A dynamic balance pressure stabilizing solidifiable plugging method for a malignant leaking formation

Abstract

This invention relates to the field of wellbore leakage plugging, specifically to a dynamic equilibrium pressure-stabilizing and solidifying method for plugging severely leaking formations. The method includes: S1 selecting a filler material based on the actual leakage situation and filling it at the leak point; S2 calculating the leakage pressure P at the leak point; S3 lowering the drill string to a position Hx below the fluid level in the wellbore; S4 preparing a hydrated gel plugging fluid; S5 commencing the plugging operation by pumping in the hydrated gel plugging fluid; and S6 monitoring the fluid level in the wellbore in real time, and determining the fluid column pressure P as the fluid level rises. t When the leakage pressure P at the leak point is out of balance, the hydrated gel plugging fluid begins to enter the lost formation; after the S6 hydrated gel plugging fluid enters the lost formation, the fluid column pressure P is controlled. t The pressure difference between the hydration gel plugging fluid and the leakage pressure P at the leak point allows the hydration gel plugging fluid to enter the leaking layer at a controllable rate, and enables the hydration gel plugging fluid to reach the leaking layer location within a predicted pumpable time, allowing the plugging fluid to penetrate the leaking layer. After implementing this method, the formation's bearing capacity at the leaking layer can be improved, and the plugging effect is significant and efficient.

Description

Technical Field

[0001] This invention relates to the field of well drilling and plugging technology, specifically to a dynamic equilibrium pressure-stabilizing and solidifiable plugging method for severely leaking formations. Background Technology

[0002] Well leakage refers to a complex phenomenon in oil and gas exploration and development where various working fluids (mud, kill fluid, cement slurry, completion fluid, and other liquids) leak into the formation under pressure differential during drilling, cementing, testing, and workover operations. It is one of the most common and complex problems in drilling and completion operations. According to statistics, the incidence of well leakage worldwide accounts for 20%-25% of all wells drilled. Moreover, well leakage treatment is a continuous research direction in oil drilling, especially the treatment of large and severe well leakage, which has become a bottleneck problem for achieving safe and rapid drilling.

[0003] Well leakage can lead to a host of associated risks, including well collapse, stuck pipe, and blowouts, resulting in prolonged drilling and completion cycles and increased operational and well control risks. During cementing, if cement slurry leaks from low-pressure, easily leaking formations, it will significantly reduce the fluid column pressure within the wellbore, affecting cementing quality and potentially triggering well control accidents. Such accidents not only result in substantial economic losses but also pose a significant threat to personnel safety.

[0004] Well leakage can be classified into permeable leakage, fracture leakage, cavernous leakage, and ruptured leakage based on geological characteristics and degree of loss. Among these, large and medium-sized severe well leakage caused by fracture, cavernous, and ruptured leakage accounts for more than 50% of all well leakage cases. However, existing well leakage plugging methods are still not ideal in formations with large fractures / cavities causing severe leakage, resulting in problems such as poor plugging technology, low success rate, and significant potential downhole safety hazards. Severe well leakage in fractured formations has become a global problem restricting the progress of oil and gas exploration and development. Improving the success rate of first-time plugging of severe well leakage is an urgent need for oilfields worldwide to ensure "safe, efficient, and economical" drilling.

[0005] Existing technologies disclose various well leakage plugging methods. For example, invention patent application number CN202210196028.1 discloses a plugging composition, plugging slurry, and leakage prevention and plugging method. Its core involves adding powdered materials, fine particulate materials, fine flake materials, and fibrous materials to the drilling fluid to prepare a plugging slurry for plugging. This can effectively seal small fractures and induced leakage, but its plugging capacity is limited for large fractured and fractured-vuggy formations. Invention patent application number CN201610293031.X discloses a combined plugging cylinder and plugging mud method for fractured formations. Results show that by plugging... The combined use of a plugging cylinder and a plugging slurry can solve the problem of in-situ fractured leakage. However, there are certain risks in lowering the plugging cylinder, and its plugging filler is a relatively soft material such as rubber tire blocks, hemp rope segments, cotton yarn, and cloth strips, which has limited effect on improving the pressure-bearing capacity of the leaking formation. The invention patent application number: CN201711058750.4 discloses a plugging agent, plugging slurry, and plugging construction method for drilling fractured leakage. Its plugging slurry is mainly composed of cement, cenospheres, microsilica, and asbestos fibers. It can play a good role in the leakage of micro-fractured formations with a fracture width of 3 to 10 mm, but the effect is poor when the fracture width exceeds 10 mm. The invention patent application number CN201310262286.6 discloses a method for cementing and plugging leaks in a packer filled with gravel. Based on conventional cementing and plugging, the method first injects gravel slurry and then pumps the gravel slurry through a large-volume pump to expand the rubber plug of the packer. This method has been applied to the Jurassic Luohe Formation of the Xifeng Oilfield in the Changqing Longdong Block and can solve vertical and horizontal fractures in the Luohe Formation. However, the success rate of plugging leaks on the first attempt is less than 20%.

[0006] Therefore, existing technologies cannot guarantee the effective retention of plugging fluid at the leak layer for large-scale venting and backflow-type leaks. Summary of the Invention

[0007] To address the challenges of large and severe leakage in fractured cavities and pits, this invention aims to provide a dynamic balance pressure-stabilizing and solidifiable plugging method for formations with severe leakage. This method employs a set of technological processes to push solidifiable plugging fluid into the leakage point, ensuring it can penetrate, remain, and prevent escape. Through solidification, it completely seals the leakage layer from the wellbore, thereby improving drilling and completion efficiency and enabling safe and rapid drilling and completion operations.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for dynamic equilibrium stabilization and solidification plugging of severely leaking formations includes the following steps: S1. Select the filler according to the actual leakage situation and fill the leak point with the filler to ensure the retention of the sealing fluid before it solidifies; S2. Calculate the bearing capacity of the formation at the leak point; S3. Lower the drill string to a position Hx below the fluid level inside the wellbore; S4. Prepare a hydrated gel-based leak-stopping solution; S4. Begin the leak sealing operation and pump in the hydrated adhesive sealant. S5. Real-time monitoring of the wellbore fluid level; when the fluid level rises, the fluid column pressure P... t When the leakage pressure P at the leak point is out of balance, the hydrated gel plugging fluid begins to enter the leakage formation. S6. After the hydrated gel plugs the leaking fluid into the lost formation, the liquid column pressure P is controlled. t The pressure difference between the hydrating gel and the leakage pressure P at the leak point allows the hydrating gel to enter the leak layer at a controllable rate, and enables the hydrating gel to reach the leak layer within a predictable pumpable time, allowing the hydrating gel to enter the leak layer and remain at the leak point.

[0009] As a further improvement to the invention, the plugging method also includes step S7. After the hydrating gel plugging fluid is pumped in, the drill string is pulled out, and the fluid column in the wellbore returns to a balanced state. At this time, the static fluid pressure at the leak point also returns to the leakage pressure P at the leak point. The hydrating gel plugging fluid leaves a 1-3 meter plug surface above the leak point. After reaching equilibrium, it is allowed to solidify for 16-24 hours. The hydrating gel plugging fluid solidifies and has a certain strength. Then, grouting is carried out to circulate and probe the plug, and drilling is resumed.

[0010] Further, in step S1, selecting the filler material based on the actual leakage situation specifically includes: ① For leakage exceeding 2 meters, select filler material with a particle size of 20-50mm; ② For leakage below 2 meters, select filler material with a particle size of 10-20mm; ③ For leaks that do not empty, no filler is needed.

[0011] To further optimize the above technical solution, in step S1, the filler material at the leakage point is filled to a depth of 1-3 meters above the leakage point.

[0012] Furthermore, in step S2, the formula for calculating the formation bearing capacity at the leak point, i.e., the leakage pressure P at the leak point, is: P = ρ1gH2 In the formula, P is the leakage pressure at the leak point; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity; H2 is the distance between the initial fluid level of the drilling fluid in the wellbore and the leak point.

[0013] Furthermore, in step S3, Hx is calculated using the following formula:

[0014] In the formula, Hx is the distance between the real-time drilling fluid level line in the wellbore and the bottom of the drill string; P represents the leakage pressure at the leak point; ρ2 is the density of the hydrated gel plugging fluid; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity.

[0015] Furthermore, the liquid column pressure P t The calculation formula is:

[0016] ∆H = H3 - H2; In the formula, ρ2 is the density of the hydrated gel plugging fluid; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity; H2 is the distance between the initial drilling fluid level line in the wellbore and the leak point; H3 is the distance between the real-time drilling fluid level line in the wellbore and the leak point. ∆H is the height of the fluid column rising inside the wellbore.

[0017] Furthermore, in step S6, after the hydrated gel plugging fluid enters the lost formation, the liquid column pressure P is controlled. t The method for determining the pressure difference between the leakage point and the leakage pressure P is as follows: After the hydrated gel plugging fluid enters the lost circulation formation, the first stage of plugging is carried out. At this stage, the pumping rate Q1 of the hydrated gel plugging fluid is less than the leakage rate Q2 per unit time, the fluid level in the wellbore does not rise, and there is no need to lift the drill string. When the pumping rate Q1 of the hydrated gel plugging fluid exceeds the leakage rate Q2 per unit time, the plugging operation enters the second stage. At this stage, the fluid level rises at a fluid injection rate V, and the drilling speed V is controlled. 钻具 , making V 钻具 =V, thereby controlling the liquid column pressure P t This causes the liquid column pressure P t The purpose is to control the pressure difference between the leakage point and the leakage pressure P.

[0018] Furthermore, the formula for calculating the liquid injection rise rate V is as follows:

[0019] In the formula, Q is the effective plugging and drainage capacity, L / min; D is the wellbore diameter.

[0020] Furthermore, the formula for calculating the effective plugging and drainage capacity Q is as follows:

[0021] In the formula, Q1 is the pumping rate of the hydrated adhesive plugging fluid; Q2 is the leakage rate per unit time.

[0022] Furthermore, in step S7, the compressive strength of the hydrated adhesive sealant after curing reaches more than 5 MPa.

[0023] Compared with the prior art, the present invention has the following beneficial effects: 1. This invention targets large and severe leakage in cracks and cavities. Based on the leakage situation on site, a filler with an appropriate particle size is selected to fill and bridge the cavities, ensuring that the hydrated cement slurry system can form a retention at the leakage layer before solidification, so that the system forms a certain sealing strength at the leakage layer after solidification.

[0024] 2. For severe loss-of-return leakage, the drilling fluid level in the wellbore is measured, and the vertical distance between the leakage site and the fluid level is calculated. This allows for the estimation of the pressure-bearing capacity at the leakage site, enabling precise pressure data to control the plugging process. Based on the pressure-bearing capacity at the leakage point, the pumping rate Q is precisely calculated to control the rise rate of the injected fluid H in the wellbore, thereby controlling the fluid column pressure P. t This causes the liquid column pressure P t The pressure difference between the leak point and the leakage pressure P is controlled, allowing the plugging fluid to enter the leak layer at a controllable rate. The hydration and gelling plugging fluid reaches the leak layer within the expected pumpable time, allowing the plugging fluid to enter the leak layer and remain at the leak point.

[0025] 3. This invention uses hydrated gel-based sealing cement slurry as the sealing medium. Based on the pressure-bearing capacity of the leaking layer, a low-density, easily retainable hydrated gel-based sealing cement slurry is prepared. Before curing, it exhibits strong thixotropy, good retention capacity, no free water, and high system stability. After curing, its strength develops rapidly, enabling the leaking layer to withstand the hydrated gel-based sealing cement slurry. This ensures that the sealing material can enter, remain, and not escape. After the sealing is implemented, it can improve the pressure-bearing capacity of the stratum at the leaking layer, overcoming the technical defects of existing conventional sealing methods.

[0026] To make the above description of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other design solutions and drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This diagram illustrates the loss of drilling fluid during a severe leakage event in the drilling process.

[0029] Figure 2 This is an illustration showing the effect of filling a leak with a certain amount and specification of filler material.

[0030] Figure 3 The drilling tool is used to inject a solidifiable plugging fluid into the leaking formation.

[0031] Explanation of reference numerals in the attached figures 1. Wellhead; 2. Liquid level before plugging; 3. Drilling fluid; 4. Leakage points; 5. Filler; 6. Can be cured sealant; 7. Liquid level line after leak sealing; 8. Drilling tools; 9. Drill string lowering position.

[0032] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, the preferred embodiments of the present invention are described in detail below. Detailed Implementation

[0033] The invention can be further understood in conjunction with the following detailed description of preferred embodiments and included examples. Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. If any definition of a specific term disclosed in the prior art differs from any definition provided herein, the definition provided herein shall prevail.

[0034] In a typical embodiment of this application, a method for dynamic equilibrium stabilization and solidification plugging of severely leaking formations is provided, comprising the following steps: S1. Select the filler according to the actual leakage situation and fill the leak point with the filler to ensure the retention of the sealing fluid before it solidifies; S2. Calculate the bearing capacity of the formation at the leak point; S3. Lower the drill string to a position Hx below the fluid level inside the wellbore; S4. Prepare a hydrated gel-based leak-stopping solution; S4. Begin the leak sealing operation and pump in the hydrated adhesive sealant. S5. Real-time monitoring of the wellbore fluid level; when the fluid level rises, the fluid column pressure P... t When the leakage pressure P at the leak point is out of balance, the hydrated gel plugging fluid begins to enter the leakage formation. S6. After the hydrated gel plugs the leaking fluid into the lost formation, the liquid column pressure P is controlled. tThe pressure difference between the hydrating gel plugging fluid and the leakage pressure P at the leak point allows the hydrating gel plugging fluid to enter the leak layer at a controllable rate and to reach the leak layer location within a predictable pumpable time, so that the plugging fluid can enter the leak layer and remain at the leak point. S7. After the hydrating gel plugging fluid is pumped in, the drill string is pulled out and the fluid column in the wellbore returns to a balanced state. At this time, the static fluid pressure at the leak point also returns to the leakage pressure P at the leak point. The hydrating gel plugging fluid leaves a 1-3 meter plug surface above the leak point. After reaching equilibrium, wait 16-24 hours for it to solidify and have a certain strength. Then, grouting is carried out again to explore and clean the plug, and drilling is resumed.

[0035] The leak-sealing principle of this invention is as follows: Before plugging: Before pumping in the plugging fluid, after the drill string is lowered to the designated position, the volume inside the wellbore increases, the fluid column rises, the pressure at the leakage point becomes unbalanced, some drilling fluid leaks into the formation, and the leakage pressure returns to balance.

[0036] After plugging: After the drill string is pulled out, the volume inside the wellbore decreases and the fluid column drops, which ensures that some of the hydrated gel plugging fluid remains in the wellbore, forming a plug and sealing the leaking layer.

[0037] In a further preferred embodiment, step S1, selecting a filler material based on the actual leakage situation, specifically includes: ① To prevent leakage of more than 2 meters, select filler material with a particle size of 20-50mm; ② To release leakage below 2 meters, select filler material with a particle size of 10-20mm; ③ If there is no leakage that does not empty, then no filler is needed.

[0038] It should be further explained that "venting" means that during drilling with a drilling pressure of 6 tons, the drilling pressure is momentarily reduced to 0, at which point the formation cannot withstand any pressure. This process is called venting.

[0039] In practical applications, gravel or other materials can be used as fillers.

[0040] In some specific embodiments, in step S1, the filler material at the leakage point is filled to a depth of 1-3 meters above the leakage point.

[0041] In some specific embodiments, in step S2, the formula for calculating the formation bearing capacity at the leak point, i.e., the leakage pressure P at the leak point, is: P = ρ1gH2, In the formula, P is the leakage pressure at the leak point; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity; H2 is the distance between the initial fluid level of the drilling fluid in the wellbore and the leak point.

[0042] In some specific embodiments, in step S3, Hx is calculated using the following formula:

[0043] In the formula, Hx is the distance between the real-time drilling fluid level line in the wellbore and the bottom of the drill string; P represents the leakage pressure at the leak point; ρ2 is the density of the hydrated gel plugging fluid; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity.

[0044] In some preferred embodiments, the hydrated adhesive plugging liquid comprises, by weight, 20-150 parts water, 3-10 parts thermosetting resin, 0.4-2 parts fiber, 0.02-0.06 parts curing agent, and 0.2-2 parts retarder. The thermosetting resin is a water-based epoxy resin, the curing agent can be one or more of slag powder, core shell, sand, and mica powder, and the retarder can be modified starch, etc.

[0045] , ∆H = H3 - H2; In the formula, ρ2 is the density of the hydrated gel plugging fluid; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity; H2 is the distance between the initial drilling fluid level line in the wellbore and the leak point; H3 is the distance between the real-time drilling fluid level line in the wellbore and the leak point. ∆H is the height of the fluid column rising inside the wellbore.

[0046] In some preferred embodiments, in step S6, after the hydrated gel plugging fluid enters the lost formation, the liquid column pressure P is controlled. t The method for determining the pressure difference between the leakage point and the leakage pressure P is as follows: After the hydrated gel plugging fluid enters the lost circulation formation, the first stage of plugging is carried out. At this stage, the pumping rate Q1 of the hydrated gel plugging fluid is less than the leakage rate Q2 per unit time, the fluid level in the wellbore does not rise, and there is no need to lift the drill string. When the pumping rate Q1 of the hydrated gel plugging fluid exceeds the leakage rate Q2 per unit time, the plugging operation enters the second stage. At this stage, the fluid level rises at a fluid injection rate V, and the drilling speed V is controlled. 钻具 , making V 钻具 =V, thereby controlling the liquid column pressure P t This causes the liquid column pressure P t The purpose is to control the pressure difference between the leakage point and the leakage pressure P.

[0047] Furthermore, the formula for calculating the liquid injection rise rate V is as follows:

[0048] In the formula, Q is the effective plugging and drainage capacity, L / min; D is the wellbore diameter.

[0049] Furthermore, the formula for calculating the effective plugging and drainage capacity Q is as follows:

[0050] In the formula, Q1 is the pumping rate of the hydrated adhesive plugging fluid; Q2 is the leakage rate per unit time.

[0051] In practical applications, the compressive strength of the hydrated adhesive sealing liquid in step S7 after curing reaches more than 5 MPa.

[0052] Example 1 Meng# well, drilled to 999m in the Huachi Formation, experienced a 3m depletion and loss of return. Figure 1 As shown, after 13 conventional plugging methods, all were ineffective, with a total loss of 1300 cubic meters and the fluid level in the wellbore 330m from the wellhead. Therefore, a dynamic balance pressure-stabilizing and solidifying plugging method for severely leaking formations was adopted to address the leakage situation in this well. The specific steps of this method are as follows: S1. Based on the leakage situation at Meng# well, select gravel with a particle size of 20-50mm as filler and fill the leakage point, referring to... Figure 2 To ensure the retention of the sealing fluid before it solidifies; S2. Calculate the bearing capacity of the formation at the leak point, i.e., the leakage pressure at the leak point, according to Formula I. P=ρ1gH2=1.04×9.81×0.669=6.83MPa (Ⅰ) S3. Lower the drill string to a position Hx below the fluid level inside the wellbore. Specifically, Hx is calculated using Formula II: (II) S4. Prepare the hydrated gelling sealant: First, place 20 tons of water in the tank, and then add 7 tons of thermosetting resin powder, 0.6 tons of fiber, 0.04 tons of curing agent, and 0.3 tons of retarder in sequence during the stirring process; S5. Begin leak sealing work, pump in hydrated cementitious leak sealing solution, refer to... Figure 3 ; S6. Real-time monitoring of the wellbore fluid level; when the fluid level rises, the pressure at the leakage point increases, and the fluid column pressure P... t The leak point pressure P is out of balance, and the leak point pressure P < the liquid column pressure P. t The hydrated gel-bonded plugging fluid began to enter the lost formation; the liquid column pressure P t Calculated using Formula III: (III) S7. After the hydrated gel plugging fluid enters the lost circulation formation, the first stage of plugging is carried out. At this time, the pumping rate Q1 of the hydrated gel plugging fluid is less than the leakage rate Q2 per unit time, the fluid level in the wellbore does not rise, and there is no need to lift the drill string. When the pumping rate Q1 of the hydrated gel plugging fluid exceeds the leakage rate Q2 per unit time, the plugging operation enters the second stage. At this time, the fluid level rises at a fluid injection rate V. The drilling speed V is controlled by adjusting the lifting speed of the drill string. 钻具 , making V 钻具 =V, thereby controlling the liquid column pressure P t This causes the liquid column pressure P t The purpose of controlling the pressure difference between the leakage point and the leakage pressure P is to allow the hydrated gel plugging fluid to enter the leakage layer at a controllable rate, and to ensure that the hydrated gel plugging fluid reaches the leakage layer within a predicted pumpable time, allowing the plugging fluid to enter the leakage layer and remain at the leakage point; wherein the injection rise velocity V is calculated by formula IV: (IV) S8. After the hydrating gel plugging fluid is pumped in, the drill string is pulled out and the fluid column in the wellbore returns to a balanced state. At this time, the hydrostatic pressure at the leak point also returns to the leakage pressure P at the leak point. The hydrating gel plugging fluid leaves a 1-3 meter plug surface above the leak point. After reaching equilibrium, wait 16-24 hours for it to solidify and develop strength. The compressive strength reaches more than 5 MPa. Then, grouting is carried out to circulate and probe the plug, and drilling is resumed.

[0053] After the above-mentioned dynamic balance pressure stabilization and solidification plugging method for malignant leakage formations was implemented in the Meng# well, the leakage was successfully plugged in one go, drilling resumed, and it has now been completed and put into production.

[0054] In summary, for severe loss-of-return leakage, this invention measures the vertical distance between the leakage site and the wellbore fluid level by measuring the drilling fluid level in the wellbore, thereby calculating the pressure-bearing capacity at the leakage site. Based on the pressure-bearing capacity at the leakage point, the pumping rate Q is precisely calculated to control the rise rate of the wellbore fluid injection H, ultimately controlling the fluid column pressure P. t This causes the liquid column pressure P t The pressure difference between the leak point and the leakage pressure is controlled, allowing the plugging fluid to enter the leaking layer at a controllable rate. The hydration and gelling plugging fluid reaches the leaking layer within a predictable pumpable time, ensuring that the plugging fluid can enter the leaking layer and remain at the leak point. This not only isolates the leakage path but also withstands the pressure. Therefore, the plugging process of this invention has a significant plugging effect, high efficiency, and strong targeting, making it suitable for treating large and medium-sized severe leakage formations, and has broad market application prospects.

[0055] Those skilled in the art will understand that the above embodiments are specific examples of implementing the present invention, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the present invention.

Claims

1. A method for dynamic equilibrium pressure stabilization and solidification plugging of severely leaking formations, characterized in that, Includes the following steps: S1. Select the filler according to the actual leakage situation and fill the leak point with the filler to ensure the retention of the sealing fluid before it solidifies; S2. Calculate the bearing capacity of the formation at the leak point; S3. Lower the drill string to a position Hx below the fluid level inside the wellbore; S4. Prepare a hydrated gel-based leak-stopping solution; S4. Begin the leak sealing operation and pump in the hydrated adhesive sealant. S5. Real-time monitoring of the wellbore fluid level; when the fluid level rises, the fluid column pressure P... t When the leakage pressure P at the leak point is out of balance, the hydrated gel plugging fluid begins to enter the leakage formation. S6. After the hydrated gel plugs the leaking fluid into the lost formation, the liquid column pressure P is controlled. t The pressure difference between the hydrating gel and the leakage pressure P at the leak point allows the hydrating gel to enter the leak layer at a controllable rate, and enables the hydrating gel to reach the leak layer within a predictable pumpable time, allowing the hydrating gel to enter the leak layer and remain at the leak point.

2. The method for dynamic equilibrium stabilization and solidification of severely leaking formations according to claim 1, characterized in that: The plugging method also includes step S7. After the hydrating gel plugging fluid is pumped in, the drill string is pulled out and the fluid column in the wellbore returns to a balanced state. At this time, the static fluid pressure at the leak point also returns to the leakage pressure P at the leak point. The hydrating gel plugging fluid leaves a 1-3 meter plug surface above the leak point. After reaching equilibrium, it is allowed to solidify for 16-24 hours. The hydrating gel plugging fluid solidifies and has a certain strength. Then, grouting is carried out to circulate and probe the plug, and drilling is resumed.

3. The method for dynamic equilibrium stabilization and solidification of severely leaking formations according to claim 1, characterized in that, In step S1, selecting the filler material based on the actual leakage situation specifically includes: ① For leakage exceeding 2 meters, select filler material with a particle size of 20-50mm; ② For leakage below 2 meters, select filler material with a particle size of 10-20mm; ③ For leaks that do not empty, no filler is needed.

4. The method for dynamic equilibrium stabilization and solidification of severely leaking formations according to claim 1, characterized in that: In step S1, the filler material at the leakage point is filled to a depth of 1-3 meters above the leakage point.

5. The method for dynamic equilibrium stabilization and solidification of severely leaking formations according to claim 1, characterized in that, In step S2, the formula for calculating the formation bearing capacity at the leak point, i.e., the leakage pressure P at the leak point, is: P = ρ1gH2 In the formula, P is the leakage pressure at the leak point; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity; H2 is the distance between the initial fluid level of the drilling fluid in the wellbore and the leak point.

6. The method for dynamic equilibrium stabilization and solidification plugging of severely leaking formations according to claim 1, characterized in that, In step S3, Hx is calculated using the following formula: In the formula, Hx is the distance between the real-time drilling fluid level line in the wellbore and the bottom of the drill string; P represents the leakage pressure at the leak point; ρ2 is the density of the hydrated gel plugging fluid; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity.

7. The method for dynamic equilibrium pressure stabilization and solidification plugging of severely leaking formations according to claim 6, characterized in that, In step S5, the liquid column pressure P t The calculation formula is: ， ∆H = H3 - H2; In the formula, ρ2 is the density of the hydrated gel plugging fluid; ρ1 is the density of the drilling fluid; g is the acceleration due to gravity; H2 is the distance between the initial drilling fluid level line in the wellbore and the leak point; H3 is the distance between the real-time drilling fluid level line in the wellbore and the leak point. ∆H is the height of the fluid column rising inside the wellbore.

8. The method for dynamic equilibrium pressure stabilization and solidification plugging of severely leaking formations according to claim 1, characterized in that, In step S6, after the hydrated gel plugging fluid enters the lost formation, the liquid column pressure P is controlled. t The method for determining the pressure difference between the leakage point and the leakage pressure P is as follows: After the hydrated gel plugging fluid enters the lost circulation formation, the first stage of plugging is carried out. At this stage, the pumping rate Q1 of the hydrated gel plugging fluid is less than the leakage rate Q2 per unit time, the fluid level in the wellbore does not rise, and there is no need to lift the drill string. When the pumping rate Q1 of the hydrated gel plugging fluid exceeds the leakage rate Q2 per unit time, the plugging operation enters the second stage. At this stage, the fluid level rises at a fluid injection rate V, and the drilling speed V is controlled. 钻具 , making V 钻具 =V, thereby controlling the liquid column pressure P t This causes the liquid column pressure P t The purpose is to control the pressure difference between the leakage point and the leakage pressure P.

9. The method for dynamic equilibrium stabilization and solidification of severely leaking formations according to claim 8, characterized in that: The formula for calculating the liquid injection rise rate V is: In the formula, Q is the effective leakage discharge rate, in L / min; D is the wellbore diameter.

10. The method for dynamic equilibrium stabilization and solidification of severely leaking formations according to claim 9, characterized in that, The formula for calculating the effective plugging and drainage capacity Q is: In the formula, Q1 is the pumping rate of the hydrated adhesive plugging fluid; Q2 is the leakage rate per unit time.

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