Cementing quality inspection method and device based on ultrasonic Lamb wave

Abstract

This invention discloses a method and apparatus for cementing quality inspection based on ultrasonic Lamb waves. The method includes: acquiring a first ultrasonic Lamb wave signal received by a first receiver and a second ultrasonic Lamb wave signal received by a second receiver; calculating the first wave energy of a zero-order symmetric Lamb wave within a first time window of the first ultrasonic Lamb wave signal, and calculating the second wave energy of a zero-order symmetric Lamb wave within a second time window of the second ultrasonic Lamb wave signal; calculating the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, a first distance, and a second distance; comparing the attenuation rate with a pre-generated attenuation rate threshold, and determining the external medium properties based on the comparison result. This approach improves the accuracy of cementing quality inspection; and it allows for independent cementing quality evaluation without the need for combined acoustic impedance information, simplifying the cementing quality inspection process and improving its efficiency.

Description

Technical Field

[0001] This invention relates to the field of exploration technology, specifically to a cementing quality testing method, apparatus, computing device, and computer storage medium based on ultrasonic Lamb waves. Background Technology

[0002] Cementing is the process of effectively sealing oil, gas, and water layers, as well as complex formations, to facilitate further drilling, production, and related follow-up operations. The quality control of cementing is a crucial aspect of oil and gas field exploration and development.

[0003] Currently, commonly used cementing quality inspection methods include cementing quality inspection methods based on CBL (acoustic amplitude logging) and / or VDL (acoustic variable density logging). However, these cementing quality inspection methods cannot accurately determine the cementing status of low-density cement, resulting in low cementing quality inspection accuracy. On the other hand, cementing quality inspection methods that combine acoustic impedance measurement and A0 bending type Lamb wave attenuation measurement are more complex to implement and have low inspection efficiency. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a cementing quality inspection method, apparatus, computing device and computer storage medium based on ultrasonic Lamb wave that overcomes or at least partially solves the above problems.

[0005] According to one aspect of the present invention, a cementing quality inspection method based on ultrasonic Lamb waves is provided, comprising:

[0006] Acquire a first ultrasonic Lamb wave signal received by a first receiver and acquire a second ultrasonic Lamb wave signal received by a second receiver; wherein, the first distance between the first receiver and the transmitter is less than the second distance between the second receiver and the transmitter, and the incident angle of the transmitter is less than a preset angle threshold;

[0007] Calculate the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within the first time window, and calculate the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within the second time window; wherein the first time window and the second time window have the same window length;

[0008] The attenuation rate of the zero-order symmetric Lamb wave is calculated based on the energy of the first wave, the energy of the second wave, the first distance, and the second distance.

[0009] The attenuation rate is compared with a pre-generated attenuation rate threshold, and the properties of the external medium are determined based on the comparison result.

[0010] In an optional implementation, the calculation of the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance further includes:

[0011] Calculate the distance difference between the second distance and the first distance, and calculate the ratio of the energy of the second wave to the energy of the first wave;

[0012] The attenuation rate of the zero-order symmetric Lamb wave is calculated based on the distance difference and the ratio.

[0013] In an optional implementation, the calculation of the first wave energy of the zero-order symmetric Lamb wave signal within the first time window further includes: extracting the envelope of the first ultrasonic Lamb wave signal within the first time window using Hilbert transform, calculating the envelope integral within the first time window, and using the envelope integral within the first time window as the first wave energy.

[0014] And / or, the calculation of the second wave energy of the zero-order symmetric Lamb wave signal within the second time window further includes: extracting the envelope of the second ultrasonic Lamb wave signal within the second time window using Hilbert transform, calculating the envelope integral within the second time window, and using the envelope integral within the second time window as the second wave energy.

[0015] In one optional implementation, the starting point of the first time window is determined as follows: the first peak of the first ultrasonic Lamb signal is determined, a preset proportion of the amplitude of the first peak in the first ultrasonic Lamb signal is taken as the first target amplitude, and the time point in the first ultrasonic Lamb signal corresponding to the first target amplitude is taken as the starting point of the first time window.

[0016] And / or, the starting point of the second time window is determined as follows: the first peak of the second ultrasonic Lamb signal is determined, a preset proportion of the amplitude of the first peak in the second ultrasonic Lamb signal is taken as the second target amplitude, and the time point in the second ultrasonic Lamb signal corresponding to the second target amplitude is taken as the starting point of the second time window.

[0017] In one optional implementation, comparing the attenuation rate with a pre-generated attenuation rate threshold and determining the external medium properties based on the comparison result further includes:

[0018] If the attenuation rate is greater than the first attenuation rate threshold, the external medium property is determined to be solid; if the attenuation rate is less than or equal to the first attenuation rate threshold, the external medium property is determined to be fluid.

[0019] In one optional implementation, comparing the attenuation rate with a pre-generated attenuation rate threshold and determining the external medium properties based on the comparison result further includes:

[0020] If the attenuation rate is greater than the first attenuation rate threshold and less than the second attenuation rate threshold, then the external medium property of the casing is determined to be slow cement.

[0021] If the attenuation rate is greater than or equal to the second attenuation rate threshold, then the external medium property of the casing is determined to be fast cement.

[0022] In an optional implementation, the method further includes:

[0023] Numerical simulation algorithms were used to simulate the following well logging models: a first well logging model with water as the external medium, a second well logging model with heavy mud as the external medium, a third well logging model with fast cement as the external medium, and a fourth well logging model with slow cement as the external medium.

[0024] Calculate the first attenuation rate of the zero-order symmetric Lamb wave under the first logging model, the second attenuation rate of the zero-order symmetric Lamb wave under the second logging model, the third attenuation rate of the zero-order symmetric Lamb wave under the third logging model, and the fourth attenuation rate of the zero-order symmetric Lamb wave under the third logging model.

[0025] The first attenuation rate threshold and / or the second attenuation rate threshold are determined based on the first attenuation rate, the second attenuation rate, the third attenuation rate, and the fourth attenuation rate.

[0026] According to another aspect of the present invention, a cementing quality testing device based on ultrasonic Lamb waves is provided, comprising:

[0027] The acquisition module is used to acquire a first ultrasonic Lamb wave signal received by a first receiver and a second ultrasonic Lamb wave signal received by a second receiver; wherein, the first distance between the first receiver and the transmitter is less than the second distance between the second receiver and the transmitter, and the incident angle of the transmitter is less than a preset angle threshold.

[0028] The calculation module is used to calculate the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within a first time window, and to calculate the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within a second time window; wherein the first time window and the second time window have the same window length; and to calculate the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance.

[0029] The determination module is used to compare the attenuation rate with a pre-generated attenuation rate threshold and determine the properties of the external medium based on the comparison result.

[0030] In one optional implementation, the calculation module is used to: calculate the distance difference between the second distance and the first distance, and calculate the ratio of the second wave energy to the first wave energy; and calculate the attenuation rate of the zero-order symmetric Lamb wave based on the distance difference and the ratio.

[0031] In one optional implementation, the calculation module is used to: extract the envelope of the first ultrasonic Lamb wave signal within a first time window using Hilbert transform, calculate the envelope integral within the first time window, and use the envelope integral within the first time window as the first wave energy.

[0032] And / or, use Hilbert transform to extract the envelope of the second ultrasonic Lamb wave signal within the second time window, calculate the envelope integral within the second time window, and use the envelope integral within the second time window as the second wave energy.

[0033] In one optional implementation, the calculation module is used to: determine the first peak of the first ultrasonic Lamb signal, take a preset proportion of the amplitude of the first peak in the first ultrasonic Lamb signal as a first target amplitude, and take the time point in the first ultrasonic Lamb signal corresponding to the first target amplitude as the starting point of the first time window.

[0034] And / or, determine the first peak of the second ultrasonic Lamb signal, take a preset proportion of the amplitude of the first peak in the second ultrasonic Lamb signal as the second target amplitude, and take the time point in the second ultrasonic Lamb signal corresponding to the second target amplitude as the starting point of the second time window.

[0035] In one optional implementation, the determining module is configured to: determine that the external medium property is a solid if the attenuation rate is greater than a first attenuation rate threshold; and determine that the external medium property is a fluid if the attenuation rate is less than or equal to the first attenuation rate threshold.

[0036] In one optional implementation, the determining module is configured to: if the attenuation rate is greater than a first attenuation rate threshold and less than a second attenuation rate threshold, then determine that the external medium property of the casing is slow cement.

[0037] If the attenuation rate is greater than or equal to the second attenuation rate threshold, then the external medium property of the casing is determined to be fast cement.

[0038] In one optional embodiment, the device further includes: a simulation module, used to simulate, respectively, a first logging model with water as the external medium, a second logging model with heavy mud as the external medium, a third logging model with fast cement as the external medium, and a fourth logging model with slow cement as the external medium using a numerical simulation algorithm.

[0039] Calculate the first attenuation rate of the zero-order symmetric Lamb wave under the first logging model, the second attenuation rate of the zero-order symmetric Lamb wave under the second logging model, the third attenuation rate of the zero-order symmetric Lamb wave under the third logging model, and the fourth attenuation rate of the zero-order symmetric Lamb wave under the third logging model.

[0040] The first attenuation rate threshold and / or the second attenuation rate threshold are determined based on the first attenuation rate, the second attenuation rate, the third attenuation rate, and the fourth attenuation rate.

[0041] According to another aspect of the present invention, a computing device is provided, comprising: a processor, a memory, a communication interface, and a communication bus, wherein the processor, the memory, and the communication interface communicate with each other via the communication bus;

[0042] The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the above-described cementing quality detection method based on ultrasonic Lamb waves.

[0043] According to another aspect of the present invention, a computer storage medium is provided, wherein at least one executable instruction is stored therein, the executable instruction causing a processor to perform the operation corresponding to the above-described cementing quality detection method based on ultrasonic Lamb waves.

[0044] The present invention discloses a cementing quality inspection method and apparatus based on ultrasonic Lamb waves, comprising: acquiring a first ultrasonic Lamb wave signal received by a first receiver and acquiring a second ultrasonic Lamb wave signal received by a second receiver; calculating the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within a first time window, and calculating the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within a second time window; calculating the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance; comparing the attenuation rate with a pre-generated attenuation rate threshold, and determining the external medium properties based on the comparison result. This scheme is beneficial for improving the accuracy of cementing quality inspection; and it can achieve cementing quality evaluation independently without the need for combined acoustic impedance information, simplifying the cementing quality inspection process and improving the efficiency of cementing quality inspection.

[0045] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0046] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0047] Figure 1 A schematic flowchart of a cementing quality inspection method based on ultrasonic Lamb waves provided by an embodiment of the present invention is shown.

[0048] Figure 2 This diagram illustrates the location of a transmitter and receiver according to an embodiment of the present invention.

[0049] Figure 3 This invention provides a schematic diagram of vibration modes of different ultrasonic Lamb waves according to an embodiment of the present invention;

[0050] Figure 4 This diagram illustrates an ultrasonic Lamb wave signal provided by an embodiment of the present invention.

[0051] Figure 5 This diagram illustrates a flow chart of another cementing quality inspection method based on ultrasonic Lamb waves provided by an embodiment of the present invention.

[0052] Figure 6 This invention provides a schematic diagram of ultrasonic Lamb wave signals for different logging models.

[0053] Figure 7 This diagram illustrates the structure of a cementing quality testing device based on ultrasonic Lamb waves, provided by an embodiment of the present invention.

[0054] Figure 8 A schematic diagram of the structure of a computing device provided in an embodiment of the present invention is shown. Detailed Implementation

[0055] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0056] Figure 1 This diagram illustrates a flow chart of a cementing quality inspection method based on ultrasonic Lamb waves according to an embodiment of the present invention. The flow chart in this embodiment is not intended to limit the order of the execution steps. Steps in the flow chart can be added to or removed as needed.

[0057] like Figure 1 As shown, the method specifically includes the following steps:

[0058] Step S110: Obtain the first ultrasonic Lamb wave signal received by the first receiver and the second ultrasonic Lamb wave signal received by the second receiver; wherein, the first distance between the first receiver and the transmitter is less than the second distance between the second receiver and the transmitter, and the incident angle of the transmitter is less than a preset angle threshold.

[0059] This invention utilizes ultrasonic Lamb waves for cementing quality inspection. Ultrasonic Lamb waves are a type of guided ultrasonic wave, a surface wave in which the medium thickness and wavelength are on the same order of magnitude. During the logging process, an ultrasonic transmitter emits an ultrasonic signal, which is obliquely incident on the casing at a certain angle, and multiple receivers receive the corresponding ultrasonic Lamb waves.

[0060] In one optional implementation, to ensure the accuracy of cementing quality detection, the transmitter and receiver are configured as follows: Figure 2 As shown. Figure 2 In the diagram, L1, L2, L3, and L4 correspond to the formation, cement sheath, casing, and wellbore, respectively. A transmitter R is installed at one end of the wellbore L4 along the logging axis, and a first receiver R1 and a second receiver R2 are installed at the other end at different well depths. The transmitter R emits ultrasonic waves, and the first and second receivers R1 and R2 receive them. The distance between the first receiver and the transmitter is a first distance, and the distance between the second receiver and the transmitter is a second distance. The first distance is less than the second distance, meaning the first receiver is closer to the transmitter, and the second receiver is farther away. The first and second receivers are parallel and mirror-symmetric to the transmitter; correspondingly, the second receiver is also mirror-symmetric to the transmitter. Figure 2 In the process, the ultrasonic wave emitted by the first receiver is obliquely incident on the sleeve L3 at an incident angle α, and the reflection angle α of the first receiver R1 and the second receiver R2 is equal to the incident angle α.

[0061] Furthermore, in a fluid-filled casing well, when the transmitter excites an ultrasonic signal at a certain angle, it will excite two different modes of ultrasonic Lamb wave signals. These two different modes of ultrasonic Lamb wave signals include a zero-order antisymmetric Lamb wave signal and a zero-order symmetric Lamb wave signal. The zero-order antisymmetric Lamb wave signal is abbreviated as A0, and it can also be called a curved Lamb wave, such as... Figure 3 As shown, the vibration characteristics of a zero-order antisymmetric Lamb wave are that the central particle vibrates laterally, while the particles on the upper and lower surfaces undergo elliptical motion with the same phase. The zero-order symmetric Lamb wave signal is abbreviated as S0, as shown... Figure 3As shown, the vibration characteristics of the zero-order symmetric Lamb wave are that the central particle of the thin plate vibrates longitudinally, while the particles on the upper and lower surfaces move in elliptical motion with opposite phases and symmetry about the center.

[0062] The ultrasonic Lamb wave signal received by the receiver includes both zero-order antisymmetric and zero-order symmetric Lamb wave signals. Since the particle vibration direction of the zero-order symmetric Lamb wave is perpendicular to the well axis, less energy leaks into the cement shear when the medium outside the casing is fluid. However, when the medium outside the casing is solid, due to the shear properties of the solid, shear coupling occurs at the casing-cement shear interface, resulting in more energy radiating into the cement shear. Therefore, this embodiment of the invention subsequently uses the zero-order symmetric Lamb wave as the basis for determining the medium outside the casing. Because a high-amplitude asymmetric Lamb wave is excited when the incident angle of the transmitter exceeds a preset angle threshold, it affects the analysis of the symmetric Lamb wave. Figure 4 As shown, Figure 4 When the transmitter's incident angle is greater than 33 degrees and the transmitter's center frequency is 250kHz, the ultrasonic Lamb wave signals received by the first receiver R1 and the second receiver R2 are as follows: Since the zero-order symmetric Lamb wave propagates the fastest, the first wave received by the first receiver R1 and the second receiver R2 is the zero-order symmetric Lamb wave, followed by the zero-order asymmetric Lamb wave and other higher-order Lamb waves. Figure 4 As can be seen, the amplitude of the first received zero-order symmetric Lamb wave is relatively small. Therefore, in this embodiment of the invention, the incident angle of the transmitter is less than a preset angle threshold to generate a high-amplitude symmetric Lamb wave, thereby improving the cementing detection accuracy. For example, the incident angle can be 15 degrees.

[0063] In one optional implementation, the ultrasonic Lamb wave excited by the transmitter is related not only to the incident angle but also to the excitation frequency of the transmitter probe and the casing thickness. Therefore, in this embodiment of the invention, the casing thickness of the well to be cemented can be obtained in advance, and ultrasonic Lamb wave signals obtained at different excitation frequencies and incident angles under that casing thickness can be simulated using a model. The excitation frequency and incident angle at which the amplitude of the zero-order symmetric Lamb wave in the ultrasonic Lamb wave signal is maximum are recorded, and the cemented quality is subsequently tested on the well using this excitation frequency and incident angle. For example, the excitation frequency in this embodiment of the invention can be 200 kHz.

[0064] After the transmitter transmits, the first receiver and the second receiver receive the corresponding ultrasonic Lamb wave signals. This step then acquires the first ultrasonic Lamb wave signal received by the first receiver and the second ultrasonic Lamb wave signal received by the second receiver. The ultrasonic Lamb wave signal received by the first receiver is the first ultrasonic Lamb wave signal, and the ultrasonic Lamb wave signal received by the second receiver is the second ultrasonic Lamb wave signal.

[0065] Step S120: Calculate the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within the first time window, and calculate the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within the second time window; wherein the first time window and the second time window have the same window length.

[0066] Since the zero-order symmetric Lamb wave attenuates continuously with increasing propagation distance, and the different properties of the external medium have different effects on the attenuation of the zero-order symmetric Lamb wave, this embodiment of the invention calculates the attenuation rate of the zero-order symmetric Lamb wave by implementing steps S120 and S130 after obtaining the first ultrasonic Lamb wave signal and the second ultrasonic Lamb wave signal.

[0067] Specifically, the first and second ultrasonic Lamb signals obtained in step S110 often contain superimposed zero-order symmetric and zero-order asymmetric Lamb waves. To accurately obtain the attenuation rate of the zero-order symmetric Lamb wave, this step predetermines a first and a second time window. Within the first time window, the first ultrasonic Lamb signal contains only zero-order symmetric Lamb waves; within the second time window, the second ultrasonic Lamb signal contains only zero-order symmetric Lamb waves. Furthermore, the first and second time windows have the same window length.

[0068] In one optional implementation, the starting point of the first time window and the starting point of the second time window can be determined as follows: The first peak of the first ultrasonic Lamb signal is determined; a preset proportion of the amplitude of the first peak in the first ultrasonic Lamb signal is used as a first target amplitude; and the time point in the first ultrasonic Lamb signal corresponding to the first target amplitude is used as the starting point of the first time window; and / or, the first peak of the second ultrasonic Lamb signal is determined; a preset proportion of the amplitude of the first peak in the second ultrasonic Lamb signal is used as a second target amplitude; and the time point in the second ultrasonic Lamb signal corresponding to the second target amplitude is used as the starting point of the second time window. Specifically, since the propagation speed of a zero-order symmetric Lamb wave is higher than that of a zero-order asymmetric Lamb wave, the first wave in both the first and second ultrasonic Lamb signals corresponds to a zero-order symmetric Lamb wave. To facilitate subsequent data processing, in this implementation, a preset proportion of the amplitude of the first peak in the ultrasonic Lamb signal is used as the starting point of the zero-order symmetric Lamb wave, that is, the time corresponding to this starting point is used as the starting point of the time window.

[0069] In another alternative implementation, the starting point of the first time window and the window length of the second time window can be determined in the following ways: Method 1: Use a fixed window length, such as 25μs, to simplify the implementation process of this method and improve the overall execution efficiency; Method 2: Calculate the duration between the time point corresponding to the first peak in the first ultrasonic Lamb wave signal and the starting point of the first time window, and use a preset multiple (such as twice) of this duration as the window length, and / or calculate the duration between the time point corresponding to the first peak in the second ultrasonic Lamb wave signal and the starting point of the second time window, and use a preset multiple (such as twice) of this duration as the window length.

[0070] After determining the first time window, the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within the first time window is calculated. This wave energy is referred to as the first wave energy. In the specific calculation process, the Hilbert transform is used to extract the envelope of the first ultrasonic Lamb wave signal within the first time window, and the envelope integral within the first time window is calculated. This envelope integral is then used as the first wave energy.

[0071] Specifically, the envelope integral can be obtained using the following formula 1:

[0072]

[0073] If the waveform sequence is x(t), then y(t) is obtained after Hilbert transform, y(t) = Hilbert(x(t)). In Formula 1, T1 and T2 are the start and end points of the time window, respectively, and S is the envelope integral in the [T1,T2] time window, which is also the wave energy in the time window.

[0074] When Equation 1 is applied to the calculation of the first wave energy, S in Equation 1 is the first wave energy, T1 and T2 are the start and end points of the first time window, respectively, and y(t) is the envelope sequence after the first ultrasonic Lamb wave undergoes Hilbert transformation.

[0075] After determining the second time window, the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within the second time window is calculated. This wave energy is referred to as the second wave energy. In the specific calculation process, a Hilbert transform is used to extract the envelope of the second ultrasonic Lamb wave signal within the two time windows, and the envelope integral within the second time window is calculated. This envelope integral is then used as the second wave energy. Applying Formula 1 to the calculation of the second wave energy, S in Formula 1 represents the second wave energy, T1 and T2 are the start and end points of the second time window, respectively, and y(t) is the envelope sequence of the second ultrasonic Lamb wave after the Hilbert transform.

[0076] Step S130: Calculate the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance.

[0077] Specifically, the distance difference between the second distance and the first distance is calculated, as well as the ratio of the second wave energy to the first wave energy; based on the distance difference and the ratio, the attenuation rate of the zero-order symmetric Lamb wave is calculated.

[0078] The attenuation rate is calculated using the following formula 2:

[0079] Attn=20log(S2 / S1) / ΔR (Formula 2)

[0080] In Formula 2, Attn is the attenuation rate of the zero-order symmetric Lamb wave, S1 is the energy of the first wave, S2 is the energy of the second wave, and ΔR is the distance difference between the second distance and the first distance, which is the distance between the first receiver and the second receiver.

[0081] Step S140: Compare the attenuation rate with the pre-generated attenuation rate threshold, and determine the properties of the external medium based on the comparison result.

[0082] Specifically, if the attenuation rate is greater than a first attenuation rate threshold, the external medium is determined to be a solid; if the attenuation rate is less than or equal to the first attenuation rate threshold, the external medium is determined to be a fluid. Further, if the attenuation rate is greater than the first attenuation rate threshold and less than a second attenuation rate threshold, the external medium is determined to be slow-moving cement; if the attenuation rate is greater than or equal to the second attenuation rate threshold, the external medium is determined to be fast-moving cement.

[0083] Therefore, the embodiments of the present invention determine the properties of the external medium based on the attenuation rate of the zero-order symmetric Lamb wave within a preset time window. Since the attenuation rates of the zero-order symmetric Lamb waves corresponding to different media outside the casing are significantly different, this scheme is beneficial to improving the accuracy of cementing quality detection. Furthermore, cementing quality evaluation can be achieved independently without the need for combined acoustic impedance information, simplifying the cementing quality detection (or cementing quality evaluation) process and improving the efficiency of cementing quality detection.

[0084] Figure 5 This diagram illustrates a flowchart of another cementing quality inspection method based on ultrasonic Lamb waves provided by an embodiment of the present invention. The flowchart in this embodiment is not intended to limit the order of the execution steps. Steps in the flowchart may be added to or removed as needed.

[0085] like Figure 5 As shown, the method specifically includes the following steps:

[0086] Step S510: Using numerical simulation algorithms, simulate the following well logging models respectively: a first well logging model with water as the outer medium of the casing, a second well logging model with heavy mud as the outer medium of the casing, a third well logging model with fast cement as the outer medium of the casing, and a fourth well logging model with slow cement as the outer medium of the casing.

[0087] Existing well logging numerical simulation software was used to construct four well logging models: a first model, a second model, a third model, and a fourth model. The casing external media differed among these models: water (i.e., free casing) in the first model, heavy mud in the second model, slow cement in the third model, and fast cement in the fourth model. All parameters were identical across the four models except for the casing external media. These other parameters included, but were not limited to, the structural framework (e.g., using...). Figure 2 The structural framework shown includes transmitter parameters (such as transmitter location, excitation power, incident angle, etc.), and parameters of the first and second receivers (such as receiver location, receiving angle, etc.).

[0088] For example, the transmitter uses a 200kHz Gaussian pulse signal, the incident angle is 15 degrees, the distance between the transmitter and the first receiver is 30cm, and the distance between the first and second receivers is 7cm, etc. The parameters in the simulation process are determined based on the parameters used in actual well logging for cementing quality testing. For example, if the incident angle in the subsequent actual well logging is 15 degrees, then the incident angle in the simulation will also be 15 degrees. In one example, the relevant parameters for different media outside the casing and the formation can be shown in Table 1:

[0089] Table 1

[0090] Material <![CDATA[Density (kg / m 3 )]]> Longitudinal wave velocity (m / s) Shear wave velocity (m / s) Thickness (mm) water 1000 1500 — 25 casing 7800 5930 3250 8 Heavy mud 2052 1340 — 25 Slow cement 1330 2250 1300 25 Quick cement 1858 3100 1700 25 strata 2500 4500 2500 40

[0091] Step S520: Calculate the first attenuation rate of the zero-order symmetric Lamb wave under the first logging model, the second attenuation rate of the zero-order symmetric Lamb wave under the second logging model, the third attenuation rate of the zero-order symmetric Lamb wave under the third logging model, and the fourth attenuation rate of the zero-order symmetric Lamb wave under the third logging model.

[0092] The system acquires the first ultrasonic Lamb wave signals from the first, second, third, and fourth well logging models output by the well logging numerical simulation software, and also acquires the second ultrasonic Lamb wave signal received by the second receiver. That is, for any well logging model, the well logging numerical simulation software outputs the first ultrasonic Lamb wave signal received by the first receiver and the second ultrasonic Lamb wave signal received by the second receiver under that well logging model. For example... Figure 6 As shown, A, B, C, and D correspond to the first logging model, the second logging model, the third logging model, and the fourth logging model, respectively. R1 corresponds to the first receiver, and R2 corresponds to the second receiver. The signal corresponding to R1 is the first ultrasonic Lamb wave signal, and the signal corresponding to R2 is the second ultrasonic Lamb wave signal. The solid curve in the figure represents the ultrasonic Lamb wave signal received by the receiver output by the numerical simulation software, and the dashed curve is the envelope of the ultrasonic Lamb wave signal.

[0093] Further calculations are performed on the first wave energy of the zero-order symmetric Lamb wave in the first time window of the first ultrasonic Lamb wave signal under any logging model, and the second wave energy of the zero-order symmetric Lamb wave in the second time window of the second ultrasonic Lamb wave signal. Then, the attenuation rate of the zero-order symmetric Lamb wave is calculated based on the first wave energy, the second wave energy, the first distance, and the second distance. The calculation process for the attenuation rate of the zero-order symmetric Lamb wave under each logging model can be referred to... Figure 1 The relevant descriptions in the embodiments will not be repeated here.

[0094] Step S530: Determine the first attenuation rate threshold and / or the second attenuation rate threshold based on the first attenuation rate, the second attenuation rate, the third attenuation rate, and the fourth attenuation rate.

[0095] Specifically, the maximum values ​​of the first and second attenuation rates, and the minimum values ​​of the third and fourth attenuation rates can be determined, and the average of these maximum and minimum values ​​can be used as the first attenuation rate threshold. For example, if the first, second, third, and fourth attenuation rates are 0.212, 0.23, 0.2995, and 0.438 respectively, then the maximum value of the first and second attenuation rates is 0.23, and the minimum value of the third and fourth attenuation rates is 0.2995. Therefore, the first attenuation rate threshold is (0.23 + 0.2995) / 2. Furthermore, since the media corresponding to the first and second attenuation rates are fluids, and the media corresponding to the third and fourth attenuation rates are solids, this first attenuation rate threshold can be used as the separation threshold between fluids and solids.

[0096] Furthermore, the average of the third and fourth attenuation rates can be used as the second attenuation rate threshold. For example, if the third and fourth attenuation rates are 0.2995 and 0.438 respectively, then the second attenuation rate threshold is (0.438 + 0.2995) / 2. This second attenuation rate threshold can be used as the dividing threshold between slow-setting cement and fast-setting cement.

[0097] Step S640: Determine the actual external medium properties using the first attenuation rate threshold and / or the second attenuation rate threshold.

[0098] Since the attenuation rates of zero-order symmetric Lamb waves corresponding to different casing external medium properties are significantly different, and the acoustic impedances of heavy mud and slow cement (low-density cement) are relatively close, the implementation method of this invention has higher accuracy than using acoustic impedance to determine the casing external medium properties.

[0099] Therefore, the embodiments of the present invention pre-simulate a first logging model with water as the external medium, a second logging model with heavy mud as the external medium, a third logging model with fast cement as the external medium, and a fourth logging model with slow cement as the external medium using numerical simulation algorithms. Then, the first attenuation rate, the second attenuation rate, the third attenuation rate, and the fourth attenuation rate of the zero-order symmetric Lamb wave under different logging models are obtained. Then, the first attenuation rate threshold and / or the second attenuation rate threshold are determined based on the first attenuation rate, the second attenuation rate, the third attenuation rate, and the fourth attenuation rate. Thus, compared with manually setting the threshold, the embodiments of the present invention have higher detection accuracy.

[0100] Figure 7 A schematic diagram of a cementing quality testing device based on ultrasonic Lamb waves, provided by an embodiment of the present invention, is shown. Figure 7 As shown, the device 700 includes: an acquisition module 710, a calculation module 720, and a determination module 730.

[0101] The acquisition module 710 is used to acquire a first ultrasonic Lamb wave signal received by a first receiver and a second ultrasonic Lamb wave signal received by a second receiver; wherein, the first distance between the first receiver and the transmitter is less than the second distance between the second receiver and the transmitter, and the incident angle of the transmitter is less than a preset angle threshold.

[0102] The calculation module 720 is used to calculate the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within a first time window, and to calculate the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within a second time window; wherein the first time window and the second time window have the same window length; and to calculate the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance;

[0103] The determination module 730 is used to compare the attenuation rate with a pre-generated attenuation rate threshold and determine the properties of the external medium based on the comparison result.

[0104] In one optional implementation, the calculation module is used to: calculate the distance difference between the second distance and the first distance, and calculate the ratio of the second wave energy to the first wave energy; and calculate the attenuation rate of the zero-order symmetric Lamb wave based on the distance difference and the ratio.

[0105] In one optional implementation, the calculation module is used to: extract the envelope of the first ultrasonic Lamb wave signal within a first time window using Hilbert transform, calculate the envelope integral within the first time window, and use the envelope integral within the first time window as the first wave energy.

[0106] And / or, use Hilbert transform to extract the envelope of the second ultrasonic Lamb wave signal within the second time window, calculate the envelope integral within the second time window, and use the envelope integral within the second time window as the second wave energy.

[0107] In one optional implementation, the calculation module is used to: determine the first peak of the first ultrasonic Lamb signal, take a preset proportion of the amplitude of the first peak in the first ultrasonic Lamb signal as a first target amplitude, and take the time point in the first ultrasonic Lamb signal corresponding to the first target amplitude as the starting point of the first time window.

[0108] And / or, determine the first peak of the second ultrasonic Lamb signal, take a preset proportion of the amplitude of the first peak in the second ultrasonic Lamb signal as the second target amplitude, and take the time point in the second ultrasonic Lamb signal corresponding to the second target amplitude as the starting point of the second time window.

[0109] In one optional implementation, the determining module is configured to: determine that the external medium property is a solid if the attenuation rate is greater than a first attenuation rate threshold; and determine that the external medium property is a fluid if the attenuation rate is less than or equal to the first attenuation rate threshold.

[0110] In one optional implementation, the determining module is configured to: if the attenuation rate is greater than a first attenuation rate threshold and less than a second attenuation rate threshold, then determine that the external medium property of the casing is slow cement.

[0111] If the attenuation rate is greater than or equal to the second attenuation rate threshold, then the external medium property of the casing is determined to be fast cement.

[0112] In one optional embodiment, the device further includes: a simulation module, used to simulate, respectively, a first logging model with water as the external medium, a second logging model with heavy mud as the external medium, a third logging model with fast cement as the external medium, and a fourth logging model with slow cement as the external medium using a numerical simulation algorithm.

[0113] Calculate the first attenuation rate of the zero-order symmetric Lamb wave under the first logging model, the second attenuation rate of the zero-order symmetric Lamb wave under the second logging model, the third attenuation rate of the zero-order symmetric Lamb wave under the third logging model, and the fourth attenuation rate of the zero-order symmetric Lamb wave under the third logging model.

[0114] The first attenuation rate threshold and / or the second attenuation rate threshold are determined based on the first attenuation rate, the second attenuation rate, the third attenuation rate, and the fourth attenuation rate.

[0115] Therefore, the embodiments of the present invention determine the properties of the external medium based on the attenuation rate of the zero-order symmetric Lamb wave within a preset time window. Since the attenuation rates of the zero-order symmetric Lamb waves corresponding to different media outside the casing are significantly different, this scheme is beneficial to improving the accuracy of cementing quality detection. Furthermore, cementing quality evaluation can be achieved independently without the need for combined acoustic impedance information, simplifying the cementing quality detection process and improving the efficiency of cementing quality detection.

[0116] This invention provides a non-volatile computer storage medium storing at least one executable instruction that can execute the cementing quality detection method based on ultrasonic Lamb waves in any of the above method embodiments.

[0117] Figure 8 A schematic diagram of a computing device according to an embodiment of the present invention is shown. The specific embodiments of the present invention do not limit the specific implementation of the computing device.

[0118] like Figure 8As shown, the computing device may include: a processor 802, a communications interface 804, a memory 806, and a communications bus 808.

[0119] The processor 802, communication interface 804, and memory 806 communicate with each other via communication bus 808. Communication interface 904 is used to communicate with other network elements such as clients or other servers. Processor 802 executes program 810, specifically performing the relevant steps described in the embodiment of the cementing quality detection method based on ultrasonic Lamb waves.

[0120] Specifically, program 810 may include program code that includes computer operation instructions.

[0121] Processor 802 may be a central processing unit (CPU), an application-specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention. The computing device includes one or more processors, which may be processors of the same type, such as one or more CPUs; or processors of different types, such as one or more CPUs and one or more ASICs.

[0122] Memory 806 is used to store program 810. Memory 806 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device. Program 810 can specifically be used to cause processor 802 to perform the operations described in the method embodiments above.

[0123] The algorithms or displays provided herein are not inherently related to any particular computer, virtual system, or other device. Various general-purpose systems can also be used in conjunction with the teachings herein. The required structure for constructing such systems is apparent from the above description. Furthermore, the embodiments of the present invention are not directed to any particular programming language. It should be understood that the content of the invention described herein can be implemented using various programming languages, and the above description of specific languages ​​is for the purpose of disclosing the best mode of implementation of the invention.

[0124] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of the invention may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0125] Similarly, it should be understood that, in order to simplify the invention and aid in understanding one or more of the various inventive aspects, features of the embodiments of the invention are sometimes grouped together in a single embodiment, figure, or description thereof in the above description of exemplary embodiments of the invention. However, this disclosure should not be construed as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, inventive aspects lie in fewer than all features of a single foregoing disclosed embodiment. Therefore, the claims following the detailed description are hereby expressly incorporated into this detailed description, wherein each claim itself is a separate embodiment of the invention.

[0126] Those skilled in the art will understand that modules in the device of the embodiments can be adaptively changed and placed in one or more devices different from that embodiment. Modules, units, or components in the embodiments can be combined into a single module, unit, or component, and further, they can be divided into multiple sub-modules, sub-units, or sub-components. Except where at least some of such features and / or processes or units are mutually exclusive, any combination can be used to combine all features disclosed in this specification (including the accompanying claims, abstract, and drawings) and all processes or units of any method or device so disclosed. Unless expressly stated otherwise, each feature disclosed in this specification (including the accompanying claims, abstract, and drawings) may be replaced by an alternative feature that serves the same, equivalent, or similar purpose.

[0127] Furthermore, those skilled in the art will understand that although some embodiments herein include certain features included in other embodiments but not others, combinations of features from different embodiments are intended to be within the scope of the invention and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

[0128] The various component embodiments of the present invention can be implemented in hardware, or as software modules running on one or more processors, or a combination thereof. Those skilled in the art will understand that microprocessors or digital signal processors (DSPs) can be used in practice to implement some or all of the functions of some or all of the components according to the embodiments of the present invention. The present invention can also be implemented as a device or apparatus program (e.g., a computer program and computer program product) for performing part or all of the methods described herein. Such programs implementing the present invention can be stored on a computer-readable medium, or can be in the form of one or more signals. Such signals can be downloaded from an Internet website, provided on a carrier signal, or provided in any other form.

[0129] It should be noted that the above embodiments are illustrative of the invention and not restrictive, and that those skilled in the art can devise alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. The invention can be implemented by means of hardware comprising several different elements and by means of a suitably programmed computer. In the unit claims enumerating several means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words can be interpreted as names. The steps in the above embodiments, unless otherwise specified, should not be construed as limiting the order of execution.

Claims

1. A cementing quality inspection method based on ultrasonic Lamb waves, characterized in that, include: Acquire a first ultrasonic Lamb wave signal received by a first receiver and acquire a second ultrasonic Lamb wave signal received by a second receiver; wherein, the first distance between the first receiver and the transmitter is less than the second distance between the second receiver and the transmitter, and the incident angle of the transmitter is less than a preset angle threshold; Calculate the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within the first time window, and calculate the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within the second time window; wherein the first time window and the second time window have the same window length; The attenuation rate of the zero-order symmetric Lamb wave is calculated based on the energy of the first wave, the energy of the second wave, the first distance, and the second distance. If the attenuation rate is less than or equal to the first attenuation rate threshold, then the external medium property is determined to be fluid. If the attenuation rate is greater than the first attenuation rate threshold and less than the second attenuation rate threshold, the external medium property is determined to be slow cement; if the attenuation rate is greater than or equal to the second attenuation rate threshold, the external medium property is determined to be fast cement. The first attenuation rate threshold and the second attenuation rate threshold are determined as follows: Numerical simulation algorithms were used to simulate the following well logging models: a first well logging model with water as the external medium, a second well logging model with heavy mud as the external medium, a third well logging model with fast cement as the external medium, and a fourth well logging model with slow cement as the external medium. Calculate the first attenuation rate of the zero-order symmetric Lamb wave under the first logging model, the second attenuation rate of the zero-order symmetric Lamb wave under the second logging model, the third attenuation rate of the zero-order symmetric Lamb wave under the third logging model, and the fourth attenuation rate of the zero-order symmetric Lamb wave under the third logging model. Determine the maximum value of the first attenuation rate and the second attenuation rate, and the minimum value of the third attenuation rate and the fourth attenuation rate. Use the average of the maximum and minimum values ​​as the first attenuation rate threshold, and use the average of the third and fourth attenuation rates as the second attenuation rate threshold.

2. The method according to claim 1, characterized in that, The calculation of the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance further includes: Calculate the distance difference between the second distance and the first distance, and calculate the ratio of the energy of the second wave to the energy of the first wave; The attenuation rate of the zero-order symmetric Lamb wave is calculated based on the distance difference and the ratio.

3. The method according to claim 2, characterized in that, The calculation of the first wave energy of the zero-order symmetric Lamb wave signal within the first time window further includes: extracting the envelope of the first ultrasonic Lamb wave signal within the first time window using Hilbert transform, calculating the envelope integral within the first time window, and using the envelope integral within the first time window as the first wave energy. And / or, the calculation of the second wave energy of the zero-order symmetric Lamb wave signal within the second time window further includes: extracting the envelope of the second ultrasonic Lamb wave signal within the second time window using Hilbert transform, calculating the envelope integral within the second time window, and using the envelope integral within the second time window as the second wave energy.

4. The method according to any one of claims 1-3, characterized in that, The starting point of the first time window is determined as follows: the first peak of the first ultrasonic Lamb signal is determined, a preset proportion of the amplitude of the first peak in the first ultrasonic Lamb signal is taken as the first target amplitude, and the time point in the first ultrasonic Lamb signal corresponding to the first target amplitude is taken as the starting point of the first time window. And / or, the starting point of the second time window is determined as follows: the first peak of the second ultrasonic Lamb signal is determined, a preset proportion of the amplitude of the first peak in the second ultrasonic Lamb signal is taken as the second target amplitude, and the time point in the second ultrasonic Lamb signal corresponding to the second target amplitude is taken as the starting point of the second time window.

5. A cementing quality testing device based on ultrasonic Lamb waves, characterized in that, include: The acquisition module is used to acquire a first ultrasonic Lamb wave signal received by a first receiver and a second ultrasonic Lamb wave signal received by a second receiver; wherein, the first distance between the first receiver and the transmitter is less than the second distance between the second receiver and the transmitter, and the incident angle of the transmitter is less than a preset angle threshold. The calculation module is used to calculate the first wave energy of the zero-order symmetric Lamb wave of the first ultrasonic Lamb wave signal within a first time window, and to calculate the second wave energy of the zero-order symmetric Lamb wave of the second ultrasonic Lamb wave signal within a second time window; wherein the first time window and the second time window have the same window length; and to calculate the attenuation rate of the zero-order symmetric Lamb wave based on the first wave energy, the second wave energy, the first distance, and the second distance. The determination module is used to determine the external medium property as fluid if the attenuation rate is less than or equal to a first attenuation rate threshold; to determine the external medium property as slow cement if the attenuation rate is greater than the first attenuation rate threshold and less than a second attenuation rate threshold; and to determine the external medium property as fast cement if the attenuation rate is greater than or equal to the second attenuation rate threshold. The first attenuation rate threshold and the second attenuation rate threshold are determined as follows: Numerical simulation algorithms were used to simulate the following well logging models: a first well logging model with water as the external medium, a second well logging model with heavy mud as the external medium, a third well logging model with fast cement as the external medium, and a fourth well logging model with slow cement as the external medium. Calculate the first attenuation rate of the zero-order symmetric Lamb wave under the first logging model, the second attenuation rate of the zero-order symmetric Lamb wave under the second logging model, the third attenuation rate of the zero-order symmetric Lamb wave under the third logging model, and the fourth attenuation rate of the zero-order symmetric Lamb wave under the third logging model. Determine the maximum value of the first attenuation rate and the second attenuation rate, and the minimum value of the third attenuation rate and the fourth attenuation rate. Use the average of the maximum and minimum values ​​as the first attenuation rate threshold, and use the average of the third and fourth attenuation rates as the second attenuation rate threshold.

6. A computing device, characterized in that, include: The processor, memory, communication interface, and communication bus are provided, wherein the processor, memory, and communication interface communicate with each other via the communication bus. The memory is used to store at least one executable instruction, which causes the processor to perform the operation corresponding to the cementing quality detection method based on ultrasonic Lamb wave as described in any one of claims 1-4.

7. A computer storage medium, characterized in that, The storage medium stores at least one executable instruction that causes the processor to perform the operation corresponding to the cementing quality inspection method based on ultrasonic Lamb waves as described in any one of claims 1-4.

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