Shaft integrity evaluation system and method

Abstract

The invention provides a shaft integrity evaluation system and method, and belongs to the technical field of well drilling, completion and cementing in oil and gas exploitation. The casing pipe external monitoring short circuit which is directly connected with the casing pipe and is lowered along with the casing pipe is adopted, a detection system is arranged in the casing pipe external monitoring short circuit so that damage deformation and stratum temperature and pressure parameters of the casing pipe can be conveniently detected, and signals are transmitted back to a ground working system through an umbilical cable. The device can detect and monitor casing damage deformation and formation temperature and pressure parameters in the well cementation and oil and gas reservoir exploitation process in real time, and the integrity of a shaft is evaluated. The method is favorable for analyzing and predicting the stress state of the underground casing and the change of the formation temperature and pressure, and has great positive significance for long-acting development of oil and gas reservoirs.

Description

Technical Field

[0001] The present invention relates to the technical field of drilling, completion and cementing in oil and gas production, and in particular to a wellbore integrity evaluation system and method. Background Art

[0002] Oil casing is an important part of the wellbore string of oil and gas fields. In traditional oil and gas field wellbore string engineering, its main function is to fix the well wall and prevent the well wall from collapsing. It is the most important physical barrier in the channel for transporting oil and gas resources from the bottom of the well to the ground. At present, my country is facing severe challenges in the exploration and exploitation of oil and gas fields. Due to different geological conditions, the stress state downhole is complex, and the pulling, pressing, bending and twisting act on the casing body, which puts high requirements on the quality and integrity of the casing itself. The integrity of the casing string is mainly reflected in the sealing and regular cross-sectional shape. Due to the long-term use of water injection to exploit oil fields, the geological activities deep in the formation have been aggravated. Many factors such as acid fracturing, repeated downhole operations and corrosion can cause different degrees of deformation of the casing (including casing reduction, one or more bending of the casing, casing flattening, severe bending deformation, casing rupture and fault, etc.). In some formations prone to collapse or formations with poor cementing quality, the casing deformation is particularly serious. Once the casing itself is deformed or damaged for some reason, it may lead to a reduction in production or even scrapping of the entire well, seriously affecting the safety and benefits of the oil and gas field, and causing huge economic losses. Therefore, the problem of casing deformation and damage has attracted great attention in the development of oil and gas in various countries around the world. If the casing deformation during the fracturing construction process can be effectively monitored and evaluated, and the information such as the downhole casing deformation position, deformation degree and formation parameters can be obtained in a timely and accurate manner, preventive measures can be taken as soon as possible to ensure the integrity of the wellbore, and guide the implementation of subsequent operations, well repair, perforation, fracturing and other measures, it will have a significant 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 production mainly include mechanical multi-arm caliper logging, acoustic imaging logging, electromagnetic flaw detection logging, downhole video detection, etc. The physical information of casing deformation is directly or indirectly transmitted back to the ground by means of logging, and the logging interpretation information is used to guide the repair measures. The existing casing deformation detection technology cannot realize the real-time monitoring and risk prediction of downhole casing deformation. The instrument needs to be lowered into the well to a certain depth before it starts working. The well needs to be shut down during the detection, causing production to be forced to stop, which not only affects the progress and production efficiency of oil and gas production, but also poses a risk of damage to the instrument and the well being measured. There are complicated detection steps, and the instrument lowered into the well is prone to obstruction, jamming or falling.

[0004] The Chinese patent with the patent number CN202991012U discloses a multi-arm caliper imaging instrument, including a cable sealing head, an upper stabilizer, a control part, an imaging arm sensor, a lower stabilizer and a counterweight joint. The cable sealing head is connected to one end of the upper stabilizer, and the other end of the upper stabilizer is connected to the control part through a telescopic arm. The control part is connected to the imaging arm sensor, and the imaging arm sensor is connected to one end of the lower stabilizer. The other end of the lower stabilizer is connected to the counterweight joint through a telescopic arm. Multiple monitoring arms are arranged around the imaging arm sensor. The tool is lowered into the well, and the inner diameter of the casing, the casing coupling, and the well temperature are monitored in real time through the monitoring arm to infer the damage of the casing. During the monitoring period of the tool lowering, oil and gas production is stopped, which affects the progress and production efficiency of oil and gas production.

[0005] A Chinese patent with patent number CN109708595A discloses a method and device for detecting downhole casing damage, wherein a casing damage detection device is lowered into a set position downhole along with a downhole production tubing, and the surrounding casings are detected in real time by the casing damage detection device during the downhole 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 inspected, the casing damage detection device is pulled out to the ground along with the production tubing, and the surrounding casings are detected in real time by the casing damage detection device during the pulling out process. This method avoids stopping oil and gas production operations by installing the tool on the oil pipe, but only one method is given, and the specific feasibility remains to be studied.

[0006] A Chinese patent with the patent number CN111594138A discloses a device for comprehensively testing the working parameters of the casing. An annular interlayer is opened inside the existing oil casing, and sensitive elements corresponding to the parameters to be tested are fixed inside the annular interlayer. The setting type and quantity of the sensitive elements can be adjusted according to actual needs to measure relevant parameters. The sensitive elements are connected to the data processing end through data cables. The device integrates batteries, transmission, and detection. It is integrated into the casing wall under the volume of existing equipment, which makes the casing wall thickness too large, which is not conducive to cementing.

[0007] In view of the problem that casing deformation induced by reservoir fracturing cannot be monitored and evaluated in real time, a Chinese patent with patent number CN112282730A discloses a real-time monitoring and evaluation method for downhole casing deformation induced by reservoir fracturing. The method adopts a combination of horizontal well pumping bridge plug perforation and casing magnetic positioning measurement, and uses a magnetic positioning instrument to measure the magnetic anomalies of casing couplings and casing in real time. By establishing a casing deformation magnetic anomaly logging response model and analyzing the characteristics of casing magnetic anomalies, the degree and development trend of downhole casing deformation are monitored and evaluated in real time. This method can infer the deformation state of the casing based on the piezomagnetic effect caused by the force on the casing before and after perforation and fracturing. However, the measured magnetic anomaly is easily affected by other forces such as pumping blockage and external interference of well deviation tension, and cannot effectively eliminate the multi-solution of logging interpretation. The established magnetic anomaly and casing deformation correlation model is based on the actual horizontal well casing deformation multi-arm wellbore logging detection results, which cannot guarantee the accuracy of the model. In addition, the real-time monitoring process is only for the stages before perforation and fracturing and does not fully consider the casing deformation problem that may be caused by the subsequent changes in reservoir pressure after fracturing. There are certain limitations in both accuracy and practicality.

[0008] A Chinese patent with patent number CN202210073242.8 discloses a wireless monitoring system for casing deformation in cementing, fracturing and production processes, including 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 by wireless transmission, and obtain the deformation position, deformation degree and number of casing deformation points of the downhole casing on the ground. However, 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, it is impossible to accurately assess the damage information of the formation casing.

[0009] The current technology can solve the problem of wellbore integrity in some oil and gas wells to a certain extent, that is, the problem of casing deformation and damage, but the assessment of wellbore integrity needs to consider various issues such as casing deformation and sealing. Therefore, it is urgent to propose a more comprehensive wellbore integrity detection / monitoring technology on the existing basis to better solve the problem of frequent abnormal deformation of casing in cementing and oil and gas reservoir exploitation. Summary of the invention

[0010] In order to solve the problems existing in the prior art, the present invention provides a wellbore integrity evaluation system, which uses a casing external monitoring short circuit directly connected to the casing and lowered with the casing, and contains a detection system inside to facilitate the detection of casing damage deformation and formation temperature and pressure parameters, and transmit the signal back to the ground working system via the umbilical cable. The present invention can detect and monitor casing damage deformation and formation temperature and pressure parameters in real time during cementing and oil and gas reservoir exploitation, and evaluate wellbore integrity. It is conducive to analyzing and predicting the stress state of downhole casing, changes in formation temperature and pressure, and has great positive significance for the long-term development of oil and gas reservoirs.

[0011] The present invention provides a wellbore integrity evaluation system, including a ground working system, a wired signal transmission system, a casing main body mechanical structure, a data processing system and a detection system;

[0012] The surface 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 arranged in the wellbore; the wired signal transmission system is connected to both the data processing system and the detection system;

[0013] The surface working system is arranged on the surface, and the casing main body mechanical structure is arranged in the wellbore;

[0014] The detection system can detect the displacement and deformation of the casing in the casing main body 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 a digital signal, and the ground working system displays the detection information; the data processing system transmits the processed digital signal to the ground working system through the wired signal transmission system.

[0015] Preferably, the ground working system includes: a signal receiving module, a data conversion module and a display module. The signal receiving module is used to receive the data signal transmitted by the wired signal transmission system, and the data signal is visually displayed through the display module after conversion by the data conversion module; the data conversion module converts the received digital signal into a signal that can be read by a computer and can process the complex downhole measurement data into the desired result; the display module is used to display the relevant data and information of the downhole casing and formation.

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

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

[0018] Preferably, the wire hole is arranged on the sealed outer wall of the sleeve, and the reinforcing rib is also provided with a wire hole.

[0019] Preferably, the detection system includes 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, a cover, a sensitive grid and a substrate, the sensitive grid is arranged on the substrate, the cover covers the sensitive grid, and the lead is connected to the cover.

[0021] Preferably, 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 on the substrate with an adhesive.

[0022] Preferably, every four strain sensors form an annular sensing strain sensor group. In the hollow interlayer of the casing main body mechanical structure, each group of annular sensing strain sensor groups is evenly distributed at an angle of 90°. Two groups of annular sensing strain sensor groups are set, one group 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 correspondingly measures the bending deformation of the casing.

[0023] Preferably, the temperature sensor and the formation pressure sensor are fixed in the hollow interlayer to measure the formation temperature and pressure at the location of the casing short joint. By continuously measuring the formation temperature and pressure, the wellbore sealing and fluid flow law are evaluated, providing direct data for the life prediction of the wellbore and the rational exploitation and dynamic evaluation of the oil and gas reservoir; the ultrasonic sensor is fixed in the hollow interlayer.

[0024] Preferably, the hollow interlayer has four chambers in total, and the displacement sensor and temperature sensor are installed in different chambers respectively; the displacement sensor is packaged and fixed according to the shape of the hollow interlayer; the temperature sensor sensing element is in contact with the sealed outer wall of the casing; the formation pressure sensor is fixed in the hollow interlayer, and its force-bearing surface can be in contact with the sealed outer wall of the casing; the ultrasonic sensor is divided into a sound wave generating device and a sound wave receiving device, which are respectively installed in two chambers and connected in the middle with a wire.

[0025] Preferably, the formation pressure sensor includes a force transmission cover, a piezoelectric sheet, an electrode, an electrode lead-out plug, an insulating block and a base, two insulating blocks are arranged on the base, one end of one insulating block extends out of one end of the base, and the other insulating block is located on the inner side of 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 to the electrode lead-out plug, the piezoelectric sheet is wrapped around the outside of the electrode and fits with the electrode, the force transmission cover is installed above the piezoelectric sheet opposite to the base, when the force transmission cover is subjected to force and the stress changes, the piezoelectric sheet is squeezed by the force transmission cover and deformed, so that the resistance value of the piezoelectric sheet changes, and the voltage applied to the piezoelectric sheet changes, and the voltage is transmitted to the instrument amplifier through the electrode lead-out plug for amplification, and then transmitted to the data processing system to obtain the pressure value.

[0026] Preferably, two ultrasonic sensors are installed on a horizontal plane at an angle of 180°, with the detection direction being axial, to detect the inner diameter of the casing, and the ovality of the casing is detected according to the reflection time of the sound wave.

[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 includes: a power supply interface, a signal input interface, a chip reset interface, a ground interface and multiple signal output interfaces, the power supply interface is connected to the 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 system; multiple signal output interfaces are respectively connected to different working sensors to control the connected working sensors.

[0029] The present invention provides a wellbore integrity evaluation method, which is used in any of the wellbore integrity evaluation systems mentioned above, and comprises the following steps:

[0030] Use strain sensors to locally measure the axial strain and circumferential strain of the casing;

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

[0032] The temperature sensor and the formation pressure sensor measure the formation temperature and pressure at the location of the casing nipple;

[0033] The ultrasonic sensor determines the surface holes and ovality information of the casing;

[0034] The above sensors are used to monitor the casing deformation position, deformation degree, casing deformation amount, formation temperature and pressure parameters, and evaluate the damage, destruction and sealing of the wellbore.

[0035] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0036] 1. The present invention adopts wired transmission mode, which transmits data and provides power to downhole sensors at the same time. It can detect and monitor downhole casing deformation and formation temperature and pressure in real time for a long time.

[0037] 2. After the casing is fixed, the micro displacement sensor of the present invention starts to record the initial position information and transmits the information to the ground working system to establish the initial oil and gas well coordinate system. When the casing is deformed or displaced, the micro displacement sensor will calculate its 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 intuitively seen, so that the deformation and damage degree of the casing can be evaluated.

[0038] 3. The present invention adds temperature and pressure sensors, and various sensors cooperate with each other to accurately obtain the corresponding casing position, deformation, formation temperature and pressure in the well. Comprehensive evaluation of wellbore integrity is of great significance for guiding wellbore repair, repeated fracturing and optimizing production parameters.

[0039] 4. The present invention uses an ultrasonic sensor to detect the ovality information of the casing. In the later stage, the service life of the casing can be comprehensively judged according to the ovality information of different short casings, and basic information can be provided for the later casing repair;

[0040] 5. The present invention continuously measures the formation temperature and pressure at the location of the monitoring short circuit outside the casing to evaluate the downhole fluid law, providing direct data for the rational exploitation and dynamic evaluation of oil and gas reservoirs.

[0041] 6. The present invention does not need to lower other logging tools, thus avoiding problems such as obstruction, jamming or falling of downhole instruments. There is no need to shut down the well, and the detection process is independent and simple, which does not affect other construction operations, reduces risks, and ensures the exploitation progress and production efficiency of oil and gas wells. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of a device for in-situ detection of casing and formation parameters in a downhole according to an embodiment of the present invention;

[0043] Figure 2 for Figure 1 A partial enlarged view of middle A;

[0044] Figure 3 (a) is a schematic diagram of the mechanical structure of the casing body of an embodiment of the present invention, and (b) is a BB-direction cross-sectional view of (a);

[0045] Figure 4 A schematic diagram of the structure of a data processing system control chip according to an embodiment of the present invention;

[0046] Figure 5 A schematic diagram of the placement of a detection device in a hollow interlayer according to an embodiment of the present invention;

[0047] Figure 6 A schematic structural diagram of a formation pressure sensor according to an embodiment of the present invention;

[0048] Figure 7 A schematic diagram of the structure of a strain sensor according to an embodiment of the present invention;

[0049] Figure 8 A working block diagram of a wellbore integrity evaluation system according to an embodiment of the present invention;

[0050] In the figure: 1-ground working system; 2-wire signal transmission system; 3-casing main mechanical structure; 4-data processing system; 5-detection system; 101-casing upper joint; 102-wire hole; 103-casing sealed outer wall; 104-hollow interlayer; 105-casing inner wall; 106-casing lower joint; 107-reinforcement rib; 108-wire hole; 301-power interface; 302-signal input interface; 303-chip reset interface; 304-ground 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 cover; 502-piezoelectric sheet; 503-electrode; 504-electrode lead plug; 505-insulating block; 506-base; 601-lead; 602-cover; 603-sensitive grid; 604-substrate. DETAILED DESCRIPTION

[0051] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0052] The present invention provides a wellbore integrity evaluation system, comprising a ground working system 1, a wired signal transmission system 2, a casing main 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 both the data processing system 4 and the detection system 5;

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

[0055] The detection system 5 is capable of detecting the displacement and deformation of the casing in the casing main body mechanical structure 3, and transmitting 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 a digital signal, and the ground working system 1 displays the detection information; the data processing system 4 transmits the processed digital signal to the ground working system 1 through the wired signal transmission system 2.

[0056] According to a specific embodiment of the present invention, the ground working system 1 includes: a signal receiving module, a data conversion module and a display module. The signal receiving module is used to receive the data signal transmitted by the wired signal transmission system 2, and the data signal is converted by the data conversion module and then visually displayed through the display module; the data conversion module converts the received digital signal into a signal that can be read by a computer and can process the complex downhole measurement data into the desired result; the display module is used to display the relevant data and information of the downhole casing and formation.

[0057] According to a specific embodiment of the present invention, the wired signal transmission system 2 receives the signal of the data processing system 4 and transmits it to the ground working system 1, and the transmission mode of the wired signal transmission system 2 is umbilical cable transmission.

[0058] According to a specific embodiment of the present invention, the casing main body mechanical structure 3 includes a casing upper joint 101, a wire 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 107. The casing upper joint 101 and the casing lower joint 106 are respectively detachably connected to the casing, the wire hole 102 is arranged on the casing, the hollow interlayer 104 is arranged between the casing sealing outer wall 103 and the casing inner wall 105, and the reinforcing rib 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 invention, the wire hole 102 is arranged on the sleeve sealing outer wall 103, and the reinforcing rib 107 is also provided with a wire hole 108.

[0060] According to a specific embodiment of the present invention, 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 .

[0061] According to a specific embodiment of the present invention, the strain sensor 401 includes a lead 601, a cover sheet 602, a sensitive grid 603 and a substrate 604, wherein the sensitive grid 603 is disposed on the substrate 604, the cover sheet 602 covers the sensitive grid 603, and the lead 601 is connected to the cover sheet 602.

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

[0063] According to a specific embodiment of the present invention, every four strain sensors 401 form an annular sensing strain sensor group 401. In the hollow interlayer 104 of the casing main body mechanical structure 3, each group of annular sensing strain sensors 401 is evenly distributed at an angle of 90°. Two groups of annular sensing strain sensors 401 are set, one group 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 correspondingly measures the bending deformation of the casing.

[0064] According to a specific embodiment of the present invention, a temperature sensor 403 and a formation pressure sensor 404 are fixed in the hollow interlayer 104 to measure the formation temperature and pressure at the location of the casing short joint. By continuously measuring the formation temperature and pressure, the wellbore sealing and fluid flow law are evaluated, providing direct data for the life prediction of the wellbore and the rational exploitation and dynamic evaluation of the oil and gas reservoirs; the ultrasonic sensor 405 is fixed in the hollow interlayer 104.

[0065] According to a specific embodiment of the present invention, the hollow interlayer 104 has four chambers in total, and the displacement sensor 402 and the temperature sensor 403 are respectively installed in different chambers; the displacement sensor 402 is packaged and fixed according to the shape of the hollow interlayer 104; the temperature sensor 403 temperature sensing element is in contact with the casing sealing outer wall 103; the formation pressure sensor 404 is fixed in the hollow interlayer 104, and its force-bearing surface can be in contact with 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 chambers and connected in the middle with a wire.

[0066] According to a specific embodiment of the present invention, the formation pressure sensor 404 includes a force transmission cover 501, a piezoelectric sheet 502, an electrode 503, an electrode lead-out plug 504, an insulating block 505 and a base 506, two insulating blocks 505 are arranged on the base 506, one end of one insulating block 505 extends out of one end of the base 506, and the other insulating block 505 is located on the inner side of the other end of the base 506, and the electrode 503 is installed between the two insulating blocks 505, one end of the electrode 503 extends out of one end of the insulating block 505 and is connected to the electrode lead-out plug 504 The piezoelectric sheet 502 is wrapped around the outside of the electrode 503 and fits with the electrode 503. The force transmission cover 501 is installed above the piezoelectric sheet 502 opposite to the base 506. When the force transmission cover 501 is subjected to stress and stress changes, the piezoelectric sheet 502 is squeezed by the force transmission cover 501 and deformed, so that the resistance value of the piezoelectric sheet 502 changes, and the voltage applied to the piezoelectric sheet 502 changes. The voltage is transmitted to the 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 a specific embodiment of the present invention, two ultrasonic sensors 405 are installed on a horizontal plane at an angle of 180°, with the detection direction being axial, to detect the inner diameter of the casing, and the ovality of the casing is detected based on the reflection time of the sound wave.

[0068] According to a specific embodiment of the present invention, the data processing system 4 includes 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 a specific embodiment of the present invention, the circuit microprocessor interface includes: a power interface 301, a signal input interface 302, a chip reset interface 303, a ground interface 304 and multiple signal output interfaces, the power interface 301 is connected to the power supply; the signal input interface 302 inputs a signal to the circuit microprocessor; when the signal is input to the circuit microprocessor, the detection system 5 does not work, and the system automatically restarts the chip through the chip reset interface 303; multiple signal output interfaces are respectively connected to different working sensors, and the working sensors connected to them are individually controlled to improve the overall efficiency of the tool.

[0070] The present invention provides a wellbore integrity evaluation method, which is used in any of the wellbore integrity evaluation systems mentioned above, and comprises the following steps:

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

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

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

[0074] The ultrasonic sensor 405 determines the surface holes and ovality information of the casing;

[0075] The above sensors are used to monitor the casing deformation position, deformation degree, casing deformation amount, formation temperature and pressure parameters, and evaluate the damage, destruction and sealing of the wellbore.

[0076] Example 1

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

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

[0079] like Figures 2 to 8 As shown, the ground working system 1 includes: a signal receiving module, a data conversion module, and a display module. The signal receiving module is used to receive the data signal transmitted by the wired signal transmission system 2, and the data signal is visually displayed through the display module after conversion by the data conversion module; the data conversion module converts the received digital signal into a signal that can be read by a computer and can process the complex downhole measurement data into the desired result through the corresponding software; 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 the signal from the data processing system 4 and transmits it to the ground working system 1, thereby performing the function of transmitting data. The transmission mode of the wired signal transmission system 2 is umbilical cable transmission.

[0081] In this embodiment, the casing main body mechanical structure 3 includes a casing upper joint 101, a wire 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 107. The casing upper joint 101 and the casing lower joint 106 are respectively connected to the casing 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 includes a strain sensor 401 , a micro displacement sensor 402 , a temperature sensor 403 , a formation pressure sensor 404 , and an ultrasonic sensor 405 .

[0084] In this embodiment, the casing main body mechanical structure 3 is designed with a hollow interlayer 104 for accommodating the data processing system 4 and the detection system 5. The hollow interlayers 104 are distributed circumferentially and there are four of them. Reinforcement ribs 107 are designed between adjacent hollow interlayers 104. The reinforcement ribs 107 are provided with wire holes 108, which enhance the strength of the casing main body mechanical structure 3 and facilitate data transmission between each hollow interlayer 104.

[0085] In this embodiment, the number of hollow interlayers 104 can be specially designed according to the shapes and placement positions of various sensors, so as to better realize the detection function.

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

[0087] In this embodiment, the surfaces of the upper sleeve joint 101 and the lower sleeve joint 106 of the main mechanical structure 1 are processed with threads for connecting with other sleeves.

[0088] In this embodiment, the strength of the casing main body mechanical structure 3 meets the requirements of downhole operations, and its size is the same as that of a normal casing, ensuring the circulation of cement slurry during the cementing process.

[0089] In this embodiment, the wire hole 108 contains a line, which connects the strain sensor 401, micro displacement sensor 402, temperature sensor 403, formation pressure sensor 404, and ultrasonic sensor 405 in the detection system 5 in different hollow interlayers 104, which aggregates different data transmissions in the data processing system 4 and finally transmits them through the wired signal transmission system 2. The whole structure is required to have good sealing performance, so a waterproof and mud-proof packaging method should be used during the packaging process.

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

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

[0092] In this embodiment, the circuit microprocessor interfaces include: power interface 301, signal input interface 302, chip reset interface 303, ground interface 304, signal output 1 interface 305, signal output 2 interface 306, signal output 3 interface 307, and signal output 4 interface 308. The power interface 301 is connected to the power supply; the signal input interface 302 inputs signals to the circuit microprocessor. The function of the backup signal input interface 303 is: if the signal input interface 302 is damaged and cannot input signals, the system automatically enables the backup signal input interface 303; the function of the chip reset interface 303 is: if the detection system 5 does not work after the signal is input to the circuit microprocessor, the system automatically restarts the chip; 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 connected to different working sensors respectively, and their working sensors can be controlled individually to improve the overall efficiency of the tool.

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

[0094] In this embodiment, the strain sensor 401 mainly includes a lead 601, a cover sheet 602, a sensitive grid 603, and a substrate 604. The sensitive grid 603 is formed by bending a thin wire with a diameter of 0.01-0.05mm and a high resistivity into a grid shape, which is the sensitive part of the strain gauge to sense the strain of the component. The sensitive grid 603 is fixed to the substrate 604 with an adhesive. The function of the substrate 604 should ensure that the strain on the component is accurately transmitted to the sensitive grid. The strain sensor 401 can measure the strain of the sleeve by a single piece. In order to measure more comprehensively and accurately, each four pieces form an annular sensing strain sensor group, which is evenly distributed at an angle of 90° in each group in the hollow interlayer 103 of the main mechanical structure 1. There are two groups of annular sensing strain sensor groups in total. One of the annular sensing strain sensor groups detects the circumferential strain of the sleeve and measures the extrusion deformation of the sleeve, and the other group detects the axial strain of the sleeve, which can measure the bending deformation of the sleeve.

[0095] In this embodiment, the micro 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 micro displacement sensor 402 will transmit its own displacement to the ground working system 1, so that the size of the casing displacement can be intuitively seen, showing the degree of casing damage and deformation.

[0096] In this embodiment, 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 short joint. By continuously measuring the formation temperature and pressure, the wellbore sealing and fluid flow law can be evaluated, providing direct data for the life prediction of the wellbore and the rational exploitation and dynamic evaluation of the oil and gas reservoir.

[0097] In this embodiment, the formation pressure sensor 404 includes a force transmission 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 cover 501 is subjected to a force and the stress changes, the piezoelectric sheet 502 also deforms, causing the resistance value of the piezoelectric sheet 502 to change, thereby causing the voltage applied to the piezoelectric sheet 502 to change, and the voltage is transmitted to the instrument amplifier through the electrode lead plug 504 for amplification, and then transmitted to the processing circuit to obtain the pressure value.

[0098] In this embodiment, the ultrasonic sensor 405 is fixed in the hollow interlayer 104, and two ultrasonic sensors are installed on the cross section at an angle of 180°. The detection direction is axial, and the inner diameter of the casing can be fully detected. The ovality of the casing can be detected according to the reflection time of the sound wave. In the later stage, the service life of the casing can be comprehensively judged according to the ovality of different short casings, and basic information can be provided for the later casing repair.

[0099] In this embodiment, the hollow interlayer 104 has four chambers, and the micro displacement sensor 402 and the temperature sensor 403 are installed in different chambers; the micro displacement sensor 402 is packaged and fixed according to the shape of the hollow interlayer 104; the temperature sensor 403 temperature sensing element is in contact with the casing sealing outer wall 103, so as to sense the formation temperature; the formation pressure sensor 404 is fixed in the hollow interlayer 104, and its force surface is mainly in contact with 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 can be installed in two chambers respectively and connected in the middle with a wire.

[0100] In this embodiment, the structure composed of the casing main body mechanical structure 3, the data processing system 4, and the detection system 5 is called the casing external monitoring short circuit. The number of casing external monitoring short circuits can be reasonably selected according to the well depth and the formation conditions. Before connecting the casing, the casing external monitoring short circuits are numbered 1, 2, 3...n in sequence, and the built-in sensors are also numbered accordingly. The detection equipment in the casing external monitoring short circuit sends the detected data once every half an hour, and the ground working system 1 can intuitively display the data on the display, and the staff can reasonably evaluate the wellbore conditions based on the data.

[0101] In this embodiment, a system for comprehensively evaluating the integrity of the wellbore is provided, which has multiple sensors built in. The strain sensor performs local and precise measurement of the axial strain and circumferential strain of the casing, the micro displacement sensor determines the displacement of the casing during the movement and change of the formation, the temperature sensor and the formation pressure sensor measure the formation temperature and pressure at the location of the casing short section, and the ultrasonic sensor can determine the surface holes and ovality information of the casing. The above sensors are used to monitor the deformation position, deformation degree, amount of casing deformation, formation temperature and pressure parameters of the casing, and evaluate the damage, destruction and sealing of the wellbore, while providing data for the evaluation and development of the later oil and gas reservoirs.

[0102] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention are included in the protection scope of the present invention.

Claims

1. A wellbore integrity evaluation system, characterized in that: It includes ground working system, wired signal transmission system, casing main body mechanical structure, data processing system and detection system; The surface 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 arranged in the wellbore; the wired signal transmission system is connected to both the data processing system and the detection system; The surface working system is arranged on the surface, and the casing main body mechanical structure is arranged in the wellbore; The detection system can detect the displacement and deformation of the casing in the casing main body 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 a digital signal, and the ground working system displays the detection information; the data processing system transmits the processed digital signal to the ground working system through the wired signal transmission system.

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 is used to receive data signals transmitted by the wired signal transmission system, and the data signals are converted by the data conversion module and visually displayed through the display module; the data conversion module converts the received digital signals into signals that can be read by the computer and can process the complex downhole measurement data into the desired results; the display module is used to display relevant data and information of 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 an umbilical cable for transmission.

4. The wellbore integrity evaluation system according to claim 1, characterized in that: The casing main body mechanical structure includes a casing upper joint, a wire hole, a casing sealing outer wall, a hollow interlayer, a casing inner wall, a casing lower joint and a reinforcing rib. The casing upper joint and the casing lower joint are respectively detachably connected to the casing. The wire hole is arranged on the casing, the hollow interlayer is arranged between the casing sealing outer wall and the casing inner wall, and the reinforcing rib is arranged between the casing sealing outer wall and the casing inner wall.

5. The wellbore integrity evaluation system according to claim 4, characterized in that: The wire hole is arranged on the sealed outer wall of the sleeve, and the reinforcing rib is also provided with a wire hole.

6. The wellbore integrity evaluation system according to claim 4, characterized in that: The detection system includes a strain sensor, a displacement sensor, a temperature sensor, a formation pressure sensor and an ultrasonic sensor.

7. The wellbore integrity evaluation system according to claim 6, characterized in that: The strain sensor comprises a lead, a cover sheet, a sensitive grid and a substrate, wherein the sensitive grid is arranged on the substrate, the cover sheet covers the sensitive grid, and the lead is connected to the cover sheet.

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

9. The wellbore integrity evaluation system according to claim 7, characterized in that: Every four strain sensors form an annular sensing strain sensor group. In the hollow interlayer of the casing main mechanical structure, each group of annular sensing strain sensor groups is evenly distributed at an angle of 90°. Two groups of annular sensing strain sensor groups are set, one group 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 correspondingly measures the bending deformation of the casing.

10. The wellbore integrity evaluation system according to claim 6, characterized in that: The temperature sensor and formation pressure sensor are fixed in the hollow interlayer to measure the formation temperature and pressure at the location of the casing short joint. By continuously measuring the formation temperature and pressure, the wellbore sealing and fluid flow law are evaluated, providing 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 is fixed in the hollow interlayer.

11. The wellbore integrity evaluation system according to claim 10, characterized in that: The hollow interlayer has four chambers in total, and the displacement sensor and temperature sensor are installed in different chambers respectively; the displacement sensor is packaged and fixed according to the shape of the hollow interlayer; the temperature sensor sensing element is in contact with the sealed outer wall of the casing; the formation pressure sensor is fixed in the hollow interlayer, and its force-bearing surface can be in contact with the sealed outer wall of the casing; the ultrasonic sensor is divided into a sound wave generating device and a sound wave receiving device, which are installed in two chambers respectively and connected in the middle with a wire.

12. The wellbore integrity evaluation system according to claim 6, characterized in that: The formation pressure sensor includes a force transmission cover, a piezoelectric sheet, an electrode, an electrode lead-out plug, an insulating block and a base. Two insulating blocks are arranged on the base, one end of one insulating block extends out of one end of the base, and the other insulating block is located on the inner side of 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 to the electrode lead-out plug, the piezoelectric sheet is wrapped around the outside of the electrode and fits the electrode, and the force transmission cover is installed above the piezoelectric sheet opposite to the base. When the force transmission cover is subjected to force and stress changes, the piezoelectric sheet is squeezed by the force transmission cover and deformed, so that the resistance value of the piezoelectric sheet changes, and the voltage applied to the piezoelectric sheet changes, and the voltage is transmitted to the instrument amplifier through the electrode lead-out plug for amplification, and then transmitted to the data processing system to obtain the pressure value.

13. The wellbore integrity evaluation system according to claim 6, characterized in that: Two ultrasonic sensors are installed on the horizontal plane at an angle of 180°. The detection direction is axial. The inner diameter of the casing is detected. The ovality of the casing is detected based on the reflection time of the sound wave.

14. The wellbore integrity evaluation system according to claim 1, characterized in that: The data processing system includes a sensor data processing component and a circuit microprocessor interface, and the sensor data processing component is composed of a signal processing microchip.

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

16. A method for evaluating wellbore integrity, characterized in that: The wellbore integrity evaluation system according to any one of claims 1 to 15 comprises the following steps: Use strain sensors to locally measure the axial strain and circumferential strain of the casing; The displacement sensor determines the displacement of the casing during the change of formation movement; The temperature sensor and the formation pressure sensor measure the formation temperature and pressure at the location of the casing nipple; The ultrasonic sensor determines the surface holes and ovality information of the casing; The above sensors are used to monitor the casing deformation position, deformation degree, casing deformation amount, formation temperature and pressure parameters, and evaluate the damage, destruction and sealing of the wellbore.

Images