CN-121984519-A - Acquisition end data compression system and method for while-drilling ultrasonic imaging logging

CN121984519ACN 121984519 ACN121984519 ACN 121984519ACN-121984519-A

Abstract

The application discloses a system and a method for compressing data at an acquisition end of ultrasonic imaging logging while drilling, which belong to the technical field of acoustic logging; the method comprises the steps of processing by using short-time Fourier transform, extracting peak time of a first reflected echo wave packet in an ultrasonic echo wave form, performing first-stage compression by using a time domain wave packet interception method to obtain a first-stage compressed data packet, performing second-stage compression by using a frequency domain wavelet transform algorithm to obtain a second-stage compressed data packet, performing third-stage compression by using an amplitude domain DPCM algorithm to obtain and store a third-stage compressed data packet, and updating acquisition parameters by using a program-controlled gain algorithm. The three-stage compression is completed at the acquisition end, the acquisition end and the main control end are mutually independent and cooperatively work, so that the transmission and storage time is reduced, and the problems of insufficient underground storage space and multiplied ground reading time caused by the increase of the logging data volume of the ultrasonic imaging while drilling are solved.

Inventors

HAO XIAOLONG
LIANG FEIYU
YAN BINGNAN
BAI FAN
Qian Ruiyu
YAN XU

Assignees

西安石油大学

Dates

Publication Date: 20260505
Application Date: 20260408

Claims (7)

1. The acquisition end data compression method of the while-drilling ultrasonic imaging logging is characterized by comprising the following steps of: s1, acquiring an original ultrasonic logging sound signal, converting the original ultrasonic logging sound signal into a digital data packet, and caching the digital data packet into a FIFO memory of a region to be compressed; S2, processing the cached digital data packet by using short-time Fourier transform to obtain frequency component distribution of different moments of the waveform, and extracting peak time of a first reflected echo wave packet in the ultrasonic echo waveform; s3, performing first-stage compression by using a time domain wave packet interception method to obtain a first-stage compressed data packet which retains effective information of a transmitted pulse wave packet and a first-time reflected echo wave packet and time information of a peak value of the first-time reflected echo wave packet; s4, performing second-stage compression on the first-stage compressed data packet by using a frequency domain wavelet transform algorithm to obtain a second-stage compressed data packet; S5, performing third-level compression on the second-level compressed data packet by using an amplitude domain DPCM algorithm to obtain a third-level compressed data packet, storing the third-level compressed data packet into a FIFO memory of a compression completion area, waiting for a main controller in a main control end hardware system to read, and updating acquisition parameters by using a program control gain algorithm.
2. The method for compression of data at the acquisition end of ultrasound imaging logging while drilling of claim 1, wherein the effective information of the transmitted pulse wave packet and the first reflected echo wave packet comprises: waveform data of 4 cycles from zero time, waveform data of 4 cycles before the peak time and waveform data of 2 cycles after the peak time of the first reflected echo wave packet.
3. The method for compression of acquisition-side data for ultrasound imaging logging while drilling of claim 1, wherein S4 comprises: S401, taking the first data point and the last data point of a transmitting pulse wave packet and a first reflected echo wave packet in a first-stage compressed data packet as symmetry axes, adopting a data symmetrical filling mode, expanding a plurality of data points on the left side and the right side respectively, and generating a new continuous output sequence; S402, constructing a high-pass filter bank and a low-pass filter bank based on db4 wavelet to obtain corresponding filter coefficients; S403, carrying out convolution operation on the new continuous output sequence and designed low-pass and high-pass filter coefficients to obtain a decomposition result, and extracting an approximate component sequence and a detail component sequence of one layer of wavelet transformation by downsampling the decomposition result; And S404, extracting the approximate component sequence, and caching the approximate component sequence as a second-stage compressed data packet to obtain the second-stage compressed data packet.
4. The method for data compression at the acquisition end of ultrasound imaging logging while drilling according to claim 1, wherein the performing third-stage compression on the second-stage compressed data packet by using an amplitude domain DPCM algorithm to obtain a third-stage compressed data packet comprises: A1, taking a first data point of a second-stage compressed data packet as an initial predicted value, and carrying out difference solving processing on current original data and the initial predicted value to obtain a difference value; a2, mapping the obtained difference value into a plurality of discrete values according to a non-uniform quantization rule to generate a quantized difference value; a3, calculating the predicted value of the current data point based on the predicted value of the previous data point and the current quantized difference value, and obtaining the difference value of the next data point; A4, repeating the steps A1-A3 to obtain a quantized difference sequence, converting the obtained quantized difference sequence from 16 bits to 8-bit coding values according to a coding rule, and sequentially forming coded data into a third-stage compressed data packet.
5. The method for compression of acquisition-side data of ultrasound imaging logging while drilling of claim 1, wherein updating acquisition parameters using a programmable gain algorithm comprises: and calculating the program-controlled amplification factor of the next acquisition period by solving the peak value data of the two wave packets of the transmitted pulse wave packet and the first reflected echo wave packet.
6. The method for compression of acquisition-side data of ultrasound imaging logging while drilling of claim 1, wherein waiting for a master controller in a master-side hardware system to read comprises: after the acquisition control command is issued, the acquisition end circularly issues a data packet reading command to enable the acquisition end to upload compressed data in the FIFO memory of the area to be uploaded in an interrupt mode until all data are read, the read data are cached into an external expansion SRAM of the main control end, and the compressed data of the whole working period are stored into the Flash memory.
7. A system of the acquisition end data compression method of the while-drilling ultrasonic imaging logging according to any one of claims 1 to 6 is characterized by comprising an acquisition end hardware system and a main control end hardware system; The acquisition end hardware system comprises an acquisition-compression controller, an internal communication interface module and a multi-channel acquisition module; The acquisition-compression controller is an FPGA minimum hardware system, and is internally integrated with a time domain wave packet interception method, a frequency domain wavelet transformation algorithm and an amplitude domain DPCM algorithm, and is used for carrying out acquisition control, data compression and communication with a main control end hardware system; The internal communication interface module takes a double-differential high-speed serial bus as a hardware basis, issues a command from the main control end hardware system to the acquisition end hardware system, and uploads data from the acquisition end hardware system to the main control end hardware system; The multi-channel acquisition module processes signals of the multi-channel ultrasonic logging transducer into digital signals and sends the digital signals to the acquisition-compression controller, and the multi-channel acquisition module comprises a transducer, an analog processing module and an AD conversion module, wherein the transducer converts received ultrasonic logging acoustic signals into electric signals; The main control end hardware system comprises a main controller, a man-machine interaction module and a Flash memory, wherein the main controller module adopts a control framework of a DSP-FPGA, the DSP is used for controlling the man-machine interaction module to carry out bidirectional transmission of commands and small amount of data between an ultrasonic imaging logging instrument while drilling and a ground system, the FPGA carries out internal command issuing and data uploading with an acquisition-compression controller through an internal communication interface module and is provided with an interface for fast uploading a large amount of stored data, the man-machine interaction module comprises a CAN bus and an RS485 bus to carry out ground test command issuing and instrument data uploading and read compressed data stored in the Flash memory module, and the Flash memory is used for storing the ultrasonic imaging logging compressed data compressed in the acquisition end hardware system and then transmitted to the main control end hardware system.

Description

Acquisition end data compression system and method for while-drilling ultrasonic imaging logging Technical Field The application relates to the technical field of acoustic logging, in particular to a system and a method for compressing data at an acquisition end of ultrasonic imaging logging while drilling. Background The ultrasonic imaging logging while drilling evaluates the stratum of the well wall by measuring the amplitude and time information of ultrasonic echo, and realizes the omnibearing scanning measurement of the well wall by the rotation of the drill collar. In order to improve measurement accuracy and azimuth coverage, a new generation of instrument is provided with a plurality of ultrasonic transducers in the circumferential direction for simultaneous measurement, uses a smaller working period for repeated spontaneous self-collection, and adopts a smaller sampling interval for high-accuracy collection. These three factors result in an increasing amount of data for ultrasound imaging logging while drilling. The increase of logging while drilling data volume brings two problems, namely that the requirements on the storage space and the circuit structure of underground instruments are larger and larger. The single-chip memory has limited capacity, and the use of multiple pieces of memory not only requires upgrades to the downhole circuitry, but also reduces the reliability of the downhole system. And secondly, after the instrument returns to the ground, the time for reading the data of the memory is multiplied. This is detrimental to on-site rapid operations and continuous upgrades of technology for high-precision while-drilling ultrasonic well logging. Disclosure of Invention Aiming at the defects in the prior art, the acquisition end data compression system and the method for the while-drilling ultrasonic imaging logging solve the problems of insufficient underground storage space and multiplied ground reading time caused by the increase of the while-drilling ultrasonic imaging logging data volume. In order to achieve the aim of the application, the application adopts the following technical scheme: first aspect: the application provides a system and a method for compressing data at an acquisition end of ultrasonic imaging logging while drilling, comprising the following steps: s1, acquiring an original ultrasonic logging sound signal, converting the original ultrasonic logging sound signal into a digital data packet, and caching the digital data packet into a FIFO memory of a region to be compressed; S2, processing the cached digital data packet by using short-time Fourier transform to obtain frequency component distribution of different moments of the waveform, and extracting peak time of a first reflected echo wave packet in the ultrasonic echo waveform; s3, performing first-stage compression by using a time domain wave packet interception method to obtain a first-stage compressed data packet which retains effective information of a transmitted pulse wave packet and a first-time reflected echo wave packet and time information of a peak value of the first-time reflected echo wave packet; s4, performing second-stage compression on the first-stage compressed data packet by using a frequency domain wavelet transform algorithm to obtain a second-stage compressed data packet; S5, performing third-level compression on the second-level compressed data packet by using an amplitude domain DPCM algorithm to obtain a third-level compressed data packet, storing the third-level compressed data packet into a FIFO memory of a compression completion area, waiting for a main controller in a main control end hardware system to read, and updating acquisition parameters by using a program control gain algorithm. Further, the effective information of the transmitted pulse wave packet and the first reflected echo wave packet includes: waveform data of 4 cycles from zero time, waveform data of 4 cycles before the peak time and waveform data of 2 cycles after the peak time of the first reflected echo wave packet. Further, the step S4 includes: S401, taking the first data point and the last data point of a transmitting pulse wave packet and a first reflected echo wave packet in a first-stage compressed data packet as symmetry axes, adopting a data symmetrical filling mode, expanding a plurality of data points on the left side and the right side respectively, and generating a new continuous output sequence; S402, constructing a high-pass filter bank and a low-pass filter bank based on db4 wavelet to obtain corresponding filter coefficients; S403, carrying out convolution operation on the new continuous output sequence and designed low-pass and high-pass filter coefficients to obtain a decomposition result, and extracting an approximate component sequence and a detail component sequence of one layer of wavelet transformation by downsampling the decomposition result; And S404, extracting the approximate component sequen