A method of conducting a deep well test

Abstract

This invention provides a construction method for deep exploration well testing, relating to the field of deep exploration well testing technology, including: Step 1, installing and pressurizing a test blowout preventer (BOP) assembly, and performing well cleaning operations after the pressure test is passed; Step 2, performing perforation operations using a tubing-transfer perforation method; Step 3, removing the perforation tubing; Step 4, running in a combined stimulation-testing process tubing; Step 5, disassembling the test BOP assembly and installing a gas production wellhead; Step 6, performing test extrusion and acidizing operations; Step 7, performing fluid drainage, sampling, and production assessment; This method solves the problems of low success rate, long construction period, and high construction cost in existing deep exploration well testing construction techniques.

Description

Technical Field

[0001] This invention belongs to the field of deep well testing technology, and more specifically, relates to a construction method for deep well testing. Background Technology

[0002] my country possesses over 30% of its deep and ultra-deep oil and gas resources, representing enormous exploration and development potential. However, in actual exploration and testing, factors such as the greater depth of deep oil and gas wells, higher temperatures and pressures, and complex downhole conditions commonly lead to numerous construction anomalies and long operation cycles, severely hindering breakthroughs in deep and ultra-deep oil and gas exploration. Currently, the success rate of deep exploration well testing is low, the construction cycle is long, and the construction costs are high. Summary of the Invention

[0003] The purpose of this invention is to address the shortcomings of existing technologies by providing a construction method for deep well testing, thereby solving the problems of low success rate, long construction period, and high construction cost in existing deep well testing construction.

[0004] To achieve the above objectives, the present invention provides a method for conducting deep exploration well testing, comprising:

[0005] Step 1: Install and test the blowout preventer assembly. After the pressure test is passed, proceed with well cleaning.

[0006] Step 2: Perform perforation operations using a tubular transfer method;

[0007] Step 3: Remove the perforation string;

[0008] Step 4: Install and test the two-stage process tubing;

[0009] Step 5: Disassemble the test blowout preventer assembly and install the gas wellhead;

[0010] Step 6: Conduct trial extrusion and acidification.

[0011] Step 7: Perform drainage, sampling, and production assessment.

[0012] Optionally, the method may further include the following steps prior to step 1:

[0013] Identify the target layer and other test layers that are shallower than the target layer;

[0014] Determine the perforation locations within the target layer and each test layer.

[0015] Optionally, determining the perforation locations within the target layer and each test layer includes:

[0016] For the target layer or each test layer, select well sections where the cementing quality meets the set quality requirements and set the perforation locations;

[0017] Well sections where the difference in rock stress magnitude is within the first range and the difference in the degree of natural fracture development is within the second range are classified as the same perforation section;

[0018] The perforation location was determined based on the numerical simulation results of fracturing gas testing.

[0019] Optionally, during perforation operations, the entire perforation well is replaced with kill fluid; removing the perforation string includes:

[0020] When the wellbore fluid is stable, deepen the perforation string to below the perforation position and circulate to stabilize it.

[0021] If well leakage occurs, reduce the density of the kill fluid, recirculate to stabilize the well, and remove the perforation string when the fluid in the wellbore is stable.

[0022] Optionally, the method may include the following steps prior to step 4:

[0023] Select the process tubing based on the wellbore size, maximum wellbore temperature, maximum wellbore pressure, tubing compressive strength, and tubing tensile strength;

[0024] The working valves are equipped with a combination of dual RDS valves and dual RD valves;

[0025] The working valve components are equipped with a permanent setting structure, in which the packer is a permanent packer.

[0026] Optionally, a dual-pressure detonator may be used for detonation during perforation operations.

[0027] Optionally, when performing perforation operations, the depth calibration and perforation operations are carried out by double verification of pre-calibration depth and perforation depth calibration, and by perforation with the blowout preventer tubing closed.

[0028] Optionally, it also includes the use of a high-temperature resistant, solid-free test working fluid.

[0029] Optionally, it also includes adding a slow-release agent and a desulfurizing agent to the high-temperature solid-free test working fluid.

[0030] Optionally, for deep exploration wells containing H2S and CO2, sulfur-resistant and corrosion-resistant materials should be selected for process tubing and well access tools.

[0031] This invention provides a method for deep well testing, which has the following advantages: The method optimizes the workflow of deep well testing. After successful pressure testing and well cleaning, perforation is performed using a tubing-transfer perforation method. The perforation tubing is then removed, and a two-stage process tubing for both perforation and testing is run. Compared to the three-stage process of perforation-modification-testing, where perforation, modification, and testing are completed in a single run, causing tubing vibration and potential downhole anomalies, this method separates the perforation, modification, and testing processes, effectively avoiding these anomalies and improving the first-time success rate. Afterward, the blowout preventer assembly is removed and installed at the wellhead for testing and acidizing, followed by drainage, sampling, and production assessment. This method effectively improves the first-time success rate of deep well testing, significantly reducing construction time and costs.

[0032] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0033] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0034] Figure 1 A flowchart of a construction method for deep well testing according to an embodiment of the present invention is shown. Detailed Implementation

[0035] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0036] This invention provides a method for conducting deep exploration well testing, comprising:

[0037] Step 1: Install and test the blowout preventer assembly. After the pressure test is passed, proceed with well cleaning.

[0038] Step 2: Perform perforation operations using a tubular transfer method;

[0039] Step 3: Remove the perforation string;

[0040] Step 4: Install and test the two-stage process tubing;

[0041] Step 5: Disassemble the test blowout preventer assembly and install the gas wellhead;

[0042] Step 6: Conduct trial extrusion and acidification.

[0043] Step 7: Perform drainage, sampling, and production assessment.

[0044] Specifically, to address the problems of low success rate, long construction period, and high cost in existing deep well testing methods, this invention provides a method for optimizing the construction process of deep well testing. After passing the pressure test and completing the well cleaning operation, perforation is performed using a tubing string transfer method. Then, the perforation string is retrieved, and a two-stage process tubing string for modification and testing is run. Compared to the three-stage process of perforation-modification-testing, this method completes perforation, modification, and testing in a single run. The construction of three processes in the test well is prone to downhole anomalies due to the vibration of the tubing caused by the perforation gun. This deep exploration well testing method separates the perforation, modification, and testing processes, which can effectively avoid the above-mentioned downhole anomalies and improve the success rate of the operation. Afterwards, the test blowout preventer assembly is removed and installed at the gas production wellhead for test extrusion and acidizing operations, followed by drainage, sampling, and production assessment. This deep exploration well testing method can effectively improve the success rate of the operation and significantly save on construction time and costs.

[0045] Furthermore, APR testing technology is commonly used for oil and gas reservoir testing in domestic exploration wells. Shallow exploration wells typically employ a three-stage perforation-stimulation-testing process to improve efficiency, meaning that a single run of tubing completes the perforation, stimulation, and testing procedures. However, in deep exploration well testing, the high static pressure of the perforation fluid column and the high total detonation pressure at the bottom of the well, combined with perforation vibration, static fluid column pressure, and detonation pressure, can easily cause problems such as tubing jamming, packer failure, and abnormal perforation gun stringing, posing a significant risk of downhole anomalies. Therefore, this deep exploration well testing method separates the perforation, stimulation, and testing procedures, effectively avoiding the aforementioned downhole anomalies and improving the first-time success rate. Specific methods include:

[0046] After installing the test blowout preventer (BOP) assembly in the wellbore and conducting a pressure test, and passing the pressure test, well cleaning operations are carried out to prepare for perforation operations. Perforation operations are performed using a tubing-transfer perforation method, with the entire perforation well replaced with kill fluid, and perforation is carried out using a perforation gun. After the perforation operation is completed, the perforation tubing is retrieved. Then, a combined modification-testing process tubing is run in, the process tubing is prepared, and the test tools are connected to the surface string. A lifting sub is installed on the upper part of each string. After inspecting all working valves, the process tubing is run into the well. After the process tubing is lowered into place, the test blowout preventer assembly is removed and installed at the gas production wellhead, and a pressure test is conducted as required. If a packer is present in the process tubing, a ball-drop pressure seat is used to seal the packer. After that, test gas injection and acidizing operations can be carried out according to the pressure test design. Then, fluid drainage, sampling, and production assessment are carried out.

[0047] Optionally, the method may further include the following steps prior to step 1:

[0048] Identify the target layer and other test layers that are shallower than the target layer;

[0049] Determine the perforation locations within the target layer and each test layer.

[0050] Specifically, before installing the blowout preventer assembly for pressure testing and well cleaning operations, the deep exploration well testing method also involves an integrated geological and engineering sweet spot evaluation. First, the location of the target layer is identified. Geologically, based on lithology, porosity, the degree of development of natural fractures, actual drilling gas logging data, and post-drilling effects, the test operation layer and number of layers are selected, including one target layer and several other test layers above the target layer. During this process, factors such as the geological quality of each well section during drilling to the target layer, wellbore cementing quality, and rock stress profile are comprehensively considered. Based on these factors, other test layers are determined. Then, the perforation locations within the target layer and each other test layer are determined.

[0051] Furthermore, since several other test layers were identified in addition to the target layer, if it is necessary to test other test layers above the target layer after the target layer has been tested, the target layer that has already been tested will be plugged and sealed, and then steps 1 to 7 will be repeated to test the other test layers.

[0052] Optionally, determining the perforation locations within the target layer and each test layer includes:

[0053] For the target layer or each test layer, select well sections where the cementing quality meets the set quality requirements and set the perforation locations;

[0054] Well sections where the difference in rock stress magnitude is within the first range and the difference in the degree of natural fracture development is within the second range are classified as the same perforation section;

[0055] The perforation location was determined based on the numerical simulation results of fracturing gas testing.

[0056] Specifically, to ensure downhole construction safety, perforation locations should not be selected in well sections with poor cementing quality. For the target layer and each other test layer, well sections with good cementing quality should be selected for perforation locations. Furthermore, to ensure the effectiveness of subsequent fracturing, well sections with similar stress levels and similar degrees of natural fracture development should be divided into perforation sections as much as possible. Finally, within the divided perforation sections, the perforation locations are selected based on the numerical simulation results of fracturing gas testing, and the number of perforation clusters and the spacing between perforation clusters are set. During the perforation process, the perforation construction within one perforation section is completed at a time.

[0057] Furthermore, it also includes the prediction of pressure stabilization conditions in the construction well section. After clarifying the location of the target layer and other test layers as well as the perforation location, the temperature and pressure environment of the construction location can be calculated through temperature and pressure gradients, which can provide a basis for subsequent construction design such as process tubing design, working valve design, and setting seal structure design.

[0058] Optionally, during perforation operations, the entire perforation well is replaced with kill fluid; removing the perforation string includes:

[0059] When the wellbore fluid is stable, deepen the perforation string to below the perforation position and circulate to stabilize it.

[0060] If well leakage occurs, reduce the density of the kill fluid, recirculate to stabilize the well, and remove the perforation string when the fluid in the wellbore is stable.

[0061] Specifically, during the process of removing the perforating string, first ensure that the wellbore fluid is stable, that is, there is no leakage or overflow of fluid in the wellbore and the fluid is kept in a stable state. Lower the perforating string below the perforation position and circulate it to stabilize the well. If there is well leakage, reduce the density of the kill fluid and recirculate it to stabilize the well. When the wellbore fluid is stable, remove the perforating string.

[0062] Optionally, the method may include the following steps prior to step 4:

[0063] Select the process tubing based on the wellbore size, maximum wellbore temperature, maximum wellbore pressure, tubing compressive strength, and tubing tensile strength;

[0064] The working valves are equipped with a combination of dual RDS valves and dual RD valves;

[0065] The working valve components are equipped with a permanent setting structure, in which the packer is a permanent packer.

[0066] Specifically, before the process tubing is run, the process tubing and related tools are optimized. Unlike shallow oil and gas well operations, deep exploration wells have higher downhole temperatures, higher pressures, and higher working fluid densities, making the design of tubing and related tools more stringent. On the one hand, the performance indicators of the tubing and related tools must meet the requirements of high temperature and high pressure conditions downhole. On the other hand, due to the complex downhole environment of deep exploration wells, it is necessary to have contingency plans in place to deal with downhole tool and equipment failures and avoid frequent tubing tripping, which would significantly increase the construction period and costs.

[0067] For the optimal selection of process tubing: the optimal process tubing is selected by comprehensively considering key indicators such as wellbore size, maximum wellbore temperature, maximum wellbore pressure, tubing compressive strength, and tubing tensile strength.

[0068] For optimal selection of working valves: Commonly used working valves in APR tubing include OMNI valves, RDS valves + RD valves, and DB valves + DBE valves. However, in actual deep exploration well operations, the working fluid generally has a high density and inevitably contains a certain amount of solid particles. Moreover, there is a lot of contaminants in the deep wellbore, which can easily clog the pressure transmission orifice of the OMNI valve, affecting the opening and closing of the valve. Furthermore, since deep exploration wells generally have small casing inner diameters, small test tool diameters, and long reservoir stimulation times, the risk of DB valve seat erosion damage is much greater than that of conventional RD valves. This increases the complexity of testing, the probability of failure, and the success rate. Therefore, in terms of working valve selection, a combination of RDS valves + RD valves is adopted, with one valve in use and one as a backup. The use of dual RDS valves and dual RD valves ensures the reliability of the working valves and avoids a decrease in the success rate of the test operation due to abnormalities in the working valves.

[0069] For optimal setting structure selection: Deep exploration wells have complex downhole conditions. To avoid frequent tubing tripping due to working valve failure, the working valves utilize a combination of dual RDS valves and dual RD valves, along with a permanent setting structure, i.e., a permanent packer. This optimization employs a "five-valve-one-packer" tubing configuration to ensure "double insurance" during construction. Simultaneously, high temperature and pressure significantly impact packer stability. Tool rubber seals are prone to aging, reduced fatigue resistance, and shortened lifespan under a two-dimensional environment of above 170℃ and 100MPa pressure. Abnormalities in tubing-related tools directly lead to downhole operational anomalies. Therefore, to minimize packer failure and other anomalies, the commonly used CHAMP and RTTS packers are replaced with HRM packers. Field tests show that the HRM packer can withstand depths exceeding 8000 meters, a pressure differential of 70MPa, and 184℃, successfully retrieving the tubing and demonstrating stable and reliable operation, ensuring the successful completion of the combined modification and testing process on the first attempt.

[0070] Optionally, a dual-pressure detonator may be used for detonation during perforation operations.

[0071] Specifically, for perforation operations, the perforation process design was optimized. High-temperature explosives have poor reliability and a high risk of non-explosion or detonation failure, especially during long-term complex operations. The perforation equipment is exposed to ultra-high temperatures for extended periods, which greatly affects the stability of the perforation projectile, pressure initiator, and detonating cord, potentially causing failure of the projectile and pressure initiator, and breakage of the detonating cord. To address the issue of ultra-high temperatures in deep exploration wells affecting the performance of perforation pyrotechnics and the accuracy of logging instruments, it is recommended to use Φ89mm steel pipes of grade 155 and wall thickness of 12mm to manufacture S... The Q-89 perforating gun has a theoretical pressure resistance of 250MPa and a temperature resistance of 220℃. It uses ultra-deep penetration projectiles (using ultra-high temperature explosives) and can perforate normally after 48 hours at 220℃, with a perforation diameter of 8.6mm and a penetration depth of 891mm when hitting an API cement target. To ensure the success rate of detonation in ultra-deep wells, a dual-pressure detonator is used, that is, a set of detonating devices is installed on the top and bottom of the perforating gun. In the event of failure of a single detonator, the other set of detonators can detonate the perforation, reducing the risk of perforation failure due to detonator failure.

[0072] Optionally, when performing perforation operations, the depth calibration and perforation operations are carried out by double verification of pre-calibration depth and perforation depth calibration, and by perforation with the blowout preventer tubing closed.

[0073] Specifically, to avoid the risk of over-explosive failure due to prolonged retention of the perforating gun in the high-temperature environment at the bottom of the well, the risk of mud settling and clogging the pressure transmission hole of the detonator due to prolonged static perforation string, and the risk of high temperature affecting the accuracy of logging instruments, a dual verification method of pre-deep calibration + perforation depth calibration and perforation with the blowout preventer closed and the tubing closed is adopted for depth calibration and perforation operations.

[0074] Optionally, it also includes the use of a high-temperature resistant, solid-free test working fluid.

[0075] Specifically, the construction method for this deep exploration well test also optimizes the design of the test working fluid. During the deep exploration well oil and gas test, the gas-water relationship of the oil and gas reservoir is more complex, there are many sources of pollution in the producing layer, and brine, H2S, carbonate, and rock cuttings are superimposed. Moreover, unlike drilling operations, the test working fluid is left to stand for a long time during the oil testing operation and cannot be circulated and adjusted in real time. Therefore, higher requirements are placed on the performance of the working fluid. A high-temperature resistant, solid-free working fluid must be selected during construction.

[0076] Optionally, it also includes adding a slow-release agent and a desulfurizing agent to the high-temperature solid-free test working fluid.

[0077] Specifically, by adding different types of slow-release agents and desulfurizers to the high-temperature resistant solid-free working fluid, the corrosion rate of the high-temperature resistant solid-free working fluid on the process tubing at high temperatures can be reduced.

[0078] Optionally, for deep exploration wells containing H2S and CO2, sulfur-resistant and corrosion-resistant materials should be selected for process tubing and well access tools.

[0079] Specifically, for deep exploration wells containing H2S and CO2, process tubing and related well access tools must be made of sulfur-resistant and corrosion-resistant materials to ensure service life and stable testing operations.

[0080] Example

[0081] like Figure 1 As shown, the present invention provides a construction method for deep exploration well testing, comprising:

[0082] Step 1: Install and test the blowout preventer assembly. After the pressure test is passed, proceed with well cleaning.

[0083] Step 2: Perform perforation operations using a tubular transfer method;

[0084] Step 3: Remove the perforation string;

[0085] Step 4: Install and test the two-stage process tubing;

[0086] Step 5: Disassemble the test blowout preventer assembly and install the gas wellhead;

[0087] Step 6: Conduct trial extrusion and acidification.

[0088] Step 7: Perform drainage, sampling, and production assessment.

[0089] In this embodiment, the method further includes the following step before step 1:

[0090] Identify the target layer and other test layers that are shallower than the target layer;

[0091] Determine the perforation locations within the target layer and each test layer.

[0092] In this embodiment, determining the perforation locations within the target layer and each test layer includes:

[0093] For the target layer or each test layer, select well sections where the cementing quality meets the set quality requirements and set the perforation locations;

[0094] Well sections where the difference in rock stress magnitude is within the first range and the difference in the degree of natural fracture development is within the second range are classified as the same perforation section;

[0095] The perforation location was determined based on the numerical simulation results of fracturing gas testing.

[0096] In this embodiment, during perforation operations, the entire perforation well is replaced with kill fluid; retrieving the perforation string includes:

[0097] When the wellbore fluid is stable, deepen the perforation string to below the perforation position and circulate to stabilize it.

[0098] If well leakage occurs, reduce the density of the kill fluid, recirculate to stabilize the well, and remove the perforation string when the fluid in the wellbore is stable.

[0099] In this embodiment, the method further includes the following step before step 4:

[0100] Select the process tubing based on the wellbore size, maximum wellbore temperature, maximum wellbore pressure, tubing compressive strength, and tubing tensile strength;

[0101] The working valves are equipped with a combination of dual RDS valves and dual RD valves;

[0102] The working valve components are equipped with a permanent setting structure, in which the packer is a permanent packer.

[0103] In this embodiment, a dual-pressure detonator is used for detonation during perforation operations.

[0104] In this embodiment, when performing perforation operations, the depth calibration and perforation operations are carried out by dual verification of pre-calibration depth and perforation depth calibration, and by perforation with the blowout preventer tubing closed.

[0105] In this embodiment, a high-temperature resistant, solid-free testing working fluid is also used.

[0106] In this embodiment, a slow-release agent and a desulfurizing agent are also added to the high-temperature resistant solid-free test working fluid.

[0107] In this embodiment, for deep exploration wells containing H2S and CO2, the process tubing and well entry tools are made of sulfur-resistant and corrosion-resistant materials.

[0108] In summary, the deep exploration well testing construction method provided by this invention, based on the evaluation of geological sweet spots to clarify the test layer, effectively improves the success rate of construction operations and significantly saves construction time and costs by optimizing the design of the construction process, process tubing and related tools, perforation process, and test working fluid.

[0109] The deep exploration well testing method provided by this invention was successfully implemented in the testing of Yuan Shen 1 well, a key risk exploration well project in the Sinopec "Deep Earth Engineering·Sichuan-Chongqing Natural Gas Base" major project. The method was successfully applied on-site, with acid fracturing testing completed successfully on the first attempt. Perforation was achieved via tubing, reaching a depth of 8806.89m, setting a new record for the deepest vertical perforation depth in Sinopec operations. The well packer was set at a depth of 8690m, setting a new record for the deepest packer setting in Sinopec testing. The packer withstood a pressure differential of up to 77MPa at 200℃, maintaining excellent sealing performance. This led to the development of a series of gas testing technologies for depths exceeding 8800m: 210MPa, 220℃ ultra-deep well perforation technology; 210℃ high-temperature deep well perforation and testing working fluid usage technology; ultra-high pressure multi-functional surface control technology; ultra-deep, high-temperature, and high-pressure testing tubing series; and ultra-deep, high-temperature, and high-pressure formation testing tools. A breakthrough in production testing was achieved at a depth of 8800m in the Sichuan Basin: a stable gas production of 3.28 × 10⁻⁶ was measured at an oil pressure of 3.88MPa using an 8mm nozzle and a 16mm orifice plate. 4 m 3 / d marks the first time Sinopec has obtained industrial gas flow in this field.

[0110] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A construction method for deep exploration well testing, characterized in that, include: Step 1: Install and test the blowout preventer assembly. After the pressure test is passed, proceed with well cleaning. Step 2: Perform perforation operations using a tubular transfer method; Step 3: Remove the perforation string; Step 4: Install and test the two-stage process tubing; Step 5: Disassemble the test blowout preventer assembly and install the gas wellhead; Step 6: Conduct trial extrusion and acidification. Step 7: Perform drainage, sampling, and production assessment.

2. The construction method for deep exploration well testing according to claim 1, characterized in that, The steps preceding step 1 also include: Identify the target layer and other test layers that are shallower than the target layer; Determine the perforation locations within the target layer and each test layer.

3. The construction method for deep exploration well testing according to claim 2, characterized in that, Determining the perforation locations within the target layer and each test layer includes: For the target layer or each test layer, select well sections where the cementing quality meets the set quality requirements and set the perforation locations; Well sections where the difference in rock stress magnitude is within the first range and the difference in the degree of natural fracture development is within the second range are classified as the same perforation section; The perforation location was determined based on the numerical simulation results of fracturing gas testing.

4. The construction method for deep exploration well testing according to claim 1, characterized in that, During perforation operations, the entire perforation well is replaced with kill fluid; the removal of the perforation string includes: When the wellbore fluid is stable, deepen the perforation string to below the perforation position and circulate to stabilize it. If well leakage occurs, reduce the density of the kill fluid, recirculate to stabilize the well, and remove the perforation string when the fluid in the wellbore is stable.

5. The construction method for deep exploration well testing according to claim 1, characterized in that, The steps preceding step 4 also include: Select the process tubing based on the wellbore size, maximum wellbore temperature, maximum wellbore pressure, tubing compressive strength, and tubing tensile strength; The working valves are equipped with a combination of dual RDS valves and dual RD valves; The working valve components are equipped with a permanent setting structure, in which the packer is a permanent packer.

6. The construction method for deep exploration well testing according to claim 1, characterized in that, When carrying out perforation operations, a dual-pressure detonator is used for detonation.

7. The construction method for deep exploration well testing according to claim 1, characterized in that, When carrying out perforation operations, the depth calibration and perforation depth calibration are verified by both pre-calibration and perforation depth calibration, and the perforation is carried out by closing the blowout preventer tubing.

8. The construction method for deep exploration well testing according to claim 1, characterized in that, It also includes the use of high-temperature resistant, solid-free testing working fluid.

9. The construction method for deep well testing according to claim 8, characterized in that, It also includes adding slow-release agents and desulfurizers to the high-temperature solid-free test working fluid.

10. The construction method for deep exploration well testing according to claim 5, characterized in that, For deep exploration wells containing H2S and CO2, sulfur-resistant and corrosion-resistant materials should be selected for process tubing and well entry tools.

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