Well cementation quality evaluation and annulus medium propagation velocity determination method and equipment

Abstract

The invention provides a well cementation quality evaluation and annulus medium propagation velocity determination method and device, and belongs to the field of well cementation quality evaluation.The determination method comprises the steps that waveform data received by a current depth point at different orientations are obtained based on oblique incidence ultrasonic logging, and the waveform data are obtained; the waveform data comprises full-wave waveforms of Lamb waves received by receivers located at different well depths; determining the average propagation time of the reflected wave corresponding to the current depth point in the annulus medium based on the waveform data received by the current depth point at different orientations; and based on the logging parameters and the average propagation time corresponding to the current depth point, determining an annular medium propagation speed corresponding to the current depth point. According to the method provided by the invention, the cement loss in the direction can be identified by independently depending on the propagation velocity of the annulus medium, so that the first-interface and second-interface evaluation of the well cementation quality is realized.

Description

Technical Field

[0001] This application relates to the field of cementing quality evaluation technology, specifically to a method for determining the propagation velocity of annular media, a device for determining the propagation velocity of annular media, a cementing quality evaluation method, a cementing quality evaluation device, an electronic device, a computer-readable storage medium, and a computer program product. Background Technology

[0002] As my country's oil and gas exploration and development gradually extends to ultra-deep formations, the high-temperature and high-pressure environment makes cement highly susceptible to the influence of high-pressure permeable layers during the cementing process. Cement sheath defects caused during cementing can affect the strength and safety of the casing. Therefore, determining the cement sheath defects between the casing and the formation is crucial for evaluating the cementing quality of deep and ultra-deep wells.

[0003] Currently, acoustic logging is the primary method for evaluating cementing quality. However, in developing this application, the inventors discovered that existing technologies have at least the following problems: commonly used cementing quality evaluation methods, such as acoustic amplitude logging (CBL) and acoustic variable density logging (VDL), are difficult to accurately evaluate the quality of the cementing interface; while the ultrasonic Lamb wave cementing quality evaluation method, which combines acoustic impedance measurement and A0 bending Lamb wave attenuation measurement, can evaluate the cementing interface more accurately, its implementation process is cumbersome. It requires a series of complex calculations to determine parameters such as attenuation rate and acoustic impedance of the media inside and outside the casing before cementing quality evaluation can be performed, resulting in low detection efficiency.

[0004] For example, Chinese patent document CN115992691A, published on April 21, 2023, proposes a cementing quality inspection method and apparatus based on ultrasonic Lamb waves. The method includes: 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 a zero-order symmetric Lamb wave within a first time window, and calculating the second wave energy of a zero-order symmetric Lamb wave 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, 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. While this method simplifies the cementing quality inspection process by eliminating the need to combine acoustic impedance information and attenuation rate for cementing quality evaluation, the attenuation rate calculation process remains complex and may require more computational resources and time to handle, affecting the timeliness and efficiency of cementing quality evaluation.

[0005] In summary, how to achieve cementing quality evaluation based on ultrasonic Lamb waves in a simple and rapid manner has become an urgent problem to be solved. Summary of the Invention

[0006] To address the technical problem that existing ultrasonic Lamb wave-based cementing quality evaluation methods are cumbersome to implement, making it difficult to quickly and easily evaluate the quality of the cementing interface, this application provides a method for determining the annular medium propagation velocity. This method can easily and quickly calculate the annular medium propagation velocity between the casing and the formation, thereby enabling rapid assessment of the annular medium type between the casing and the formation. Furthermore, this application also provides a cementing quality evaluation method that can identify azimuth cement defects solely based on the annular medium propagation velocity, thereby achieving evaluation of the first and second interfaces of cementing quality.

[0007] To achieve the above objectives, the first aspect of this application provides a method for determining the propagation velocity in annular media, the method comprising the following steps: acquiring waveform data received at different azimuths of a current depth point based on oblique incidence ultrasonic logging, the waveform data including Lamb wave full-wave waveforms received by receivers located at different well depths; determining the average propagation time of the reflected wave corresponding to the current depth point in the annular media based on the waveform data received at different azimuths of the current depth point; and determining the propagation velocity of the annular media corresponding to the current depth point based on the logging parameters and the average propagation time corresponding to the current depth point.

[0008] In an exemplary embodiment of this application, determining the average propagation time of the reflected wave corresponding to the current depth point in the annular medium based on waveform data received at different azimuths of the current depth point may include: determining the full-wave waveform to be processed at different azimuths of the current depth point based on the waveform data received at different azimuths of the current depth point; determining the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths based on the full-wave waveform to be processed at different azimuths of the current depth point; and averaging the arrival time differences between the direct wave and the reflected wave corresponding to the current depth point at different azimuths to obtain the average propagation time of the reflected wave corresponding to the current depth point in the annular medium.

[0009] In an exemplary embodiment of this application, determining the full-wave waveform to be processed at different orientations based on waveform data received at different orientations at the current depth point may include: comparing the distances between different receivers and the transmitter; and determining the Lamb wave full-wave waveform received by the receiver furthest from the transmitter as the full-wave waveform to be processed at different orientations at the current depth point.

[0010] In an exemplary embodiment of this application, determining the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths based on the full-wave waveforms to be processed at different azimuths may include: performing waveform processing on the full-wave waveforms to be processed at the current depth point at different azimuths to obtain the full-wave waveform envelopes corresponding to the current depth point at different azimuths; determining the direct wave envelope peak and the reflected wave envelope peak corresponding to the current depth point at different azimuths based on the full-wave waveform envelopes corresponding to the current depth point at different azimuths; and performing subtraction operations on the arrival time of the direct wave envelope peak and the arrival time of the reflected wave envelope peak corresponding to the current depth point at different azimuths to obtain the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths.

[0011] In one exemplary embodiment of this application, the waveform processing may be a Hilbert transform.

[0012] In an exemplary embodiment of this application, determining the annular medium propagation velocity at the current depth point based on the logging parameters and average propagation time at the current depth point may include: determining the annular thickness at the current depth point based on the logging parameters; determining the direct wave phase velocity at the current depth point based on waveform data received at different azimuths at the current depth point; and determining the annular medium propagation velocity at the current depth point based on the annular thickness, the direct wave phase velocity, and the average propagation time at the current depth point.

[0013] In one exemplary embodiment of this application, the propagation velocity of the annular medium corresponding to the current depth point can be determined according to the following formula:

[0014] (CAL-D) / (cosθ*V case )-2CAL*tanθ / V phase =ΔT,

[0015] θ = arcsin(V) case / V phase );

[0016] Among them, V phase V is the propagation velocity of the annular medium between the casing and the formation at the current depth point. case θ is the phase velocity of the curved Lamb wave in the casing at the current depth point, θ is the refraction angle from the casing to the annulus at the current depth point, CAL is the open hole measurement diameter at the current depth point, D is the casing outer diameter at the current depth point, and ΔT is the average propagation time of the reflected wave received at the current depth point in the annulus.

[0017] In an exemplary embodiment of this application, the method for determining the propagation velocity of the annular medium may further include: performing azimuth imaging on the propagation velocity of the annular medium corresponding to each depth point within the target depth segment to obtain the imaging result of the propagation velocity of the annular medium within the target depth segment.

[0018] The second aspect of this application provides a cementing quality evaluation method, which includes the following steps: obtaining the annular medium propagation velocity of a target depth segment using the annular medium propagation velocity determination method described above; determining the annular medium type of the target depth segment based on the annular medium propagation velocity of the target depth segment; and determining the cementing interface bonding quality evaluation result of the target depth segment based on the annular medium type of the target depth segment.

[0019] In an exemplary embodiment of this application, determining the annular medium type of the target depth segment based on the annular medium propagation velocity of the target depth segment may include: comparing the annular medium propagation velocity of the target depth segment with a first velocity threshold and a second velocity threshold respectively; if the annular medium propagation velocity of the target depth segment is less than the first velocity threshold, then the annular medium type of the target depth segment is determined to be drilling fluid; if the annular medium propagation velocity of the target depth segment is between the first velocity threshold and the second velocity threshold, then the annular medium type of the target depth segment is determined to be contaminated cement; if the annular medium propagation velocity of the target depth segment is greater than the second velocity threshold, then the annular medium type of the target depth segment is determined to be pure cement; wherein, the first velocity threshold is less than the second velocity threshold.

[0020] In an exemplary embodiment of this application, determining the annular medium type of the target depth segment based on the propagation velocity of the annular medium between the casing and the formation at the target depth segment may include: obtaining an acoustic property interpretation chart of an experimental sample, the experimental sample including: pure cement, contaminated cement, and drilling fluid; comparing the propagation velocity of the annular medium at the target depth segment with the acoustic property interpretation chart of the experimental sample to determine the annular medium type of the target depth segment.

[0021] In an exemplary embodiment of this application, determining the cement interface bonding quality evaluation result of the target depth segment based on the annular medium type of the target depth segment may include: if the annular medium type of the target depth segment is pure cement, then the cement interface bonding quality evaluation result of the target depth segment is determined to be excellent; if the annular medium type of the target depth segment is contaminated cement, then the cement interface bonding quality evaluation result of the target depth segment is determined to be medium; if the annular medium type of the target depth segment is drilling fluid, then the cement interface bonding quality evaluation result of the target depth segment is determined to be poor.

[0022] A third aspect of this application provides an annular medium propagation velocity determination device, comprising: a data acquisition module for acquiring waveform data received at different azimuths of a current depth point based on oblique incidence ultrasonic logging, the waveform data including Lamb wave full-wave waveforms received by receivers located at different well depths; a propagation time determination module for determining the average propagation time of the reflected wave corresponding to the current depth point in the annular medium based on the waveform data received at different azimuths of the current depth point; and a first velocity determination module for determining the annular medium propagation velocity corresponding to the current depth point based on the logging parameters corresponding to the current depth point and the average propagation time.

[0023] The fourth aspect of this application provides a cementing quality evaluation device, which includes: a second velocity determination module for obtaining the annular medium propagation velocity of a target depth segment using the annular medium propagation velocity determination method described above; an annular medium type determination module for determining the annular medium type of the target depth segment based on the annular medium propagation velocity of the target depth segment; and a cementing quality evaluation module for determining the cementing interface bonding quality evaluation result of the target depth segment based on the annular medium type of the target depth segment.

[0024] A fifth aspect of this application provides an electronic device comprising a processor and a memory, the memory storing at least one computer program, the at least one computer program being loaded and executed by one or more of the processors to cause the processors to perform the annular medium propagation velocity determination method as described above, or to perform the cementing quality evaluation method as described above.

[0025] A sixth aspect of this application provides a computer-readable storage medium storing at least one piece of program code, which is loaded and executed by a processor to cause a computer to perform the annular medium propagation velocity determination method as described above, or to perform the cementing quality evaluation method as described above.

[0026] The seventh aspect of this application provides a computer program product, including a computer program, characterized in that, when executed by a processor, the computer program implements the method for determining the propagation velocity of annular medium as described above, or executes the method for evaluating cementing quality as described above.

[0027] The technical solution provided in this application has at least the following technical effects:

[0028] (1) The method for determining the propagation velocity of the annular medium provided in this application is the first to use the average propagation time of the reflected wave in the annular medium during ultrasonic Lamb wave logging to calculate the propagation velocity of the annular medium. Using this method, the propagation velocity of the annular medium between the casing and the formation can be calculated simply and quickly, thus laying the foundation for rapid assessment of the type of annular medium between the casing and the formation.

[0029] (2) The method for determining the propagation velocity of the annular medium provided in this application also proposes a formula for inverting the propagation velocity of the annular medium using parameters such as the average propagation time of the reflected wave in the annular medium, the annular thickness, and the direct wave phase velocity. The formula can be used to directly calculate the propagation velocity of the annular medium in different casing wells, and the calculation results are relatively reliable and are not affected by the eccentricity of the downhole casing.

[0030] (3) The cementing quality evaluation method provided in this application is the first to use the propagation velocity of the annular medium between the casing and the formation to identify the azimuth cement deficiency that occurs during the cementing process. It can realize the evaluation of the first and second interfaces of cementing quality by relying solely on ultrasonic Lamb wave logging, which solves the problem that the current evaluation of cementing quality in deep and ultra-deep wells is limited to interface bonding.

[0031] (4) The annular medium propagation velocity determination device, cementing quality evaluation device and computer program product provided in this application provide a software device that can realize the annular medium propagation velocity determination method and the cementing quality evaluation method. Using this software device, the cementing quality first and second interface evaluation can be completed faster and more accurately.

[0032] (5) The electronic device and computer-readable storage medium provided in this application provide a hardware device that can realize the method for determining the propagation speed of annular medium or the method for evaluating cementing quality. Using this hardware device can ensure that the above-mentioned software device or equipment is safer and more reliable during operation, and reduce failures and risks.

[0033] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings:

[0035] Figure 1 A flowchart illustrating the method for determining the propagation velocity of annular medium provided in an embodiment of this application;

[0036] Figure 2A A cross-sectional schematic diagram of the ultrasonic oblique-incidence casing well model provided in the embodiments of this application;

[0037] Figure 2B A schematic diagram of the propagation trajectory of an ultrasonic oblique-incidence casing well model provided in an embodiment of this application;

[0038] Figure 3 A schematic diagram of the propagation paths of reflected waves and direct waves provided in the embodiments of this application;

[0039] Figure 4 A schematic diagram of the waveforms received by the near and far receivers and the waveforms obtained by Hilbert transform, provided in an embodiment of this application;

[0040] Figure 5 A schematic diagram of annular medium propagation velocity imaging between the casing and the formation provided in an embodiment of this application;

[0041] Figure 6 A schematic flowchart illustrating the cementing quality evaluation method provided in this application embodiment;

[0042] Figure 7 This is a structural block diagram of the annular medium propagation velocity determination device provided in the embodiments of this application;

[0043] Figure 8 A structural block diagram of the cementing quality evaluation device provided in the embodiments of this application;

[0044] Figure 9 This is a structural block diagram of an electronic device provided in an embodiment of this application.

[0045] Explanation of reference numerals in the attached figures

[0046] 101-Data acquisition module, 102-Propagation time determination module, 103-First velocity determination module, 201-Second velocity determination module, 202-Annular medium type determination module, 203-Cementing quality evaluation module, 301-Processor, 302-Memory. Detailed Implementation

[0047] The specific embodiments of this application will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the embodiments of this application.

[0048] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other.

[0049] In this application, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used to describe the relative positional relationships of components in relation to the directions shown in the accompanying drawings or in relation to vertical, perpendicular, or gravitational directions. Terms such as "first" and "second" are used merely for ease of description and distinction and should not be construed as indicating or implying relative importance.

[0050] In the description of this application, it should also be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," etc., should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integrated connections; they can refer to direct connections or indirect connections; they can refer to wired connections or wireless connections. Those skilled in the art can understand the specific meaning of the above terms in this application depending on the specific circumstances.

[0051] In the process of developing this application, the inventors discovered that the existing technology has at least the following problems: commonly used cementing quality evaluation methods, such as acoustic amplitude logging (CBL) and acoustic variable density logging (VDL), can only qualitatively evaluate the bonding quality of the interface between the casing and the cement sheath, and are powerless to detect the interface between the cement sheath and the wellbore, and cannot identify the location of bonding defects; while ultrasonic leakage Lamb waves are a powerful tool for detecting bonding defects in multi-layer media, current cementing quality evaluation methods based on ultrasonic Lamb waves require a series of complex calculations to determine parameters such as attenuation rate and acoustic impedance of the media inside and outside the casing before cementing quality evaluation can be performed, resulting in low detection efficiency. Furthermore, the inventors' research has found that the propagation velocity of the annular medium between the casing and the formation can be used as an indicator of cement sheath defects, thereby enabling the evaluation of cementing quality.

[0052] Based on this, and addressing the technical problem that the implementation process of existing cementing quality evaluation methods based on ultrasonic Lamb waves is relatively cumbersome, leading to difficulties in simply and quickly evaluating the quality of the two interfaces of cementing, this application provides a method for determining the propagation velocity of the annular medium. This method uses a single-transmitter, two-receiver ultrasonic oblique incidence probe to excite antisymmetric A0-type Lamb waves (or Lamb waves) and symmetrical S0-type Lamb waves in the casing. After processing the full-waveform, the arrival time difference values ​​of the direct wave and the reflected wave are extracted, and then the propagation velocity of the annular medium between the casing and the formation is calculated. Furthermore, this application also provides a cementing quality evaluation method that uses the propagation velocity of the annular medium between the casing and the formation to determine the type of annular medium, thereby achieving the evaluation of the first and second interfaces of cementing quality. Compared to existing cementing quality evaluation methods, this application can quickly and accurately calculate the propagation velocity of the annular medium between the casing and the formation, and directly apply the annular medium propagation velocity alone to quickly assess the material type between the casing and the formation, and can also identify azimuthal cement deficiencies. In practice, the above method can be executed by an electronic device, which can be a server, terminal, or other device with processing capabilities.

[0053] The technical solutions of this application will now be described in detail with reference to the accompanying drawings and embodiments. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described again in some embodiments.

[0054] like Figure 1 As shown in the figure, this application provides a method for determining the propagation velocity in an annular medium, which includes the following steps:

[0055] Step S101: Based on oblique incidence ultrasonic logging, acquire waveform data received at different azimuths at the current depth point.

[0056] Step S102: Based on the waveform data received at different orientations at the current depth point, determine the average propagation time of the reflected wave corresponding to the current depth point in the annular medium.

[0057] Step S103: Based on the logging parameters and average propagation time corresponding to the current depth point, determine the propagation velocity of the annular medium corresponding to the current depth point.

[0058] It should be noted that curved Lamb wave logging and caliper logging can be performed by setting up a curved Lamb wave logging tool within the target depth range, thereby obtaining waveform data at different azimuths of various depth points within the target depth range. During the logging process, an ultrasonic transmitter emits an ultrasonic signal, which is obliquely incident on the casing at a certain angle and received by a receiver. To ensure the accuracy of cementing quality detection, after the ultrasonic signal is obliquely incident on the casing at a certain angle, multiple receivers are usually set up at different well depths to receive the corresponding ultrasonic Lamb waves. Therefore, the waveform data in step S101 should include the full wave waveform of the Lamb waves received by multiple receivers located at different well depths.

[0059] For example, the transmitter and receiver of a curved Lamb wave logging tool can adopt oblique incidence transmitter excitation and oblique incidence receiver modes, with a receiver distance between 30cm and 40cm. Figure 2A A cross-section of the ultrasonic oblique-incidence casing well model is shown. It can be seen that the ultrasonic oblique-incidence casing well model consists of, from the inside out, a curved Lamb wave logging tool, well mud, casing, and cement sheath. The radius of the well mud (distance from the well axis) is r1, the radius of the casing (distance from the well axis) is r2, and the radius of the cement sheath (distance from the well axis) is r3. Figure 2B The ultrasonic oblique incidence casing well model is shown. The probe emits sound source at an incident angle of θ, and the receiver receives the tortuous Lamb wave leaking in the casing at the same angle. The source distance of the near receiver is y, and the distance between the far receiver and the near receiver is d.

[0060] Assume there are n depth points in the target depth segment, where i represents the nth depth point in the target depth segment, and 1 ≤ i ≤ n. When i = 1, it indicates that the curved Lamb wave logging tool is located at the first depth point of the target depth segment. At this time, by rotating the curved Lamb wave logging tool once in the well according to the preset number of rotations, waveform data received at different azimuths of the first depth point in the target depth segment can be obtained. Similarly, when i = 2, by rotating the curved Lamb wave logging tool once at the second depth point according to the preset number of rotations, waveform data received at different azimuths of the second depth point in the target depth segment can be obtained. And so on, when i = n, by rotating the curved Lamb wave logging tool once at the nth depth point according to the preset number of rotations, waveform data received at different azimuths of the nth depth point in the target depth segment can be obtained.

[0061] During well logging, a curved Lamb wave logging tool can be rotated in the well to measure the full wave waveform at different azimuths. The transmission can be repeated a preset number of times after one rotation. For example, it can be rotated 36 times to obtain waveform data received at a certain depth in 36 azimuths.

[0062] As the ultrasonic Lamb wave signal propagates along the casing, energy leaks into the cement sheath and is reflected at the formation interface; these reflected signals are also received by the sensor. Therefore, the average propagation time of the Lamb wave in the annular material between the casing and the formation can be calculated using the direct and reflected Lamb wave signals, thus enabling the inversion of the propagation velocity of the annular medium between the casing and the formation.

[0063] Figure 3 The propagation paths of the reflected and direct waves are shown. It can be seen that after the Lamb wave ultrasonic signal is obliquely incident on the cannula at a certain angle, a portion of the Lamb wave signal travels along the cannula (i.e., the direct wave propagates through the cannula). Figure 3 The Lamb wave signal that travels directly from path A to B to the receiver is called the direct wave signal. The other part of the Lamb wave signal is reflected by the cement and stratum interface (i.e., Figure 3 The Lamb wave signal (path A—C—B) reaches the receiver, and this part of the Lamb wave signal is called the reflected wave signal.

[0064] Subtracting the time required for the Lamb wave signal at a certain azimuth to travel from A to C and then to B within the cement sheath (i.e., the arrival time of the reflected wave from the outside of the annulus) from the time required for the Lamb wave signal at that azimuth to travel directly from A to B within the casing (i.e., the arrival time of the direct wave from the casing) yields the Lamb wave propagation time (or the time difference between the direct and reflected waves) at the current depth point at that azimuth. The physical meaning of this Lamb wave propagation time is the propagation time of the Lamb wave within the annulus (such as the cement sheath) between the casing and the formation.

[0065] By averaging the Lamb wave propagation time at different azimuths of the current depth point, the average propagation time of the reflected wave at the current depth point in the annular medium can be obtained. Specifically, assuming the preset number of times is m, that is, the curved Lamb wave logging tool needs to rotate m times around the well circumference at each depth point in the target depth segment, j represents the azimuth position of any depth point in the target depth segment in the annular direction, and 1≤j≤m. When the curved Lamb wave logging tool is located at the i-th depth point in the target depth segment, when j=1, it means that the curved Lamb wave logging tool is in the first azimuth of the i-th depth point; when j=2, it means that the curved Lamb wave logging tool is in the second azimuth of the i-th depth point; and so on, when j=m, it means that the curved Lamb wave logging tool is in the m-th azimuth of the i-th depth point. Then the average propagation time of the reflected wave at the i-th depth point in the annular medium can be determined according to the following formula (1).

[0066]

[0067] In the formula, ΔT iis the average propagation time of the reflected wave at the i-th depth point in the annulus medium, ΔT ij is the propagation time of the reflected wave at the j-th azimuth of the i-th depth point in the annulus medium, m is the number of rotations of the flexural Lamb wave logging tool set at the i-th depth point around the wellbore, and 1 ≤ j ≤ m.

[0068] Here, it should be noted that the purpose of averaging the Lamb wave propagation time to obtain the average Lamb wave propagation time is to better cooperate with logging parameters such as the annulus thickness in the subsequent process to calculate a more reasonable propagation velocity of the annulus medium. This is because casing eccentricity is common in the wellbore, so the annulus thickness (such as the cement sheath thickness) at different azimuths is not the same, and the corresponding Lamb wave propagation times will naturally deviate. If the propagation velocity of the annulus medium corresponding to the current depth point is determined only by the Lamb wave propagation time at a certain azimuth, it will inevitably affect the calculation accuracy of the propagation velocity of the annulus medium. Given the known well diameter and casing outer diameter, the average value of the annulus thickness of the entire casing well can be determined. Even if there is casing eccentricity in the wellbore, it will only cause deviation in the annulus thickness at a certain azimuth and does not affect the average value of the annulus thickness. Therefore, on the premise of determining the average value of the annulus thickness, if the Lamb wave propagation times at different azimuths are averaged to obtain the average Lamb wave propagation time, then the propagation velocity of the annulus medium between the casing and the formation obtained by inversion using the logging parameters and the average Lamb wave propagation time is relatively reliable.

[0069] In this way, by executing the above steps S101 to S103, the propagation velocity of the annulus medium can be calculated using the average propagation time of the reflected wave in the annulus medium during the ultrasonic Lamb wave logging process. Using this method, the propagation velocity of the annulus medium between the casing and the formation can be calculated simply and quickly, thereby laying a foundation for rapidly evaluating the type of annulus medium between the casing and the formation.

[0070] In addition, the propagation velocity of the annulus medium corresponding to each depth point within the target depth interval can also be obtained by repeatedly executing the above steps S101 to S103, thereby completing the inversion of the propagation velocity of the annulus medium between the casing and the formation for the entire measurement depth interval.

[0071] Specifically, after obtaining the calculation result of the propagation velocity of the annulus medium corresponding to the i-th depth point, it is judged whether 1 ≤ i < n is satisfied. If it is satisfied, it jumps to step S101 to continue calculating the propagation velocity of the annulus medium corresponding to the i + 1-th depth point. If it is not satisfied, the calculation terminates, and the calculation results of the propagation velocities of the annulus medium corresponding to each depth point in the target depth interval are output.

[0072] It's important to note that Lamb waves propagate within the casing. Upon reaching the annulus (between the casing and the formation), a mode conversion occurs, transforming the wave into either a longitudinal (P) or transverse (S) wave. The specific type of wave is determined by the state of the annulus medium (solid or liquid). In other words, when the annulus medium is liquid, the propagation speed refers to the P-wave velocity; when the annulus medium is solid, the propagation speed refers to the S-wave velocity.

[0073] Furthermore, in one possible implementation, in step S102, the process of determining the average propagation time of the reflected wave corresponding to the current depth point in the annular medium based on the waveform data received at different orientations of the current depth point may include, but is not limited to, the following sub-steps S1021 to S1023.

[0074] Sub-step S1021: Based on the waveform data received at different orientations of the current depth point, determine the full-wave waveform to be processed at different orientations of the current depth point.

[0075] Sub-step S1022: Based on the full-wave waveform to be processed at different azimuths of the current depth point, determine the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths.

[0076] Sub-step S1023: Calculate the average time difference between the direct wave and the reflected wave corresponding to the current depth point at different orientations to obtain the average propagation time of the reflected wave corresponding to the current depth point in the annular medium.

[0077] Generally speaking, waveform data received by both the far-field receiver and the near-field receiver can be used to calculate the time difference of arrival between the direct wave and the reflected wave. However, considering that the source distance between the far-field receiver and the transmitter is greater than that between the near-field receiver and the transmitter, the measurement results are less affected by instrument eccentricity. Therefore, it is recommended to use the waveform data received by the far-field receiver to calculate the time difference of arrival between the direct wave and the reflected wave, so as to improve the accuracy of Lamb wave propagation time calculation.

[0078] For example, the distances between different receivers and transmitters can be compared first, and the Lamb wave full-wave waveform received by the receiver farthest from the transmitter can be determined as the full-wave waveform to be processed at different azimuths of the current depth point. Then, based on the full-wave waveform to be processed, the Lamb wave propagation time difference at the j-th azimuth of the i-th depth point can be determined according to the following formula (2).

[0079] ΔT ij =T 2,ij -T 1,ij (2)

[0080] In the formula, ΔT ijLet T be the time difference of Lamb wave propagation at the j-th orientation of the i-th depth point. 2,ij Let T be the arrival time of the reflected wave at the j-th orientation of the i-th depth point. 1,ij Let be the arrival time of the direct wave at the j-th orientation of the i-th depth point.

[0081] Furthermore, in one possible implementation, in sub-step S1022, the process of determining the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths based on the full-wave waveform to be processed at different azimuths of the current depth point may include, but is not limited to, the following sub-steps S10221 to S10223.

[0082] Sub-step S10221: Perform waveform processing on the full-wave waveform to be processed at different orientations of the current depth point to obtain the full-wave waveform envelope corresponding to the current depth point at different orientations.

[0083] For example, Hilbert transform can be performed on waveform data received at different orientations at the current depth point to obtain the envelope of the full-wave waveform, i.e., Hibert_wave = hilbert(wave). Figure 4 The waveforms received by the far receiver and the near receiver, as well as the waveform obtained by Hilbert transform, are shown. It can be seen that the times corresponding to the peaks of the waveform envelopes are T1 (i.e., the arrival time of the peak of the direct wave envelope) and T2 (i.e., the arrival time of the peak of the reflected wave envelope), respectively. The difference between the two is the propagation time of the Lamb wave in the cement ring.

[0084] Of course, this application is not limited to this. In addition to using Hilbert transform to obtain the envelope of the full-wave waveform, there are other methods to achieve this purpose, such as the square envelope method, wavelet transform, adaptive filtering method, etc.

[0085] Sub-step S10222: Based on the full-wave envelope corresponding to the current depth point at different orientations, determine the direct wave envelope peak and the reflected wave envelope peak corresponding to the current depth point at different orientations.

[0086] For example, envelope peaks can be identified by finding local maxima within the full-wave envelope, and then the direct-wave envelope peaks and reflected-wave envelope peaks can be distinguished. Alternatively, a peak detection algorithm can be applied to detect peaks within the full-wave envelope, and then, based on the signal's start time, the earlier peak on the time axis can be selected as the direct-wave envelope peak, while subsequent peaks can be considered as the reflected-wave envelope peaks.

[0087] Sub-step S10223: Perform the difference calculation on the arrival time of the direct wave envelope peak and the arrival time of the reflected wave envelope peak corresponding to the current depth point at different azimuths to obtain the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths.

[0088] Furthermore, in one possible implementation, in step S103, the process of determining the propagation velocity of the annular medium at the current depth point based on the logging parameters and average propagation time at the current depth point may include, but is not limited to, the following sub-steps S1031 to S1033.

[0089] Sub-step S1031: Based on the logging parameters, determine the annulus thickness corresponding to the current depth point.

[0090] Sub-step S1032: Based on the waveform data received at different azimuths at the current depth point, determine the direct wave phase velocity corresponding to the current depth point.

[0091] Sub-step S1033: Based on the annular thickness, direct wave phase velocity and average propagation time corresponding to the current depth point, determine the annular medium propagation velocity corresponding to the current depth point.

[0092] Furthermore, the propagation velocity of the annular medium corresponding to the i-th depth point can be determined according to the following formulas (3) and (4).

[0093] (CAL-D) / (cosθ*V case )-2CAL*tanθ / V phase =ΔT (3)

[0094] θ = arcsin(V) case / V phase (4)

[0095] In the formula, V phase V represents the propagation velocity of the annular medium between the casing and the formation at the i-th depth point. case Let θ be the phase velocity of the curved Lamb wave (i.e., the direct wave) in the casing at the i-th depth point, θ be the refraction angle from the casing to the annulus medium at the i-th depth point, CAL be the measured well diameter of the open hole at the i-th depth point, D be the outer diameter of the casing at the i-th depth point, and ΔT be the average propagation time difference of the Lamb wave at the i-th depth point.

[0096] This application applies the above inversion formulas (3) to (4) to several different cased well examples, and the calculation results show that the inversion accuracy of the propagation velocity of the annular medium is high.

[0097] Furthermore, in one possible implementation, the annular medium propagation velocity determination method may further include step S104, performing azimuth imaging on the annular medium propagation velocity corresponding to each depth point within the target depth segment to obtain the annular medium propagation velocity imaging result for the target depth segment. By simulating and imaging the annular medium propagation velocity at different azimuths during well logging, richer information on cement sheath bonding quality can be obtained, providing detailed imaging and simulation support for a deeper understanding of cement sheath defects caused during cementing, thereby ensuring the production efficiency and safety of oil and gas wells.

[0098] For example, Figure 5 The imaging results of the propagation velocity of the annular medium between the casing and the formation are shown, in which, Figure 5 The first level is the depth level. Figure 5 The second path is the gamma curve. Figure 5 The third and fourth channels are waveform density maps of two locations within the 36 sector waveforms. Figure 5 The fifth one is U-USIT_USLG. Figure 5 The sixth channel in the image is for azimuth annular medium propagation velocity imaging. Figure 5 The seventh channel represents the average propagation velocity of the annular medium in the 36 sectors.

[0099] like Figure 6 As shown in the embodiments of this application, a cementing quality evaluation method is also provided, which includes the following steps:

[0100] Step S201: Determine the propagation velocity of the annular medium in the target depth segment.

[0101] Specifically, the propagation velocity of the annular medium in the target depth segment can be obtained by referring to the method for determining the propagation velocity of the annular medium in the above embodiments, which will not be repeated here.

[0102] Step S202: Determine the type of annular medium in the target depth segment based on the propagation velocity of the annular medium in the target depth segment.

[0103] Step S203: Based on the annular medium type of the target depth section, determine the cementing quality evaluation result of the cementing interface in the target depth section.

[0104] Furthermore, in one possible implementation, in step S202, the calculated result of the propagation velocity of the annular medium at the target depth can be compared with the acoustic characteristic interpretation chart of the laboratory sample to determine whether the type of annular medium between the casing and the formation is pure cement, contaminated cement, or drilling fluid.

[0105] Of course, this application is not limited to this; other methods are also applicable to determining the annular medium type at the target depth. For example, in implementing this application, the inventors discovered that as the average Lamb wave propagation time (i.e., the time difference between the arrival of the direct wave and the reflected wave) gradually decreases, the propagation velocity of the annular medium obtained by inversion gradually increases. This indicates that the type of annular medium between the casing and the formation is closer to pure cement, resulting in better cementing quality. Conversely, as the average Lamb wave propagation time (i.e., the time difference between the arrival of the direct wave and the reflected wave) gradually increases, the propagation velocity of the annular medium obtained by inversion gradually decreases. This indicates that the type of annular medium between the casing and the formation is closer to drilling mud, resulting in poorer cementing quality. Based on this, in step S202, the type of annular medium between the casing and the formation can also be determined by comparing the annular medium propagation velocity with a velocity threshold.

[0106] For example, a first velocity threshold and a second velocity threshold can be set, with the first velocity threshold being less than the second velocity threshold. The propagation velocity of the annular medium in the target depth segment is compared with the first velocity threshold and the second velocity threshold, respectively. If the propagation velocity of the annular medium in the target depth segment is less than the first velocity threshold, the annular medium type in the target depth segment is determined to be drilling fluid; if the propagation velocity of the annular medium in the target depth segment is between the first velocity threshold and the second velocity threshold, the annular medium type in the target depth segment is determined to be contaminated cement; if the propagation velocity of the annular medium in the target depth segment is greater than the second velocity threshold, the annular medium type in the target depth segment is determined to be pure cement.

[0107] Furthermore, in one possible implementation, the process of determining the cementing quality evaluation result of the cementing interface in step S203 based on the annular medium type in the target depth section is as follows:

[0108] (1) If the annular medium type in the target depth section is pure cement, the cementing quality evaluation result of the cementing interface in the target depth section is determined to be excellent.

[0109] (2) If the annular medium type in the target depth section is contaminated cement, the cementing interface bonding quality evaluation result of the target depth section is determined to be medium.

[0110] (3) If the annular medium type in the target depth section is drilling fluid, the cementing quality evaluation result of the cementing interface in the target depth section is determined to be poor.

[0111] Furthermore, the implementation environment of this embodiment includes at least one terminal and one server, and the aforementioned method for determining the propagation velocity of the annular medium (or the aforementioned cementing quality evaluation method) is executed on the terminal or the server, respectively. The terminal and the server can establish a communication connection to achieve interactive information transmission.

[0112] The terminal can be any electronic product that can interact with the user through one or more methods such as keyboard, touchpad, touch screen, voice interaction, etc., such as PC (Personal Computer), PPC (Pocket Personal Computer), tablet computer, etc.

[0113] A server can be a single server, a server cluster consisting of multiple servers, or a cloud server that provides basic cloud computing services such as cloud services, cloud databases, cloud computing, cloud functions, cloud storage, network services, cloud communication, middleware services, domain name services, security services, CDN (Content Delivery Network), and big data and artificial intelligence platforms.

[0114] like Figure 7 As shown in the figure, this application embodiment also provides an annular medium propagation speed determination device, which includes a data acquisition module 101, a propagation time determination module 102, and a first speed determination module 103.

[0115] The data acquisition module 101 is used to acquire waveform data received at different azimuths of the current depth point based on oblique incidence ultrasonic logging. The waveform data includes Lamb wave full waveforms received by receivers located at different well depths.

[0116] The propagation time determination module 102 is used to determine the average propagation time of the reflected wave corresponding to the current depth point in the annular medium based on the waveform data received at different orientations of the current depth point.

[0117] The first velocity determination module 103 is used to determine the propagation velocity of the annular medium at the current depth point based on the logging parameters and average propagation time corresponding to the current depth point.

[0118] like Figure 8 As shown in the figure, this application embodiment also provides a cementing quality evaluation device, which includes a second velocity determination module 201, an annular medium type determination module 202, and a cementing quality evaluation module 203.

[0119] The second velocity determination module 201 is used to obtain the annular medium propagation velocity of the target depth segment by employing the annular medium propagation velocity determination method described above.

[0120] The annular medium type determination module 202 is used to determine the annular medium type of the target depth segment based on the propagation speed of the annular medium in the target depth segment.

[0121] The cementing quality evaluation module 203 is used to determine the cementing interface bonding quality evaluation results for the target depth section based on the annular medium type.

[0122] It should be noted that the annular medium propagation velocity determination device and cementing quality evaluation device provided in the above embodiments are only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the internal structure of the equipment can be divided into different functional modules to complete all or part of the functions described above. Furthermore, the annular medium propagation velocity determination device and the annular medium propagation velocity determination method provided in the above embodiments belong to the same concept, and their specific implementation process is detailed in the method embodiments, which will not be repeated here. Similarly, the cementing quality evaluation device and the cementing quality evaluation method provided in the above embodiments belong to the same concept, and their specific implementation process is detailed in the method embodiments, which will not be repeated here.

[0123] like Figure 9 As shown in the embodiments of this application, an electronic device is also provided, which includes a processor 301 and a memory 302. The memory stores at least one computer program, which is loaded and executed by one or more of the processors to enable the processors to implement the annular medium propagation velocity determination method in the above embodiments, or to implement the cementing quality evaluation method in the above embodiments.

[0124] Of course, the electronic device may also have wired or wireless network interfaces, keyboards, and input / output interfaces for input and output. The electronic device may also include other components for implementing the various functions of the device, which will not be elaborated here.

[0125] This application also provides a computer-readable storage medium storing at least one piece of program code, which is loaded and executed by a processor to enable a computer to implement the annular medium propagation speed determination method in the above embodiments, or to implement the cementing quality evaluation method in the above embodiments.

[0126] Optionally, the computer-readable storage medium may be a read-only memory (ROM), a random access memory (RAM), a compact disc read-only memory (CD-ROM), a magnetic tape, a floppy disk, or an optical disc data storage device, etc. Those skilled in the art will understand that all or part of the steps in the methods of the above embodiments can be implemented by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in each embodiment of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disc.

[0127] This application also provides a computer program product, including a computer program that, when executed by a processor, implements the above-described method for determining the propagation velocity of annular media, or implements the above-described method for evaluating cementing quality.

[0128] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0129] The preferred embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this application, various simple modifications can be made to the technical solution of this application, and these simple modifications all fall within the protection scope of this application.

[0130] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this application will not describe the various possible combinations separately.

[0131] Furthermore, various different implementations of this application can be combined in any way, as long as they do not violate the spirit of this application, they should also be regarded as the content disclosed in this application.

Claims

1. A method for determining the propagation velocity in an annular medium, characterized in that, The method for determining the propagation velocity in the annular medium includes: Based on oblique incidence ultrasonic logging, waveform data received at different azimuths at the current depth point are acquired. The waveform data includes Lamb wave full waveforms received by receivers located at different well depths. Based on the waveform data received at different orientations at the current depth point, determine the average propagation time of the reflected wave corresponding to the current depth point in the annular medium; Based on the logging parameters and average propagation time corresponding to the current depth point, determine the propagation velocity of the annular medium at the current depth point.

2. The method for determining the propagation velocity of an annular medium according to claim 1, characterized in that, The step of determining the average propagation time of the reflected wave corresponding to the current depth point in the annular medium based on waveform data received at different azimuths at the current depth point includes: Based on the waveform data received at different azimuth positions at the current depth point, determine the full-wave waveform to be processed at different azimuth positions at the current depth point; Based on the full-wave waveforms to be processed at the current depth point in different azimuths, determine the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point in different azimuths; The average time difference between the arrival of the direct wave and the reflected wave at different azimuths of the current depth point is calculated to obtain the average propagation time of the reflected wave at the current depth point in the annular medium.

3. The method for determining the propagation velocity of an annular medium according to claim 2, characterized in that, The process of determining the full-wave waveform to be processed at different azimuths based on waveform data received at the current depth point at different azimuths includes: Compare the distances between different receivers and transmitters; The Lamb wave full-wave waveform received by the receiver furthest from the transmitter is determined as the full-wave waveform to be processed at different azimuths of the current depth point.

4. The method for determining the propagation velocity in an annular medium according to claim 2, characterized in that, The process of determining the arrival time difference between the direct wave and the reflected wave corresponding to the current depth point at different azimuths based on the full-wave waveform to be processed at the current depth point at different azimuths includes: The full-wave waveforms to be processed at the current depth point in different orientations are processed to obtain the full-wave waveform envelopes corresponding to the current depth point in different orientations. Based on the full-wave envelope corresponding to the current depth point at different azimuths, determine the direct wave envelope peak and the reflected wave envelope peak corresponding to the current depth point at different azimuths; The arrival times of the direct wave envelope peaks and the reflected wave envelope peaks at different azimuths of the current depth point are subtracted to obtain the arrival time difference between the direct wave and the reflected wave at different azimuths of the current depth point.

5. The method for determining the propagation velocity in an annular medium according to claim 4, characterized in that, The waveform processing is a Hilbert transform.

6. The method for determining the propagation velocity in an annular medium according to claim 1, characterized in that, The determination of the annular medium propagation velocity at the current depth point based on the logging parameters and average propagation time at the current depth point includes: Based on the logging parameters, determine the annulus thickness corresponding to the current depth point; Based on the waveform data received at different azimuths at the current depth point, determine the direct wave phase velocity corresponding to the current depth point; Based on the annular thickness, direct wave phase velocity, and average propagation time at the current depth point, the propagation velocity of the annular medium at the current depth point is determined.

7. The method for determining the propagation velocity of an annular medium according to claim 6, characterized in that, The propagation velocity of the annular medium at the current depth point is determined using the following formula: (CAL-D) / (cosθ*V case )-2CAL*tanθ / V phase =ΔT, θ=arcsin(V case / V phase ); Among them, V phase V is the propagation velocity of the annular medium between the casing and the formation at the current depth point. case θ is the phase velocity of the curved Lamb wave in the casing at the current depth point, θ is the refraction angle from the casing to the annulus at the current depth point, CAL is the open hole measurement diameter at the current depth point, D is the casing outer diameter at the current depth point, and ΔT is the average propagation time of the reflected wave received at the current depth point in the annulus.

8. The method for determining the propagation velocity in an annular medium according to claim 1, characterized in that, The method for determining the propagation velocity in the annular medium further includes: Azimuth imaging is performed on the propagation velocity of the annular medium at each depth point within the target depth segment to obtain the imaging results of the propagation velocity of the annular medium within the target depth segment.

9. A method for evaluating cementing quality, characterized in that, The cementing quality evaluation method includes: The propagation velocity of the annular medium at the target depth is obtained by using the method for determining the propagation velocity of the annular medium according to any one of claims 1 to 8. Based on the propagation velocity of the annular medium at the target depth, determine the type of annular medium at the target depth. Based on the annular medium type at the target depth, the cementing quality evaluation results of the cementing interface at the target depth are determined.

10. The cementing quality evaluation method according to claim 9, characterized in that, The determination of the annular medium type at the target depth range based on the propagation velocity of the annular medium at the target depth range includes: The propagation velocity of the annular medium in the target depth segment is compared with the first velocity threshold and the second velocity threshold, respectively; If the propagation velocity of the annular medium in the target depth section is less than the first velocity threshold, then the annular medium type in the target depth section is determined to be drilling fluid. If the propagation velocity of the annular medium in the target depth segment is between the first velocity threshold and the second velocity threshold, then the annular medium type in the target depth segment is determined to be contaminated cement. If the propagation velocity of the annular medium in the target depth segment is greater than the second velocity threshold, then the annular medium type in the target depth segment is determined to be pure cement. The first speed threshold is less than the second speed threshold.

11. The cementing quality evaluation method according to claim 9, characterized in that, The determination of the annular medium type at the target depth range based on the propagation velocity of the annular medium at the target depth range includes: Obtain an interpretation chart of the acoustic properties of the experimental samples, which include: pure cement, contaminated cement, and drilling fluid; By comparing the propagation velocity of the annular medium at the target depth with the interpretation chart of the acoustic characteristics of the experimental sample, the type of annular medium at the target depth is determined.

12. A device for determining the propagation velocity of an annular medium, characterized in that, The device for determining the propagation velocity of the annular medium includes: The data acquisition module is used to acquire waveform data received at different azimuths of the current depth point based on oblique incidence ultrasonic logging. The waveform data includes Lamb wave full waveforms received by receivers located at different well depths. The propagation time determination module is used to determine the average propagation time of the reflected wave corresponding to the current depth point in the annular medium based on the waveform data received at different azimuths of the current depth point. The first velocity determination module is used to determine the propagation velocity of the annular medium at the current depth point based on the logging parameters and average propagation time corresponding to the current depth point.

13. A cementing quality evaluation device, characterized in that, The cementing quality evaluation device includes: The second velocity determination module is used to obtain the annular medium propagation velocity of the target depth segment by employing the annular medium propagation velocity determination method according to any one of claims 1 to 8. The annular medium type determination module is used to determine the annular medium type at the target depth segment based on the propagation velocity of the annular medium at the target depth segment. The cementing quality evaluation module is used to determine the cementing interface bonding quality evaluation results for the target depth range based on the annular medium type.

14. An electronic device, characterized in that, The electronic device includes a processor and a memory, the memory storing at least one computer program, which is loaded and executed by one or more of the processors to cause the processors to perform the method for determining the propagation velocity of the annular medium as described in any one of claims 1 to 8, or to perform the method for evaluating cementing quality as described in any one of claims 9 to 11.

15. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one piece of program code, which is loaded and executed by a processor to cause the computer to perform the method for determining the propagation velocity of the annular medium as described in any one of claims 1 to 8, or to perform the method for evaluating cementing quality as described in any one of claims 9 to 11.

16. A computer program product, comprising a computer program, characterized in that, When the computer program is executed by the processor, it implements the method for determining the propagation velocity of the annular medium as described in any one of claims 1 to 8, or it implements the cementing quality evaluation method as described in any one of claims 9 to 11.

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