CN205036370U - A device for evaluating two interface cement of cased well tie quality - Google Patents

Abstract

The utility model relates to a device for evaluating the cement bonding quality of the two interfaces of a casing well. In one embodiment, the device includes: an ultrasonic emitting device, an ultrasonic receiving device and a control system; the ultrasonic emitting device and the ultrasonic receiving device are located at the measuring sub, and the measuring sub is connected to the control system; the control system includes a storage module and an upload module , to control the rotation of the ultrasonic emitting device and the ultrasonic receiving device; the ultrasonic emitting device emits ultrasonic waves to the inner wall of the cased well at an incident angle θ _i ; the ultrasonic receiving device receives the echo signal, and the processing system compares the echo signal with the echo signal The echo signal is compared and processed to obtain the cement bond quality corresponding to the position where the echo signal is formed in the cased hole. The embodiment of the utility model realizes the detection of cementing conditions at different interfaces of the cementing cement by emitting directional ultrasonic waves to excite and form a circumferential pattern in the cased well, and processing the echo information.

Description

A device for evaluating the cement bonding quality of the two interfaces of cased wells

technical field

The utility model relates to an acoustic logging technology, in particular to a device for evaluating the cement bonding quality of two interfaces (cement and formation interface) of a casing well.

Background technique

The detection and evaluation of cement bonding quality in cased wells is of great significance to oil well engineering and oilfield development, mainly including the evaluation of the bonding status of the first interface (casing and cement interface) and the second interface. The earliest CBL/VDL cement bond logging is a commonly used detection method in cementing quality detection. Among them, CBL can be used to quantitatively judge the cement bond quality of the first interface; VDL can be used to qualitatively judge the cement bond quality of the second interface. However, both techniques only measure the average cementation quality within a certain longitudinal distance in the circumferential direction of the cement sheath, which cannot reflect the uneven distribution of cement in the circumferential direction, that is, there is no azimuth resolution, and the longitudinal resolution is low.

Sector measurement technology and ultrasonic pulse technology make up for the inability to conduct circumferential detection of the bonding quality of an interface. There are two types of sector measurement techniques: one is the method in which the sound source is centered and the receiver is divided into sectors to receive; the second is the method in which both the emission and the reception are close to the inner wall of the casing to measure the sector attenuation. Ultrasonic pulse emission instruments can distinguish the acoustic characteristics of the material in contact with the outer wall of the casing according to the method of measuring casing resonance waves, and can be used to evaluate the cement bonding quality of an interface in the circumferential and longitudinal directions. In addition, the combination of conventional pulse and flexural wave imaging technology can perform three-dimensional imaging of the casing outer ring space, determine the shape of the material outside the casing at the measurement azimuth, and generate a result map of solid-liquid-gas cementing quality evaluation. However, due to the influence of various factors on the collected signals, there is no application of this technology in the evaluation of the cement bond quality of the two interfaces in the field application examples at home and abroad.

Most of the cementing quality detection methods and technologies currently used are only suitable for evaluating the cementation quality of the first interface, and there are still some difficulties in the detection of the cementing quality of the second interface. Therefore, there is an urgent need for a detection device for the cementing quality of the two interfaces, which can easily and conveniently realize the detection of the cementing quality of the two cementing interfaces.

Utility model content

The purpose of this utility model is to address the deficiencies of the prior art, and propose a device that uses ultrasonic waves to excite circumferential patterns in a cased well, thereby detecting the bonding quality of the cement and formation interface in the cased well.

In order to achieve the above purpose, the utility model provides a device for evaluating the cement bonding quality of the two interface of the cased well, the device includes:

Ultrasonic transmitting device, ultrasonic receiving device and control system;

The ultrasonic transmitting device and the ultrasonic receiving device are located in the measuring sub-section, and the measuring sub-section is connected with the control system;

The control system includes a storage module and an upload module, which are used for storing and transmitting echo signals, and controlling the rotation of the ultrasonic transmitting device and the ultrasonic receiving device;

The ultrasonic emitting device emits ultrasonic waves to the inner wall of the cased well at an incident angle _θi , and the ultrasonic wave excites the circumferential mode in the cased well, and each layer of the medium in the cased well reflects the ultrasonic wave to form a reflected wave, where the incident angle _θi is the radiation surface of the ultrasonic emitting device At the intersection of the central axis and the inner wall of the cased well, the angle between the central axis and the normal line;

The ultrasonic receiving device receives the echo signal and sends the echo signal to the storage module for storage. The upload module uploads the echo to the processing system, and the processing system compares the echo signal with the echo signal received in the free casing mode. , to obtain the cement bond quality corresponding to the position where the echo signal is formed in the cased hole.

Preferably, the ultrasonic receiving device is located between the intersection point and the reflection point.

Preferably, the reflection point is located at the intersection of the reflected wave emitted at the reflection angle θ _r from the self-intersection point and the inner wall of the cased well.

Preferably, the ultrasonic transmitting device includes a transmitting transducer and a transmitting sound system.

Preferably, the ultrasonic receiving device includes a receiving transducer and a receiving sound system.

Preferably, free casing is a cased well where the cement layer is completely fluid.

Preferably, the device for evaluating the cement bonding quality of the two interfaces of the cased well further includes a coupling block for better contact between the ultrasonic emitting device and the ultrasonic receiving device and the inner wall of the cased well.

Preferably, the device for evaluating the cement bonding quality of the interface between the cased hole and the cased well further includes a protection sub-joint for protecting the measurement sub-joint.

The embodiment of the utility model realizes a device for evaluating the cement bonding quality of the two interfaces of the cased well, which detects the cementing quality of the cement interface by exciting the lowest order circumferential mode generated in the cased well, and combines the ultrasonic emitting device with the The ultrasonic receiving devices are arranged at intervals in the horizontal circumferential direction in the cased well, which increases the amount of information contained in the echo signal. By placing one or more sets of ultrasonic emitting devices and ultrasonic receiving devices, or using the control system to rotate the ultrasonic emitting device and ultrasonic receiving device, the generated echo signal contains the overall structural information of the cased well, and matches the echo signal data. It can effectively detect the bonding condition of cement on different interfaces.

Description of drawings

Fig. 1 is a schematic diagram of a device for evaluating the cement bonding quality of the two interfaces of a cased well provided by an embodiment of the present invention;

Fig. 2 is a schematic diagram of the working principle of the ultrasonic transmitting device and the ultrasonic receiving device provided by the embodiment of the present invention;

Fig. 3 is a schematic diagram of the dispersion curve of the circumferential mode provided by the embodiment of the present invention;

Fig. 4 is a schematic diagram of different cement bonding states in a cased well provided by an embodiment of the present invention;

Fig. 5 is a schematic diagram of measurement waveforms in different cemented states provided by the embodiment of the present invention.

detailed description

The utility model will be described in detail, clearly and completely below in conjunction with the accompanying drawings and specific embodiments. In the accompanying drawings, it is obvious that the described embodiments are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

Schematic diagram of a device used to evaluate the quality of cement bonding at the interface of a cased well. As shown in Figure 1, the device includes: an ultrasonic transmitting device, an ultrasonic receiving device and a control system.

The ultrasonic transmitting device 101 includes a transmitting transducer and a transmitting sound system, and the ultrasonic receiving device 102 includes a receiving transducer and a receiving sound system. The ultrasonic transmitting device 101 and the ultrasonic receiving device 102 are located on the measuring sub-section 103 and are connected to the control system 104 ;

The control system 104 can control the rotation of the ultrasonic emitting device 101 and the ultrasonic receiving device 102 to adjust their relative positions in the cased well. In addition, the control system 104 also includes a storage module and an upload module, which are used to temporarily store echo signals with a large amount of data, and the stored signals are finally transmitted to the processing system 106 via the cable 105 for subsequent processing.

The protection nipple 107 is located in front of the measuring nipple 103, and is mainly used to protect the measuring nipple from being damaged by foreign objects ahead in the cased well during operation.

When the measuring device works in a cased well, the surrounding medium generally consists of fluid 108 , casing 109 , cement 110 and formation 111 from inside to outside.

Specifically, the ultrasonic transmitting device 101 and the ultrasonic receiving device 102 are arranged at intervals in the circumferential direction, and placed horizontally into the cased well. In one example, the ultrasonic wave is excited at a point in the cased well (where the ultrasonic transmitting device 101 is located), and there is a certain distance between the ultrasonic receiving device 102 and the excitation source, and the echo signal received by the ultrasonic receiving device includes information about the ultrasonic emission. The structural integrity information between the two points of the device and the ultrasonic receiving device can detect one surface of the cased well at one time, greatly improving the detection efficiency.

In one example, the control system 104 can control the angular orientation of the ultrasonic emitting device 101 and the ultrasonic receiving device 102 in the cased well, so as to achieve the purpose of detecting the circumferential cementation in the cased well within the range of 0 to 360 degrees. The ultrasonic transmitting device 101 transmits ultrasonic waves to the inner wall of the cased well at an incident angle θ _i , the ultrasonic waves excite the circumferential mode in the cased well, and each layer of the medium in the cased well reflects the ultrasonic waves to form reflected waves, where the incident angle θ _i is the angle of the ultrasonic transmitting device 101 The angle between the central axis and the normal at the intersection of the central axis of the radial surface and the inner wall of the cased well.

Fig. 2 is a schematic diagram of the working principle of the ultrasonic transmitting device and the ultrasonic receiving device provided by the embodiment of the present invention. The media from the inside to the outside in the cased well in Fig. 2 are fluid 201, casing 202, cement 203 and formation 204, respectively. The ultrasonic waves emitted by the ultrasonic emitting device 205 are emitted to the inner wall of the casing in the form of rays, and the included angle θi between the rays and the normal direction at the intersection point A of the inner wall of the casing is θ _i . The ultrasonic emission device 205 excites ultrasonic waves into the cased well at an incident angle _θi , and the ultrasonic waves propagate along the casing wall in the circumferential direction (circumferential mode). , and one and multiple reflections occur on the first interface and the second interface, and the other part passes through the cement and the formation.

In an example, the fluid filled in the cased well is water, and the inner and outer radii of the casing are 0.11m and 0.122m respectively, and the dispersion curves of the circumferential modes in the fluid-filled casing and the hollow casing are obtained through numerical calculation. As shown in FIG. 3 , the horizontal axis in FIG. 3 represents the frequency, and the vertical axis represents the incident angle of the ultrasonic waves emitted by the ultrasonic emitting device to the inner wall of the casing. The dotted line 301 in the figure indicates the circumferential mode in the hollow tube, and the solid black line 302 indicates the circumferential mode in the liquid-filled tube. The analysis shows that when the frequency of the transmitted sound wave is between 100 kHz and 200 kHz, and the incident angle is between 20 degrees and 30 degrees, the mode at the position of the velocity "plateau" formed by multiple modes in the liquid-filled tube contributes to the received waveform. At maximum, this velocity "plateau" roughly coincides with the lowest order circumferential mode in the hollow tube. Therefore, in this embodiment, the optimum ultrasonic frequency emitted by the ultrasonic emitting device 25 is between 100 kHz and 200 kHz, and the incident angle should be between 20 and 30 degrees.

In one example, the ultrasonic receiving device 206 receives the echo signal, and compares and processes the echo signal actually measured in the cased hole with the echo signal received in the free casing mode to obtain the formation of the echo signal in the cased hole The location corresponds to the cement bond quality.

Specifically, the ultrasonic receiving device 206 at a certain angle to the ultrasonic emitting device can receive echo signals, and these signals mainly include two parts, one part is the reflected wave from the fluid-casing interface, and the other part is the excited circumferential mode in the Reflected waves generated by interaction with different media while propagating in a cased hole. The latter is mainly from the reflected waves generated on the first interface and the second interface. Considering that the amount of data of the echo signal received by the receiving device 206 is relatively large, the speed at which downhole data is transmitted to the surface is currently relatively low. Therefore, the received signal in this embodiment will be temporarily stored in the control system 104, and then the stored data will be uploaded to the processing system 106 through the cable 105 for subsequent processing. When the cementation quality of the two interfaces cemented with cement in the cased hole is different, the shape of the received signal is different. Like other cementing quality acoustic logging devices in the field, when using the received signal to evaluate the cementing quality, the measured signal should be compared with the received signal in the free casing cemented state in the same cased well environment.

The device for evaluating the cement bonding quality of the two interfaces of the cased well also includes a coupling block, which is used for better contact between the ultrasonic transmitting device and the ultrasonic receiving device and the inner wall of the cased well. In one example, in order to ensure better contact between the ultrasonic emitting device and the ultrasonic receiving device and the inner wall of the cased well, a coupling block may be loaded on the ultrasonic emitting device and the ultrasonic receiving device.

The ultrasonic receiving device is located between the intersection point and the reflection point. As shown in Figure 2, the position of the ultrasonic receiving device should be located between the circumferential angles determined by two points. segment best.

It should be noted that when the ultrasonic emitting device emits ultrasonic waves to the inner wall of the cased well, the incident angle _θi satisfies the velocity "platform" formed by the circumferential mode excited in the main frequency range of the sound source, and only corresponds to the hollow casing with the same parameters. The lowest-order mode excited in . As shown in Figure 2, the cased well in which the ultrasonic transmitting device 205 and the ultrasonic receiving device 206 work is a fluid-filled cased well, and the circumferential mode of excitation corresponds to part 302 in Figure 3, and the requirement for the incident angle is that of the circumferential mode generated by the excitation. The "platform" formed by the dispersion curve is consistent with the lowest-order mode in the hollow tube, that is, the lowest-order mode in part 301 in Figure 3, and only the lowest-order mode is required to be excited within the working frequency range of the sound source. In the frequency range of the sound wave emitted by the ultrasonic transmitting device 205, when the incident angle _θi is sufficient to mainly excite the sound wave of the lowest order circumferential mode in the casing, the advantage is that the mode wave contained in the signal received by the ultrasonic receiving device 206 propagates The speed is basically the same, which reduces the time-domain waveform dispersion and tailing phenomenon caused by different mode wave propagation speeds, and is beneficial to the application of received signals to detect and analyze the cementation quality of different cement cementation interfaces.

The ultrasonic receiving device is located between the intersection point and the reflection point. As shown in Figure 2, the position of the ultrasonic receiving device should be located between the circumferential angles determined by two points. segment best.

The reflection point is located at the intersection of the reflected wave emitted at the reflection angle θ _r from the self-intersection point and the inner wall of the cased well. As shown in Figure 2, point B refers to the intersection point after the reflected wave emitted from point A at the reflection angle θ _r (which is equal to the incident angle θ _i in value) reaches the inner wall of the casing.

Free casing is a cased well where the cement layer is completely fluid. As shown in Figure 4, the medium from inside to outside in the cased well of the embodiment of the utility model is fluid 401, casing 402, cement 403 and formation 404. When the cement layer is completely fluid 405, it is called free casing. The fluid 405 here may be the same as the fluid 401 or different.

The echo signal mainly includes two parts, one is the reflected wave from the fluid-casing interface, and the other is the reflected wave generated by the interaction of the excited circumferential mode with different media when propagating in the cased well. As shown in Figure 2, the ultrasonic emitting device 205 emits directional ultrasonic waves to the inner wall of the casing, and this part of the sound waves can excite the circumferential modes in the casing 202, and the appropriate incident angle _θi mainly excites the stronger lowest-order mode, A part of the sound wave in the circumferential mode propagates in the casing, and the part propagating in the casing is first received by the ultrasonic receiving device 206, and the other part propagates into the cement 203 and the formation 204, and is transmitted between the casing 202 and the cement 203. Reflected waves and transmitted waves are formed on the cemented surface and the cemented surface between the cement 203 and the formation 204 , and the reflected wave part can be finally received by the ultrasonic receiving device 206 .

In the process of processing the echo signal, a time window is taken, and the average energy of the waveform in the time window is calculated, and the average energy of the time window taken at the detection position is compared with the average energy of the waveform in the same time window of the free casing method to obtain the relative amplitude. value, and use it to evaluate the cement bonding quality of the cased well interface. Typically, there are four cement states in a cased well. As shown in Figure 4, Figure 4 is divided into four areas A, B, C and D, where A area represents the state of the free casing; B area represents the interface between casing 402 and cement 403 where cement is missing, and the missing layer consists of Fluid 405 is replaced, which is a state of missing interface; area C indicates that cement and casing 402 and formation 404 are well cemented respectively, which is a state of complete cementation; area D indicates that cement is missing on the interface between cement 403 and formation 404, and the missing layer It is replaced by fluid 405, which is the state where the two interfaces are missing. In one example, assuming that the fluid in the cement missing part is water, the measurement waveforms under four different cementation states are respectively given. The placement of the ultrasonic receiving device is basically the same as that of the ultrasonic receiving device 206 shown in FIG. 2 . Specifically, the included angle with the r-axis in the radial direction is 40°, and the received waveforms in four cemented states are respectively shown. As shown in Figure 5, 501 in Figure 5 is the received signal in the free casing state, 502 is the received signal in the cemented state of the first interface, 503 is the received signal in the cemented state of the two interfaces, and 504 is the received signal in the fully cemented state . Window processing is performed on the received signals under different cementation states respectively, and the average energy of the signal in a certain time window under different cementation states is obtained. The calculation formula can be expressed as In the formula, t ₀ and t ₁ represent the start and end time of the time window for processing the received signal, respectively. t ₀ should be around the arrival time of the circumferential mode wave from the casing and cement bonded surface, and t ₁ should be around 3-5 cycles after the arrival time of the circumferential mode wave from the cement and formation bonded surface; A _i is within the time window The amplitude corresponding to the collection point; n _t is the number of collection points in the time window. In this embodiment, the start and end times of the processing window are t ₀ =0.066ms and t ₁ =0.091ms respectively.

Furthermore, based on the average energy of the signal in the time window obtained under the condition of free casing, the average energy obtained under several other cemented states is compared with the value of free casing, and different ratios are obtained. The calculation results show that the ratios of fully cemented, missing one interface and missing two interfaces to free casing are 0.34, 1.67 and 2.47, respectively. It can be seen that under different cementation states, the average energy of the signal in the time window is different, among which the relative energy of complete cementation is the lowest, and the relative energy of the absence of two interfaces is the highest. In addition, during actual processing, the position of the time window can be appropriately moved according to parameters such as casing specification and cement thickness in the cased well.

According to the relative position of the ultrasonic emitting device and the ultrasonic receiving device, place one or more groups of ultrasonic emitting devices and ultrasonic receiving devices, or use the control system to rotate the ultrasonic emitting device and ultrasonic receiving device to detect the cement bonding quality of the two interfaces around the well . If the same group of transmitting and receiving devices is used for circumferential rotation measurement, or multiple groups of transmitting and receiving devices are arranged along the inner wall of the casing, the receiving signals at different angles and azimuths at the same depth point can be obtained. Furthermore, the received signals at different depths and different circumferential orientations can be obtained by measuring at different depth points. By properly processing the received signal, a two-dimensional grayscale image reflecting the cementation state of the cement is finally obtained, and the cementation quality imaging result map of the two interfaces is obtained by judging the amplitude of the grayscale image.

The utility model provides a device and technology for ultrasonically detecting the cementation of the two interfaces of cementing in a casing well. Quality, while the technique can also be used to judge the situation of complete cementation and a missing interface.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present utility model in detail. Within the protection scope of the utility model, any modification, equivalent replacement, improvement, etc. within the spirit and principles of the utility model shall be included in the protection scope of the utility model.

Claims (8)

1. for evaluating a device for cased well second interface Cementation Quality, it is characterized in that, described device comprises: ultrasonic transmission device, ultrasonic probe, ultrasonic receiver and control system;

Described ultrasonic transmission device and described ultrasonic probe, ultrasonic receiver are positioned at measurement pipe nipple, and described measurement pipe nipple is connected with described control system;

Described control system comprises storage module and upper transmission module, for storage and the transmission of echo-signal, and, control the rotation of described ultrasonic transmission device and described ultrasonic probe, ultrasonic receiver;

Described ultrasonic transmission device is with incidence angle θ _iwall emission ultrasonic wave in cased well, described ultrasonic wave encourages circumferential pattern in described cased well, and in described cased well, ultrasonic wave described in each layer dieletric reflection forms back wave, wherein, described incidence angle θ _ithe radiating surface axis of described ultrasonic transmission device and the point of intersection of described cased well inwall, the angle of described axis and normal;

Described ultrasonic probe, ultrasonic receiver receives echo-signal, and described echo-signal is sent to memory module stores, described echo is uploaded to treatment system by described upper transmission module, the echo-signal received under described echo-signal and free pipe mode is carried out contrast and is processed by described treatment system, obtains the Cementation Quality that in cased well, echo-signal forming position is corresponding.

2. device according to claim 1, is characterized in that, described ultrasonic probe, ultrasonic receiver is between described intersection point and pip.

3. device according to claim 2, is characterized in that, described pip is positioned at from described intersection point with angle of reflection θ _rthe intersection point of the back wave sent and described cased well inwall.

4. device according to claim 1, is characterized in that, described ultrasonic transmission device comprises transmitting transducer and launches sonic system.

5. device according to claim 1, is characterized in that, described ultrasonic probe, ultrasonic receiver comprises receiving transducer and receives sonic system.

6. device according to claim 1, is characterized in that, the cased well of described free pipe to be cement layer be completely fluid.

7. device according to claim 1, is characterized in that, described device also comprises coupling block, better contacts with described ultrasonic probe, ultrasonic receiver for described ultrasonic transmission device with described cased well inwall.

8. device according to claim 1, is characterized in that, described device also comprises protection pipe nipple, for the protection of described measurement pipe nipple.