A wellbore integrity evaluation system and method

Abstract

The application provides a wellbore integrity evaluation system and method, and belongs to the field of drilling and cementing technology in oil and gas exploitation. The application adopts a casing-out monitoring short circuit which is directly connected with a casing and is lowered along with the casing. The casing-out monitoring short circuit contains a detection system to facilitate detection of casing damage and deformation and formation temperature and pressure parameters, and transmits signals back to a ground working system through a umbilical cable. The application can realize real-time detection and monitoring of casing damage and deformation and formation temperature and pressure parameters in the process of cementing and oil and gas reservoir exploitation, and evaluate wellbore integrity. The application is favorable for analyzing and predicting the stress state of the downhole casing and the changes of formation temperature and pressure, and has great positive significance for long-term development of oil and gas reservoirs.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of drilling and cementing technology in oil and gas exploitation, and particularly relates to a wellbore integrity evaluation system and method. BACKGROUND

[0002] The oil casing is an important component of the wellbore string in the oil and gas field, and mainly plays a role in fixing the well wall and preventing the well wall from collapsing in the traditional wellbore string engineering of the oil and gas field, and is the most important entity barrier in the channel for conveying oil and gas resources from the well bottom to the ground. At present, China is facing severe challenges in the exploration and exploitation of oil and gas fields. Due to different geological conditions, the stress state under the well is complex, and the casing body is subjected to the combined action of tension, compression, bending and torsion, which puts higher requirements on the quality and integrity of the casing itself. The casing string integrity mainly reflects the sealing property and the regularity of the cross-sectional shape. Due to the long-term development of oil fields by the water injection method, the geological activities in the deep formation are intensified, and many factors such as acidizing and fracturing reconstruction, repeated downhole operations and corrosion can cause the casing to deform to different degrees (including casing diameter reduction, casing bending at one or more places, casing flattening, severe bending deformation, casing rupture and breakage, etc.). In some easy-caving formations or formations with poor cementing quality, the casing deformation is particularly serious. Once the casing itself deforms or is damaged due to some reasons, it may lead to production reduction or even abandonment of the whole well, which seriously affects the safety and efficiency of the oil and gas field and causes huge economic losses. Therefore, the casing deformation and damage problem has attracted great attention in the development of oil and gas resources in the world. If the casing deformation during fracturing operation can be effectively monitored and evaluated, and the information such as the deformation position, deformation degree and formation parameters of the downhole casing is obtained in a timely and accurate manner, preventive measures can be taken in the first time to ensure the integrity of the wellbore and guide the implementation of subsequent operations, well repair, perforation and fracturing, which will have great positive significance for the long-term development of oil and gas reservoirs.

[0003] At present, the commonly used detection methods for casing deformation in the process of oil and gas exploitation mainly include mechanical multi-arm caliper logging, acoustic imaging logging, electromagnetic flaw detection logging and downhole video detection, etc. The casing deformation physical information is directly or indirectly transmitted back to the ground through logging means, and the logging interpretation information is used to guide the repair measures. The existing casing deformation detection technology cannot realize real-time monitoring and risk prediction of the downhole casing deformation, and the instrument needs to be lowered into the well to a certain depth before starting to work. During the detection, the well needs to be closed, which causes the production to be forced to stop, affecting the progress and production efficiency of oil and gas exploitation, and also causing damage risk to the instrument and the measured well. There are problems such as complicated detection steps, and the instrument lowered into the well is prone to resistance, sticking or falling.

[0004] The Chinese patent with the patent number CN202991012U discloses a multi-arm well bore imager, comprising a cable sealing head, an upper centralizer, a control member, an imaging arm sensor, a lower centralizer and a counterweight joint. The cable sealing head is connected to one end of the upper centralizer. The other end of the upper centralizer is connected to the control member through an extension arm. The control member is connected to the imaging arm sensor. The imaging arm sensor is connected to one end of the lower centralizer. The other end of the lower centralizer is connected to the counterweight joint through an extension arm. A plurality of monitoring arms are arranged around the imaging arm sensor. The tool is lowered into the well. The casing inner diameter, casing coupling and well temperature are monitored in real time through the monitoring arms, so as to infer the damage condition of the casing. The oil and gas exploitation is stopped during the monitoring of the tool lowering, which affects the progress and production efficiency of the oil and gas exploitation.

[0005] The Chinese patent with the patent number CN109708595A discloses a downhole casing damage detection method and device. The casing damage detection device is lowered into the downhole with the oil extraction pipe column to a set position. The surrounding casing is detected in real time by the casing damage detection device during the lowering process. After the casing damage detection device is lowered to the set position, the casing section at the set position is continuously monitored in real time by the casing damage detection device. When the oil and gas well pump is detected, the casing damage detection device is lifted with the oil extraction pipe column to the ground. The surrounding casing is detected in real time by the casing damage detection device during the lifting process. The method avoids the stoppage of oil and gas exploitation by installing the tool on the oil pipe. However, only one method is given, and the specific feasibility needs to be studied.

[0006] The Chinese patent with the patent number CN111594138A discloses a device for comprehensively testing casing working parameters. A ring-shaped interlayer is formed in the existing oil casing. Sensing elements corresponding to the parameters to be tested are fixedly arranged in the ring-shaped interlayer. The types and quantities of the sensing elements can be adjusted according to actual needs to measure related parameters. The sensing elements are connected to a data processing end through data lines. The device integrates a battery, transmission and detection. The device is integrated in the casing wall under the volume of the existing equipment, which makes the casing wall too thick and is not conducive to cementing.

[0007] Aiming at the problem that the casing deformation induced by current reservoir fracturing reconstruction cannot be realized real-time monitoring and evaluation, the Chinese patent with patent number CN112282730A discloses a real-time monitoring and evaluation method for casing deformation induced by reservoir fracturing reconstruction. The method adopts a combined working mode of horizontal well pumping setting bridge plug perforation and casing magnetic positioning measurement, uses a magnetic positioning instrument to measure casing coupling and casing magnetic anomaly in real time, and through the established casing deformation magnetic anomaly logging response mode and the analysis of casing magnetic anomaly characteristics, the real-time monitoring and evaluation of the casing deformation degree and development trend is realized. The method can infer the casing deformation state according to the piezomagnetic effect of the casing caused by stress before and after perforation fracturing, but the measured magnetic anomaly is easily affected by other forces such as pumping blockage and well deviation tension, which cannot effectively exclude the multiple solutions of logging interpretation. The established magnetic anomaly and casing deformation correlation model is based on the actual horizontal well casing deformation multi-arm well diameter logging detection results, which cannot guarantee the accuracy of the model. Moreover, the real-time monitoring process is only for the stages before and during perforation fracturing, and the casing deformation problem caused by the subsequent changes of reservoir pressure after fracturing is not fully considered. Therefore, the method has certain limitations in accuracy and practicability.

[0008] The Chinese patent with patent number CN202210073242.8 discloses a casing deformation wireless monitoring system for cementing, fracturing and production processes, which includes a downhole casing deformation wireless monitor, a transmission channel, a signal relay device and a ground receiving system. The main principle is to use the annular stress strain gauge in the downhole casing deformation wireless monitor to detect the deformation of the attached casing, and transmit the data to the ground through wireless transmission. The information such as the downhole casing deformation position, deformation degree and casing deformation point number is obtained on the ground, but the wireless transmission through the built-in lithium battery has limited power and cannot guarantee long-term real-time monitoring. At the same time, through the detection of a single annular stress strain gauge, the damage information of the formation casing cannot be accurately evaluated.

[0009] The current technology can solve the problem of wellbore integrity in some oil and gas wells to a certain extent, i.e. casing deformation damage problem, but the evaluation of wellbore integrity needs to consider casing deformation, sealing and other problems. Therefore, it is urgent to propose a comprehensive wellbore integrity detection / monitoring technology based on the existing technology to better solve the problem of frequent casing abnormal deformation in cementing and oil and gas reservoir exploitation. SUMMARY

[0010] In order to solve the problems in the prior art, the wellbore integrity evaluation system is provided, a short joint outside the casing is connected with the casing and is lowered along with the casing, the inside of the short joint contains a detection system, the deformation and damage of the casing and the formation temperature and pressure parameters are detected, and the signals are transmitted back to the ground working system through the umbilical cable.

[0011] The wellbore integrity evaluation system comprises a ground working system, a wired signal transmission system, a casing main mechanical structure, a data processing system and a detection system.

[0012] The ground working system is connected with the wired signal transmission system, and the wired signal transmission system, the data processing system and the detection system are arranged in the wellbore.

[0013] The ground working system is arranged on the ground, and the casing main mechanical structure is arranged in the wellbore.

[0014] The detection system can detect the displacement and deformation of the casing in the casing main mechanical structure, and transmit the detection information to the ground working system and the data processing system through the wired signal transmission system, the data processing system processes the detection information into digital signals, and the ground working system displays the detection information, and the data processing system transmits the processed digital signals to the ground working system through the wired signal transmission system.

[0015] Preferably, the ground working system comprises a signal receiving module, a data conversion module and a display module, the signal receiving module is used for receiving the data signals transmitted by the wired signal transmission system, the data conversion module converts the data signals, and the display module directly displays the converted data signals; the data conversion module converts the received digital signals into signals readable by a computer and processes the complex measurement data in the wellbore into the desired results; and the display module is used for displaying the related data and information of the casing and the formation in the wellbore.

[0016] Preferably, the wired signal transmission system receives the signals of the data processing system and transmits the signals to the ground working system, and the transmission mode of the wired signal transmission system is umbilical cable transmission.

[0017] Preferably, the casing body mechanical structure comprises a casing upper joint, a wire hole, a casing sealing outer wall, a hollow sandwich, a casing inner wall, a casing lower joint and a reinforcing rib plate, the casing upper joint and the casing lower joint are respectively detachably connected with the casing, the wire hole is arranged on the casing, the hollow sandwich is arranged between the casing sealing outer wall and the casing inner wall, and the reinforcing rib plate is arranged between the casing sealing outer wall and the casing inner wall.

[0018] Preferably, the wire hole is arranged on the casing sealing outer wall, and a wire hole is further arranged on the reinforcing rib plate.

[0019] Preferably, the detection system comprises a strain sensor, a displacement sensor, a temperature sensor, a formation pressure sensor and an ultrasonic sensor.

[0020] Preferably, the strain sensor comprises a lead wire, a cover sheet, a sensitive grid and a substrate, the sensitive grid is arranged on the substrate, the cover sheet covers the sensitive grid, and the lead wire is connected with the cover sheet.

[0021] Preferably, the sensitive grid is curved into a grid shape by a wire with a diameter of 0.01-0.05 mm, and the sensitive grid is fixed on the substrate by an adhesive.

[0022] Preferably, four strain sensors form a ring-shaped sensing strain sensor group, each group of ring-shaped sensing strain sensor groups is uniformly distributed at an angle of 90° in the hollow sandwich of the casing body mechanical structure, and two groups of ring-shaped sensing strain sensor groups are arranged, one group of which detects the circumferential strain of the casing to measure the extrusion deformation of the casing, and the other group detects the axial strain of the casing to correspondingly measure the bending deformation of the casing.

[0023] Preferably, the temperature sensor and the formation pressure sensor are fixed in the hollow sandwich to measure the formation temperature and pressure at the position of the casing segment, to evaluate the wellbore sealing property and fluid flow rule through continuous measurement of the formation temperature and pressure, and to provide direct data for the life prediction of the wellbore and the reasonable exploitation and dynamic evaluation of the oil and gas reservoir, and the ultrasonic sensor is fixed in the hollow sandwich.

[0024] Preferably, the hollow sandwich has four cavities, the displacement sensor and the temperature sensor are respectively installed in different cavities, the displacement sensor is packaged and fixed according to the shape of the hollow sandwich, the temperature sensing element of the temperature sensor is attached to the casing sealing outer wall, the formation pressure sensor is fixed in the hollow sandwich, the stress surface of which can be attached to the casing sealing outer wall, and the ultrasonic sensor is divided into an acoustic wave generating device and an acoustic wave receiving device, which are respectively installed in two cavities and connected by a wire in the middle.

[0025] Preferably, the formation pressure sensor comprises a force transmission upper cover, a piezoelectric sheet, an electrode, an electrode lead plug, two insulating blocks and a base, one end of one of the two insulating blocks extends out of one end of the base, the other insulating block is located inside the other end of the base, the electrode is installed between the two insulating blocks, one end of the electrode extends out of one end of the insulating block and is connected with the electrode lead plug, the piezoelectric sheet is wrapped outside the electrode and is attached to the electrode, the force transmission upper cover is installed above the piezoelectric sheet opposite to the base, when the force transmission upper cover is stressed to change the stress, the piezoelectric sheet is extruded by the force transmission upper cover to change the resistance of the piezoelectric sheet, so that the voltage applied to the piezoelectric sheet changes, the voltage is transmitted to an instrument amplifier through the electrode lead plug for amplification, and then transmitted to a data processing system to obtain the pressure value.

[0026] Preferably, two ultrasonic sensors are installed on a horizontal plane, and the detection direction is axial, and the detection is performed on the inner diameter of the casing.

[0027] Preferably, the data processing system comprises a sensor data processing component and a circuit microprocessor interface, and the sensor data processing component is composed of a signal processing microchip.

[0028] Preferably, the circuit microprocessor interface comprises a power supply interface, a signal input interface, a chip reset interface, a ground interface and a plurality of signal output interfaces, the power supply interface is connected with a power supply; the signal input interface inputs a signal to the circuit microprocessor; when the signal is input to the circuit microprocessor and the detection system does not work, the chip is automatically restarted through the chip reset interface at this time; the plurality of signal output interfaces are respectively connected with different working sensors to control the working sensors connected therewith.

[0029] The application provides a wellbore integrity evaluation method, which is used for any wellbore integrity evaluation system and comprises the following steps:

[0030] The strain sensor is used for local measurement of axial strain and circumferential strain of the casing;

[0031] The displacement sensor determines the displacement of the casing during the movement change of the formation;

[0032] The temperature sensor and the formation pressure sensor measure the formation temperature and pressure at the position of the casing segment;

[0033] The ultrasonic sensor judges the surface hole and the ovality information of the casing;

[0034] The above sensors are used for monitoring the deformation position, deformation degree, deformation quantity of the casing and the formation temperature and pressure parameters, and the damage, destruction and sealing performance of the wellbore are evaluated.

[0035] Compared with the prior art, the application has the following beneficial effects:

[0036] 1. The application adopts a wired transmission mode, which transmits data and provides power for downhole sensors at the same time. The downhole casing deformation and formation temperature and pressure can be detected and monitored in real time for a long time.

[0037] 2. The displacement sensor of the application records the initial position information after the casing is fixed and transmits the information to the ground working system to establish the initial oil and gas well coordinate system. When the casing emits deformation or displacement, the displacement sensor calculates the displacement amount and transmits the displacement amount to the ground working system. At this time, the ground system calculates new position information according to the displacement amount. According to the comparison between the new coordinate and the initial coordinate, the displacement information of the casing can be directly observed, so that the deformation amount and damage degree of the casing can be evaluated.

[0038] 3. The application increases temperature and pressure sensors. Various sensors cooperate with each other to accurately obtain the position, deformation condition, formation temperature and pressure of the corresponding casing in the well. The wellbore integrity is comprehensively evaluated, which is of great significance for guiding wellbore repair, repeated fracturing and optimizing production parameters.

[0039] 4. The application adopts an ultrasonic sensor to detect the ovality information of the casing. In the later period, the service life of the casing can be comprehensively evaluated according to the ovality information of different short casings, and basic information for later casing repair can be provided.

[0040] 5. The application continuously measures the formation temperature and pressure of the position where the monitoring short circuit of the casing is located to evaluate the downhole fluid rule and provide direct data for rational exploitation and dynamic evaluation of oil and gas reservoirs.

[0041] 6. The application does not need to lower other logging tools, avoids the problems of downhole instrument resistance, sticking or falling, does not need to shut down the well, and the detection process is independent and simple, does not affect other construction operations, reduces the risk, and ensures the exploitation progress and production efficiency of the oil and gas well. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The figure is a schematic diagram of the device for detecting casing and formation parameters in situ in an embodiment of the application;

[0043] Figure 2 The figure is a schematic diagram of the device for detecting casing and formation parameters in situ in an embodiment of the application; Figure 1 The figure is a partial enlarged view of A in the figure;

[0044] Figure 3 The figure (a) is a schematic diagram of the mechanical structure of the casing body in an embodiment of the application, and the figure (b) is a B-B cross-sectional view of (a);

[0045] Figure 4 The figure is a schematic diagram of the data processing system control chip structure in an embodiment of the application;

[0046] Figure 5 The hollow sandwich of one embodiment of the application is provided with a detection setting display intention;

[0047] Figure 6 The formation pressure sensor structure of one embodiment of the application is shown schematically;

[0048] Figure 7 The strain sensor structure of one embodiment of the application is shown schematically;

[0049] Figure 8 The working block diagram of the wellbore integrity evaluation system of one embodiment of the application is shown;

[0050] In the figure: 1-ground working system; 2-wired signal transmission system; 3-casing body mechanical structure; 4-data processing system; 5-detection system; 101-casing upper joint; 102-threading hole; 103-casing sealing outer wall; 104-hollow sandwich; 105-casing inner wall; 106-casing lower joint; 107-stiffening rib plate; 108-wire hole; 301-power supply interface; 302-signal input interface; 303-chip reset interface; 304-grounding interface; 305-first signal output interface; 306-second signal output interface; 307-third signal output interface; 308-fourth signal output interface; 401-strain sensor; 402-displacement sensor; 403-temperature sensor; 404-formation pressure sensor; 405-ultrasonic sensor; 501-force transmission upper cover; 502-piezoelectric sheet; 503-electrode; 504-electrode lead-out plug; 505-insulating block; 506-base; 601-lead wire; 602-cover sheet; 603-sensitive grid; 604-substrate. DETAILED DESCRIPTION

[0051] The specific embodiments of the application will be described in detail below with reference to the accompanying drawings.

[0052] The application provides a wellbore integrity evaluation system, which comprises a ground working system 1, a wired signal transmission system 2, a casing body mechanical structure 3, a data processing system 4 and a detection system 5.

[0053] The ground working system 1 is connected to the wired signal transmission system 2, and the wired signal transmission system 2, the data processing system 4 and the detection system 5 are arranged in the wellbore; the wired signal transmission system 2 is connected to the data processing system 4 and the detection system 5.

[0054] The ground working system 1 is arranged on the ground, and the casing body mechanical structure 3 is arranged in the wellbore.

[0055] The detection system 5 can detect the displacement and deformation of the casing in the casing body mechanical structure 3, and transmit the detection information to the ground working system 1 and the data processing system 4 through the wired signal transmission system 2. The data processing system 4 processes the detection information into digital signals, and the ground working system 1 displays the detection information. The data processing system 4 transmits the processed digital signals to the ground working system 1 through the wired signal transmission system 2.

[0056] According to a specific embodiment of the present application, the ground working system 1 comprises a signal receiving module, a data conversion module and a display module. The signal receiving module is used to receive the data signals transmitted by the wired signal transmission system 2, and the data conversion module converts the received digital signals into signals readable by a computer and processes the complex measurement data in the well into the desired results. The display module is used to display the related data and information of the casing and the formation in the well.

[0057] According to a specific embodiment of the present application, the wired signal transmission system 2 receives the signals from the data processing system 4 and transmits them to the ground working system 1. The wired signal transmission system 2 transmits the signals in the form of umbilical cable transmission.

[0058] According to a specific embodiment of the present application, the casing body mechanical structure 3 comprises a casing upper joint 101, a wire passing hole 102, a casing sealing outer wall 103, a hollow sandwich layer 104, a casing inner wall 105, a casing lower joint 106 and a reinforcing rib plate 107. The casing upper joint 101 and the casing lower joint 106 are respectively detachably connected with the casing. The wire passing hole 102 is arranged on the casing. The hollow sandwich layer 104 is arranged between the casing sealing outer wall 103 and the casing inner wall 105. The reinforcing rib plate 107 is arranged between the casing sealing outer wall 103 and the casing inner wall 105.

[0059] According to a specific embodiment of the present application, the wire passing hole 102 is arranged on the casing sealing outer wall 103, and a wire hole 108 is further arranged on the reinforcing rib plate 107.

[0060] According to a specific embodiment of the present application, the detection system 5 comprises a strain sensor 401, a displacement sensor 402, a temperature sensor 403, a formation pressure sensor 404 and an ultrasonic sensor 405.

[0061] According to a specific embodiment of the present application, the strain sensor 401 comprises a lead wire 601, a cover sheet 602, a sensitive grid 603 and a substrate 604. The sensitive grid 603 is arranged on the substrate 604, the cover sheet 602 covers the sensitive grid 603, and the lead wire 601 is connected with the cover sheet 602.

[0062] According to a specific embodiment of the present application, the sensitive grid 603 is curved into a grid shape by a wire with a diameter of 0.01-0.05 mm, and the sensitive grid 603 is fixed on the substrate 604 by an adhesive.

[0063] According to a specific embodiment of the present application, four strain sensors 401 form a ring-shaped sensing strain sensor 401 group, and each ring-shaped sensing strain sensor 401 group is uniformly distributed at an angle of 90° in the hollow interlayer 104 of the casing body mechanical structure 3. Two ring-shaped sensing strain sensor 401 groups are arranged, one of which detects the circumferential strain of the casing to measure the extrusion deformation of the casing, and the other detects the axial strain of the casing to measure the bending deformation of the casing.

[0064] According to a specific embodiment of the present application, the temperature sensor 403 and the formation pressure sensor 404 are fixed in the hollow interlayer 104 to measure the formation temperature and pressure at the location of the casing segment, to evaluate the wellbore sealing and fluid flow law by continuously measuring the formation temperature and pressure, and to provide direct data for the life prediction of the wellbore and the reasonable exploitation and dynamic evaluation of the oil and gas reservoir; the ultrasonic sensor 405 is fixed in the hollow interlayer 104.

[0065] According to a specific embodiment of the present application, the hollow interlayer 104 has four cavities, and the displacement sensor 402 and the temperature sensor 403 are respectively installed in different cavities; the displacement sensor 402 is packaged and fixed according to the shape of the hollow interlayer 104; the temperature sensing element of the temperature sensor 403 is attached to the casing sealing outer wall 103; the formation pressure sensor 404 is fixed in the hollow interlayer 104, and its stress surface can be attached to the casing sealing outer wall 103; the ultrasonic sensor 405 is divided into a sound wave generating device and a sound wave receiving device, which are respectively installed in two cavities and connected by wires in the middle.

[0066] According to one specific embodiment of the present application, the formation pressure sensor 404 comprises a force transmission upper cover 501, a piezoelectric sheet 502, an electrode 503, an electrode lead-out plug 504, two insulating blocks 505 arranged on a base 506, one end of one insulating block 505 extending out of one end of the base 506, and the other insulating block 505 located inside the other end of the base 506, the electrode 503 being installed between the two insulating blocks 505, one end of the electrode 503 extending out of one end of the insulating block 505 and being connected with the electrode lead-out plug 504, the piezoelectric sheet 502 being wrapped outside the electrode 503 and being attached to the electrode 503, and the force transmission upper cover 501 being installed above the piezoelectric sheet 502 opposite to the base 506, when the force transmission upper cover 501 is stressed to change the stress, the piezoelectric sheet 502 is extruded by the force transmission upper cover 501 to change the resistance of the piezoelectric sheet 502, so that the voltage applied to the piezoelectric sheet 502 is changed, the voltage is transmitted to an instrument amplifier through the electrode lead-out plug 504 for amplification, and then transmitted to the data processing system 4 to obtain the pressure value.

[0067] According to one specific embodiment of the present application, two ultrasonic sensors 405 are installed on the horizontal plane, forming an angle of 180°, and detecting the axial direction and the inner diameter of the casing, and detecting the casing ovality according to the reflection time of the sound wave.

[0068] According to one specific embodiment of the present application, the data processing system 4 comprises a sensor data processing component and a circuit microprocessor interface, and the sensor data processing component is composed of a signal processing microchip.

[0069] According to one specific embodiment of the present application, the circuit microprocessor interface comprises a power supply interface 301, a signal input interface 302, a chip reset interface 303, a ground interface 304, and a plurality of signal output interfaces, the power supply interface 301 being connected with a power supply; the signal input interface 302 inputting signals to the circuit microprocessor; when the signals are input to the circuit microprocessor and the detection system 5 does not work, the system automatically restarts the chip through the chip reset interface 303; and the plurality of signal output interfaces are respectively connected with different working sensors to individually control the working sensors connected therewith, thereby improving the overall efficiency of the tool.

[0070] The present application provides a wellbore integrity evaluation method for any wellbore integrity evaluation system described above, comprising the following steps:

[0071] The strain sensor 401 is used to locally measure the axial strain and the circumferential strain of the casing;

[0072] The displacement sensor 402 determines the displacement of the casing during the movement change of the formation;

[0073] The temperature sensor 403 and the formation pressure sensor 404 measure the formation temperature and pressure at the position of the casing nipple;

[0074] The ultrasonic sensor 405 judges the surface hole and ellipticity information of the casing;

[0075] The casing deformation position, deformation degree, casing deformation quantity, and formation temperature and pressure parameters are monitored by using the above sensors, and the damage, destruction, and sealing of the wellbore are evaluated.

[0076] Embodiment 1

[0077] According to one specific embodiment of the present application, the wellbore integrity evaluation system of the present application is described in detail below.

[0078] As shown in Figure 1 , a wellbore integrity evaluation system for evaluating wellbore integrity by monitoring downhole temperature and pressure and casing deformation, comprising a ground working system 1, a wired signal transmission system 2, a casing main mechanical structure 3, a data processing system 4, and a detection system 5.

[0079] As shown in Figures 2 to 8 , the ground working system 1 comprises a signal receiving module, a data conversion module, and a display module, the signal receiving module is used to receive data signals transmitted by the wired signal transmission system 2, and after conversion by the data conversion module, the data signals are directly displayed by the display module; the data conversion module converts the received digital signals into signals readable by a computer and processes the complex downhole measurement data through corresponding software to obtain the desired results; the display module is used to display the relevant data and information of the downhole casing and formation.

[0080] In this embodiment, the wired signal transmission system 2 receives signals from the data processing system 4 and transmits them to the ground working system 1, thereby playing a data transmission function, and the transmission mode of the wired signal transmission system 2 is umbilical cable transmission.

[0081] In this embodiment, the casing main mechanical structure 3 comprises a casing upper joint 101, a wire passing hole 102, a casing sealing outer wall 103, a hollow interlayer 104, a casing inner wall 105, a casing lower joint 106, and a reinforcing rib plate 107, and the casing upper joint 101 and the casing lower joint 106 are respectively connected with the casing by threads.

[0082] In this embodiment, the data processing system 4 processes the data of the sensors in the detection system 5 into transmittable digital signals.

[0083] In this embodiment, the detection system 5 comprises a strain sensor 401, a displacement sensor 402, a temperature sensor 403, a formation pressure sensor 404, and an ultrasonic sensor 405.

[0084] In the embodiment, the sleeve body mechanical structure 3 is designed with hollow sandwich layers 104 for accommodating the data processing system 4 and the detection system 5, the hollow sandwich layers 104 are distributed circumferentially, the number is 4, reinforcing rib plates 107 are designed between adjacent hollow sandwich layers 104, the reinforcing rib plates 107 are provided with wire holes 108, which strengthens the strength of the sleeve body mechanical structure 3 and facilitates data transmission between each hollow sandwich layer 104.

[0085] In the embodiment, the number of the hollow sandwich layers 104 can be specially designed according to the shape and placement position of various sensors, so as to better realize the detection function.

[0086] In the embodiment, the sleeve sealing outer wall 103 is provided with a wire passing hole 102, so that the internal cable is connected with the external cable for transmitting data and electric energy.

[0087] In the embodiment, the sleeve upper joint 101 and the sleeve lower joint 106 of the main body mechanical structure 1 are provided with threads on the surface for connecting with other sleeves.

[0088] In the embodiment, the strength of the sleeve body mechanical structure 3 itself meets the requirements of downhole operation, the size is the same as that of the normal sleeve, and the circulation of the cement slurry is ensured in the cementing process.

[0089] In the embodiment, the wire hole 108 contains a circuit, which connects the strain sensor 401, the displacement sensor 402, the temperature sensor 403, the formation pressure sensor 404 and the ultrasonic sensor 405 in the detection system 5 in different hollow sandwich layers 104, transmits and collects different data in the data processing system 4, and finally transmits through the wired signal transmission system 2. The whole structure requires good sealing, so waterproof and mud-resistant packaging methods should be used in the packaging process.

[0090] In the embodiment, the wired signal transmission system 2 adopts umbilical cable transmission, which can not only transmit detection parameters, but also provide electric energy for downhole equipment; the umbilical cable is fixed on the outside of the sleeve, and as the sleeve enters the oil and gas well, the umbilical cable is connected with different sleeve short sections through the wire passing hole 102, and the phase angle should be optimized for accurate perforation to avoid the cable. The umbilical cable structure is fine, anti-bending and stretching, anti-corrosion and not easy to damage, and the cost is low.

[0091] In the embodiment, the data processing system 4 is divided into a sensor data processing assembly composed of a general signal processing microchip.

[0092] In the embodiment, the circuit microprocessor interface has: a power supply interface 301, a signal input interface 302, a chip reset interface 303, a ground interface 304, a signal output 1 interface 305, a signal output 2 interface 306, a signal output 3 interface 307, and a signal output 4 interface 308. The power supply interface 301 is connected with a power supply. The signal input interface 302 inputs a signal to the circuit microprocessor. The function of the standby signal input interface 303 is to automatically enable the standby signal input interface 303 if the signal input interface 302 is damaged and cannot input a signal. The function of the chip reset interface 303 is to automatically restart the chip if the signal input to the circuit microprocessor is not detected by the system 5. The signal output 1 interface 305, the signal output 2 interface 306, the signal output 3 interface 307, and the signal output 4 interface 308 can be respectively connected with different working sensors, and the working sensors can be individually controlled to improve the overall efficiency of the tool.

[0093] In the embodiment, the detection system 5 includes a strain sensor 401, a displacement sensor 402, a temperature sensor 403, a formation pressure sensor 404, and an ultrasonic sensor 405.

[0094] In the embodiment, the strain sensor 401 mainly includes a lead wire 601, a cover sheet 602, a sensitive grid 603, and a substrate 604. The sensitive grid 603 is a grid-shaped sensitive part of a strain gauge sensing member, which is formed by bending a thin wire with a diameter of 0.01-0.05 mm and a high resistance coefficient. The sensitive grid 603 is fixed on the substrate 604 by an adhesive. The function of the substrate 604 is to accurately transmit the strain on the member to the sensitive grid. One piece of the strain sensor 401 can measure the strain of the casing. In order to measure more comprehensively and accurately, four pieces form a ring-shaped sensing strain sensor group, which is uniformly distributed at an angle of 90° in the hollow layer 103 of the main mechanical structure 1. There are two ring-shaped sensing strain sensor groups in total. One of the ring-shaped sensing strain sensor groups detects the circumferential strain of the casing and measures the extrusion deformation of the casing, and the other group detects the axial strain of the casing and measures the bending deformation of the casing.

[0095] In the embodiment, the displacement sensor 402 starts to record the initial position information of the casing after the casing is fixed and transmits the information to the ground working system 1. When the casing is deformed or displaced, the displacement sensor 402 transmits the displacement amount to the ground working system 1, so that the size of the displacement of the casing can be directly observed, and the degree of damage and deformation of the casing is shown.

[0096] In the embodiment, the temperature sensor 403 and the formation pressure sensor 404 are fixed in the hollow sandwich 104 to measure the formation temperature and pressure at the position of the casing spool, and the formation temperature and pressure are continuously measured to evaluate the wellbore sealing and fluid flow rule, and provide direct data for the life prediction of the wellbore and the reasonable exploitation and dynamic evaluation of the oil and gas reservoir.

[0097] In the embodiment, the formation pressure sensor 404 comprises a force transmission upper cover 501, a piezoelectric sheet 502, an electrode 503, an electrode lead plug 504, an insulating material 505, and a base 506. When the force transmission upper cover 501 is stressed to change the stress, the piezoelectric sheet 502 also deforms to change the resistance of the piezoelectric sheet 502, so that the voltage applied to the piezoelectric sheet 502 changes. The voltage is transmitted to an instrument amplifier through the electrode lead plug 504 for amplification, and then transmitted to a processing circuit to obtain the pressure value.

[0098] In the embodiment, the ultrasonic sensor 405 is fixed in the hollow sandwich 104, and two 180°-angle ultrasonic sensors are installed in the cross section to detect the axial direction and comprehensively detect the casing inner diameter. According to the reflection time of the sound wave, the casing ovality can be detected, and the service life of the casing can be comprehensively judged according to the ovality of different short casings in the later period, and basic information for casing repair in the later period is provided.

[0099] In the embodiment, the hollow sandwich 104 has four cavities, and the displacement sensor 402 and the temperature sensor 403 are installed in different cavities. The displacement sensor 402 is packaged and fixed according to the shape of the hollow sandwich 104. The temperature sensing element of the temperature sensor 403 is attached to the casing sealing outer wall 103 to facilitate sensing the formation temperature. The formation pressure sensor 404 is fixed in the hollow sandwich 104, and its stress surface mainly adheres to the casing sealing outer wall 103. The ultrasonic sensor 405 is divided into a sound wave generating device and a sound wave receiving device, and can be installed in two cavities and connected by wires in the middle.

[0100] In the embodiment, the casing main body mechanical structure 3, the data processing system 4, and the detection system 5 form a casing outer monitoring spool. The number of casing outer monitoring spools can be reasonably selected according to the well depth and formation conditions. Before connecting the casing, the casing outer monitoring spools are numbered in sequence as 1, 2, 3, …, n, and the built-in sensors are also numbered accordingly. The detection equipment in the casing outer monitoring spool sends the detected data every half hour, and the ground working system 1 can visually display the data on the display. The workers can reasonably evaluate the wellbore condition according to the data.

[0101] In the embodiment, a system for comprehensively evaluating wellbore integrity is provided with multiple sensors. The strain sensor is used to accurately measure the axial strain and circumferential strain of the casing, the displacement sensor is used to determine the displacement of the casing during the change of formation movement, the temperature sensor and the formation pressure sensor are used to measure the formation temperature and pressure at the position of the casing segment, and the ultrasonic sensor can determine the surface hole and ovality information of the casing. The above sensors are comprehensively used to monitor the casing deformation position, deformation degree, casing deformation quantity, and formation temperature and pressure parameters, and the like, to evaluate the damage, destruction and sealing performance of the wellbore, and to provide data for the evaluation and development of the oil and gas reservoir in the later stage.

[0102] The above only describes the preferred embodiments of the present application and is not used to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application is included in the protection scope of the present application.

Claims

1. A wellbore integrity evaluation system, characterized in that, It includes a ground working system, a wired signal transmission system, the main mechanical structure of the casing, a data processing system, and a detection system; The ground working system is connected to the wired signal transmission system, and the wired signal transmission system, the data processing system, and the detection system are installed inside the wellbore; the wired signal transmission system is connected to both the data processing system and the detection system. The surface working system is located on the surface, and the casing main mechanical structure is located inside the wellbore. The casing main mechanical structure includes an upper casing connector, a through hole, a casing sealing outer wall, a hollow interlayer, a casing inner wall, a casing lower connector, and reinforcing ribs. The upper casing connector and the lower casing connector are detachably connected to the casing. The through hole is located on the casing. The hollow interlayer is located between the casing sealing outer wall and the casing inner wall. The reinforcing ribs are located between the casing sealing outer wall and the casing inner wall. The detection system is installed inside the hollow interlayer and can detect the displacement and deformation of the casing in the mechanical structure of the casing body. It transmits the detection information to the ground working system and the data processing system through a wired signal transmission system. The data processing system processes the detection information into a digital signal, and the ground working system displays the detection information. The data processing system then transmits the processed digital signal back to the ground working system through the wired signal transmission system. The detection system includes strain sensors and displacement sensors. The displacement sensors are packaged and fixed according to the shape of a hollow sandwich. After the casing is fixed, the displacement sensors start recording initial position information and transmit the information to the ground working system to establish an initial oil and gas well coordinate system. When the casing undergoes deformation or displacement, the displacement sensors calculate their own displacement and transmit the displacement to the ground working system. At this time, the ground system calculates new position information based on the displacement. By comparing the new coordinates with the initial coordinates, the displacement information of the casing can be seen intuitively, thereby assessing the deformation and damage of the casing. The strain sensor is installed inside the hollow interlayer of the casing body mechanical structure.

2. The wellbore integrity evaluation system according to claim 1, characterized in that, The ground working system includes a signal receiving module, a data conversion module, and a display module. The signal receiving module receives data signals from the wired signal transmission system, which are then converted by the data conversion module and displayed intuitively by the display module. The data conversion module converts the received digital signals into signals that can be read by a computer and processes complex downhole measurement data into the desired results. The display module displays relevant data and information about the downhole casing and formation.

3. The wellbore integrity evaluation system according to claim 1, characterized in that, The wired signal transmission system receives signals from the data processing system and transmits them to the ground working system. The wired signal transmission system uses umbilical cable transmission.

4. The wellbore integrity evaluation system according to claim 1, characterized in that, The through hole is provided on the outer wall of the sleeve seal, and the reinforcing rib is also provided with an electrical wire hole.

5. The wellbore integrity evaluation system according to claim 1, characterized in that, The detection system also includes temperature sensors, formation pressure sensors, and ultrasonic sensors.

6. The wellbore integrity evaluation system according to claim 5, characterized in that, The strain sensor includes leads, a cover plate, a sensitive grid, and a substrate. The sensitive grid is disposed on the substrate, the cover plate covers the sensitive grid, and the leads are connected to the cover plate.

7. The wellbore integrity evaluation system according to claim 6, characterized in that, The sensitive grid is formed by bending a wire with a diameter of 0.01-0.05 mm into a grid shape, and the sensitive grid is fixed to the substrate with an adhesive.

8. The wellbore integrity evaluation system according to claim 6, characterized in that, Four strain sensors form a ring-shaped strain sensor group. Each ring-shaped strain sensor group is evenly distributed at a 90° angle. Two ring-shaped strain sensor groups are set up. One group detects the circumferential strain of the sleeve and measures the extrusion deformation of the sleeve. The other group detects the axial strain of the sleeve and measures the bending deformation of the sleeve.

9. The wellbore integrity evaluation system according to claim 5, characterized in that, Temperature and formation pressure sensors are fixed inside the hollow interlayer to measure formation temperature and pressure at the location of the casing sub. By continuously measuring formation temperature and pressure, wellbore sealing and fluid flow patterns are assessed, providing direct data for wellbore life prediction and rational exploitation and dynamic evaluation of oil and gas reservoirs. Ultrasonic sensors are also fixed inside the hollow interlayer.

10. The wellbore integrity evaluation system according to claim 9, characterized in that, The hollow sandwich structure has four chambers, with displacement and temperature sensors installed in different chambers. The temperature sensor's sensing element is in contact with the outer wall of the casing seal. The formation pressure sensor is fixed inside the hollow sandwich structure, and its force-bearing surface is in contact with the outer wall of the casing seal. The ultrasonic sensor consists of a sound wave generator and a sound wave receiver, which are installed in two chambers respectively and connected by a wire.

11. The wellbore integrity evaluation system according to claim 5, characterized in that, The formation pressure sensor includes a force-transmitting cover, a piezoelectric element, an electrode, an electrode lead-out plug, an insulating block, and a base. Two insulating blocks are mounted on the base, with one end of one insulating block extending out of one end of the base and the other insulating block located inside the other end of the base. The electrode is installed between the two insulating blocks, with one end extending out of one end of the insulating block and connected to the electrode lead-out plug. The piezoelectric element is wrapped around the electrode and fits against it. The force-transmitting cover is mounted above the piezoelectric element, which is opposite to the base. When the force-transmitting cover is subjected to stress, the piezoelectric element deforms under the pressure of the cover, causing a change in its resistance and a change in the voltage applied to it. This voltage is transmitted to an instrumentation amplifier for amplification via the electrode lead-out plug and then transmitted to a data processing system to obtain the pressure value.

12. The wellbore integrity evaluation system according to claim 5, characterized in that, Two ultrasonic sensors are installed on a horizontal plane at a 180° angle, with the detection direction being axial, to detect the inner diameter of the sleeve. The ellipticity of the sleeve is detected based on the reflection time of the sound waves.

13. The wellbore integrity evaluation system according to claim 5, characterized in that, The data processing system includes a sensor data processing component and a circuit microprocessor interface. The sensor data processing component is composed of a signal processing microchip.

14. The wellbore integrity evaluation system according to claim 13, characterized in that, The circuit microprocessor interface includes: a power interface, a signal input interface, a chip reset interface, a ground interface, and multiple signal output interfaces. The power interface is connected to a power source; the signal input interface inputs signals to the circuit microprocessor; when a signal is input to the circuit microprocessor and the detection system is not working, the system automatically restarts the chip through the chip reset interface; the multiple signal output interfaces are connected to different working sensors to control the connected working sensors.

15. A method for evaluating wellbore integrity, characterized in that, The wellbore integrity evaluation system according to any one of claims 5-14 includes the following steps: The axial and circumferential strains of the casing are measured locally using strain sensors. Displacement sensors determine the amount of displacement of the casing during formation movement and changes; Temperature sensors and formation pressure sensors measure the formation temperature and pressure at the location of the casing sub. Ultrasonic sensors determine the surface pores and ellipticity information of the sleeve; The above sensors are used to monitor the location, degree, and quantity of casing deformation, as well as formation temperature and pressure parameters, to evaluate the damage, failure, and sealing performance of the wellbore.

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