniently during data analysis. Therefore, the system adopts a ground clock synchronization module time service mode and communicates with the in-well collection subsystem through RS485, a GPS satellite can provide accurate UTC time information in a global range, the ground clock synchronization module transmits the GPS information to a main control module of the in-well collection subsystem through RS485 after receiving the GPS information, the main control module converts the GPS data into standard time information by analyzing the GPS data and stamps a time on a data file, and the purpose of time service of an instrument is achieved.

The above description is only exemplary of the present invention and should not be taken as limiting the scope of the present invention, as any modifications, equivalents, improvements and the like made within the spirit and principles of the present invention are intended to be included within the scope of the present invention.

Claims

1. An in-well three-component seismic data acquisition system, comprising:

2. The system of claim 1, wherein the acquisition subsystem comprises a three-component detector, an analog signal preprocessing module, a main control module, an ADC sampling and calibration circuit module, a clock synchronization module and a power circuit module, wherein the main control module is a minimum system built by taking STM32 as a core, the clock synchronization module is connected with the main control module through an RS485 data line to ensure the synchronous acquisition of the system, and the power circuit module adopts a 12V power supply to supply power to the system through converting voltage by a DC-DC conversion unit; the three-component wave detector is sequentially connected with the analog signal preprocessing module and the ADC sampling and calibrating circuit module and is connected with the main control module through the SPI interface, and the clock synchronization module is arranged on the ground.

3. The system of claim 2,

the analog signal preprocessing module is added with a bidirectional transient voltage suppression tube at the front end of signal input, and the bidirectional transient voltage suppression tube comprises a Butterworth low-pass filter circuit for filtering.

4. The system of claim 2, wherein the ADC sampling and calibration circuitry module: sampling is carried out by adopting a 32-bit analog-to-digital converter ADS1282, when a monitoring pin of the 32-bit analog-to-digital converter ADS1282 is at a low level, data are output to a main control module from an SDO port of the 32-bit analog-to-digital converter ADS1282, and the data are connected with the 32-bit analog-to-digital converter ADS1282 through a DAC1282 chip to serve as a calibration circuit.

5. The system of claim 2, wherein the master control module employs an STM32F4 series product STM32F407ZFT 6.

6. The system of claim 1, wherein the analog signal transmission unit comprises two transformers and a logging cable between the two transformers, one transformer is connected with the modulation unit, the other transformer is connected with the demodulation unit, the modulation unit is converted into the analog signal through the DAC, the analog signal is coupled to the logging cable through the transformers for transmission, and the analog signal is recovered into the digital signal through a completely symmetrical reverse process after being transmitted to the other end of the logging cable.