CN113899773A

CN113899773A - Denoising method and device for nuclear magnetic resonance signal and storage medium

Info

Publication number: CN113899773A
Application number: CN202010574811.8A
Authority: CN
Inventors: 司兆伟; 田超国; 林发武; 殷秋丽; 耿雪杰; 刘得芳; 庄东志
Original assignee: Petrochina Co Ltd
Current assignee: Petrochina Co Ltd
Priority date: 2020-06-22
Filing date: 2020-06-22
Publication date: 2022-01-07

Abstract

The embodiment of the application discloses a denoising processing method and device for a nuclear magnetic resonance signal and a storage medium, and belongs to the technical field of oil fields. The method comprises the following steps: acquiring a nuclear magnetic resonance signal of a target rock core, wherein the nuclear magnetic resonance signal is obtained after a nuclear magnetic resonance experiment is carried out on the target rock core; performing signal decomposition processing on the nuclear magnetic resonance signal to obtain a plurality of component signals; carrying out signal-noise separation processing on the plurality of component signals by a zero crossing point method to obtain noise signals in the plurality of component signals; and denoising the noise signals in the multiple component signals to realize the denoising of the nuclear magnetic resonance signals. According to the embodiment of the application, the signal-noise separation can be carried out on the multiple component signals separated from the nuclear magnetic resonance signal through the zero crossing point method, the noise signal in the nuclear magnetic resonance signal is obtained, then the nuclear magnetic resonance signal is denoised, and the signal-noise separation accuracy is ensured and the denoising accuracy is improved because the signal-noise separation threshold value is not required to be preset.

Description

Denoising method and device for nuclear magnetic resonance signal and storage medium

Technical Field

The embodiment of the application relates to the technical field of oil fields, in particular to a denoising method and device for a nuclear magnetic resonance signal and a storage medium.

Background

With the development of science and technology, the application field of nuclear magnetic resonance technology is more and more extensive, for example, the nuclear magnetic resonance technology can be applied to the field of oil fields. For example, the saturation of the irreducible water and the saturation of the oil under the dynamic condition of the reservoir can be measured through nuclear magnetic resonance technology, and then the relative permeability of the reservoir can be determined. However, since the nuclear magnetic resonance signals detected by the nuclear magnetic resonance technology usually include noise signals that affect the research on the oilfield parameters, the noise signals in the nuclear magnetic resonance signals are usually required to be denoised.

At present, the nuclear magnetic resonance signal can be denoised by an EMD (empirical mode decomposition) method. When the nuclear magnetic resonance signal is processed by the EMD method, a signal-to-noise separation threshold can be set, and the noise signal in the nuclear magnetic resonance signal is separated by the signal-to-noise separation threshold and then subjected to denoising processing.

However, since the signal-to-noise separation threshold is set in advance, signal-to-noise separation by the signal-to-noise separation threshold may cause inaccuracy of the separated noise signal, resulting in low accuracy of the denoising process.

Disclosure of Invention

The embodiment of the application provides a denoising processing method and device for a nuclear magnetic resonance signal and a storage medium, and can solve the problem of low accuracy of denoising the nuclear magnetic resonance signal in the related technology. The technical scheme is as follows:

in one aspect, a method for denoising a nuclear magnetic resonance signal is provided, where the method includes:

acquiring a nuclear magnetic resonance signal of a target rock core, wherein the nuclear magnetic resonance signal is obtained after a nuclear magnetic resonance experiment is performed on the target rock core;

performing signal decomposition processing on the nuclear magnetic resonance signal to obtain a plurality of component signals;

performing signal-noise separation processing on the multiple component signals by a zero crossing point method to obtain noise signals in the multiple component signals;

and denoising the noise signals in the component signals to realize the denoising of the nuclear magnetic resonance signals.

In some embodiments, the performing signal-to-noise separation processing on the plurality of component signals by using a zero-crossing method to obtain a noise signal in the plurality of component signals includes:

determining the number of zero-crossing points corresponding to each component signal in the plurality of component signals;

determining the component signal with the maximum number change of zero-crossing points in the plurality of component signals as a signal-noise separation signal;

determining a component signal whose decomposition order precedes the signal-to-noise separation signal as a noise signal among the plurality of component signals.

In some embodiments, the determining, as the signal-to-noise separation signal, the component signal in which the number of zero-crossing points varies the greatest includes:

establishing a plane direct coordinate system by taking the decomposition sequence of the component signals as a horizontal coordinate and taking the number of zero-crossing points as a vertical coordinate;

determining a zero crossing point change curve according to the decomposition sequence of the component signals and the zero crossing point of each component signal in the plane rectangular coordinate system;

determining a curve slope corresponding to each component signal in the zero-crossing point number change curve;

dividing the curve slope corresponding to the (i + 1) th component signal in the plurality of component signals by the curve slope corresponding to the ith component signal to obtain a plurality of slope ratios, wherein i is a positive integer greater than or equal to 1;

and determining the i +1 th component signal corresponding to the curve slope with the maximum ratio in the plurality of slope ratios as a signal-to-noise separation signal.

In some embodiments, after the performing signal-to-noise separation processing on the multiple component signals by using a zero-crossing method to obtain noise signals in the multiple component signals, the method further includes:

respectively superposing the noise signals in the component signals with the trend signals in the component signals to obtain a plurality of noise superposed signals;

superposing the reference signals in the component signals with the trend signal respectively to obtain a plurality of reference superposed signals;

and when the curve trends of the noise superposed signals are the same as the curve trend of the trend signal, and the curve trends of the reference superposed signals are not the same as the curve trend of the trend signal, determining that the noise signals pass the noise accuracy verification.

In some embodiments, after the denoising processing of the noise signal in the plurality of component signals, the method further includes:

obtaining a relation graph of displacement pressure change and pump inlet saturation change of the target rock core, wherein the relation graph is obtained after a pump pressing experiment is carried out on the target rock core;

determining a hole roar radius distribution diagram of the target core according to a relation diagram of the displacement pressure change and the intake pump saturation change;

processing the reference signals in the multiple component signals to obtain a nuclear magnetic resonance T2 spectrum of the denoised nuclear magnetic resonance signals;

and when the similarity between the nuclear magnetic resonance T2 spectrum and the croup radius distribution map is larger than or equal to a similarity threshold value, determining that the nuclear magnetic resonance signal is successfully denoised.

In another aspect, an apparatus for denoising a nuclear magnetic resonance signal is provided, the apparatus including:

the device comprises a first acquisition module, a second acquisition module and a third acquisition module, wherein the first acquisition module is used for acquiring a nuclear magnetic resonance signal of a target rock core, and the nuclear magnetic resonance signal is obtained after a nuclear magnetic resonance experiment is performed on the target rock core;

the decomposition module is used for performing signal decomposition processing on the nuclear magnetic resonance signal to obtain a plurality of component signals;

the separation module is used for carrying out signal-noise separation processing on the component signals through a zero crossing point method to obtain noise signals in the component signals;

and the denoising module is used for denoising the noise signals in the multiple component signals so as to realize the denoising of the nuclear magnetic resonance signals.

In some embodiments, the separation module comprises:

the first determining submodule is used for determining the number of zero-crossing points corresponding to each component signal in the plurality of component signals;

a second determining submodule, configured to determine, as a signal-to-noise separation signal, a component signal that has a largest change in the number of zero-crossing points among the plurality of component signals;

a third determining sub-module for determining a component signal whose decomposition order precedes the signal-to-noise separation signal as a noise signal among the plurality of component signals.

In some embodiments, the second determination submodule is to:

In some embodiments, the apparatus further comprises:

the first superposition module is used for superposing the noise signals in the component signals with the trend signals in the component signals respectively to obtain a plurality of noise superposed signals;

the second superposition module is used for superposing the reference signals in the component signals with the trend signal respectively to obtain a plurality of reference superposed signals;

the first determination module is used for determining that the noise signals pass the noise accuracy verification when the curve trends of the noise superposition signals are the same as the curve trend of the trend signal and the curve trends of the reference superposition signals are not the same as the curve trend of the trend signal.

In some embodiments, the apparatus further comprises:

the second acquisition module is used for acquiring a relation graph of displacement pressure change and pump inlet saturation change of the target rock core, wherein the relation graph is obtained after a pump pumping experiment is carried out on the target rock core;

the second determining module is used for determining a croup radius distribution map of the target core according to a relation graph of the displacement pressure change and the intake pump saturation change;

the processing module is used for processing the reference signals in the multiple component signals to obtain a nuclear magnetic resonance T2 spectrum of the denoised nuclear magnetic resonance signals;

and the third determination module is used for determining that the nuclear magnetic resonance signal is successfully denoised when the similarity between the nuclear magnetic resonance T2 spectrum and the croup radius distribution diagram is greater than or equal to a similarity threshold value.

In another aspect, a terminal is provided, where the terminal includes a memory for storing a computer program and a processor for executing the computer program stored in the memory to implement the steps of the method for denoising a nuclear magnetic resonance signal.

In another aspect, a computer-readable storage medium is provided, in which a computer program is stored, and the computer program, when executed by a processor, implements the steps of the method for denoising nuclear magnetic resonance signals.

In another aspect, a computer program product containing instructions is provided, which when run on a computer causes the computer to perform the steps of the method for denoising nuclear magnetic resonance signals described above.

The technical scheme provided by the embodiment of the application can at least bring the following beneficial effects:

in the embodiment of the application, after the nuclear magnetic resonance signal is decomposed into the plurality of component signals, the plurality of component signals can be subjected to signal-noise separation through a zero crossing point method, so that the noise signal in the nuclear magnetic resonance signal is obtained, and the nuclear magnetic resonance signal is denoised.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic illustration of an implementation environment provided by an embodiment of the present application;

fig. 2 is a flowchart of a method for denoising a nuclear magnetic resonance signal according to an embodiment of the present disclosure;

fig. 3 is a flowchart of a method for denoising a nuclear magnetic resonance signal according to an embodiment of the present disclosure;

FIG. 4 is a schematic illustration of nuclear magnetic resonance signals of a target core provided in an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of an EDM decomposition of a nuclear magnetic resonance signal provided by an embodiment of the present application;

fig. 6(a) is a schematic diagram of a change curve of the number of zero crossings provided in the embodiment of the present application;

FIG. 6(b) is a graph of a plurality of slope ratio profiles provided by an embodiment of the present application;

fig. 7 is a schematic diagram of a superimposed signal provided by an embodiment of the present application;

FIG. 8 is a borehole roar radius profile of a target core as provided by an embodiment of the present disclosure;

FIG. 9(a) is a nuclear magnetic resonance attenuation spectrum before denoising according to an embodiment of the present application;

FIG. 9(b) is an inverted spectrum of a pre-denoised NMR T2 provided by an embodiment of the present application;

FIG. 10(a) is a denoised NMR attenuation spectrum according to an embodiment of the present disclosure;

FIG. 10(b) is a denoised NMR T2 inverted spectrum according to an embodiment of the present disclosure;

fig. 11 is a schematic structural diagram of a nuclear magnetic resonance signal denoising processing apparatus according to an embodiment of the present disclosure;

FIG. 12 is a schematic structural diagram of a separation module provided in an embodiment of the present application;

fig. 13 is a schematic structural diagram of another apparatus for denoising nuclear magnetic resonance signals according to an embodiment of the present disclosure;

fig. 14 is a schematic structural diagram of another apparatus for denoising nuclear magnetic resonance signals according to an embodiment of the present disclosure;

fig. 15 is a schematic structural diagram of a terminal according to an embodiment of the present application.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

Before explaining the method for denoising a nuclear magnetic resonance signal provided in the embodiment of the present application in detail, an application scenario and an implementation environment provided in the embodiment of the present application are introduced.

First, an application scenario related to the embodiment of the present application is described.

With the maturity of the nmr technology, the nmr technology has been applied more and more widely in the field of oil fields, for example, the nmr technology can be used to measure the saturation of the bound water and the saturation of the oil under the dynamic condition of the reservoir, and further determine the relative permeability of the reservoir. In order to obtain accurate oil field parameters, after a nuclear magnetic resonance signal is obtained, the nuclear magnetic resonance signal needs to be denoised by an EMD method. However, when processing the nuclear magnetic resonance signal by the EMD method, the noise signal in the nuclear magnetic resonance signal is separated by a signal-to-noise separation threshold set in advance, and then the noise is removed. Since the signal-noise separation threshold is set in advance, signal-noise separation is performed by the signal-noise separation threshold, which may cause inaccuracy of the separated noise signal and low accuracy of the denoising process.

Based on the application scene, the embodiment of the application provides a denoising processing method of a nuclear magnetic resonance signal, which can improve the denoising accuracy.

Next, an implementation environment related to the embodiments of the present application will be described.

Referring to FIG. 1, FIG. 1 is a schematic diagram illustrating an implementation environment in accordance with an example embodiment. The implementation environment includes at least one terminal 101 and a signal acquisition device 102, and the terminal 101 can be in communication connection with the signal acquisition device 102. The communication connection may be a wired connection or a wireless connection, which is not limited in this embodiment of the present application.

The terminal 101 may be any electronic product capable of performing human-Computer interaction with a user through one or more modes such as a keyboard, a touch pad, a touch screen, a remote controller, voice interaction, or handwriting equipment, for example, a PC (Personal Computer), a mobile phone, a smart phone, a PDA (Personal Digital Assistant), a wearable device, a pocket PC (pocket PC), a tablet Computer, a smart car, a smart television, a smart sound box, and the like.

The information acquisition device 102 may be capable of being used to acquire nuclear magnetic resonance signals.

Those skilled in the art should understand that the terminal 101 and the information collecting device 102 are only examples, and other existing or future terminals or devices may be applicable to the embodiments of the present application, and are included in the scope of the embodiments of the present application and are included herein by reference.

The method for denoising nuclear magnetic resonance signals provided by the embodiments of the present application will be explained in detail with reference to the drawings.

Fig. 2 is a flowchart of a method for denoising a nuclear magnetic resonance signal according to an embodiment of the present application, where the method is applied to a terminal. Referring to fig. 2, the method includes the following steps.

Step 201: and acquiring a nuclear magnetic resonance signal of the target rock core, wherein the nuclear magnetic resonance signal is obtained after a nuclear magnetic resonance experiment is carried out on the target rock core.

Step 202: the nuclear magnetic resonance signal is subjected to signal decomposition processing to obtain a plurality of component signals.

Step 203: and performing signal-noise separation processing on the plurality of component signals by a zero crossing point method to obtain noise signals in the plurality of component signals.

Step 204: and denoising the noise signals in the multiple component signals to realize the denoising of the nuclear magnetic resonance signals.

In some embodiments, the signal-to-noise separating the plurality of component signals by a zero-crossing method to obtain a noise signal in the plurality of component signals includes:

determining the component signal with the maximum change of the number of zero-crossing points in the plurality of component signals as a signal-noise separation signal;

the component signal whose decomposition order precedes the signal-to-noise separation signal is determined as a noise signal among the plurality of component signals.

In some embodiments, determining the component signal of which the number of zero-crossing points changes most among the plurality of component signals as the signal-to-noise separation signal includes:

in the plane rectangular coordinate system, determining a zero crossing point change curve according to the decomposition sequence of the plurality of component signals and the zero crossing point of each component signal;

determining the curve slope corresponding to each component signal in the zero crossing point number change curve;

and determining the i +1 th component signal corresponding to the curve slope with the maximum ratio in the plurality of slope ratios as the signal-to-noise separation signal.

In some embodiments, after performing signal-to-noise separation processing on the plurality of component signals by a zero-crossing method to obtain a noise signal in the plurality of component signals, the method further includes:

respectively superposing the reference signals in the component signals with the trend signal to obtain a plurality of reference superposed signals;

and when the curve trends of the multiple noise superposed signals are the same as the curve trend of the trend signal, and the curve trends of the multiple reference superposed signals are not the same as the curve trend of the trend signal, determining that the noise signals pass the noise accuracy verification.

In some embodiments, after denoising the noise signal in the plurality of component signals, the method further includes:

and when the similarity of the nuclear magnetic resonance T2 spectrum and the croup radius distribution diagram is greater than or equal to a similarity threshold value, determining that the nuclear magnetic resonance signal is successfully denoised.

All the above optional technical solutions can be combined arbitrarily to form optional embodiments of the present application, and details of the embodiments of the present application are not repeated.

Fig. 3 is a flowchart of a method for denoising a nuclear magnetic resonance signal according to an embodiment of the present disclosure, and with reference to fig. 3, the method includes the following steps.

Step 301: the terminal obtains a nuclear magnetic resonance signal of the target rock core, wherein the nuclear magnetic resonance signal is obtained after a nuclear magnetic resonance experiment is carried out on the target rock core.

In order to obtain the relevant parameters of the target core, a nuclear magnetic resonance experiment can be usually performed on the target core, and at this time, the terminal can obtain a nuclear magnetic resonance signal of the target core by performing the nuclear magnetic resonance experiment on the target core.

As an example, the terminal can directly perform a nuclear magnetic resonance experiment on the target core, and perform signal acquisition to obtain a nuclear magnetic resonance signal. The nuclear magnetic resonance experiment can be performed on the target rock core by the signal acquisition equipment, the nuclear magnetic resonance signal is acquired by signal acquisition, and the nuclear magnetic resonance signal is sent to the terminal after the nuclear magnetic resonance signal is acquired. That is, the terminal can acquire the nuclear magnetic resonance signal through signal acquisition, and can also receive the nuclear magnetic resonance signal that signal acquisition equipment sent.

For example, the terminal can perform a nuclear magnetic resonance experiment on a core of a well in a certain oil field to obtain a schematic diagram of a nuclear magnetic resonance signal as shown in fig. 4, where the experiment conditions include a temperature of 25 degrees celsius, an echo time of 0.2 milliseconds, a waiting time of 6 seconds, 2000 echoes, and a superposition number of 32.

Step 302: and the terminal carries out signal decomposition processing on the nuclear magnetic resonance signal to obtain a plurality of component signals.

Since the nuclear magnetic resonance signal includes many unwanted signals, for example, many noise signals, it is generally necessary to decompose the nuclear magnetic resonance signal in order to separate the noise signal from the nuclear magnetic resonance signal.

As an example, the terminal can perform signal decomposition processing on the nuclear magnetic resonance signal by an EMD method. Of course, the signal decomposition processing may be performed on the nuclear magnetic resonance signal in other manners.

In some embodiments, when the terminal decomposes the nuclear magnetic resonance signal in an EMD manner, the terminal can determine the nuclear magnetic resonance signal as an input signal, and determine all maximum value points and minimum value points of the input signal; determining an upper envelope line formed by all maximum value points and a lower envelope line formed by all minimum value points in the nuclear magnetic resonance signal in a cubic spline interpolation fitting mode; determining a mean signal between an upper envelope line and a lower envelope line; subtracting the mean signal from the nuclear magnetic resonance signal to obtain a first reference signal; when the first reference signal does not meet the condition of the intrinsic mode function, the first reference signal is used as an input signal, and the operation of determining all maximum value points and minimum value points of the input signal is returned until the first reference signal meets the condition of the intrinsic mode function, and the first reference signal is determined as a component signal; when the first reference signal is a component signal, subtracting the first reference signal from the input signal to obtain a second reference signal; determining whether the second reference signal is a monotone signal or whether the number of extreme points of the second reference signal is 1; when the second reference signal is a monotone signal or the number of extreme points of the second reference signal is 1, determining that the decomposition is finished; and when the second reference signal is not the monotone signal and the number of the extreme points of the second reference signal is not 1, determining the second reference signal as an input function, and returning to the operation of determining all the maximum points and the minimum points of the input signal until the second reference signal is the monotone signal or the number of the extreme points of the second reference signal is 1.

Note that the eigenmode function condition can be set in advance, for example, the eigenmode function condition includes that in the signal length, the number of extreme points is the same as the number of zero-crossing points or differs by 1 at most, and the average value of the upper and lower envelope lines is equal to 0.

For example, the terminal performs signal decomposition processing on the nuclear magnetic resonance signal shown in fig. 4 by the EMD method to obtain a schematic diagram of 10 component signals shown in fig. 5, and the 10 component signals in fig. 5 are sequentially arranged according to the decomposition order. The first 9 of the 10 component signals are IMF (Intrinsic Mode Function) signals, and the last is a trend signal.

Step 303: and the terminal performs signal-noise separation processing on the multiple component signals by a zero crossing point method to obtain noise signals in the multiple component signals.

The signal can be decomposed into a plurality of component signals through the above step 302, but it is not clear which component signals are noise signals in the plurality of component signals, and therefore, the terminal needs to perform signal-noise separation processing on the plurality of component signals through a zero-crossing point method to obtain the noise signals in the plurality of component signals.

As an example, the operation of the terminal performing signal-to-noise separation processing on the multiple component signals by using a zero-crossing method to obtain a noise signal in the multiple component signals at least includes: determining the number of zero-crossing points corresponding to each component signal in a plurality of component signals; determining the component signal with the maximum change of the number of zero-crossing points in the plurality of component signals as a signal-noise separation signal; the component signal whose decomposition order precedes the signal-noise separation signal is determined as a noise signal among the plurality of component signals.

As an example, the operation of the terminal determining the component signal, of which the number of zero-crossing points changes the most, among the plurality of component signals as the signal-to-noise separation signal at least includes: establishing a plane direct coordinate system by taking the decomposition sequence of the component signals as a horizontal coordinate and the number of zero-crossing points as a vertical coordinate; in a plane rectangular coordinate system, determining a zero crossing point change curve according to the decomposition sequence of a plurality of component signals and the zero crossing point of each component signal; determining the curve slope corresponding to each component signal in the zero crossing point number change curve; dividing the curve slope corresponding to the (i + 1) th component signal in the multiple component signals by the curve slope corresponding to the ith component signal to obtain multiple slope ratios, wherein i is a positive integer greater than or equal to 1; and determining the i +1 th component signal corresponding to the curve slope with the maximum ratio in the plurality of slope ratios as the signal-to-noise separation signal.

For example, the terminal can determine the schematic diagram of the change curve of the number of zero-crossing points as shown in fig. 6(a) in the rectangular plane coordinate system through the decomposition order of the 10 component signals and the number of zero-crossing points of each component signal as shown in fig. 5; then, the curve slope corresponding to each component signal in the zero-crossing point number change curve is determined, and the curve slope corresponding to the (i + 1) th component signal in the plurality of component signals is divided by the curve slope corresponding to the ith component signal, so as to obtain a plurality of slope ratio distribution graphs as shown in fig. 6 (b). Since the IMF corresponding to the largest slope ratio among the plurality of slope ratios is IMF6, the terminal can determine the 6 th component signal as a signal-to-noise separated signal and the 1 st to 5 th separated signals as noise signals.

In some embodiments, after the terminal performs signal-to-noise separation processing on the multiple component signals by using a zero-crossing point method to obtain noise signals in the multiple component signals, it is also possible to verify whether the obtained signals are noise signals, that is, the terminal is able to verify the accuracy of the obtained noise signals.

In some embodiments, the operation of the terminal to verify the accuracy of the resulting noise signal comprises at least: respectively superposing the noise signals in the component signals and the trend signals in the component signals to obtain a plurality of noise superposed signals; respectively superposing the reference signals in the multiple component signals with the trend signal to obtain multiple reference superposed signals; and when the curve trends of the plurality of noise superimposed signals are the same as the curve trend of the trend signal and the curve trends of the plurality of reference superimposed signals are not the same as the curve trend of the trend signal, determining that the noise signals pass the noise accuracy verification.

For example, the terminal can superimpose the first 9 component signals IMF and the last trend signal RES in the 10 component signals shown in fig. 5 to obtain schematic diagrams of 9 superimposed signals shown in fig. 7, and it can be known from fig. 7 that the curve trend of the first 5 component signals is the same as that of the trend signal, and the curve trend of the 6 th to 9 th component signals is different from that of the trend signal, so that it can be determined that the first 5 component signals are noise signals, and the 6 th to 9 th component signals are useful signals, that is, the 6 th to 9 th component signals are reference signals. Thus, the terminal can determine that the noise signal passes the noise accuracy verification.

In some embodiments, when there is a curve trend in the curve trends of the plurality of noise superimposed signals that is different from the curve trend of the trend signal, or there is a curve trend in the curve trends of the plurality of reference superimposed signals that is the same as the curve trend of the trend signal, it is determined that the noise signal has not passed the noise accuracy verification.

Step 304: and the terminal carries out denoising processing on the noise signals in the component signals so as to realize denoising of the nuclear magnetic resonance signals.

As an example, the terminal can superimpose other component signals except the noise signal in the multiple component signals to obtain a denoised nuclear magnetic resonance signal, so as to implement denoising of the nuclear magnetic resonance signal.

In some embodiments, after the terminal performs denoising processing on the noise signals in the multiple component signals, it can also determine whether denoising of the nuclear magnetic resonance signals is successful.

As an example, the operation of the terminal determining whether denoising of the nuclear magnetic resonance signal is successful at least includes: obtaining a relation graph of displacement pressure change and pump inlet saturation change of the target rock core, wherein the relation graph is obtained after a pump pressing experiment is carried out on the target rock core; determining a hole roar radius distribution diagram of a target core according to a relation graph of displacement pressure change and intake pump saturation change; processing the reference signals in the multiple component signals to obtain a nuclear magnetic resonance T2 spectrum of the denoised nuclear magnetic resonance signals; and when the similarity between the nuclear magnetic resonance T2 spectrum and the croup radius distribution map is greater than or equal to the similarity threshold value, determining that the nuclear magnetic resonance signal is successfully denoised.

Since the mercury-in saturation degree will gradually increase until the mercury-in saturation degree is stabilized along with the increase of the displacement pressure. Because different displacement pressures represent different pore throat radii and the mercury inlet saturation change value corresponding to each displacement pressure represents the relative frequency of the pore throat radius, the test equipment can determine the pore throat radius distribution map of the target core according to the relation graph of displacement pressure change and pump inlet saturation change, for example, obtain the pore throat radius distribution map shown in fig. 8; in the nuclear magnetic resonance T2 spectrum, the T2 value is positively correlated with the pore throat radius, so that the test equipment can further verify whether the denoising of the nuclear magnetic resonance signal is successful by comparing whether the pore throat radius distribution of the rock core is similar to the T2 spectrum form after the nuclear magnetic resonance denoising.

It should be noted that the similarity threshold can be set in advance, for example, the similarity threshold can be 95%, 90%, and so on.

In some embodiments, after denoising the noise signals in the multiple component signals, the terminal can further determine the denoising effect on the nuclear magnetic resonance signals.

As an example, the terminal can reconstruct a nuclear magnetic resonance attenuation spectrum before denoising and a nuclear magnetic resonance attenuation spectrum after denoising, invert the nuclear magnetic resonance attenuation spectrum before denoising by using an SIRT (transient iterative reconstruction technique) method to obtain a nuclear magnetic resonance T2 inversion spectrum before denoising, and invert the nuclear magnetic resonance attenuation spectrum after denoising by using the SIRT method to obtain a nuclear magnetic resonance T2 inversion spectrum after denoising; by comparing the denoised nuclear magnetic resonance T2 inverted spectrum with the nuclear magnetic resonance T2 inverted spectrum before denoising, the denoising effect of the nuclear magnetic resonance signal can be determined.

For example, the terminal can change the number of times of superposition to obtain the nmr attenuation spectra before denoising as shown in fig. 9(a) with different numbers of times of superposition, and as the number of times of superposition increases, the signal amplitude increases, and the curve form more conforms to the nmr T2 spectrum (transverse relaxation) theoretical curve form. The SIRT method is used to invert the signals in fig. 9(a), and nuclear magnetic resonance T2 inverted spectra with different stacking times before denoising are obtained as shown in fig. 9 (b). In the case where the number of times of stacking does not exceed 128, the nuclear magnetic resonance T2 inverted spectrum shown in fig. 9(b) shows a bimodal distribution, and when the number of times of stacking reaches 256, the nuclear magnetic resonance T2 inverted spectrum shown in fig. 9(b) shows a monomodal distribution. The phenomenon of tailing of the nuclear magnetic resonance T2 inverted spectra of different stacking times is serious. The nuclear magnetic resonance attenuation spectrum of the graph 9(a) is denoised by the terminal, the nuclear magnetic resonance attenuation spectra with different superposition times after denoising shown in the graph 10(a) are obtained, peaks and burrs of signals are well suppressed, the signals in the graph 10(a) are inverted by the SIRT method, the nuclear magnetic resonance T2 inverted spectra with different superposition times after denoising shown in the graph 10(b) are obtained, the nuclear magnetic resonance T2 inverted spectra after denoising are distributed in a single peak mode, and the tailing phenomenon is effectively inhibited.

Step 305: and the terminal displays the denoised nuclear magnetic resonance signal.

In order to enable workers to know the denoised nuclear magnetic resonance signals, the terminal can display the nuclear magnetic resonance signals.

In some embodiments, the terminal can not only display the denoised nmr signal, but the terminal can also determine the relevant parameters of the target core according to the denoised nmr signal.

In the embodiment of the application, after the terminal decomposes the nuclear magnetic resonance signal of the target rock core into a plurality of component signals, the plurality of component signals can be subjected to signal-to-noise separation through a zero crossing point method, so that the noise signal in the nuclear magnetic resonance signal is obtained, whether the separated noise signal is accurate or not can be verified, and the nuclear magnetic resonance signal is denoised when the determined noise signal is accurate. Because a signal-noise separation threshold does not need to be preset, and the accuracy of the noise signal is further verified, the signal-noise separation accuracy and the self-adaptability are ensured, and the accuracy of the denoising processing is improved.

After explaining the method for denoising a nuclear magnetic resonance signal provided in the embodiment of the present application, a device for denoising a nuclear magnetic resonance signal provided in the embodiment of the present application is introduced next.

Fig. 11 is a schematic structural diagram of a nuclear magnetic resonance signal denoising processing apparatus provided in an embodiment of the present application, which may be implemented by software, hardware, or a combination of the two to be part or all of a terminal. Referring to fig. 11, the apparatus includes: a first acquisition module 1101, a decomposition module 1102, a separation module 1103, and a denoising module 1104.

The first obtaining module 1101 is configured to obtain a nuclear magnetic resonance signal of a target core, where the nuclear magnetic resonance signal is obtained after a nuclear magnetic resonance experiment is performed on the target core;

a decomposition module 1102, configured to perform signal decomposition processing on the nuclear magnetic resonance signal to obtain a plurality of component signals;

a separation module 1103, configured to perform signal-to-noise separation processing on the multiple component signals by using a zero-crossing point method, so as to obtain noise signals in the multiple component signals;

a denoising module 1104, configured to perform denoising processing on a noise signal in the multiple component signals, so as to achieve denoising of the nuclear magnetic resonance signal.

In some embodiments, referring to fig. 12, the separation module 1103 includes:

a first determining submodule 11031, configured to determine the number of zero-crossing points corresponding to each of the plurality of component signals;

a second determining sub-module 11032, configured to determine, as a signal-to-noise separation signal, a component signal in which the number of zero-crossing points in the plurality of component signals changes the largest;

a third determining sub-module 11033 for determining a component signal whose decomposition order precedes the signal-noise separation signal as a noise signal among the plurality of component signals.

In some embodiments, the second determination submodule 11032 is configured to:

In some embodiments, referring to fig. 13, the apparatus further comprises:

a first superimposing module 1105, configured to superimpose the noise signals in the multiple component signals with the trend signals in the multiple component signals, respectively, so as to obtain multiple noise superimposed signals;

a second superposition module 1106, configured to superpose the reference signals in the multiple component signals with the trend signal, respectively, to obtain multiple reference superposed signals;

a first determining module 1107, configured to determine that the noise signal passes the noise accuracy verification when the curve trend of the noise superimposed signals is the same as the curve trend of the trend signal, and the curve trend of the reference superimposed signals is not the same as the curve trend of the trend signal.

In some embodiments, referring to fig. 14, the apparatus further comprises:

a second obtaining module 1108, configured to obtain a relational graph between the displacement pressure change and the pump inlet saturation change of the target core, where the relational graph is obtained after a pump pumping experiment is performed on the target core;

a second determining module 1109, configured to determine a croup radius distribution diagram of the target core according to a relation diagram between the displacement pressure change and the intake pump saturation change;

the processing module 1110 is configured to process a reference signal in the multiple component signals to obtain a nuclear magnetic resonance T2 spectrum of the denoised nuclear magnetic resonance signal;

a third determining module 1111, configured to determine that denoising the nuclear magnetic resonance signal is successful when a similarity between the nuclear magnetic resonance T2 spectrum and the croup radius distribution map is greater than or equal to a similarity threshold.

It should be noted that: in the embodiment, when the apparatus for denoising a nuclear magnetic resonance signal performs denoising on the nuclear magnetic resonance signal, only the division of the functional modules is illustrated, and in practical application, the functions may be distributed by different functional modules according to needs, that is, the internal structure of the apparatus is divided into different functional modules, so as to complete all or part of the functions described above. In addition, the embodiment of the apparatus for denoising a nuclear magnetic resonance signal and the embodiment of the method for denoising a nuclear magnetic resonance signal provided in the above embodiments belong to the same concept, and specific implementation processes thereof are described in the method embodiments in detail and are not described herein again.

Fig. 15 is a block diagram of a terminal 1500 according to an embodiment of the present disclosure. The terminal 1500 may be a portable mobile terminal such as: a smartphone, a tablet, a laptop, or a desktop computer. Terminal 1500 may also be referred to as user equipment, a portable terminal, a laptop terminal, a desktop terminal, or other names.

In general, terminal 1500 includes: a processor 1501 and memory 1502.

Processor 1501 may include one or more processing cores, such as a 4-core processor, an 8-core processor, or the like. The processor 1501 may be implemented in at least one hardware form of a DSP (Digital Signal Processing), an FPGA (Field-Programmable Gate Array), and a PLA (Programmable Logic Array). Processor 1501 may also include a main processor and a coprocessor, where the main processor is a processor for Processing data in an awake state, and is also referred to as a Central Processing Unit (CPU); a coprocessor is a low power processor for processing data in a standby state. In some embodiments, the processor 1501 may be integrated with a GPU (Graphics Processing Unit), which is responsible for rendering and drawing the content required to be displayed on the display screen. In some embodiments, processor 1501 may also include an AI (Artificial Intelligence) processor for processing computational operations related to machine learning.

The memory 1502 may include one or more computer-readable storage media, which may be non-transitory. The memory 1502 may also include high-speed random access memory, as well as non-volatile memory, such as one or more magnetic disk storage devices, flash memory storage devices. In some embodiments, a non-transitory computer readable storage medium in the memory 1502 is configured to store at least one instruction for execution by the processor 1501 to implement the method for denoising nuclear magnetic resonance signals provided by the method embodiments of the present application.

In some embodiments, the terminal 1500 may further include: a peripheral interface 1503 and at least one peripheral. The processor 1501, memory 1502, and peripheral interface 1503 may be connected by buses or signal lines. Various peripheral devices may be connected to peripheral interface 1503 via buses, signal lines, or circuit boards. Specifically, the peripheral device includes: at least one of a radio frequency circuit 1504, a display 1505, a camera assembly 1506, an audio circuit 1507, a positioning assembly 1508, and a power supply 1509.

The peripheral interface 1503 may be used to connect at least one peripheral related to I/O (Input/Output) to the processor 1501 and the memory 1502. In some embodiments, the processor 1501, memory 1502, and peripheral interface 1503 are integrated on the same chip or circuit board; in some other embodiments, any one or two of the processor 1501, the memory 1502, and the peripheral interface 1503 may be implemented on separate chips or circuit boards, which is not limited in this embodiment.

The Radio Frequency circuit 1504 is used to receive and transmit RF (Radio Frequency) signals, also known as electromagnetic signals. The radio frequency circuitry 1504 communicates with communication networks and other communication devices via electromagnetic signals. The radio frequency circuit 1504 converts an electrical signal into an electromagnetic signal to transmit, or converts a received electromagnetic signal into an electrical signal. Optionally, the radio frequency circuit 1504 includes: an antenna system, an RF transceiver, one or more amplifiers, a tuner, an oscillator, a digital signal processor, a codec chipset, a subscriber identity module card, and so forth. The radio frequency circuit 1504 can communicate with other terminals via at least one wireless communication protocol. The wireless communication protocols include, but are not limited to: the world wide web, metropolitan area networks, intranets, generations of mobile communication networks (2G, 3G, 4G, and 5G), Wireless local area networks, and/or WiFi (Wireless Fidelity) networks. In some embodiments, the radio frequency circuit 1504 may further include NFC (Near Field Communication) related circuits, which are not limited in this application.

The display screen 1505 is used to display a UI (User Interface). The UI may include graphics, text, icons, video, and any combination thereof. When the display screen 1505 is a touch display screen, the display screen 1505 also has the ability to capture touch signals on or over the surface of the display screen 1505. The touch signal may be input to the processor 1501 as a control signal for processing. In this case, the display screen 1505 may also be used to provide virtual buttons and/or a virtual keyboard, also referred to as soft buttons and/or a soft keyboard. In some embodiments, display 1505 may be one, providing the front panel of terminal 1500; in other embodiments, display 1505 may be at least two, each disposed on a different surface of terminal 1500 or in a folded design; in still other embodiments, display 1505 may be a flexible display disposed on a curved surface or a folded surface of terminal 1500. Even further, the display 1505 may be configured in a non-rectangular irregular pattern, i.e., a shaped screen. The Display 1505 can be made of LCD (Liquid Crystal Display), OLED (Organic Light-Emitting Diode), and other materials.

The camera assembly 1506 is used to capture images or video. Optionally, the camera assembly 1506 includes a front camera and a rear camera. Generally, a front camera is disposed at a front panel of the terminal, and a rear camera is disposed at a rear surface of the terminal. In some embodiments, the number of the rear cameras is at least two, and each rear camera is any one of a main camera, a depth-of-field camera, a wide-angle camera and a telephoto camera, so that the main camera and the depth-of-field camera are fused to realize a background blurring function, and the main camera and the wide-angle camera are fused to realize panoramic shooting and VR (Virtual Reality) shooting functions or other fusion shooting functions. In some embodiments, camera assembly 1506 may also include a flash. The flash lamp can be a monochrome temperature flash lamp or a bicolor temperature flash lamp. The double-color-temperature flash lamp is a combination of a warm-light flash lamp and a cold-light flash lamp, and can be used for light compensation at different color temperatures.

The audio circuitry 1507 may include a microphone and speaker. The microphone is used for collecting sound waves of a user and the environment, converting the sound waves into electric signals, and inputting the electric signals to the processor 1501 for processing or inputting the electric signals to the radio frequency circuit 1504 to realize voice communication. For stereo capture or noise reduction purposes, multiple microphones may be provided, each at a different location of the terminal 1500. The microphone may also be an array microphone or an omni-directional pick-up microphone. The speaker is used to convert electrical signals from the processor 1501 or the radio frequency circuit 1504 into sound waves. The loudspeaker can be a traditional film loudspeaker or a piezoelectric ceramic loudspeaker. When the speaker is a piezoelectric ceramic speaker, the speaker can be used for purposes such as converting an electric signal into a sound wave audible to a human being, or converting an electric signal into a sound wave inaudible to a human being to measure a distance. In some embodiments, the audio circuitry 1507 may also include a headphone jack.

The positioning component 1508 is used to locate the current geographic position of the terminal 1500 for navigation or LBS (Location Based Service). The Positioning component 1508 may be a Positioning component based on the united states GPS (Global Positioning System), the chinese beidou System, or the russian galileo System.

Power supply 1509 is used to power the various components in terminal 1500. The power supply 1509 may be alternating current, direct current, disposable or rechargeable. When the power supply 1509 includes a rechargeable battery, the rechargeable battery may be a wired rechargeable battery or a wireless rechargeable battery. The wired rechargeable battery is a battery charged through a wired line, and the wireless rechargeable battery is a battery charged through a wireless coil. The rechargeable battery may also be used to support fast charge technology.

In some embodiments, the terminal 1500 also includes one or more sensors 1510. The one or more sensors 1510 include, but are not limited to: acceleration sensor 1511, gyro sensor 1512, pressure sensor 1513, fingerprint sensor 1514, optical sensor 1515, and proximity sensor 1516.

The acceleration sensor 1511 may detect the magnitude of acceleration on three coordinate axes of the coordinate system established with the terminal 1500. For example, the acceleration sensor 1511 may be used to detect components of the gravitational acceleration in three coordinate axes. The processor 1501 may control the touch screen display 1505 to display the user interface in a landscape view or a portrait view according to the gravitational acceleration signal collected by the acceleration sensor 1511. The acceleration sensor 1511 may also be used for acquisition of motion data of a game or a user.

The gyroscope sensor 1512 can detect the body direction and the rotation angle of the terminal 1500, and the gyroscope sensor 1512 and the acceleration sensor 1511 cooperate to collect the 3D motion of the user on the terminal 1500. The processor 1501 may implement the following functions according to the data collected by the gyro sensor 1512: motion sensing (such as changing the UI according to a user's tilting operation), image stabilization at the time of photographing, game control, and inertial navigation.

Pressure sensor 1513 may be disposed on a side bezel of terminal 1500 and/or underneath touch display 1505. When the pressure sensor 1513 is disposed on the side frame of the terminal 1500, the holding signal of the user to the terminal 1500 may be detected, and the processor 1501 performs left-right hand recognition or shortcut operation according to the holding signal collected by the pressure sensor 1513. When the pressure sensor 1513 is disposed at a lower layer of the touch display 1505, the processor 1501 controls the operability control on the UI interface according to the pressure operation of the user on the touch display 1505. The operability control comprises at least one of a button control, a scroll bar control, an icon control and a menu control.

The fingerprint sensor 1514 is configured to capture a fingerprint of the user, and the processor 1501 identifies the user based on the fingerprint captured by the fingerprint sensor 1514, or the fingerprint sensor 1514 identifies the user based on the captured fingerprint. Upon recognizing that the user's identity is a trusted identity, the processor 1501 authorizes the user to perform relevant sensitive operations including unlocking the screen, viewing encrypted information, downloading software, paying, and changing settings, etc. The fingerprint sensor 1514 may be disposed on the front, back, or side of the terminal 1500. When a physical key or vendor Logo is provided on the terminal 1500, the fingerprint sensor 1514 may be integrated with the physical key or vendor Logo.

The optical sensor 1515 is used to collect ambient light intensity. In one embodiment, processor 1501 may control the brightness of the display on touch screen 1505 based on the intensity of ambient light collected by optical sensor 1515. Specifically, when the ambient light intensity is high, the display brightness of the touch display screen 1505 is increased; when the ambient light intensity is low, the display brightness of the touch display screen 1505 is turned down. In another embodiment, the processor 1501 may also dynamically adjust the shooting parameters of the camera assembly 1506 based on the ambient light intensity collected by the optical sensor 1515.

A proximity sensor 1516, also known as a distance sensor, is typically provided on the front panel of the terminal 1500. The proximity sensor 1516 is used to collect the distance between the user and the front surface of the terminal 1500. In one embodiment, when the proximity sensor 1516 detects that the distance between the user and the front surface of the terminal 1500 gradually decreases, the processor 1501 controls the touch display 1505 to switch from the bright screen state to the dark screen state; when the proximity sensor 1516 detects that the distance between the user and the front surface of the terminal 1500 gradually becomes larger, the processor 1501 controls the touch display 1505 to switch from the breath screen state to the bright screen state.

Those skilled in the art will appreciate that the configuration shown in fig. 15 does not constitute a limitation of terminal 1500, and may include more or fewer components than shown, or some components may be combined, or a different arrangement of components may be employed.

In some embodiments, a computer-readable storage medium is provided, in which a computer program is stored, and the computer program, when executed by a processor, implements the steps of the method for denoising nuclear magnetic resonance signals in the above embodiments. For example, the computer-readable storage medium may be a ROM (Read-Only Memory), a RAM (Random Access Memory), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and the like.

It is noted that the computer-readable storage medium referred to in the embodiments of the present application may be a non-volatile storage medium, in other words, a non-transitory storage medium.

It should be understood that all or part of the steps for implementing the above embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented in software, may 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. The computer instructions may be stored in the computer-readable storage medium described above.

That is, in some embodiments, there is also provided a computer program product containing instructions which, when run on a computer, cause the computer to perform the steps of the method for denoising nuclear magnetic resonance signals described above.

The above-mentioned embodiments are provided by way of example and not intended to limit the embodiments, and any modifications, equivalents, improvements, etc. made within the spirit and principle of the embodiments should be included in the scope of the embodiments.

Claims

1. A denoising processing method of a nuclear magnetic resonance signal is characterized by comprising the following steps:

2. The method according to claim 1, wherein the performing signal-to-noise separation processing on the plurality of component signals by a zero-crossing method to obtain a noise signal in the plurality of component signals comprises:

3. The method of claim 2, wherein the determining a component signal, of the plurality of component signals, in which the number of zero-crossings varies most, as a signal-to-noise separation signal comprises:

4. The method according to claim 1, wherein after the signal-to-noise separation processing is performed on the plurality of component signals by a zero-crossing method to obtain a noise signal in the plurality of component signals, the method further comprises:

5. The method of claim 1, wherein denoising the noise signal of the plurality of component signals, further comprising:

6. An apparatus for denoising a nuclear magnetic resonance signal, the apparatus comprising:

7. The apparatus of claim 6, wherein the separation module comprises:

8. The apparatus of claim 7, wherein the second determination submodule is to:

9. The apparatus of claim 6, wherein the apparatus further comprises:

10. The apparatus of claim 6, wherein the apparatus further comprises:

11. A computer-readable storage medium, characterized in that the storage medium has stored therein a computer program which, when being executed by a processor, carries out the steps of the method according to any one of claims 1 to 5.