Integrated testing string of gas well liquid production profile and downhole television and testing method

Abstract

The present application relates to oil and gas well testing technology field, is a kind of gas well liquid production profile and downhole television integrated testing string and testing method, the former includes photoelectric composite cable and sequentially connected together from top to bottom coiled tubing, centralizer, check valve, light source and downhole television terminal, check valve outside is spaced apart and is provided with a plurality of circulating flushing nozzle, the lower end of photoelectric composite cable sequentially passes through coiled tubing, centralizer, check valve is connected with light source and downhole television terminal respectively after, and photoelectric composite cable can collect temperature data and sound data.The present application is reasonable and compact, realizes the collection of liquid production profile data and the monitoring of the opening condition of each perforation cluster with one testing string, solves the problem of long construction cycle and high cost of respectively monitoring gas well liquid production profile, downhole television perforation hole after fracturing, provides strong guidance for reservoir and fracturing effect evaluation, fracturing scheme optimization.

Description

Technical Field

[0001] This invention relates to the field of oil and gas well testing and production technology, and is an integrated testing string and testing method for gas well production profile and downhole television. Background Technology

[0002] China possesses abundant low-permeability shale oil and gas resources, which are expected to become important replacement resources. Pilot tests of low-permeability shale oil and gas have been conducted in the Songliao Basin, Ordos Basin, Junggar Basin, and Sichuan Basin. These tests have confirmed that multi-stage cluster volumetric fracturing in horizontal wells has become a key technology for improving energy return (EUR) and efficient development. However, due to the strong heterogeneity of the reservoirs, the production capacity varies greatly after staged fracturing. Therefore, it is urgent to understand the production capacity and fracturing effect of each stage and cluster to provide important data for fine reservoir classification, optimization of fracturing stimulation schemes, and selection of layers for repeated fracturing.

[0003] Patent document with application number 201811193875.2, entitled "Downhole Television Testing String and Testing Method for Horizontal Well Coiled Tubing", discloses that: using coiled tubing with fiber optic cable, the upper end of the fiber optic cable is connected to the terminal of the ground display instrument, and the lower end of the fiber optic cable is connected to the downhole television testing terminal. The fiber optic cable is used for signal transmission, and the cable is used to provide power transmission. The downhole television testing string for horizontal well coiled tubing can complete visual inspection in the horizontal well section, and has the characteristics of simple operation and accurate results.

[0004] Patent document with application number 201910640346.0, entitled "A Production Profile Monitoring Method Based on Distributed Fiber Optic Sound Monitoring and Distributed Fiber Optic Temperature Monitoring," discloses that: the sound signal reflected back from the single-mode acoustic fiber and the temperature signal reflected back from the multi-mode temperature fiber are processed using the DTS / DAS injection-production well production profile interpretation module, and finally the real-time flow rate and water content of each production section of the injection-production well are obtained, which can complete "full well section production profile testing in one well entry operation."

[0005] A journal article titled "Analysis of the Uniformity of Fracture Initiation in Multiple Clusters Based on Perforation Imaging Monitoring" discloses that by using continuous tubing with cable, the degree of borehole erosion is monitored by perforation imaging, and then the uniformity of fracture initiation in each cluster and the proppant entry are analyzed. This provides important basis for optimizing pumping procedures, reducing borehole erosion, and improving the success rate of temporary plugging.

[0006] Post-fracturing perforation visualization monitoring and production profile monitoring are two testing methods that can evaluate the reservoir and fracturing effect from different perspectives. Each process has its own advantages. For gas well production profile testing, distributed fiber optic monitoring has a significant advantage over array multi-probe testing technology. However, currently, visualization and production profile monitoring are carried out separately, and the two technologies have not been able to complement each other. Summary of the Invention

[0007] This invention provides an integrated testing string and method for gas well production profile and downhole television monitoring, overcoming the shortcomings of the prior art. It can effectively solve the problems of long construction cycle and high cost associated with existing methods of separately monitoring production profiles of gas-producing horizontal wells and monitoring downhole perforations after fracturing.

[0008] One of the technical solutions of this invention is achieved through the following measures: an integrated test string and test method for gas well production profile and downhole television, comprising a photoelectric composite cable and coiled tubing, centralizer, check valve, light source, and downhole television terminal connected sequentially from top to bottom. Several circulating well-washing nozzles are spaced apart on the outside of the check valve. The lower end of the photoelectric composite cable passes through the coiled tubing, centralizer, and check valve in sequence and is connected to the light source and downhole television terminal respectively. The photoelectric composite cable is capable of collecting temperature data and sound data.

[0009] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions:

[0010] The aforementioned optoelectronic composite cable may include at least three single-mode optical fibers and at least one multimode optical fiber, wherein one multimode optical fiber is used to collect sound data, one single-mode optical fiber is used to collect temperature data, and the other two single-mode optical fibers are respectively connected to a light source and an underground television terminal.

[0011] The second technical solution of the present invention is achieved through the following measures: a testing method, comprising the following steps:

[0012] The first step is to clean the sand and debris out of the well and then shut it off.

[0013] The second step is to assemble the integrated test string for gas well production profile and downhole television, and then test whether the integrated test string for gas well production profile and downhole television is working properly. If it is, proceed to the third step; otherwise, check the integrated test string for gas well production profile and downhole television.

[0014] The third step, with the well shut in, is to run in the gas well production profile and downhole television integrated test string. After running it 150 to 250 meters, the gas well production profile and downhole television integrated test string are checked. If they are normal, the string is continued to be run; if they are not normal, it is pulled out and checked again.

[0015] The fourth step involves lowering the integrated testing string for gas well production profile and downhole television to 20 to 30 meters above the perforation cluster. Then, the lowering speed is reduced, and the surface data acquisition equipment is connected to the optical fiber composite cable. The downhole television terminal is used to monitor the changes in the perforation holes. After monitoring all perforation clusters is completed, the connection between the surface data acquisition equipment and the optical fiber composite cable is disconnected.

[0016] The fifth step is to use a photoelectric composite cable to monitor the formation temperature while the well is shut in. Once the formation temperature stabilizes, the well is opened for production.

[0017] Step 6: Select 2 to 3 nozzles for production. When the output is stable under each production system, collect temperature and sound data. After recording qualified temperature and sound data, propose the gas well production profile and downhole television integrated test string.

[0018] Step 7: Based on the opening status of each perforation cluster monitored by the downhole television terminal, analyze the erosion of the perforation holes in each perforation cluster, evaluate the fracture initiation law and the uniformity of opening of each perforation cluster under different fracturing pump injection parameters; based on the temperature and sound data collected by the optical fiber composite cable, and combined with the opening status of each perforation cluster monitored by the downhole television terminal, obtain the production profile interpretation results.

[0019] The following are further optimizations and / or improvements to the second technical solution of the above invention:

[0020] In the sixth step above, when the output is stable under each production system, one of the single-mode optical fibers of the optoelectronic composite cable collects temperature data, and one of the multimode optical fibers of the optoelectronic composite cable collects sound data. Then, qualified temperature data and sound data are recorded.

[0021] The second step above involves testing whether the gas well production profile and the integrated downhole television testing string are working properly, including: testing whether the fiber optic cable loss is normal; testing whether the light source is normal; and testing whether the downhole television terminal clearly monitors the opening status of each perforation cluster.

[0022] The second step mentioned above, which tests whether the gas well production profile and the downhole television integrated test string are working properly, also includes: pumping clean water into the coiled tubing at a rate of 44 to 55 liters per minute to test whether the circulating well-washing nozzle is working properly.

[0023] The third step above involves inspecting the gas well production profile and the downhole television integrated testing string, including: testing whether the fiber optic loss of the optical fiber composite cable is normal; and testing whether the light source and downhole television terminal can clearly observe the casing coupling.

[0024] In the fourth step above, if the area in front of the downhole TV terminal is blurry and the orifice is covered by sand, clean water is pumped into the coiled tubing and sprayed out through the circulating well-washing nozzle for cleaning.

[0025] This invention has a reasonable and compact structure and is easy to use. It has been applied and verified in multiple blocks such as deep shale gas. It enables the acquisition of production profile data and monitoring of the opening status of each perforation cluster in a single test string. It solves the problems of long construction cycles and high costs associated with separately monitoring gas well production profiles and monitoring downhole TV perforations after fracturing. It improves the accuracy of interpretation results and provides strong guidance for reservoir and fracturing effect evaluation and fracturing scheme optimization. Attached Figure Description

[0026] Appendix Figure 1 This is a schematic diagram of the front sectional structure when used in Example 1.

[0027] The codes in the attached diagram are as follows: 1 is the optical-electric composite cable, 2 is the coiled tubing, 3 is the centralizer, 4 is the check valve, 5 is the light source, 6 is the downhole television terminal, and 7 is the circulating well-washing nozzle. Detailed Implementation

[0028] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0029] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0030] The present invention will be further described below with reference to embodiments and accompanying drawings:

[0031] Example 1: As shown in the attached document Figure 1 As shown, the integrated test string for gas well production profile and downhole television includes a photoelectric composite cable 1 and, from top to bottom, coiled tubing 2, centralizer 3, check valve 4, light source 5, and downhole television terminal 6 connected together. Several circulating well-washing nozzles 7 are spaced apart on the outside of the check valve 4. The lower end of the photoelectric composite cable 1 passes through the coiled tubing 2, centralizer 3, and check valve 4 in sequence and is connected to the light source 5 and the downhole television terminal 6 respectively. The photoelectric composite cable 1 can collect temperature data and sound data.

[0032] Based on the requirements, light source 5 is a known LED light source, and downhole television terminal 6 is a known downhole imaging device. This invention has been applied and verified in multiple blocks, including deep shale gas formations. It enables the acquisition of production profile data and monitoring of the opening status of each perforation cluster in a single test run. This solves the problems of long construction cycles and high costs associated with separately monitoring gas well production profiles and monitoring downhole perforations after fracturing, improving the accuracy of interpretation results and providing strong guidance for reservoir and fracturing effect evaluation and fracturing scheme optimization.

[0033] The above-mentioned gas well production profile and downhole television integrated testing string can be further optimized and / or improved according to actual needs:

[0034] Example 2: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, the optoelectronic composite cable 1 includes at least three single-mode optical fibers and at least one multimode optical fiber. One multimode optical fiber is used to collect sound data, one single-mode optical fiber is used to collect temperature data, and the other two single-mode optical fibers are connected to the light source 5 and the downhole television terminal 6, respectively.

[0035] According to the requirements, the optical-electric composite cable 1 also includes a cable with at least two cores. One core is connected to the light source 5 to supply power to the light source 5, and the other core is connected to the downhole television terminal 6 to supply power to the downhole television terminal 6. The single-mode optical fiber is a known distributed optical fiber temperature sensing system (DTS), and the multimode optical fiber is a known distributed optical fiber acoustic sensing system (DAS), so that accurate downhole data can be obtained.

[0036] Example 3: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, the test method includes the following steps:

[0037] The first step is to clean the sand and debris out of the well and then shut it off.

[0038] The second step is to assemble the integrated test string for gas well production profile and downhole television, and then test whether the integrated test string for gas well production profile and downhole television is working properly. If it is, proceed to the third step; otherwise, check the integrated test string for gas well production profile and downhole television.

[0039] The third step, with the well shut in, is to run in the gas well production profile and downhole television integrated test string. After running it 150 to 250 meters, the gas well production profile and downhole television integrated test string are checked. If they are normal, the string is continued to be run; if they are not normal, it is pulled out and checked again.

[0040] The fourth step involves lowering the integrated testing string for gas well production profile and downhole television to 20 to 30 meters above the perforation cluster. Then, the lowering speed is reduced, and the ground data acquisition equipment is connected to the photoelectric composite cable 1. The downhole television terminal 6 is used to monitor the changes in the perforation holes. After monitoring all perforation clusters is completed, the connection between the ground data acquisition equipment and the photoelectric composite cable 1 is disconnected.

[0041] The fifth step is to use the photoelectric composite cable 1 to monitor the formation temperature while the well is shut in. Once the formation temperature stabilizes, the well is opened for production.

[0042] Step 6: Select 2 to 3 nozzles for production. When the output is stable under each production system, collect temperature and sound data. After recording qualified temperature and sound data, propose the gas well production profile and downhole television integrated test string.

[0043] Step 7: Based on the opening status of each perforation cluster monitored by the downhole television terminal 6, analyze the erosion of the perforation holes of each perforation cluster, evaluate the fracture initiation law of each perforation cluster and the uniformity of opening of each perforation cluster under different fracturing pump injection parameters; based on the temperature and sound data collected by the optical fiber composite cable 1, and combined with the opening status of each perforation cluster monitored by the downhole television terminal 6, obtain the production profile interpretation results.

[0044] In this way, the interpretation results of the production profile can reflect the main contributing sections of gas production at the toe and heel ends. It can optimize the fracturing scheme for reservoirs with poor physical properties and oil and gas content, improve the reservoir utilization rate, and provide strong guidance for reservoir and fracturing effect evaluation and fracturing scheme optimization.

[0045] The above testing methods can be further optimized and / or improved according to actual needs:

[0046] Example 4: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, in step six, when the output is stable under each production system, one of the single-mode optical fibers of the optoelectronic composite cable 1 collects temperature data, and one of the multimode optical fibers of the optoelectronic composite cable 1 collects sound data. Then, qualified temperature data and sound data are recorded.

[0047] Example 5: As an optimization of the above examples, as shown in the appendix. Figure 1 As shown, the second step of testing the gas well production profile and the integrated downhole television testing string to ensure normal operation includes: testing whether the fiber optic loss of the optical fiber composite cable 1 is normal; testing whether the light source 5 is normal; and testing whether the opening status of each perforation cluster monitored by the downhole television terminal 6 is clear. This allows for timely detection of abnormalities in the gas well production profile and the integrated downhole television testing string, preventing monitoring failures due to downhole anomalies and reducing monitoring costs.

[0048] Example 6: As an optimization of the above examples, as shown in the appendix Figure 1 As shown, the second step of testing whether the gas well production profile and the integrated downhole television testing string are working properly also includes: pumping clean water into the coiled tubing 2 at a rate of 44 to 55 liters per minute to test whether the circulating well-washing nozzle 7 is working properly. This ensures that the circulating well-washing nozzle 7 can work properly in the wellbore, promptly flushing areas where the downhole television terminal 6 camera image is unclear, and allowing for clear observation of the wellbore.

[0049] Example 7: As an optimization of the above embodiments, as shown in the appendix Figure 1As shown, the third step of inspecting the gas well production profile and the integrated downhole television testing string includes: testing whether the fiber optic loss of the optical fiber composite cable 1 is normal; and testing whether the casing coupling can be clearly observed by the light source 5 and the downhole television terminal 6. This allows for the timely detection of abnormalities in the gas well production profile and the integrated downhole television testing string, preventing monitoring failures due to downhole anomalies and reducing monitoring costs.

[0050] Example 8: As an optimization of the above examples, as shown in the appendix Figure 1 As shown, in the fourth step, if the area in front of the downhole television terminal 6 is blurry or the orifice is covered by sediment, clean water is pumped into the coiled tubing 2 and sprayed out through the circulating well-washing nozzle 7 for cleaning. This ensures that the area in front of the downhole television terminal 6 is clean, facilitating the monitoring of the wellbore by the downhole television terminal 6.

[0051] The specific process of the test method in this embodiment is as follows:

[0052] The first step involved horizontal gas well X1707, with a vertical depth of 3700 meters and a horizontal section length of 1200 meters. After fracturing using a perforated bridge plug in 23 stages, the well was de-fracturing and trial production was initiated. The bridge plug was drilled through coiled tubing, and the well was flushed clean, with the entire wellbore filled with clean water before shutting in.

[0053] The second step involves assembling a 6600-meter-long integrated testing string for gas well production profiles and downhole television. The photoelectric composite cable 1, running inside the coiled tubing 2, comprises a 3-core cable and 6 optical fibers. Two of the 6 optical fibers are multimode fibers, and the other four are single-mode fibers. One of the two multimode fibers is used to collect sound data, while the other is a spare. Two of the four single-mode fibers are connected to the light source 5 and the downhole television terminal 6, respectively. The other single-mode fiber collects temperature data, and the remaining single-mode fiber is a spare. The 3-core cable... The first core cable in the cable is connected to the light source 5, the second core cable is connected to the downhole television terminal 6, and the third core cable is reserved. After connecting the ground data acquisition equipment to the optical fiber composite cable 1, the fiber loss of the optical fiber composite cable 1 is tested to see if it is normal; the light source 5 is tested to see if it is normal; the opening status of each perforation cluster monitored by the downhole television terminal 6 is tested to see if it is clear; clean water is pumped into the coiled tubing 2 at a rate of 44 to 55 liters / minute to test if the circulating well washing nozzle 7 is normal; after the gas well production profile and the downhole television integrated test string are working normally, proceed to the next step.

[0054] The third step, with the well shut in, is to run the integrated test string for gas well production profile and downhole television. After running it 200 meters, the fiber optic loss of the optical fiber composite cable 1 is tested to see if it is normal. Then, it is continued to run. The test light source 5 and the downhole television terminal 6 are tested to see if the casing coupling can be clearly observed. After the integrated test string for gas well production profile and downhole television is normal, it is continued to run.

[0055] The fourth step involves lowering the integrated testing string for gas well production profile and downhole television to a position 20 meters above the 23rd perforation cluster (3890-3892 meters). The string is then lowered at a rate of 3 meters per minute. When the lower end of the integrated testing string reaches the 23rd perforation cluster, it is lowered at a rate of 1 meter per minute, and the changes in the perforation holes of the 23rd perforation cluster are monitored.

[0056] After the monitoring of the 23rd perforation cluster was completed, the integrated test string for gas well production profile and downhole television was continued to be run at a speed of 3 meters per minute. When it reached the 22nd perforation cluster (4000-4002 meters), it was run at a speed of 1 meter per minute, and the changes in the perforation holes of the 22nd perforation cluster were monitored.

[0057] When the 18th perforation cluster was detected, the downhole TV terminal 6 showed that the bottom of the casing ahead was covered with sand covering the perforation holes. The surface pump was started and clean water was pumped into the coiled tubing 2 at a rate of 50 liters / minute. Water was sprayed out from the downhole circulating well washing nozzle 7 to clean the sand. Then monitoring continued. After monitoring of all perforation clusters was completed, the connection between the surface data acquisition equipment and the optical fiber composite cable was disconnected.

[0058] The fifth step is to connect the ground data acquisition equipment to the single-mode optical fiber used to collect temperature information, monitor the formation temperature under well shut-in conditions, and start production after the formation temperature stabilizes 36 hours after well shut-in.

[0059] Step 6: Select 4mm, 5mm, and 6mm nozzles for production, and produce for 12 hours under each production system. The output is stable. Record qualified temperature and sound data. After monitoring, propose the gas well production profile and downhole television integrated test string.

[0060] Step 7: Based on the monitoring of the perforation clusters by the downhole TV terminal 6, proppant entered 70% of the perforations in well X1707. At the toe and heel ends, the uniform fracturing degree was good, with perforation abrasion ranging from 20% to 270%, averaging 75%. The 12th, 13th, and 14th grade perforation clusters, with high clay content, showed low perforation abrasion and less proppant entry. The production profile interpretation results indicate that the toe and heel ends are the main contributing sections for gas production, while the 12th, 13th, and 14th grade perforation clusters, with high clay content, have a lower gas production contribution rate. The logging and well logging data for the 12th, 13th, and 14th grade perforation clusters indicate poor physical properties and oil and gas content, resulting in low fracturing utilization and poor production improvement. Geological steerable drilling should avoid these types of reservoirs to increase the encounter rate of high-quality reservoirs. Simultaneously, for reservoirs with poor physical properties and oil and gas content, continuous optimization of fracturing schemes is needed to improve reservoir utilization.

[0061] The above technical features constitute the embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A testing method using an integrated testing string for gas well production profiles and downhole television, characterized in that... The integrated testing string for gas well production profile and downhole television includes a photoelectric composite cable and, from top to bottom, coiled tubing, centralizer, check valve, light source, and downhole television terminal connected together. Several circulating well-washing nozzles are spaced apart on the outside of the check valve. The lower end of the photoelectric composite cable passes through the coiled tubing, centralizer, and check valve in sequence and is connected to the light source and downhole television terminal respectively. The photoelectric composite cable can collect temperature data and sound data. The optical-electric composite cable includes at least three single-mode optical fibers and at least one multimode optical fiber. One multimode optical fiber is used to collect sound data, one single-mode optical fiber is used to collect temperature data, and the other two single-mode optical fibers are connected to a light source and an underground television terminal, respectively. The testing method using the integrated downhole television testing string for gas well production profiles includes the following steps: The first step is to clean the sand and debris out of the well and then shut it off. The second step is to assemble the integrated test string for gas well production profile and downhole television, and then test whether the integrated test string for gas well production profile and downhole television is working properly. If it is, proceed to the third step; otherwise, check the integrated test string for gas well production profile and downhole television. The third step, with the well shut in, is to run in the gas well production profile and downhole television integrated test string. After running it 150 to 250 meters, the gas well production profile and downhole television integrated test string are checked. If they are normal, the string is continued to be run; if they are not normal, it is pulled out and checked again. The fourth step involves lowering the integrated testing string for gas well production profile and downhole television to 20 to 30 meters above the perforation cluster. Then, the lowering speed is reduced, and the surface data acquisition equipment is connected to the optical fiber composite cable. The downhole television terminal is used to monitor the changes in the perforation holes. After monitoring all perforation clusters is completed, the connection between the surface data acquisition equipment and the optical fiber composite cable is disconnected. The fifth step is to use a photoelectric composite cable to monitor the formation temperature while the well is shut in. Once the formation temperature stabilizes, the well is opened for production. Step 6: Select 2 to 3 nozzles for production. When the output is stable under each production system, collect temperature and sound data. After recording qualified temperature and sound data, propose the gas well production profile and downhole television integrated test string. The seventh step is to analyze the perforation erosion of each perforation cluster based on the opening status of each perforation cluster monitored by the downhole television terminal, and evaluate the fracture initiation law and opening uniformity of each perforation cluster under different fracturing pump injection parameters. Based on the temperature and sound data collected by the optical fiber composite cable, and combined with the opening status of each perforation cluster monitored by the downhole television terminal, the production profile interpretation results were obtained. In the sixth step, when the output is stable under each production system, one of the single-mode optical fibers of the optoelectronic composite cable collects temperature data, and one of the multimode optical fibers of the optoelectronic composite cable collects sound data. Then, qualified temperature and sound data are recorded.

2. The testing method using an integrated testing string for gas well production profile and downhole television as described in claim 1, characterized in that... The second step, testing the gas well production profile and whether the downhole television integrated test string is working properly, includes: testing whether the fiber optic cable loss is normal; testing whether the light source is normal; and testing whether the opening status of each perforation cluster monitored by the downhole television terminal is clear.

3. The testing method using an integrated testing string for gas well production profiles and downhole television as described in claim 2, characterized in that... The second step, testing whether the gas well production profile and downhole television integrated test string are working properly, also includes: pumping clean water into the coiled tubing at a rate of 44 to 55 liters per minute to test whether the circulating well-washing nozzle is working properly.

4. The testing method using an integrated testing string for gas well production profile and downhole television as described in claim 1, 2, or 3, characterized in that... The third step involves inspecting the gas well production profile and the integrated downhole television testing string, including: testing whether the fiber optic loss of the optical fiber composite cable is normal; and testing whether the light source and downhole television terminal can clearly observe the casing coupling.

5. The testing method using an integrated testing string for gas well production profile and downhole television as described in claim 1, 2, or 3, characterized in that... In the fourth step, if the area in front of the downhole TV terminal is blurry and the orifice is covered by sediment, clean water is pumped into the coiled tubing and sprayed out through the circulating well-washing nozzle for cleaning.

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