Coiled tubing horizontal well comprehensive leak detection method

Abstract

The present application relates to a kind of coiled tubing horizontal well comprehensive leak detection method, the method comprises: packer leak detection, downhole television investigation, multi-arm casing damage detection, sound amplitude instrument frequency test, the method is carried by coiled tubing instrument into well, the packer is verified by mechanical setting to find out lost section, the downhole television and multi-arm, sound amplitude instrument cooperate to determine the specific location of loss, and the sound amplitude instrument accurately judges the loss point by fluid noise.The comprehensive leak detection method provided by the present application provides a variety of solutions for complex well conditions in unconventional oil and gas wells, and can be combined according to well conditions to lower into instrument, greatly improve the accuracy and success rate of leak detection.

Description

TECHNICAL FIELD

[0001] The present application relates to a coiled tubing head for oil and gas fields, more particularly to a comprehensive leak detection method for coiled tubing horizontal wells. BACKGROUND

[0002] In recent years, with the continuous development of unconventional oil and gas wells, the situation of casing leakage and damage caused by formation, production or engineering reasons is increasing. Once the casing of unconventional oil and gas wells is deformed and leaks, not only can't it be normally pumped, but also the formation material may flow into the casing, and the sand-water mixture may flow into the oil and gas reservoir, affecting the already fractured section, and even stopping production.

[0003] In order to ensure the normal fracturing production of unconventional oil and gas wells, it is necessary to repair or plug the casing damage and casing deformation. In order to achieve the purpose of repairing and plugging, it is necessary to accurately find out the depth, size and shape of the leakage and deformation. At present, the conventional packer leak detection method is restricted by most actual well conditions, and can only find the approximate position of the leakage, and there are still problems of passability, and the detailed information of the leakage and casing damage site cannot be completely explored, providing limited information for the next plugging scheme. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a comprehensive leak detection method for coiled tubing horizontal wells, which can maximize the uncertainty of downhole problems and improve the accuracy of leak detection technology.

[0005] The technical scheme adopted by the present application to solve the technical problem is: a comprehensive leak detection method for coiled tubing horizontal wells is constructed, comprising the following steps:

[0006] (1) Level the well site to meet the requirements of bearing construction equipment and ensure that there is enough operating space around the wellhead; according to the basic data of horizontal well drilling, well structure, wellbore and trajectory information, determine the size of the coiled tubing used for leak detection operation and the specification of the instrument, simulate the running of the coiled tubing, and ensure its passability during running; ensure that the wellhead device of the coiled tubing is pressure tested qualified before operation, and confirm the latest bridge plug setting depth and perforation data;

[0007] (2) Connect the pump truck, water tank, ground high pressure filter and ground pipeline and test pressure qualified, install the coiled tubing guide, injection head, and insert the coiled tubing, test the function of the blowout preventer; install the wellhead conversion flange, connect the injection head, blowout box, blowout preventer and blowout pipe, complete the wellhead installation, and ensure that the length of the downhole instrument is less than the length of the blowout pipe; complete the tensile test of the coiled tubing connector on the ground, overall pressure test, adjust the position of the lock pin of the leak detection packer to the lower position, test the communication of the downhole television, multi-arm and sound amplitude instrument, and complete the multi-arm calibration;

[0008] (3) According to the coiled tubing through-washing operation scheme, the through-washing and debris fishing in the wellbore are completed to ensure that the instrument can be normally lowered, and the downhole television and amplitude instrument test have a good liquid environment;

[0009] (4) The coiled tubing connector is made, and the lost circulation packer tool string is replaced. After the overall pressure test is qualified, the coiled tubing is lowered after depth calibration. The packer is initially set at a position above the resistance position. After the packer string is lifted by a certain distance, it is lowered again. The packer is set;

[0010] (5) Each time the packer is set and pressure tested, if it is qualified, it indicates that there is no leakage in the tested section. Then, the middle point of the lower well section distance is determined by the half-division method in the interval below the setting point to set and seal again. If the pressure test is not qualified, it is determined whether there is liquid leakage at the wellhead. If not, it is determined that the leakage point is in the wellbore. Then, the middle point of the upper well section distance is determined by the half-division method in the interval above the setting point to set and seal again until the leakage point position is determined in the appropriate interval range;

[0011] (6) After the leakage point interval is determined, the packer is released and lowered to the resistance position. The resin ball is put into the coiled tubing. The pump is started to circulate to the circulation valve of the packer. The well is washed until the return fluid is clear water without impurities. The packer string is lifted;

[0012] (7) The wireline coiled tubing is replaced. The instrument is prepared before entering the well according to steps (1) and (2). The cable seal head and the remaining amount are managed before the wireline coiled tubing pressure test. The multi-arm instrument calibration, downhole television communication detection, and cable on-off insulation detection are completed before entering the well. The well is entered. The depth at the wellhead is zeroed. According to the leakage well section determined in steps (4) and (5), the downhole television cooperates with the multi-arm to make the second time into the well test. The downhole television images the leakage section while the amplitude instrument noise test is started. Finally, the multi-arm is started to measure the leakage section;

[0013] (8) After the test data is recorded, the test instrument is lifted to the wellhead, and the test is ended;

[0014] (9) The downhole television video data, noise frequency data, and multi-arm well diameter data obtained by the test are extracted and divided. The data includes the optical imaging, depth, acoustic frequency, wellbore diameter, and events of the corresponding points of the leakage section;

[0015] (10) the data collected are subjected to image processing, depth correction, filtering and denoising, effective data obtained from the lost circulation section are comprehensively analyzed, and a three-dimensional stereogram of the casing damage point is drawn; the position of the leakage point can be qualitatively judged according to the fluid noise quality and vibration frequency of the acoustic amplitude instrument, and the size and shape of the leakage point can be quantitatively analyzed in combination with the distance of the well diameter expansion or contraction section measured by the multi-arm and the downhole television imaging; specifically, the leakage point shows abnormal high-frequency vibration on the frequency spectrum, and the closer to the point, the more active the acoustic wave band, generally, the size of the leakage point is positively correlated with the vibration frequency, and a small part of the leakage point may have low-frequency vibration, the acoustic frequency characteristics of which are different from those of the normal well section, and the well diameter value at the position is obviously larger or smaller than the standard inner diameter of the normal casing; the three-dimensional imaging of the abnormal well diameter is quantified, and the leakage point information is comprehensively judged according to the characteristics of the downhole television imaging, such as obvious holes and fractures.

[0016] According to the above scheme, the packer comprises an upper joint, a rubber sleeve, a slip, a cylinder, a friction block and a transposition pin connected in sequence from top to bottom, the rubber sleeve is a sealing part of the packer, a sealing mode is achieved by changing a state of the transposition pin and pressing down a tubing to be set; the upper part of the slip is provided with a slip sleeve, and the cylinder is provided with a spring inside the cylinder, and the spring is located between the slip and the friction block.

[0017] According to the above scheme, the acoustic amplitude instrument judges the type and direction of the fluid by measuring the noise amplitude and frequency generated by the fluid flowing in the pipe or the cement ring channel outside the pipe.

[0018] According to the above scheme, in the step (5), whether the casing is lost is judged by the pressure holding capacity of the closed space through the casing pressure test.

[0019] According to the above scheme, when the downhole television, the multi-arm or the acoustic amplitude instrument is put into the well for testing in the step (7), a magnetic positioning and gamma device is matched at the uppermost end of the combined instrument, which is used for judging the real-time measurement depth of each instrument and depth correction in the later period.

[0020] According to the above scheme, in the steps (9) and (10), the leakage point is observed by comparing the abnormal noise event measured by the acoustic amplitude instrument with the downhole television imaging at the corresponding depth, and if the wellbore environment is turbid, the image information is extracted and the recognition degree is enhanced.

[0021] The continuous tubing horizontal well comprehensive leakage finding method has the following beneficial effects:

[0022] 1. When the packer fails to find the leakage point, the leakage point can be more accurately found by using the instrument based on optics and acoustics.

[0023] 2、The main difference between the present application and the existing leak finding process method is that more abundant leak point information can be obtained, including its shape, size, depth and orientation. And the setting method of the packer is improved, from the original rubber cylinder pressing mode to the up and down setting, which increases the setting times of the packer and reduces the risk of sticking caused by rubber cylinder damage. The sealing pressure of the packer is higher. The leak finding process method also integrates the acoustic amplitude instrument based on the acoustic principle. In the case of poor downhole television imaging or multi-arm unable to detect casing deformation, the fluid noise frequency is monitored, which is more conducive to finding small hole leakage and improving the accuracy and precision of leak finding.

[0024] 3、If the leak point can be judged in the vertical section, the downhole television, multi-arm and acoustic amplitude instrument can also be connected with the logging winch for testing in the cable downhole mode, which can greatly improve the up and down speed, reduce the testing time and improve the leak finding efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0025] The present application will be further described below in conjunction with the drawings and examples, wherein:

[0026] Figure 1 is a test process schematic diagram of the present application;

[0027] Figure 2 is a test process flowchart of the present application;

[0028] Figure 3 is a leak finding packer schematic diagram of the present application;

[0029] Figure 4 is a general test instrument schematic diagram of the present application;

[0030] Figure 5 is an acoustic amplitude instrument schematic diagram of the present application. DETAILED DESCRIPTION

[0031] In order to have a clearer understanding of the technical features, purposes and effects of the present application, the specific implementation mode of the present application will be described in detail with reference to the drawings.

[0032] The present application provides a comprehensive leak finding method for coiled tubing horizontal wells. According to the well conditions, the instrument is combined and lowered to achieve the purpose of leak finding. The overall leak finding scheme is more perfect, the leak finding process is more accurate, and the speculative judgment of downhole complex conditions can be effectively eliminated.

[0033] The specific implementation process of the horizontal well comprehensive leak finding method is shown in the accompanying Figure 1 Figure 2 It can be understood that Figure 2 the process does not have to be implemented in its entirety, and appropriate auxiliary content can be added according to the actual well conditions to help complete the process, which all belong to the method protection content.

[0034] 1. The method comprises the following steps:

[0035] (1) Well site, well head, wellbore preparation

[0036] Level the well site to meet the requirements of bearing construction equipment, and ensure that there is enough working space around the well head. According to the basic data of horizontal well drilling, wellbore structure, wellbore and trajectory information, determine the size of the coiled tubing used for leak detection operation and the specifications of the instruments, simulate the running of the coiled tubing, and ensure its passability during running. Before the coiled tubing operation, ensure that the well head device pressure test is qualified, and confirm the latest bridge plug setting depth and perforation data.

[0037] (2) Equipment installation and debugging

[0038] Connect the pump truck, water tank, ground high-pressure filter and ground pipeline and pass the pressure test, install the coiled tubing guide, injection head, and insert the coiled tubing, test the function of the blowout preventer. Install the well head conversion flange, connect the injection head, blowout preventer box, blowout preventer and blowout pipe, complete the well head installation, and ensure that the length of the downhole instrument is less than the length of the blowout pipe. Complete the tension test of the coiled tubing connector on the ground, overall pressure test, adjust the shift lock pin of the leak detection packer to the lower position, test the communication of the downhole television, multi-arm and sound amplitude instrument, and complete the multi-arm calibration.

[0039] (3) Coiled tubing through well flushing

[0040] According to the coiled tubing through well flushing construction scheme, complete the through well flushing and debris fishing in the wellbore to ensure that the instrument can be normally lowered, and the downhole television and sound amplitude instrument have a good liquid environment.

[0041] (4) Lowering the leak detection packer

[0042] Make the coiled tubing connector, replace the leak detection packer tool string, and after overall pressure test is qualified, depth zero, lower the coiled tubing. Keep the speed stable during lowering, and if resistance is encountered, the pressure shall not exceed the maximum tonnage of the setting pressure. The initial setting of the packer is set above the resistance position, and after lifting the packer string by a certain distance, the packer is lowered again, and the packer completes the setting.

[0043] (5) Determine the interval of the leakage point

[0044] Each time the setting pressure test is qualified, it indicates that there is no leakage in the tested section, and then the middle point of the lower well section distance is determined by the half division method below the setting point for re-setting; if the pressure test is not qualified, determine whether there is liquid leakage at the well head device, if not, determine that the leakage point is in the wellbore, then continue to determine the middle point of the upper well section distance above the setting point by the half division method for re-setting, until the location of the leakage point is found. Finally, the location of the leakage point is determined within a proper interval range.

[0045] (6) Ball washing

[0046] After determining the leakage interval, the packer is unsealed and lowered to the resistance position, and a resin ball is put into the coiled tubing. Pumping is started and circulated to the packer circulation valve. The well is washed until the flowback fluid is clear water without impurities. The packer string is pulled out.

[0047] (6) Downhole TV, multi-arm, acoustic amplitude instrument

[0048] Replace the cable coiled tubing, and complete the instrument preparation before entering the well according to steps (1) and (2). Before pressure testing the cable coiled tubing, complete the cable seal head and residual amount management. Before entering the well, complete the multi-arm instrument calibration, downhole TV communication detection, and cable on-off insulation detection. Start entering the well, set the wellhead depth to zero, and use the downhole TV and multi-arm to make the second trip into the well for testing according to the leakage interval determined in steps (4) and (5). While the downhole TV is imaging and observing the leakage interval, turn on the acoustic amplitude instrument for noise testing. Finally, turn on the multi-arm for uphole testing. During the uphole testing process, do not lower the pipe string.

[0049] (7) Upwardly pull the test pipe string to the wellhead

[0050] After completing the test data recording, pull the test instrument to the wellhead and end the test.

[0051] (8) Data extraction

[0052] Extract and divide the downhole TV video data, noise frequency data, and multi-arm well diameter data obtained during the test. The data includes optical imaging, depth, acoustic frequency, wellbore diameter, and events corresponding to the leakage interval.

[0053] (9) Data correction and interpretation

[0054] Perform image processing, depth correction, and filtering and denoising on the collected data, comprehensively analyze the effective data obtained from the leakage interval, and draw a three-dimensional stereogram of the casing damage points.

[0055] (10) Results submission

[0056] According to the test result report, guide the next casing damage repair scheme.

[0057] Preferably, the leak-finding packer comprises, from top to bottom, an upper connector, a rubber sleeve, a slip, a cylinder, a friction sleeve, and a transposition pin. The rubber sleeve is the main sealing part of the packer, and the sealing method is achieved by changing the state of the transposition pin, pressing down the tubing for setting, and the setting frequency depends on the service life of the rubber sleeve. The upper part of the slip is provided with a slip sleeve. The cylinder is provided with a spring, which is located at the lower part of the slip and the upper part of the friction block.

[0058] The downhole television, multi-arm testing, and acoustic amplitude instrument pipe string can be connected with the coiled tubing built-in single-core cable, and a test can be performed at one time. The downhole television is provided with an optical probe, which can probe the running condition in real time. The multi-arm can quantitatively analyze the size and shape of the casing damage. The acoustic amplitude instrument can be connected with the multi-arm and downhole television instrument at one time, and the acoustic amplitude instrument is connected at the lower end of the multi-arm and the upper end of the downhole television during the test.

[0059] Preferably, the acoustic amplitude instrument can determine the type and direction of the fluid by measuring the noise amplitude and frequency generated by the fluid flowing in the pipe or the cement ring channel outside the pipe, and can detect the leakage points that cannot be found by conventional leakage detection methods and abnormal events in the well, thereby improving the accuracy and success rate of the leakage detection method.

[0060] Preferably, the acoustic amplitude instrument comprises a sensor assembly, a circuit system, an upper joint, a compression sleeve, a lower joint, an outer cylinder, and a noise transducer.

[0061] Preferably, the sensor assembly is located at the upper end of the circuit system according to the direction of the instrument during the test. The noise transducer is located between the circuit system and the sensor assembly, and both are built in the outer cylinder. The upper joint is located at the lower end of the circuit system and is built in the compression sleeve. The lower joint is located at the upper end of the sensor assembly and is used to connect the upper instrument.

[0062] Preferably, before the well flushing in step (3), in addition to the connection of the conventional tool string, if the tool length for detecting the leakage of the packer in step (4) cannot be reached, an appropriate length and weight of the adaptive tool should be added to perform the well flushing, so as to simulate the passability of the rigid tool in step (4).

[0063] Preferably, after the packer is set in steps (4) and (5) in step (7), the stability of the closed space is determined by the casing pressure test to determine whether there is leakage.

[0064] Preferably, the downhole television, multi-arm, and acoustic amplitude instrument in step (7) can be combined by the field engineer according to the downhole condition. Each instrument needs to work in a water environment.

[0065] Preferably, when any one or two or more of the downhole television, multi-arm, and acoustic amplitude instrument are combined and put into the well for testing in step (7), a magnetic positioning and gamma device needs to be connected at the uppermost end of the combined instrument, which is mainly used to determine the real-time measurement depth of each instrument and the depth correction in the later stage.

[0066] Preferably, the casing damage abnormal point measured by the multi-arm or the noise abnormal event measured by the acoustic amplitude instrument is compared with the corresponding depth of the downhole television imaging to observe the leakage point. If the wellbore environment is turbid, the image information can be feature extracted to enhance the recognition degree.

[0067] Preferably, steps (9) and (10) can qualitatively determine the leak point position according to the fluid noise quality and vibration frequency of the acoustic amplitude instrument, and quantitatively analyze the leak size and shape by combining the distance of the well diameter expansion or contraction section measured by the multi-arm and the downhole television imaging. Specifically, the leak point shows abnormal high-frequency vibration in the frequency spectrum, and the closer to the point, the more active the sound wave band. Generally, the size of the leak point is positively correlated with the vibration frequency, and a small part of the leak point may have low-frequency vibration. The sound frequency characteristics are different from the normal well section, and the well diameter value at the position is obviously larger or smaller than the standard inner diameter of the normal casing. The three-dimensional imaging of the abnormal well diameter is quantified, and the downhole television imaging is analyzed to have obvious hole, fracture and other leak point characteristics to comprehensively judge the leak point information.

[0068] Preferably, if steps (4) and (5) cannot be performed due to casing changes, step (6) can be directly performed, which still belongs to the content of the method.

[0069] Preferably, the description of the components does not include all parts, for example, a part in the components of an instrument can be composed of more micro elements.

[0070] According to the specific embodiment of the present application, in the method, when the well site, wellhead and wellbore are prepared, sufficient clean water is ensured on site to meet the water supply demand of the coiled tubing and ground circulation pipeline water pressure test. The operation site is ensured to have testing and circulation conditions. Since some problem wells may be under pressure during coiled tubing operation, the wellhead should be prepared according to the well control standard to prevent and control the plan.

[0071] According to the specific embodiment of the present application, in the method, when the equipment is installed and debugged, the pump truck, ground high-pressure filter and ground pipeline are connected. The ground pipeline needs to be tested according to the standard, and can continue only when it meets the requirements.

[0072] According to the specific embodiment of the present application, in the method, when the well is washed, a matching tool with a length and weight equivalent to the packer should be added to simulate the passability of the rigid tool at the maximum inclination. The critical length of the rigid tool when passing through the maximum dogleg can be calculated by using the geometric analysis method as a reference.

[0073] Further, a strong magnetic adsorption tool should be added to the tool string to salvage iron filings in the well and ensure the smooth environment of the wellbore.

[0074] According to the specific embodiment of the present application, the leak sealing packer in the method is shown in the attached Figure 3As shown, the injection head direction control rod should be slowly operated when the packer is lowered, and the tubing should be slowly and uniformly lowered when passing through the blowout preventer and fracturing wellhead, the full angle change rate is large, and the horizontal section. Do not continuously raise the coiled tubing before lowering to the position. After reaching the predetermined position, the coiled tubing is raised and lowered. When it is necessary to set, the pipe string is raised by a certain distance, the displacement lock pin at the lower end of the friction block enters the setting position, and then the pipe string is slowly lowered. The friction sleeve and the casing generate a friction force to extend the slips and clamp the inner wall of the casing. Continuing to lower the pipe string compresses the rubber cylinder, closes the annular space between the tubing and the casing, and realizes the setting of the packer.

[0075] Specifically, the packer has a set state and a non-set state, and the state transition is completed by changing the position of the displacement lock pin by raising the tubing. The rubber cylinder diameter in the set state is greater than the leak detection casing diameter, and the rubber cylinder diameter in the non-set state is less than the friction block diameter. Of course, the diameter of the rubber cylinder and the size of the packer can be different according to different application scenarios. If the packer cannot be lowered due to the change in the section, the maximum matching outer diameter of each part of the packer can be appropriately changed. The specific size is not specifically limited.

[0076] Further, the packer is initially set at a position above the resistance position within a proper range, and the depth is recorded. The packer is tested by pressing the oil layer casing, and the pressure is stabilized. If the pressure test is not qualified, it is judged that there is at least one leak point in the pressure test area, and the amount of liquid leakage is calculated.

[0077] Further, each time the packer is set and tested, if it is qualified, a new set position is determined in the interval below the set point by half division method; if the test is not qualified, the leakage is calculated, and a new set position is determined in the interval above the set point by half division method, until the leak point position is found. After the leak point is found, it is determined whether there is a leak point in the lower section of the leak point by calculating the amount of leakage. Finally, the leak point position is confirmed within a proper range.

[0078] Further, the packer is unsealed and lowered to the bottom of the casing to the resistance position, a resin ball is put into the coiled tubing, and the pump is opened for circulation to the circulation valve at the upper end of the packer. After the circulation valve is opened, the well is washed with clean water at a suitable displacement until the backflow fluid is clean and free of impurities.

[0079] According to the specific embodiment of the present application, the downhole television, multi-arm, and amplitude instrument test pipe string in the method is as shown in the accompanying drawings. Figure 4 As shown, before entering the well, the remaining amount of the cable in the coiled tubing needs to be managed and the on-off insulation performance of the cable needs to be detected. After the instrument is debugged and connected and the overall pressure test is qualified in the blowout preventer, it can enter the well. During normal lowering, the coiled tubing should be kept at a uniform and slow state when passing through the blowout preventer and fracturing wellhead. Every time a distance is lowered, the coiled tubing is raised and lowered for testing, the suspended weight is checked, and the suspended weight value is recorded. During the lowering process, the change in the suspended weight of the pipe string is closely observed, and the pressure should not exceed the maximum tonnage of the set lower pressure after encountering resistance.

[0080] The multi-arm instrument can select appropriate number of arm claws according to the requirements of wellbore environment and actual measurement accuracy.

[0081] Further, according to the leakage detection of the packer, the upper end of the determined leakage section is slowly and uniformly observed for the downhole television imaging and the amplitude noise frequency monitoring is started. If resistance is encountered in the process, the appropriate displacement pump is used to inject clean water. After the well fluid is stabilized, the lowering continues.

[0082] In the instrument of the test pipe string, the outer diameter of the instrument is much smaller than the diameter of the casing, and the instrument is provided with flexible and rotary connectors to ensure good passability of the measuring instrument. If the instrument cannot be normally lowered due to severe deformation of the casing, the specific shape of the casing deformation can also be probed by the downhole television and the amplitude instrument.

[0083] The amplitude instrument is shown in the accompanying drawings Figure 5 The red area is the sound wave emission area and the signal modulation area. In order to adapt to the application needs of the actual scene, a thermometer or a flow pressure gauge can also be combined at the lower end thereof.

[0084] Further, the amplitude instrument adopts two modes of continuous testing and point testing during the testing. The continuous measurement is used for rough measurement of the depth, temperature, flow, pressure and noise. The point measurement is used for detailed measurement of the noise signal. In most cases, due to the movement of the instrument, the shaking of the tubing and the cable, a large low-frequency interference signal is generated, which causes the instrument to be saturated and distorted. In order to avoid this situation, the continuous measurement mode can be used to determine the leakage section, and then the point measurement mode is used for measurement with appropriate spatial resolution in the section.

[0085] The specific operation steps of the amplitude instrument during measurement are as follows: 1) the instrument first starts continuous measurement at a slow and uniform speed, monitors the change of the noise spectrum, and adjusts the appropriate gain value if the noise spectrum amplitude is too high or too low. The abnormal sections of noise, temperature, flow and pressure are recorded during the testing process. This process is repeated once, and the leakage well section is determined by repeating the curve. 2) After determining the measurement section, the instrument is placed at the starting point of the measurement section, the drum or winch brake is stopped, and the first point and the second point are tested in turn after the instrument or the tubing and the cable are completely prohibited. Appropriate measurement time and spatial resolution are selected for each measurement point.

[0086] In addition, each section of the instrument is electrically connected through metal pins and sockets, and the ports are all provided with O-shaped sealing rubber rings to ensure that the pressure fluid does not leak into the instrument from the position under the pressure environment.

[0087] Further, after the downhole television and the amplitude instrument are tested, the test pipe string is lowered to the lower part of the leakage section. It should be noted that the multi-arm instrument should be located at the lower part of the leakage section according to the magnetic positioning and the measurement data of the gamma, combined with the instrument zero length.

[0088] Further, the multi-arm instrument arm claw is opened, and any lowering operation is prohibited during the upper measurement.

[0089] The leakage finding method provided in the present application is a comprehensive solution based on mechanics, photoelectricity and acoustics, and has strong practical significance for finding the causes of leakage in a casing change well with complex well conditions. The method can greatly eliminate the uncertain factors in the well, overcome the problems that cannot be solved by conventional leakage finding methods, reduce the impact of complex working conditions, and improve production efficiency.

[0090] The embodiments of the present application are described above in combination with the drawings, but the present application is not limited to the above specific embodiments, and the above specific embodiments are only illustrative but not restrictive. Those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection of the present application.

Claims

1. A method of comprehensive leak detection for coiled tubing horizontal wells, characterized in that, The method comprises the following steps: (1) leveling the well site to meet the requirements of bearing construction equipment, and ensuring that there is sufficient working space around the wellhead; according to the basic data of horizontal well drilling, wellbore structure, wellbore and passing track information, the size of the coiled tubing used for leak finding operation and the specifications of the instruments are determined, the coiled tubing is simulated to be run in, and the passability of the coiled tubing in the running-in process is ensured; before the coiled tubing operation, the wellhead device of the coiled tubing is ensured to pass the pressure test, the latest bridge plug setting depth and perforation data are confirmed; (2) connecting the pump truck, water tank, ground high-pressure filter and ground pipeline and passing the pressure test, installing the coiled tubing guide, injection head, inserting the coiled tubing, testing the function of the blowout preventer; installing the wellhead conversion flange, connecting the injection head, blowout preventer box, blowout preventer and blowout pipe, completing the wellhead installation, and ensuring that the length of the instrument run into the well is less than the length of the blowout pipe; on the ground, the tension test of the coiled tubing connector is completed, the overall pressure test is completed, the shift lock pin of the leak detection packer is adjusted to the lower position, the communication of the downhole television, multi-arm and acoustic amplitude instrument is tested, and the multi-arm scale is completed; (3) according to the coiled tubing through well flushing construction scheme, the through well flushing and debris fishing in the wellbore are completed, and it is ensured that the instrument can be normally lowered, and the downhole television and acoustic amplitude instrument have a good liquid environment; (4) the coiled tubing connector is made, the leak finding packer tool string is replaced, after the overall pressure test is qualified, the depth is calibrated to zero, and the coiled tubing is lowered; the packer is initially set above the position where resistance is encountered, after the packer string is lifted by a certain distance, the packer is lowered again, and the packer is set; (5) each time the packer is set and tested, if it is qualified, it indicates that there is no leakage in the tested section, then the middle point of the distance of the lower well section in the interval below the setting point is determined again for setting and sealing according to the half division method; if the pressure test is not qualified, it is determined whether there is liquid leakage in the wellhead device, if not, it is determined that the leakage point is in the wellbore, then the middle point of the distance of the upper well section in the interval above the setting point is determined again for setting and sealing according to the half division method, until the leakage point position is determined in a proper interval range; (6) after the leakage point interval is determined, the packer is released and lowered to the position where resistance is encountered, the resin ball is put into the coiled tubing, the pump is started to circulate to the circulation valve of the packer, the well is washed and circulated until the returned fluid is clear water without impurities, and the packer string is lifted; (7) the wireline coiled tubing is replaced, the instrument is prepared before being run into the well according to steps (1) and (2), the cable seal head and the remaining amount are managed before the wireline coiled tubing is pressure tested, the multi-arm instrument scale, downhole television communication test and cable on-off insulation test are completed before the wireline coiled tubing is run into the well; the wireline coiled tubing is started to be run into the well, the wellhead depth is zeroed, the downhole television cooperates with the multi-arm to make the second time of running-in test according to the leakage well section determined in steps (4) and (5), the downhole television is used to image and observe the leakage section while the acoustic amplitude instrument is used to test the noise, and finally the multi-arm is used to measure the leakage section; (8) after the test data are recorded, the test instrument is lifted to the wellhead, and the test is ended; (9) the downhole television video data, noise frequency data, multi-arm well diameter data obtained by the test are extracted and divided; the data include the optical imaging, depth, acoustic frequency, wellbore diameter and events of the corresponding points of the leakage section. (10) image processing, depth correction, filtering and denoising are performed on the collected data, effective data obtained from the lost section are comprehensively analyzed, and a three-dimensional stereogram of the casing damage point is drawn; the position of the leakage point can be qualitatively judged according to the fluid noise quality and vibration frequency of the acoustic amplitude instrument, and the size and shape of the leakage point can be quantitatively analyzed in combination with the distance of the well diameter expansion or contraction section measured by the multi-arm at the point and the downhole television imaging; specifically, the leakage point shows abnormal high-frequency vibration on the frequency spectrum, and the closer to the point, the more active the acoustic wave band, generally, the size of the leakage point is positively correlated with the vibration frequency, and a small part of the leakage point may have low-frequency vibration, the acoustic frequency characteristics of which are different from those of the normal well section, and the well diameter value at the position is obviously larger or smaller than the standard inner diameter of the normal casing; the three-dimensional imaging of the abnormal well diameter is quantified, and the leakage point information is comprehensively judged by analyzing the downhole television imaging with obvious hole, fracture and other leakage point characteristics; The acoustic amplitude instrument determines the type and direction of the fluid by measuring the noise amplitude and frequency generated by the fluid flowing in the pipe or the cement sheath channel outside the pipe; in step (5), the pressure holding capacity of the closed space is determined by the casing pressure test to determine whether it is lost; when the downhole television, multi-arm or acoustic amplitude instrument is tested, a magnetic positioning and gamma device is connected to the uppermost end of the combined instrument to determine the real-time measurement depth of each instrument and the depth correction in the later stage; in steps (9) and (10), the leakage point is observed by comparing the noise anomaly event measured by the acoustic amplitude instrument with the downhole television imaging at the corresponding depth, and if the wellbore environment is turbid, the image information is feature extracted to enhance its recognition. The downhole television, multi-arm and acoustic amplitude instrument string used in the leakage finding method can be connected with the coiled tubing built-in single-core cable at the same time, and one test is performed, the downhole television has an optical probe that can probe the running condition in real time, the multi-arm can quantitatively analyze the size and shape of the casing damage, and the acoustic amplitude instrument can be connected with the multi-arm and downhole television for one test, and is connected at the lower end of the multi-arm and the upper end of the downhole television during the test.

2. The coiled tubing, horizontal well, integrated leak detection method of claim 1, wherein, The packer comprises an upper joint, a rubber sleeve, a slip, a cylinder, a friction block and a transposition pin connected in sequence from top to bottom, the rubber sleeve is a sealing part of the packer, the sealing mode is changed by changing the state of the transposition pin, and the tubing is pressed down to be sealed; the upper part of the slip is provided with a slip sleeve, the cylinder is provided with a spring, and the spring is located between the slip and the friction block.

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