A rapid well workover method based on coordinated operations of coiled tubing and conventional workover.

Abstract

This invention relates to the field of well workover operations in oil and gas extraction, specifically disclosing a rapid well workover method based on the coordinated operation of coiled tubing and conventional workover. The method involves clear downhole condition survey and construction objectives: obtaining downhole condition information through wellhead data acquisition, downhole imaging detection, and formation parameter analysis to clarify the well workover objectives; development of a coordinated operation plan: breaking down the entire well workover process into several sub-processes, matching coiled tubing operations or conventional workover operations according to the core requirements of each sub-process; phased coordinated construction implementation: sequentially carrying out coiled tubing and conventional workover operations according to the plan, with seamless transitions between sub-processes; dynamic adjustment and quality control during the construction process: real-time monitoring of construction parameters, dynamic adjustment of the coordinated plan based on operational results and unforeseen circumstances, and verification of workover quality through multi-dimensional testing after completion. This invention achieves efficient handling of complex well workover scenarios, shortens the operation cycle, reduces construction costs, and expands the applicability of well workover operations.

Description

Technical Field

[0001] This invention relates to the field of well workover technology in oil and gas extraction, and specifically to a rapid well workover method based on the coordinated operation of coiled tubing and conventional well workover. Background Technology

[0002] In the process of oil and gas extraction, well workover operations are a crucial link in ensuring the normal production of oil and water wells. Their core objective is to resolve downhole faults (such as tubing blockage, wax deposition, and sand production) and restore wellbore integrity and production capacity. Currently, the mainstream well workover operation methods in the industry are mainly divided into two categories: coiled tubing workover and conventional well workover operations.

[0003] Coiled tubing operations, with their characteristics of continuous operation without moving the tubing string, offer significant advantages such as high efficiency, short operation cycle, minimal formation damage, and small wellhead equipment footprint, making them widely used in simple procedures like wellbore cleaning, sand flushing, unclogging, and acid fracturing. However, due to the structural characteristics and operational limitations of coiled tubing, it has significant limitations in well workover operations: it cannot complete core procedures such as running the original downhole tubing string, running specific functional tubing strings (such as packer strings, test strings, etc.), or handling complex downhole debris, making it difficult for a single coiled tubing operation to cover all well workover needs.

[0004] Conventional well workover operations employ workover rigs to run and pull tubing strings, which offers the advantage of comprehensive process coverage. It can perform tasks that coiled tubing cannot, such as running and pulling the original tubing string, running customized process tubing strings, and handling complex debris. However, it also suffers from problems such as low construction efficiency, long operation cycle, large equipment investment, and high risk of formation disturbance. Especially in simple cleaning processes, its operation cost and time cost are significantly higher than those of coiled tubing operations.

[0005] In existing technologies, coiled tubing operations and conventional workover operations are mostly used independently, without a systematic collaborative mechanism. When encountering complex workover scenarios (such as heavy oil / wax accumulation in the production tubing, tubing blockage preventing circulation), a single operation method either cannot complete the operation or requires multiple repetitions, leading to extended operation cycles and soaring construction costs. For example, in the workover process of heavy oil wells, if a new sucker rod is directly run after the sucker rod is pulled out using conventional operations, it is prone to re-blockage due to residual heavy oil / wax in the tubing cavity; while using only coiled tubing for cleaning cannot complete the sucker rod pulling and lowering operation, resulting in a stalemate. Therefore, there is an urgent need in the field for a collaborative workover method that can fully leverage the advantages of both and compensate for their respective shortcomings, in order to overcome the limitations of the existing independent application of coiled tubing operations and conventional workover operations. Summary of the Invention

[0006] To address the problems existing in the prior art, the present invention aims to provide a rapid well workover method based on the coordinated operation of coiled tubing and conventional well workover. By systematically planning the operation process and coordination logic of the two, the advantages of high efficiency and short cycle of coiled tubing operation and the comprehensive coverage of conventional well workover operation procedures can be fully utilized.

[0007] The technical solution adopted by this invention to solve its technical problem is: a rapid well workover method based on the coordinated operation of coiled tubing and conventional well workover, comprising the following steps:

[0008] S1. Downhole working condition survey and construction objectives are clarified: Downhole working condition information is obtained through wellhead data acquisition, downhole imaging detection, and formation parameter analysis to clarify the well workover construction objectives;

[0009] S2. Collaborative Operation Plan Development: The entire well workover process is broken down into several sub-processes. Based on the core requirements of each sub-process, either coiled tubing operation or conventional well workover operation is matched, and process connection nodes, technical requirements, and emergency plans are planned.

[0010] S3. Phased and coordinated construction implementation: The coiled tubing and conventional well workover operations are carried out sequentially according to the plan, with sub-processes being connected.

[0011] S4. Dynamic adjustment and quality control during construction: Real-time monitoring of construction parameters, dynamic adjustment of collaborative plans based on operational results and unforeseen circumstances, and verification of well repair quality through multi-dimensional testing after construction is completed.

[0012] Specifically, the downhole operating condition information in step S1 includes the original well string structure and integrity, the type and distribution characteristics of blockages in the wellbore, formation pressure and permeability, and fault type; the construction objectives include at least one of the following: clearing blockages in the well string cavity, pulling out the original well string, handling downhole debris, and establishing a circulation channel.

[0013] Specifically, the sub-process matching logic in step S2 is as follows: sub-processes that require cleaning, unblocking, and establishing circulation are assigned to coiled tubing operations; sub-processes that require tripping the original well string, running a specific functional string, and handling complex debris are assigned to conventional well workover operations.

[0014] Specifically, the emergency plan in step S2 includes: when the tubing string is found to be blocked and circulation cannot be established during routine well workover operations, an emergency cleaning procedure for coiled tubing is initiated, and routine well workover operations are resumed after the circulation channel is established.

[0015] Specifically, the key scenarios for collaborative construction in step S3 include well repair work on wells blocked by heavy oil or wax, well repair work on wells where the tubing is blocked and circulation cannot be established, and well repair work on wells with complex debris and tubing cleaning.

[0016] Specifically, the well workover process for heavy oil or wax-blocked wells is as follows: conventional well workover operation to pull out the original well sucker rod → high-pressure flushing of coiled tubing + chemical unblocking to remove heavy oil or wax blockage from the tubing string → conventional well workover operation to run in a new sucker rod and complete docking inspection.

[0017] Specifically, the procedure for preventing well workover due to tubing blockage is as follows:

[0018] 1) During routine well workover operations, attempt to run in conventional drill strings to clear the circulation channels. If clearing fails, stop the routine operation.

[0019] 2) Activate the emergency coordination plan for coiled tubing operations, lower the coiled tubing to the blockage location, use high-pressure jetting to break through the blockage, establish a temporary circulation channel, and continuously flush until the return fluid is clear;

[0020] 3) Conventional workover operations are based on the circulation channel established by coiled tubing, and conventional workover tubing strings are run in to complete subsequent fault handling.

[0021] Specifically, the detailed process for the combined well workover involving complex debris and tubing cleaning is as follows:

[0022] 1) Conventional well workover operations involve using a workover rig to retrieve the original well production tubing and expose the location of any objects that have fallen into the well.

[0023] 2) Run coiled tubing with retrieval tools to locate and retrieve small objects, while cleaning residual impurities from the inner wall of the tubing string.

[0024] 3) During routine well workover operations, a new production tubing string is run in, and cementing and sealing tests of the tubing string are completed;

[0025] 4) Coiled tubing operation: Run coiled tubing into the new tubing string to perform final cleaning and circulation testing of the inner cavity.

[0026] Specifically, the flushing pressure and discharge rate of the coiled tubing are calculated as follows:

[0027] Flushing pressure P = k × h × ρ × g / d, discharge rate Q = π × d² × v / 4; k is the pressure resistance coefficient of the blockage, k = 1.2~1.5 for heavy oil, k = 1.8~2.2 for wax blockage; h is the thickness of the blockage, in mm; ρ is the density of the flushing fluid, in kg / m³. 3 g is the acceleration due to gravity, in m / s². 2 ; d is the inner diameter of the tubing, in mm; v is the optimal flow rate of the flushing fluid, ranging from 1.5 to 2.0 m / s.

[0028] Specifically, the dynamic adjustment and coordination scheme in step S4 includes: when there are still residual blockages in the tubing string after the coiled tubing is cleaned, extending the coiled tubing operation time or combining it with conventional well workover for composite cleaning; when the tubing string is stuck during conventional well workover, coiled tubing is used to detect and remove the blockage before resuming conventional operation.

[0029] The present invention has the following beneficial effects:

[0030] The present invention designs a rapid well workover method based on the coordinated operation of coiled tubing and conventional well workover. By systematically planning the operation process and coordination logic of the two, it fully leverages the advantages of high efficiency and short cycle of coiled tubing operation, as well as the advantage of comprehensive coverage of conventional well workover operation procedures. This enables efficient handling of complex well workover scenarios, shortens the operation cycle, reduces construction costs, and expands the applicability of well workover operations. Detailed Implementation

[0031] The technical solutions in the embodiments of the present invention will be described clearly, completely, and in further detail below. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0032] A rapid well workover method based on the coordinated operation of coiled tubing and conventional workover utilizes a closed-loop process of "downhole condition analysis - coordinated plan formulation - phased construction - dynamic adjustment" to precisely match and coordinate coiled tubing operations with conventional well workover operations according to procedural requirements. The method includes the following steps:

[0033] 1. Overall steps:

[0034] 1) Process breakdown: The entire well workover process is broken down into several sub-processes, and the core requirements of each sub-process are determined, such as rapid cleaning, precise tubing string tripping, and establishing circulation.

[0035] 2) Job matching: Sub-processes that require rapid cleaning, unblocking, and circulation establishment are assigned to coiled tubing operations, while sub-processes that require tripping the original well string, running a specific functional string, and handling complex debris are assigned to conventional workover operations.

[0036] 3) Connection planning: Clarify the connection nodes and technical requirements of adjacent processes. For example, after the sucker rod is pulled out in a conventional well workover, the coiled tubing needs to be cleaned within 4 hours to prevent the residual medium in the tubing from solidifying. After the coiled tubing is cleaned, a new sucker rod needs to be run in within 2 hours in a conventional well workover to ensure the continuity of operations.

[0037] 4) Emergency plan: In response to possible emergencies during construction, such as the discovery of a blocked tubing or inability to establish circulation during routine operations, a pre-set collaborative adjustment plan is prepared, such as initiating an emergency cleaning procedure for the coiled tubing, and resuming routine operations after the circulation channel is established.

[0038] 2. Use cases:

[0039] 1) Scenario 1: Well repair due to blockage by heavy oil or wax

[0040] Step 1 (Routine well workover): Use a workover rig to retrieve the original well sucker rod, and simultaneously record the wear and wax buildup on the sucker rod.

[0041] Step 2 (Continuous tubing operation): Run continuous tubing into the inner cavity of the production tubing string. Use a combination of high-pressure flushing and chemical unblocking agent injection to clean the heavy oil / wax blockage in the tubing string. Monitor the backflow of flushing fluid in real time to ensure that the blockage is completely removed.

[0042] Step 3 (Routine well workover): After the coiled tubing is pulled out, a new sucker rod is immediately run in, the tubing string is connected and the sealing is checked, and production is resumed.

[0043] 2) Scenario 2: Tubing blockage prevents circulation and well workover

[0044] Step 1 (Routine Well Workover): Attempt to run conventional drill string to clear the circulation channel. If clearing fails, stop the routine operation.

[0045] Step 2 (Continuous tubing operation): Activate the emergency coordination plan, lower the continuous tubing to the blockage location, use high-pressure jetting to break through the blockage, establish a temporary circulation channel, and continuously flush until the return fluid is clear.

[0046] Step 3 (Routine Well Workover): Based on the circulation channel established by the coiled tubing, run in a routine well workover string to complete subsequent fault handling, such as tripping up or down the damaged string, running in a packer, etc.

[0047] 3) Scenario 3: Complex debris + tubing cleaning combined well workover

[0048] Step 1 (Routine Well Workover): Use a workover rig to retrieve the original well production tubing and expose the location of any objects that have fallen into the well.

[0049] Step 2 (Continuous tubing operation): Lower the continuous tubing equipped with a retrieval tool, accurately locate and retrieve small objects, and clean any remaining impurities from the inner wall of the tubing string.

[0050] Step 3 (Routine well workover): Run in a new production tubing string and complete tubing cementing and sealing tests.

[0051] Step 4 (coiled tubing operation): Run in coiled tubing to perform final cleaning and circulation testing of the new tubing string's interior to ensure the quality of the operation.

[0052] 3. If residual blockage remains in the tubing cavity after coiled tubing cleaning: Extend the coiled tubing operation time, adjust the flushing pressure and unblocking agent ratio, or combine mechanical scraping with coiled tubing flushing for cleaning in conjunction with conventional workover; If the tubing string gets stuck during conventional workover: Suspend conventional operations, use coiled tubing insertion detection tools to identify the stuck location, and release the stuck blockage through high-pressure flushing or small-scale retrieval before resuming conventional operations; If there are abnormal fluctuations in formation pressure: Adjust the flushing fluid discharge and pressure during coiled tubing operations to avoid formation disturbance, and coordinate with conventional workover to accelerate the tubing string insertion speed and shorten the wellbore exposure time.

[0053] 4. To ensure the accuracy and efficiency of collaborative operations, this invention provides the following key technical parameter calculation models to guide scheme formulation and construction adjustments:

[0054] 1) Calculation of parameters for coiled tubing cleaning operation: For heavy oil / wax blockage cleaning scenarios, the flushing pressure P and displacement Q of the coiled tubing need to be calculated based on the blockage thickness h and the tubing inner diameter d:

[0055] P = k×h×ρ×g / d (Formula 1);

[0056] Q =π×d²×v / 4 (Formula 2);

[0057] Where: k is the pressure resistance coefficient of the blockage (k=1.2~1.5 for heavy oil, k=1.8~2.2 for wax blockage), ρ is the density of the flushing fluid (kg / m³), g is the acceleration due to gravity (m / s²), and v is the optimal flow velocity of the flushing fluid in the tubing (taken as 1.5~2.0 m / s to ensure that the blockage remains suspended and does not deposit).

[0058] 2) Calculation of work cycle reduction rate: The relationship between the coordinated work cycle T and the single conventional work cycle T1 and the single coiled tubing work cycle T2, and the calculation of the reduction rate η:

[0059] T=T1+T2 (Formula 3);

[0060] η=(T1-T2) / T×100% (Formula 4);

[0061] This formula can quantify the efficiency improvement effect of collaborative work and guide the optimization of the solution.

[0062] This invention significantly improves efficiency: by precisely coordinating coiled tubing and conventional workover, it avoids repetitive construction and redundant procedures in a single operation mode, and shortens the operation cycle by 30% to 50% compared to a single conventional workover (for example, the workover cycle for heavy oil wax plugging wells is shortened from the traditional 72 hours to less than 36 hours).

[0063] This invention significantly reduces costs: it reduces the ineffective standby time of conventional well workover equipment and the functional redundancy of continuous tubing operations, resulting in a 25% to 40% reduction in construction costs compared to conventional well workover alone.

[0064] The scope of application of this invention has been expanded: it solves complex well workover scenarios that cannot be completed with a single continuous tubing or conventional workover (such as heavy oil wax blockage + tubing string tripping failure, blockage removal + debris handling failure), and expands the adaptable working conditions for well workover operations.

[0065] This invention improves operational safety: through a dynamic adjustment mechanism and emergency plan, it effectively responds to unexpected situations during construction (such as blockage of the tubing preventing circulation), reducing the risks of wellbore collapse and formation contamination.

[0066] This invention offers high flexibility: it allows for flexible adjustment of the process matching logic between coiled tubing and conventional well workover according to different downhole conditions and construction objectives, adapting to the workover needs of different types of oil and water wells.

[0067] Example 1: Wax plugging workover operation in a heavy oil well

[0068] A heavy oil well in an oilfield experienced a sudden drop in production. Testing determined that the blockage was caused by wax plugging inside the production tubing, with a thickness of approximately 20 mm. The tubing inner diameter is 114 mm. The original sucker rod showed localized wear. The goal of the well workover was to remove the wax plug and replace the sucker rod to restore production. The method of this invention was used for well workover, and the specific steps are as follows:

[0069] 1) Conventional well workover: The original well sucker rod was retrieved using an XJ-35 workover rig, which took 8 hours. The wear position of the sucker rod was recorded simultaneously.

[0070] 2) Coiled tubing operation: Run in φ73mm coiled tubing, and perform high-pressure flushing + diesel-based unblocking agent injection according to the calculated parameters. Continue the operation for 6 hours, and the backflow fluid is clear. Check and confirm that there is no residual wax blockage in the tubing string.

[0071] 3) Routine well workover: Run in a new φ22mm sucker rod, complete tubing connection and seal test, which takes 6 hours.

[0072] Operating condition survey: The distribution range of wax plugs (500~800m from the wellhead) was confirmed by downhole imaging detection. The formation pressure was 12MPa. The construction objectives were defined as cleaning the wax plugs and replacing the sucker rod.

[0073] Plan formulation: The process is broken down into the following steps: pull out the original well sucker rod (conventional) → remove wax plug (coiled tubing) → run in the new sucker rod (conventional). Connection requirements: the coiled tubing operation shall be started within 3 hours after the conventional rod pull-out is completed, and the conventional rod running operation shall be started within 2 hours after the cleaning is completed. According to Formula 1, the coiled tubing flushing pressure is calculated as P = 2.0 × 20 × 1000 × 9.8 / 114 ≈ 3421 kPa. According to Formula 2, the flushing discharge rate is calculated as Q = π × 0.114² × 1.8 / 4 ≈ 0.018 m³ / s (i.e., 64.8 m³ / h).

[0074] Quality acceptance: Downhole imaging showed that the tubing was unobstructed, and production returned to normal levels (15 t / d) after production was started.

[0075] Results Calculation: The total operation cycle was 20 hours, which is 72.2% shorter than a single conventional well workover (72 hours); the total cost was 180,000 yuan, which is 43.75% lower than a single conventional well workover (320,000 yuan).

[0076] Example 2: A water well tubing string was blocked, making it impossible to establish a circulation well workover operation.

[0077] During routine well workover of a water injection well, when attempting to establish circulation by running the drill string, a blockage was discovered in the tubing string, preventing the flushing fluid from being returned. The initial assessment indicated a blockage caused by sand and cement residue. The method described in this invention was used for emergency treatment.

[0078] 1) Coiled tubing operation: Run in φ89mm coiled tubing, equip it with a jet plugging tool to break through the blockage, flush for 4 hours according to the calculated parameters to achieve normal return of flushing fluid.

[0079] 2) Routine well repair: Resume routine circulation operations, flush continuously for 2 hours, and clear any remaining blockages.

[0080] Operating condition survey: The blockage location was determined to be 300m from the wellhead by using a coiled tubing-mounted imaging tool. The blockage consisted of sand (15mm thick) and cement residue. The construction objective was to establish a circulation channel and remove the blockage.

[0081] Solution formulation: Activate the emergency coordination plan. The procedure is: suspend routine operation → clean the coiled tubing after blockage → resume routine operation. According to Formula 1, the coiled tubing flushing pressure is P = 1.6 × 15 × 1000 × 9.8 / 127 ≈ 1823 kPa, and the discharge rate is Q = π × 0.127² × 1.6 / 4 ≈ 0.020 m³ / s (i.e., 72 m³ / h).

[0082] Results Calculation: The emergency response took a total of 6 hours, avoiding rework of routine operations (estimated rework time of 24 hours), saving 60% in operating costs, successfully establishing a circulation channel, and ensuring the smooth progress of subsequent well repair operations.

[0083] This invention is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0084] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A rapid well workover method based on coordinated operations of coiled tubing and conventional workover, characterized in that, Includes the following steps: S1. Downhole working condition survey and construction objectives are clarified: Downhole working condition information is obtained through wellhead data acquisition, downhole imaging detection, and formation parameter analysis to clarify the well workover construction objectives; S2. Collaborative Operation Plan Development: The entire well workover process is broken down into several sub-processes. Based on the core requirements of each sub-process, either coiled tubing operation or conventional well workover operation is matched, and process connection nodes, technical requirements, and emergency plans are planned. S3. Phased and coordinated construction implementation: The coiled tubing and conventional well workover operations are carried out sequentially according to the plan, with sub-processes being connected. S4. Dynamic adjustment and quality control during construction: Real-time monitoring of construction parameters, dynamic adjustment of collaborative plans based on operational results and unforeseen circumstances, and verification of well repair quality through multi-dimensional testing after construction is completed.

2. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 1, characterized in that, The downhole operating information in step S1 includes the original well string structure and integrity, the type and distribution characteristics of blockages in the wellbore, formation pressure and permeability, and fault type; the construction objectives include at least one of the following: clearing blockages in the well string cavity, pulling out the original well string, handling downhole debris, and establishing a circulation channel.

3. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 1, characterized in that, The sub-process matching logic in step S2 is as follows: sub-processes that require cleaning, unblocking, and establishing circulation are assigned to coiled tubing operations; sub-processes that require tripping the original well string, running a specific functional string, and handling complex debris are assigned to routine well workover operations.

4. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 1, characterized in that, The emergency plan in step S2 includes: when the tubing string is found to be blocked and circulation cannot be established during routine well workover operations, an emergency cleaning procedure for coiled tubing is initiated, and routine well workover operations are resumed after the circulation channel is established.

5. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 1, characterized in that, Key scenarios for collaborative construction in step S3 include well repair work on wells blocked by heavy oil or wax, well repair work on wells where circulation cannot be established due to tubing blockage, and well repair work on wells with complex debris and tubing cleaning.

6. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 5, characterized in that, The specific procedure for well workover of heavy oil or wax plugged wells is as follows: conventional workover operation to pull out the original well sucker rod → high-pressure flushing of coiled tubing + chemical unblocking to clean the heavy oil or wax plug in the tubing string → conventional workover operation to run in the new sucker rod and complete the docking test.

7. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 5, characterized in that, The specific procedure for well workover when tubing blockage prevents the establishment of circulation is as follows: 1) During routine well workover operations, attempt to run in conventional drill strings to clear the circulation channels. If clearing fails, stop the routine operation. 2) Activate the emergency coordination plan for coiled tubing operations, lower the coiled tubing to the blockage location, use high-pressure jetting to break through the blockage, establish a temporary circulation channel, and continuously flush until the return fluid is clear; 3) Conventional workover operations are based on the circulation channel established by coiled tubing, and conventional workover tubing strings are run in to complete subsequent fault handling.

8. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 5, characterized in that, The specific process for the combined well workover involving complex debris and tubing cleaning is as follows: 1) Conventional well workover operations involve using a workover rig to retrieve the original well production tubing and expose the location of any objects that have fallen into the well. 2) Run coiled tubing with retrieval tools to locate and retrieve small objects, while cleaning residual impurities from the inner wall of the tubing string. 3) During routine well workover operations, a new production tubing string is run in, and cementing and sealing tests of the tubing string are completed; 4) Coiled tubing operation: Run coiled tubing into the new tubing string to perform final cleaning and circulation testing of the inner cavity.

9. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover, as described in claim 6, 7, or 8, is characterized in that... The flushing pressure and discharge rate of the coiled tubing are calculated as follows: Flushing pressure P = k × h × ρ × g / d, discharge rate Q = π × d² × v / 4; k is the pressure resistance coefficient of the blockage, k = 1.2~1.5 for heavy oil, k = 1.8~2.2 for wax blockage; h is the thickness of the blockage, in mm; ρ is the density of the flushing fluid, in kg / m³. 3 g is the acceleration due to gravity, in m / s². 2 ; d is the inner diameter of the tubing, in mm; v is the optimal flow rate of the flushing fluid, ranging from 1.5 to 2.0 m / s.

10. The rapid well workover method based on the coordinated operation of coiled tubing and conventional workover as described in claim 1, characterized in that, The dynamic adjustment and coordination scheme in step S4 includes: if there are still residual blockages in the tubing string after the coiled tubing is cleaned, extend the coiled tubing operation time or combine it with conventional workover for composite cleaning; if the tubing string is stuck during conventional workover, use coiled tubing to detect and remove the blockage before resuming conventional operation.