Intelligent adaptive data acquisition and processing method and device for nuclear magnetic resonance

Abstract

The embodiment of the present application provides a nuclear magnetic resonance intelligent adaptive data acquisition and processing method and device, which relates to the field of data processing technology. The method includes: in an initial observation mode, setting initial measurement parameters for the instrument, and using the values ​​of the measurement parameters to transmit a pulse sequence and collect data; preprocessing and inverting the collected data to obtain an inversion result; optimizing the measurement parameters according to the inversion result, and transmitting and collecting the next round of pulse sequences according to the optimized measurement parameters, so as to improve the quality of downhole nuclear magnetic resonance logging data acquisition and reduce the emission energy consumption of the downhole nuclear magnetic resonance instrument, thereby obtaining more efficient and accurate detection of formation fluid signals and providing high-quality data for reservoir evaluation.

Description

Technical Field

[0001] The present application relates to the field of data processing technology, and in particular to a method and device for intelligent adaptive nuclear magnetic resonance data acquisition and processing. Background Art

[0002] Well logging technology is a set of geophysical measurement methods in wells. It can detect the side profile of the well through ultrasonic, nuclear magnetic resonance, electrical and other methods to obtain continuous physical information on the earth, and well logging technology plays a vital role in the detection of oil. NMR logging while drilling (or LWD) and cable NMR logging (or cable logging) are two common logging methods. Compared with other logging methods, the biggest feature of the above two NMR logging methods is that the response signal is independent of the rock skeleton. Specifically, cable logging uses cables to transmit data from downhole to the ground. The cable transmission rate can reach up to 500kb / s, and the downhole NMR echo data, quality control data and instrument motion status data can be transmitted to the ground in real time after processing; in addition, the cable in cable logging can not only transmit data, but also bear the task of powering the downhole instrument from the ground. Therefore, cable logging does not care about the energy consumption of logging instruments. Compared with cable logging, the advantage of LWD is that it can measure highly deviated wells and horizontal wells, and can measure the stratigraphic information of uninvaded layers, providing geologists with the coveted original stratigraphic parameters for geological guidance. The data transmission mode of LWD is mud pulse, and its maximum transmission rate is 50bit / s. The data transmission rate is low, and it is difficult to achieve real-time transmission of downhole nuclear magnetic data. In addition, LWD does not have direct ground power supply like cable logging. It is powered by turbine generators and downhole battery packs, so the requirements for downhole instruments are very strict. During the process of NMR logging while drilling, high-power radio frequency pulses need to be emitted. The power consumption of the instrument during the measurement depends on the setting of the measurement parameters, and the measurement parameters affect the quality of the collected data. Therefore, the selection of measurement parameters for downhole nuclear magnetic logging instruments is crucial. During operation, if the number of echoes is too large, there will be measurement redundancy, resulting in power consumption waste; if the number of echoes is too small, the measurement of the long relaxation components of the fluid will be insufficient, reducing the data quality. Therefore, it is necessary to optimize the measurement parameters in real time according to the formation and fluid characteristics to improve data quality and reduce instrument power consumption. Summary of the invention

[0003] The embodiments of the present application provide a method and device for intelligent adaptive data acquisition and processing of nuclear magnetic resonance, which are used to improve the quality of downhole nuclear magnetic resonance logging data acquisition and reduce the transmission energy consumption of downhole nuclear magnetic resonance instruments, thereby achieving more efficient and accurate detection of formation fluid signals.

[0004] In a first aspect, an embodiment of the present application provides a nuclear magnetic resonance intelligent adaptive data acquisition and processing device, the device comprising:

[0005] Adaptive nuclear magnetic resonance data acquisition main control circuit; wherein the main control circuit is used to pre-process and invert the collected echo data to obtain an inversion result. wherein the pre-processing is used to eliminate the interference of noise on the echo data, and the inversion is used to obtain the formation T2 spectrum and calculate the formation parameters;

[0006] The main control circuit is also used to determine the formation attributes according to the inversion results, and to change the observation mode in real time according to the formation attributes, to match the values ​​of corresponding measurement parameters according to the observation mode, and to use the measurement parameters to transmit a new round of pulse sequences and collect data; wherein the observation mode includes a non-reservoir observation mode or a reservoir observation mode; the non-reservoir observation mode is an observation mode applied to formation attributes that are non-reservoir; and the reservoir observation mode is an observation mode applied to formation attributes that are reservoir.

[0007] Optionally, the formation attribute includes a reservoir and a non-reservoir; the main control circuit is specifically used to determine that the current observation mode is a reservoir observation mode when the formation attribute is a reservoir;

[0008] When the formation attribute is non-reservoir, the current observation mode is determined to be the non-reservoir observation mode.

[0009] Optionally, the acquisition parameters include: polarization time TW, echo interval TE, number of echoes NE and number of superpositions RN; the pulse sequence is a 90°-180°-180° PMG pulse sequence.

[0010] Optionally, the preprocessing includes: phase-sensitive detection, cross-phase pairing or phase rotation; and the inversion includes a downhole fast singular value decomposition SVD inversion algorithm.

[0011] Optionally, the reservoir and non-reservoir observation modes satisfy the relationship: T W >3T1 and 3N E T E >T 2,max .

[0012] The measurement parameters in the non-reservoir observation mode are: a long polarization time measurement, the measurement parameters are, T W1 9s, T E1 0.9ms, N E1 is 100; four short polarization time measurements, the measurement parameters are, T W2 0.2s, T E2 0.6ms, N E2 is 10.

[0013] The measurement parameters in the reservoir observation mode are: a long polarization time measurement, the measurement parameters are, TW1 9s, T E1 0.9ms, N E1 is 800; four short polarization time measurements, the measurement parameters are, T W2 0.2s, T E2 0.6ms, N E2 is 10. W is the polarization time, T E is the echo interval, N E is the number of echoes, T1 is the transverse relaxation time, and T2 is the longitudinal relaxation time.

[0014] Optionally, the main control circuit includes the following items: a communication module, a data processing module, a data storage module and a timing control module. The communication module is used to communicate with the ground system; the data processing module is used for preprocessing and T2 inversion of the original echo data; the data storage module is used to store the real and imaginary signals after phase-sensitive detection and the inverted T2 spectrum; the timing control module is used to generate control timing, control other circuits to generate radio frequency pulses, and condition and collect analog echo signals. Optionally, the communication module includes the following items: a CAN communication module, an RS-485 communication module and an SPI communication module;

[0015] The CAN communication module is used to communicate with the ground system during the logging process. The ground system sends configuration parameters to the main control circuit for parameter configuration and controls the start and stop of the operation. During the operation, the main control circuit uploads some key formation parameters and the current instrument status to the ground.

[0016] The RS-485 communication module is used to communicate with the nuclear magnetic logging instrument through the RS-485 module on the ground host computer, on the one hand to complete the frequency sweep and calibration of the instrument, and on the other hand to read out the echo data stored in the storage module during the downhole operation;

[0017] The SPI module is used to complete the communication between the DSP and the FPGA in the main control circuit. During the communication, the DSP acts as the host and the FPGA acts as the slave. On the one hand, the DSP sends the next round of measurement parameters to the FPGA through the SPI module, and on the other hand, the FPGA transmits the real and imaginary signals of the collected raw echo data obtained through phase-sensitive detection back to the DSP.

[0018] Optionally, the data storage module includes a NAND FLASH controller and a NAND FLASH high-temperature storage chip. The NAND FLASH controller completes the reading, writing, erasing of data to the memory, as well as bad block management, data verification and power-off recovery; the data storage module is used to store the real and imaginary signals obtained after phase-sensitive detection of the collected original echo data during operation, and to store the inverted T2 spectrum on the other hand; after the operation is completed, the data is uploaded on the ground through specific instructions.

[0019] Optionally, the timing control module includes a transmission timing, an isolation timing, a discharge timing and an acquisition timing; the transmission timing is used to generate a corresponding digital timing signal according to the value of the acquisition parameter, and control the antenna to generate a CPMG pulse sequence through a power amplifier circuit and an antenna drive circuit;

[0020] The discharge timing is used to provide the energy required for transmitting radio frequency pulses using energy storage capacitors for nuclear magnetic resonance (NMR);

[0021] The isolation timing is used to keep the isolation circuit in an on state during the RF pulse transmission stage and the discharge stage; and the isolation circuit in a off state during the data acquisition stage;

[0022] The acquisition timing is used to control the data acquisition circuit to complete data acquisition.

[0023] In a second aspect, an embodiment of the present application provides a method for intelligent adaptive data acquisition and processing of nuclear magnetic resonance applied to a device as described in any one of the first aspects, the method comprising: determining an initial observation mode, matching a corresponding acquisition parameter value for the initial observation mode, and using the acquisition parameter value to transmit a pulse sequence and acquire data; wherein the initial observation mode comprises: a non-reservoir observation mode;

[0024] Preprocessing and inverting the collected data to obtain an inversion result; wherein the preprocessing is used to eliminate the interference of noise on the echo data; and the inversion is used to calculate the porosity of the formation;

[0025] Determine formation properties according to the inversion results, determine the current observation mode according to the formation properties, and transmit and collect data for the next round of pulse sequences according to the current observation mode; wherein the current observation mode includes a non-reservoir observation mode or a reservoir observation mode; the non-reservoir observation mode is an observation mode applied to formation properties that are non-reservoir; and the reservoir observation mode is an observation mode applied to formation properties that are reservoir.

[0026] In a third aspect, an embodiment of the present application provides an electronic device comprising: at least one processor and a memory; the memory stores computer-executable instructions; the at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the data acquisition method for while-drilling nuclear magnetic resonance logging provided in the second aspect.

[0027] In a fourth aspect, an embodiment of the present application provides a computer-readable storage medium, in which computer execution instructions are stored. When a processor executes the computer execution instructions, a data acquisition method for while-drilling nuclear magnetic resonance logging as provided in the second aspect is implemented.

[0028] The embodiment of the present application provides a data acquisition device, method and storage medium for nuclear magnetic resonance logging, which can determine the initial observation mode, match the value of the corresponding acquisition parameter for the initial observation mode, and use the value of the acquisition parameter to transmit the pulse sequence and collect data; wherein the initial observation mode includes: non-reservoir observation mode; pre-processing and inversion of the collected data to obtain inversion results; wherein the pre-processing is used to eliminate the interference of noise on the echo data; the inversion is used to calculate the porosity of the formation; the formation attribute is determined according to the inversion result, the current observation mode is determined according to the formation attribute, and the next round of pulse sequence emission and data collection is performed according to the current observation mode; wherein the current observation mode includes non-reservoir observation mode or reservoir observation mode; the non-reservoir observation mode is an observation mode applied to the formation attribute of non-reservoir; the reservoir observation mode is an observation mode applied to the formation attribute of reservoir. In this way, pulse sequences can be emitted and corresponding data can be collected under the parameters corresponding to different observation modes, and the data can be processed to obtain data processing results, thereby obtaining more accurate detection results. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0030] Figure 1 A schematic diagram of a downhole operation system of an adaptive nuclear magnetic resonance logging data acquisition device provided in an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a system for uploading ground data and frequency sweeping and calibration modes of an adaptive nuclear magnetic resonance logging data acquisition device provided in an embodiment of the present application;

[0032] Figure 3 A functional schematic diagram of a main control circuit provided in an embodiment of the present application;

[0033] Figure 4 A schematic diagram of the structure of an electronic device provided in an embodiment of the present application;

[0034] Figure 5 A schematic diagram of a flow chart of a data acquisition method for logging while drilling provided by an embodiment of the present invention;

[0035] Figure 6 A schematic diagram of switching an observation mode provided in an embodiment of the present application;

[0036] Figure 7 A schematic diagram of the principle of a phase-sensitive detection algorithm provided in an embodiment of the present application;

[0037] Figure 8 A schematic diagram of the principle of a downhole fast SVD inversion algorithm provided in an embodiment of the present application;

[0038] Fig. 9 This is a schematic diagram of the working process of the master control DSP chip provided in the embodiment of the present application;

[0039] Fig.10 This is a schematic diagram of the master control FPGA chip flow provided in the embodiment of this application.

[0040] The above drawings have shown clear embodiments of the present application, which will be described in more detail later. These drawings and text descriptions are not intended to limit the scope of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. DETAILED DESCRIPTION

[0041] Exemplary embodiments will be described in detail herein, examples of which are shown in the accompanying drawings. When the following description refers to the drawings, the same numbers in different drawings represent the same or similar elements unless otherwise indicated. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present disclosure. Instead, they are merely examples of devices and methods consistent with some aspects of the present disclosure as detailed in the appended claims.

[0042] One possible implementation of the NMR logging method is to use NMR logging, which uses mud pulses for data transmission. However, the data transmission rate is low, making it difficult to achieve real-time transmission of downhole NMR data, and the power consumption required to transmit radio frequency pulses for logging while drilling is very high.

[0043] Therefore, an embodiment of the present application provides a data acquisition method for logging while drilling. Based on the above-mentioned problems, during the logging process, the initial observation mode can be determined, and the corresponding acquisition parameter values ​​can be matched for the initial observation mode, and the values ​​of the acquisition parameters can be used to transmit the pulse sequence and collect data; the collected data are preprocessed and inverted to obtain the inversion results of the data; the formation properties are determined according to the inversion results, the current observation mode is determined according to the formation properties, and the next round of pulse sequence transmission and data collection are performed according to the current observation mode.

[0044] In this way, it is possible to transmit pulse sequences and collect data under the parameters corresponding to different observation modes, process the data to obtain data processing results, and obtain more accurate detection results.

[0045] For example, Figure 1 A schematic diagram of a downhole operation system of an adaptive nuclear magnetic resonance logging data acquisition device provided in an embodiment of the present application. Figure 1 As shown, the device includes an adaptive nuclear magnetic resonance logging data acquisition main control circuit.

[0046] The main control circuit is used to determine the initial observation mode, match the value of the corresponding acquisition parameter for the initial observation mode, and use the value of the acquisition parameter to transmit the pulse sequence and collect data, wherein the initial observation mode includes: non-reservoir observation mode; the main control circuit is used to pre-process and invert the data collected by the main control circuit to obtain the inversion result; wherein the pre-processing is used to eliminate the interference of noise on the echo data; the inversion is used to calculate the porosity of the formation;

[0047] The main control circuit is also used to determine the formation attributes according to the inversion results, determine the current observation mode according to the formation attributes, and transmit the next round of pulse sequence and collect data according to the current observation mode; wherein the current observation mode includes a non-reservoir observation mode or a reservoir observation mode; the non-reservoir observation mode is an observation mode applied to formation attributes that are non-reservoir; and the reservoir observation mode is an observation mode applied to formation attributes that are reservoir.

[0048] Specifically, the communication module in the main control circuit communicates with the telemetry system through the controller area network (CAN) bus, and then communicates with the ground system; an external large-capacity non-volatile memory is connected to store the real and imaginary signals after phase-sensitive detection during data processing; the data processing circuit receives the data collected by the signal transmission and data acquisition related circuits on the one hand, and processes the received raw data on the other hand, including preprocessing and T2 inversion, and automatically adjusts the observation mode and acquisition parameters of the next round of data acquisition according to the T2 inversion results; the timing control module generates pulse transmission timing and acquisition timing control signals to control the transmission and data acquisition related circuits.

[0049] For example, Figure 2 A system schematic diagram of data uploading, frequency sweeping and calibration modes of an adaptive nuclear magnetic resonance logging data acquisition device provided in an embodiment of the present application.

[0050] Specifically, the communication module in the main control circuit communicates directly with the host computer through the RS-485 (a serial bus) bus. At this time, the instrument has three working modes: sweep mode, calibration mode, and data upload mode. The sweep mode determines the optimal operating frequency of the instrument; the calibration mode determines the optimal width of the RF pulse; the data upload mode stores the real and imaginary data after phase-sensitive detection and the inverted T2 spectrum stored in the operating mode.

[0051] For example, Figure 3 This is a functional schematic diagram of the main control circuit provided in the embodiment of the present application. The main control circuit includes: a communication module, a data storage module, a data processing module, and a timing control module.

[0052] The communication module includes CAN module, RS-485 module and serial peripheral interface (SPI) module.

[0053] Specifically, the CAN module is composed of a CAN controller eCAN and a CAN driver integrated in a microprocessor (digital signal processor, DSP) chip to complete the communication with the telemetry system during downhole operations.

[0054] Specifically, the RS-485 module consists of the serial communication interfaces SCIA and SCIB integrated in the DSP chip, and an external level conversion chip to complete the communication with the host computer on the ground on the one hand, and receive the data of the auxiliary measurement board during operation on the other hand. Its function is to monitor the working status of other circuit boards, including the transmitting board, the receiving board, the temperature of the probe, the strength of the radio frequency magnetic field, and the two high-voltage signals of the transmitting board.

[0055] Specifically, the SPI module completes the communication between the DSP chip and the field programmable gate array (FPGA) chip. On the one hand, before the pulse sequence is transmitted, the acquisition parameters are sent to the FPGA according to the results of T2 inversion; on the other hand, after the FPGA collects the original echo data, it performs phase-sensitive detection on the original echo data and transmits the obtained real and imaginary signals back to the DSP chip for the next step of processing.

[0056] The data storage module is composed of a NAND FLASH controller implemented by FPGA and a NAND FLASH high-temperature storage chip.

[0057] Specifically, the NAND FLASH controller has five major functions, including controlling the reading, writing, and erasing of the NAND FLASH high-temperature storage chip and the bad block management, data verification, and power-off recovery of the NAND FLASH high-temperature storage chip.

[0058] Bad block management requires skipping bad blocks during reading, writing, and erasing of NAND FLASH memory.

[0059] Data verification checks and corrects errors caused by bit flipping during data storage when reading the NAND FLASH memory.

[0060] Power failure recovery solves the problem of memory storage address error caused by power failure when the nuclear magnetic resonance instrument is working.

[0061] The data processing module includes echo data preprocessing and T2 inversion. Specifically, data preprocessing includes phase-sensitive detection, cross-phase pairing, and phase rotation. The preprocessing is used to eliminate the interference of noise on the echo data. The inversion package is a downhole fast singular value decomposition SVD inversion algorithm. Phase-sensitive detection is completed in FPGA, and cross-phase pairing, phase rotation, and downhole fast singular value decomposition SVD inversion are completed in DSP.

[0062] The timing control module generates the pulse sequence transmission control timing, and the antenna drive circuit controls the antenna to generate the CPMG pulse sequence through the power amplifier circuit; the data acquisition timing control acquisition circuit filters and amplifies the original echo data, and then converts the analog signal into a digital signal and transmits it to the FPGA chip for the next step of processing. It includes the transmission timing, discharge timing, isolation timing, and receiving timing.

[0063] The emission timing is to generate the corresponding digital timing signal according to the acquisition parameters; the discharge timing is that NMR uses energy storage capacitors to provide the energy required for transmitting RF pulses. Since the antenna of the nuclear magnetic resonance logging instrument undertakes both the task of pulse emission and the task of echo signal detection, the energy storage is short-circuited to a high-voltage state when the pulse is emitted, and it is in a low-voltage state when the echo signal is detected. Therefore, the energy of the energy storage short-circuit must be released before the echo signal is detected after the 180° RF pulse is emitted. The isolation timing is that the RF pulse is emitted at a high voltage and the acquisition circuit is at a low voltage. In the RF pulse emission stage and the discharge stage, the isolation circuit is in the open state to prevent the high voltage from damaging the acquisition circuit; in the data acquisition stage, the isolation circuit is in the closed stage. At this time, the antenna is in a low-voltage state, and the analog to digital converter (A / D) can collect the echo signal.

[0064] The antenna of the nuclear magnetic resonance logging instrument is used as both a transmitting device and a receiving device. The radio frequency pulses emitted by the antenna will interfere with data acquisition, such as ringing, DC bias, etc. In addition, the environment and instrument vibration will also affect the acquisition, mainly manifested as noise. Therefore, the collected original echo data must be preprocessed to eliminate the above-mentioned influences, so that the inversion results are closer to the real formation. For different nuclear magnetic resonance logging instruments, the differences in instrument structure and measurement methods lead to different actual signals measured. Therefore, it is necessary to preprocess the echo data according to the characteristics of the instrument itself to obtain the echo string signal of the formation. In this patent, the preprocessing uses phase-sensitive detection, cross-phase pairing, and phase rotation to eliminate ringing, DC bias and noise. Since the processing is carried out underground, the inversion results immediately affect the parameters of the next round of data acquisition, so the real-time requirements for data processing are extremely high. The peripheral support circuits of the general-purpose processor CPU are extremely large and cannot work in a high temperature and high pressure environment. It cannot meet the requirements of underground high temperature and high pressure and limited instrument volume. Therefore, the downhole processor must be resistant to high temperature and high pressure, highly integrated and have fast computing speed. In summary, a digital signal processor is used to complete the echo data processing.

[0065] For different NMR logging instruments, differences in instrument structure and measurement methods lead to different actual signals measured. Therefore, echo data preprocessing should be performed according to the characteristics of the instrument itself to obtain the echo string signal of the formation.

[0066] It should be noted that it should be understood that the division of the various modules of the above device is only a division of logical functions. In actual implementation, they can be fully or partially integrated into one physical entity, or they can be physically separated. And these modules can all be implemented in the form of software calling through processing elements; they can also be all implemented in the form of hardware; some modules can also be implemented in the form of software called by processing elements, and some modules can be implemented in the form of hardware. In the implementation process, each step of the above method or each module above can be completed by the hardware integrated logic circuit in the processor element or the instructions in the form of software.

[0067] For example, the above modules may be one or more integrated circuits configured to implement the above methods, such as one or more application specific integrated circuits (ASIC), or one or more microprocessors (digital signal processors, DSP), or one or more field programmable gate arrays (FPGA), etc. For another example, when a module above is implemented in the form of a processing element scheduling program code, the processing element may be a general-purpose processor, such as a central processing unit (CPU) or other processor that can call program code. For another example, these modules may be integrated together and implemented in the form of a system-on-a-chip (SOC).

[0068] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented using software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When loading and executing computer program instructions on a computer, the process or function according to the embodiment of the present application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, a computer, a server or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) mode to another website site, computer, server or data center. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or a data center that includes one or more available media integration. The available medium can be a magnetic medium, (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid state disk (SSD)), etc.

[0069] For example, Figure 4 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present application. Figure 4 As shown, the device may include: a processor 401 and a memory 402 .

[0070] The processor 401 executes the computer-executable instructions stored in the memory, so that the processor 401 executes the solutions in the above embodiments.

[0071] Processor 401 can be a general-purpose processor, including a central processing unit CPU, a network processor (NP), etc.; it can also be a digital signal processor DSP, an application-specific integrated circuit ASIC, a field programmable gate array FPGA or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components.

[0072] The memory 402 stores computer executable instructions, and may include random access memory (RAM), and may also include non-volatile memory (non-volatile memory), such as at least one disk storage. Optionally, the device may also include: a system bus 403, and the memory 402 may be connected to the processor 401 through the system bus 403 and complete the communication between them.

[0073] The system bus 403 may be a peripheral component interconnect (PCI) bus or an extended industry standard architecture (EISA) bus, etc. The system bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, only one thick line is used in the figure, but it does not mean that there is only one bus or one type of bus.

[0074] An embodiment of the present application further provides a computer-readable storage medium, in which computer instructions are stored. When the computer instructions are executed on a computer, the computer executes the solution of the above embodiment.

[0075] An embodiment of the present application also provides a chip for executing instructions, which is used to execute the solution in the above embodiment.

[0076] An embodiment of the present application also provides a computer program product, which includes a computer program stored in a computer-readable storage medium. At least one processor can read the computer program from the computer-readable storage medium, and when at least one processor executes the computer program, the solution in the above embodiment can be implemented.

[0077] The data acquisition device for NMR logging while drilling provided by the embodiment of the present application has been described above. The method provided by the embodiment of the present application and running in the data acquisition device for NMR logging while drilling is described below. Those skilled in the art can understand that the method and the device can be combined and referenced with each other.

[0078] For example, Figure 5A flow chart of a method for collecting data for logging while drilling provided in an embodiment of the present application. Figure 5 As shown, the method may include the following steps:

[0079] S501, determining an initial observation mode, matching corresponding acquisition parameter values ​​for the initial observation mode, and using the acquisition parameter values ​​to transmit a pulse sequence and acquire data.

[0080] In the embodiment of the present application, the initial observation mode includes: a non-reservoir observation mode.

[0081] For example, when the instrument is started and data is collected for the first time, the collection mode is preset to a non-reservoir observation mode for reservoir identification. The main control circuit then makes a judgment based on the results of the data collected in the previous round after processing, and then selects an observation mode that is suitable for the current formation.

[0082] For example, Figure 6 A schematic diagram of switching an observation mode provided in an embodiment of the present application.

[0083] If the current formation is determined to be a reservoir, the observation mode is selected according to the logging purpose. If the logging purpose is to calculate the porosity, fine measurement is performed. In this patent, two groups of observation methods are used for data collection, such as Figure 6 As shown, Group A T W 9s, N E 0.9ms, T E 1000; Group B T W 0.2s, T E 0.6ms, N E The A group mainly measures the effective porosity, i.e., the clay bound water porosity and the movable fluid porosity, while the B group mainly measures the clay bound water porosity. The A group and the B group are measured alternately. The advantage of this is that the pore size range is large and the amount of data is large. If the purpose of logging is to identify fluids, double T is used. W Double T E Comprehensive logging method.

[0084] S502: pre-process and invert the collected data to obtain an inversion result.

[0085] In the embodiment of the present application, preprocessing is used to eliminate the interference of noise on echo data, and inversion is used to calculate the porosity of the formation. The data may include echo data.

[0086] Exemplarily, in the step shown in S501, different measurement parameters can be selected according to different observation modes to perform pulse sequence emission and data collection, and the collected data can be processed downhole, mainly including echo data preprocessing and T2 inversion.

[0087] The echo data preprocessing includes phase-sensitive detection, phase rotation, and cross-phase pairing of echo data. Due to the extremely high real-time requirements for data, in order to improve the resolution of the instrument, the results of this round of data processing determine the parameters of the next round of data acquisition. The traditional T2 inversion method is complicated, time-consuming, and will increase the energy consumption of the instrument, so downhole fast singular value decomposition (SVD) inversion is adopted.

[0088] For example, Figure 7 A schematic diagram of the principle of a phase-sensitive detection algorithm provided in an embodiment of the present application is shown in FIG. Figure 7 As shown in Figure 1, the principle of the phase-sensitive detection algorithm is to use the convolution of the measured signal and the reference signal to obtain the signal amplitude and phase. Let the expression of the measured sinusoidal signal x(n) be

[0089]

[0090] However, in actual NMR logging operations, due to the influence of the instrument itself, environmental white noise, and ringing during the acquisition process, the measured signal between adjacent 180° pulses under the CPMG pulse sequence can be expressed as:

[0091]

[0092] Where: A is the echo signal amplitude; is the signal phase; N is the number of sampling points; u(n) is the Gaussian noise caused by the active device and the external random white noise that is unrelated to the measured signal.

[0093] The reference signal is a standard sine-cosine function:

[0094] r1(n)=cos(2πn / N)

[0095] r2(n)=sin(2πn / N)

[0096] Perform cross-correlation operations on x(n) with r1(n) and r2(n), respectively, and we get:

[0097]

[0098] Same reason

[0099]

[0100] Since the noise u(n) is uncorrelated with the reference signal, R(n) = 0, so the above equation can be simplified to:

[0101]

[0102] Through these two components, the amplitude and phase of the spin echo signal can be accurately obtained.

[0103]

[0104] It can be seen that for nuclear magnetic resonance logging signals, the use of digital phase-sensitive detection algorithm can filter out noise unrelated to the echo signal and various ringing in the signal acquisition process from the collected data, thereby extracting the amplitude and phase of the echo signal and significantly improving the signal-to-noise ratio.

[0105] For example, Figure 8 The schematic diagram of the principle of a downhole fast SVD inversion algorithm provided in the embodiment of the present application. Figure 8 As shown, the observed nuclear magnetic resonance echo signal Y = [y1, y2, y3...y n ] T (n can represent the number of echoes) is the result of the interaction of multiple transverse relaxation components. It is consistent with the T2 spectrum distribution X = [x1, x2, x3...x m ](m can be expressed as the number of T2 spectrum points) The relationship between X and Y can be:

[0106] Y=AX+ε

[0107] Where:

[0108]

[0109] Where ε represents the noise signal.

[0110] The above equation is an ill-conditioned equation. SVD singular value decomposition first decomposes the A matrix A=UΣV T , U is an M×N orthogonal matrix, V is an N×N orthogonal matrix, Σ=diag[σ1,σ2,…,σ k ,0…0] is an N-order diagonal matrix, σ1≥σ2≥…≥σ k is a singular value. The cutoff value σ is obtained from the signal-to-noise ratio SNR out , according to this cutoff value, the matrix Σ is truncated, that is, σ<σ is replaced by 0 out The singular values ​​of the new matrix Σ new , and finally X=VΣ new U T Y is solved for X to obtain the T2 spectrum.

[0111] Since the SVD singular value decomposition and the use of truncation or damping methods to solve the instability problem have high algorithm complexity, long time consumption, high precision requirements, and do not meet the high real-time requirements of the well, in this example, part of the algorithm is placed on the ground for preprocessing: the elements in the matrix A can be obtained by pre-arranging points before drilling, so it can be obtained that M = VΣnew U T It is stored in an external non-volatile memory. When data inversion is performed underground, the M value is read from the memory, and the X=MY operation is performed to obtain the T2 spectrum distribution.

[0112] After processing the echo data, on the one hand, only key formation parameters such as porosity, bound fluid porosity, movable fluid porosity, permeability and instrument motion state parameters such as drilling speed, temperature, pressure, etc. can be transmitted to the ground. On the other hand, the instrument observation mode and drilling trajectory can be automatically adjusted based on the processing results.

[0113] Due to the extremely high requirements for real-time data, in order to improve the resolution of the instrument, the results of this round of data processing determine the parameters of the next round of data acquisition. The traditional T2 inversion method is complicated, time-consuming, and will increase the energy consumption of the instrument, so downhole fast SVD inversion is adopted.

[0114] S503, determining formation attributes according to the inversion result, determining the current observation mode according to the formation attributes, and transmitting the next round of pulse sequence and data acquisition according to the current observation mode.

[0115] For example, if the current formation is determined to be a non-reservoir formation, the non-reservoir observation mode is selected for rough measurement in the next round of data acquisition, that is, T W 15s, N E 500, T E is 0.9, such as Figure 3 As shown, the observation method of group C is the non-reservoir observation method.

[0116] For example, in a non-reservoir observation mode, after data acquisition, the steps shown in S502 are performed to obtain a T2 spectrum, and then the total porosity is calculated based on the T2 spectrum. The total porosity is the integral of the entire time domain T2 spectrum S(T2) over time:

[0117]

[0118] Due to T E =0.9, so clay bound water cannot be measured, so the effective porosity is measured in the non-reservoir observation mode. According to the local formation characteristics, select an appropriate porosity threshold φ V , if φ t <=φ V , then the current reservoir is judged as a non-reservoir; if φ t >φ V The current formation is determined to be a reservoir.

[0119] In the reservoir, according to the purpose before logging, if the purpose of logging is to measure porosity, in the reservoir observation mode, after data acquisition, S502 obtains the T2 spectrum, and then the total porosity is calculated based on this T2 spectrum. Under fine measurement, the total porosity is the superposition of two observation methods:

[0120]

[0121] according to Figure 6 , Group A measures the effective porosity, and Group B measures the clay bound water porosity. t <=φ V The current reservoir is judged as a non-reservoir; if φ t >φ V The current formation is determined to be a reservoir.

[0122] For example, if the current formation is not a reservoir, the next round of observation mode is selected as a non-reservoir observation mode; if the current formation is a reservoir, an observation mode is selected for fine measurement according to the purpose before measurement. After the observation mode is selected, the steps shown in S501-S503 are repeated.

[0123] Based on the contents described in the above embodiments, in order to better understand the embodiments of the present application, refer to Fig. 9 , Fig.10 . Fig. 9 Schematic diagram of the working process of the master digital signal processing (DPS) chip provided in the embodiment of the present application, Fig.10 A schematic diagram of the working process of a field programmable gate array (FPGA) chip provided in an embodiment of the present application.

[0124] Fig. 9As for the DSP chip workflow of the main control circuit, the downhole operation process of the system includes: initialization after the system is powered on, including the DSP chip initializing the internal register phase-locked loop, general-purpose input / output (GPIO), timer 1, timer 2 and other modules, and then setting the initial value of the global parameter. Then check the system. If there is a problem with the self-test result, the measurement is terminated; if the self-test result is normal, the main control circuit waits for the command to be sent. When the CAN controller module receives the data, it determines whether the data is sent to this node according to the identifier of the received message. If not, it is discarded. If so, the instruction is parsed to complete the configuration of the DSP and FPGA parameters. When the logging start instruction arrives, the DSP sends a start command to the FPGA. The DSP waits for the FPGA control instrument other modules to complete the pulse sequence transmission and data acquisition. In the polarization stage, the DSP completes the next step of processing the real and imaginary signals returned by the FPGA: phase-sensitive detection, cross-phase pair, and downhole fast singular value decomposition SVD inversion and stores the T2 spectrum in the NAND FLASH memory. The DSP then determines the formation attributes based on the inversion results and reconfigures the next round of acquisition parameters for the FPGA to perform the next round of logging until the ground system issues a stop command. The ground operation process of the system includes: initialization after the system is powered on, including the DSP chip initializing the internal register phase-locked loop, general GPIO, timer 1, timer 2 and other modules, and then setting the initial values ​​of the global parameters. Then the system is checked. If there is a problem with the self-test result, the measurement is terminated; if the self-test result is normal, the main control circuit waits for the command to be sent. When the RS-485 module receives the command, it decodes the command. When it is a data upload instruction, the DSP controls the NAND FLASH memory through the NAND FLAHS controller to read and verify the data, and uploads the verified data to the host computer through the RS-485 bus.

[0125] Fig.10 As for the workflow of the main control circuit FPGA chip, when working underground, the DSP chip first sends configuration information, and the FPGA generates different timing control signals according to different configuration information, and then controls other parts of the instrument to complete pulse sequence transmission and data acquisition, calibration and frequency sweep. In addition, after the instrument completes the pulse sequence transmission and collects the data to the FPGA chip, the FPGA also performs phase-sensitive detection on the collected echo data, and then transmits the calculated real and imaginary signals back to the DSP. Then the FPGA waits for the DSP to complete data preprocessing and inversion within the polarization time, and returns a new round of measurement parameters for the next round of pulse sequence transmission and echo collection.

[0126] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A nuclear magnetic resonance intelligent adaptive data acquisition and processing device, characterized in that: The device comprises: an adaptive nuclear magnetic resonance data acquisition main control circuit; The main control circuit is used to pre-process and invert the collected echo data to obtain an inversion result; the pre-processing is used to eliminate the interference of noise on the echo data; the inversion is used to obtain the formation T2 spectrum and calculate the formation parameters; The main control circuit is also used to determine the formation attributes according to the inversion result, and to change the observation mode in real time according to the formation attributes, match the value of the corresponding acquisition parameter according to the observation mode, and use the acquisition parameter to transmit a new round of pulse sequence and collect data; wherein the observation mode includes a non-reservoir observation mode or a reservoir observation mode; the non-reservoir observation mode is an observation mode applied to the formation attribute of non-reservoir; the reservoir observation mode is an observation mode applied to the formation attribute of reservoir; The main control circuit includes: a communication module, a data processing module, a data storage module and a timing control module; the data processing module is used for preprocessing and T2 inversion of the original echo data; The communication module includes: a control area network CAN communication module, an RS-485 communication module and a serial peripheral device interface SPI communication module; The CAN communication module is used to communicate with the ground system during the logging process. The ground system sends configuration parameters to the main control circuit for parameter configuration and controls the start and stop of the operation. During the operation, the main control circuit uploads some key formation parameters and the current instrument status to the ground. The RS-485 communication module is used to communicate with the nuclear magnetic logging instrument through the RS-485 module on the ground host computer, on the one hand to complete the frequency sweep and calibration of the instrument, and on the other hand to read out the echo data stored in the storage module during downhole operation; The serial peripheral device interface SPI communication module is used to complete the communication between the microprocessor DSP and the field programmable gate array FPGA in the main control circuit. During the communication, the DSP acts as the host and the FPGA acts as the slave. On the one hand, the DSP sends the next round of measurement parameters to the FPGA through the SPI module, and on the other hand, the FPGA transmits the real and imaginary signals of the collected original echo data obtained by phase-sensitive detection back to the DSP. The data storage module includes a NAND FLASH controller and a NAND FLASH storage chip; the NAND FLASH controller is used to complete the reading, writing, erasing, bad block management, data verification, and power-off recovery of data to the memory; The data storage module is used to store the real and imaginary signals of the collected original echo data after phase-sensitive detection during operation, and to store the inverted T2 spectrum on the other hand; after the operation is completed, the data is uploaded on the ground through specific instructions; The timing control module includes a transmission timing, an isolation timing, a discharge timing and a collection timing; The transmission timing is used to generate a corresponding digital timing signal according to the value of the acquisition parameter, and control the antenna to generate a CPMG pulse sequence through a power amplifier circuit and an antenna drive circuit; The discharge timing is used to provide the energy required for transmitting radio frequency pulses using energy storage capacitors for nuclear magnetic resonance (NMR); The isolation timing is used to keep the isolation circuit in an on state during the RF pulse transmission stage and the discharge stage; and the isolation circuit in a off state during the data acquisition stage; The acquisition timing is used to control the data acquisition circuit to complete data acquisition.

2. The device according to claim 1, characterized in that The formation attributes include reservoir and non-reservoir; the main control circuit is specifically used to determine that the current observation mode is a reservoir observation mode when the formation attribute is a reservoir; When the formation attribute is non-reservoir, the current observation mode is determined to be the non-reservoir observation mode.

3. The device according to claim 2, characterized in that The acquisition parameters include: polarization time T W , echo interval T E 、Number of echoes E And the number of superpositions R N ; The pulse sequence is a 90°-180°-180° C PMG pulse sequence.

4. The device according to any one of claims 1 to 3, characterized in that: The preprocessing includes: phase-sensitive detection, cross-phase pair or phase rotation; the inversion includes downhole fast singular value decomposition SVD inversion algorithm.

5. The device according to any one of claims 1 to 3, characterized in that: The measurement parameters in the non-reservoir observation mode are: a long polarization time measurement, the measurement parameters are, T W1 9s, T E1 0.9ms, N E1 is 100; four short polarization time measurements, the measurement parameters are, T W2 0.2s, T E2 0.6ms, N E2 is 10; The measurement parameters in the reservoir observation mode are: a long polarization time measurement, the measurement parameters are, T W1 9s, T E1 0.9ms, N E1 is 800; four short polarization time measurements, the measurement parameters are, T W2 0.2s, T E2 0.6ms, N E2 is 10; the T W is the polarization time, T E is the echo interval, N E is the number of echoes.

6. A method for intelligent adaptive data acquisition and processing of nuclear magnetic resonance, characterized in that: The device is applied to any one of claims 1 to 5, the device comprising: an adaptive nuclear magnetic resonance data acquisition main control circuit, the main control circuit comprising: a communication module, a data processing module, a data storage module and a timing control module, wherein the communication module comprises: a control area network CAN communication module, an RS-485 communication module and a serial peripheral device interface SPI communication module; the data storage module comprises: a NAND FLASH controller and a NAND FLASH storage chip; the timing control module comprises: a transmission timing, an isolation timing, a discharge timing and an acquisition timing, and the method comprises: Determine an initial observation mode, match the value of a corresponding acquisition parameter for the initial observation mode, and use the value of the acquisition parameter to transmit a pulse sequence and collect data; wherein the initial observation mode includes: a non-reservoir observation mode; During the logging process, the CAN communication module receives the configuration parameters sent by the ground system, performs parameter configuration based on the configuration parameters, controls the start and stop of the operation, and uploads some key formation parameters and the current instrument status to the ground during the operation; The RS-485 communication module completes the frequency sweep and calibration of the instrument, and reads the echo data stored in the storage module during downhole operation; The serial peripheral device interface SPI communication module completes the communication between the microprocessor DSP and the field programmable gate array FPGA in the main control circuit, so that the DSP acts as the host and the FPGA acts as the slave during communication; the DSP sends the next round of measurement parameters to the FPGA through the SPI module, and the FPGA transmits the real and imaginary signals obtained by the phase-sensitive detection of the collected original echo data back to the DSP; During the operation, the data storage module stores the real and imaginary signals of the collected raw echo data after phase-sensitive detection, and stores the inverted T2 spectrum; after the operation is completed, the data is uploaded on the ground through specific instructions; Preprocessing and inverting the collected data to obtain an inversion result; wherein the preprocessing is used to eliminate the interference of noise on the echo data; and the inversion is used to calculate the porosity of the formation; Determine formation attributes according to the inversion result, determine the current observation mode according to the formation attributes, and perform the emission and data acquisition of the next round of pulse sequence according to the current observation mode; wherein the current observation mode includes a non-reservoir observation mode or a reservoir observation mode; the non-reservoir observation mode is an observation mode applied to formation attributes that are non-reservoir; the reservoir observation mode is an observation mode applied to formation attributes that are reservoir; The NAND FLASH controller completes the reading, writing, erasing, bad block management, data verification, and power-off recovery of data to the memory; According to the value of the acquisition parameter, the transmission timing generates a corresponding digital timing signal, which controls the antenna to generate a CPMG pulse sequence through a power amplifier circuit and an antenna drive circuit; The discharge timing is used to provide the energy required for transmitting radio frequency pulses for nuclear magnetic resonance NMR using energy storage capacitors; Through the isolation timing, the isolation circuit is controlled to be in an on state during the radio frequency pulse transmission stage and the discharge stage, and the isolation circuit is controlled to be in an off state during the data acquisition stage; Through the acquisition timing, the data acquisition circuit is controlled to complete data acquisition.

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