While-drilling spraying borehole wall protection device and method

Abstract

The borehole wall protection device comprises a double-wall drill rod, the double-wall drill rod comprises an inner barrel and an outer barrel, a first circulation channel is formed in the inner barrel, and a second circulation channel is formed between the inner barrel and the outer barrel; the lower end of the double-wall drill rod is connected with a spraying nipple and a drill bit, the drill bit is connected with the first circulating channel, and the spraying nipple is connected with the second circulating channel; wherein during drilling, first fluid used for well drilling flows in the first circulation channel and the second circulation channel, and the first fluid flows into a well from a well mouth through the first circulation channel and flows back to the well mouth through the second circulation channel in the well; when well leakage occurs, the first circulating channel is closed, and second fluid for leaking stoppage circulates in the second circulating channel; and when the well wall is unstable, the first circulating channel is closed, and third fluid used for strengthening the well wall circulates in the second circulating channel.

Description

Technical Field

[0001] This invention relates to a wellbore wall protection device and method for spraying while drilling, belonging to the field of oil and gas drilling technology. Background Technology

[0002] As oil and gas exploration and development moves towards deeper, ultra-deeper and unconventional formations, the geological conditions encountered become increasingly complex. In some areas, reservoirs are deeply buried and diverse in type, with some structural fault zones, faults and fractures developed, stress concentrations, and broken formations, making them prone to complex situations such as well leakage and wellbore instability.

[0003] Under current drilling conditions, methods such as simplified drill string assembly for plugging while drilling, consolidation-specific plugging, and cement plug sealing are commonly used. However, if these methods are not addressed promptly, they can lead to loss of return, wellbore collapse, or even stuck pipe. In some high-stress concentration areas, after the drill bit breaks through the lower formation, the upper well section loses support, resulting in severe wellbore collapse and a high risk of blockage, stuck pipe, or even burying the drill string. To improve wellbore reinforcement and reduce complex downhole failures caused by fractured wellbore leakage and wellbore instability, it is necessary to explore new methods for maintaining wellbore stability. Summary of the Invention

[0004] To address the aforementioned technical problems in the existing technology, this invention proposes a wellbore wall protection device and method for spraying while drilling. Before drilling to the predicted fracture zone or fracture development section, the drill string is pulled out and replaced with a double-walled drill pipe equipped with a spraying tool. Drilling fluid is injected into the inner cylinder of the double-walled drill pipe to carry rock cuttings in circulation, while a solidifying liquid is injected into the outer cylinder. Under pressure, the liquid is evenly sprayed onto the newly formed wellbore surface, quickly sealing cracks and cavities, consolidating and protecting the wellbore, improving wellbore strength, and reducing the risk of leakage and rockfall.

[0005] This invention proposes a wellbore wall protection device for spraying while drilling, comprising:

[0006] A double-walled drill pipe, comprising an inner cylinder and an outer cylinder, wherein a first circulation channel is formed inside the inner cylinder and a second circulation channel is formed between the inner cylinder and the outer cylinder;

[0007] The lower end of the double-walled drill rod is connected to a spraying sub and a drill bit. The drill bit is connected to the first circulation channel, and the spraying sub is connected to the second circulation channel.

[0008] During drilling, a first fluid for drilling flows through the first circulation channel and the second circulation channel. The first fluid flows from the wellhead into the downhole through the first circulation channel and flows back to the wellhead through the second circulation channel.

[0009] In the event of well leakage, the first circulation channel is closed, and the second circulation channel is circulated with a second fluid used to plug the leakage;

[0010] In the event of wellbore instability, the first circulation channel is closed, and a third fluid for reinforcing the wellbore circulates in the second circulation channel.

[0011] A further improvement of the present invention is that the spraying sub is disposed below the double-walled drill pipe and above the drill bit; the spraying sub is provided with a plurality of nozzles, and the second liquid or the third fluid is sprayed out along the nozzles.

[0012] A further improvement of the present invention is that the spraying short section includes a spraying short section outer cylinder, the upper end of which is connected to the outer cylinder of the double-walled drill rod; a spraying short section inner cylinder is provided inside the spraying short section outer cylinder, and the upper end of the spraying short section inner cylinder is connected to the inner cylinder of the double-walled drill rod.

[0013] The nozzle is provided on the outer cylinder of the spraying section.

[0014] A further improvement of the present invention is that the nozzle includes a sealing nozzle, and the sealing nozzle has a nozzle tube disposed inside it in the radial direction of the spraying section, and the spraying direction is in the radial direction of the spraying section.

[0015] A further improvement of the present invention is that the nozzle includes a protective nozzle, the protective nozzle has a nozzle tube inside, the inner side of the nozzle tube is along the radial direction of the spraying section, and the outer side is at a certain angle to the radial direction of the spraying section; the spraying direction is at a certain angle to the radial direction of the spraying section.

[0016] A further improvement of the present invention is that a number of ribs are provided between the inner and outer cylinders of the double-walled drill pipe.

[0017] A further improvement of the present invention is that the upper end of the double-walled drill pipe is provided with a wellhead conversion head, the wellhead conversion head including a first interface and a second interface for connecting to the drilling hydrant, the first interface being connected to the first circulation channel, and the second interface being connected to the second circulation channel.

[0018] According to another aspect of the invention, a wellbore wall protection method for drilling spraying is also proposed, characterized in that it is implemented using a wellbore wall protection device for drilling spraying according to the invention.

[0019] A further improvement of the present invention is that it includes:

[0020] Before drilling to the geologically predicted fault zone or fracture development section, the conventional drilling tool assembly in the well is pulled out;

[0021] The wellbore wall protection device, which is sprayed while drilling, is assembled on the ground and then drilled down to the bottom of the well.

[0022] Drilling begins, and the first fluid is circulated through the double-walled drill pipe.

[0023] Spraying operations are carried out when well leakage or wellbore instability occurs;

[0024] After the spraying operation is completed, continue drilling using the combination of double-walled drill pipe and drill bit until the fracture zone or crack zone is drilled through. Once it is confirmed that a stable stratum has been entered, the drill bit is pulled out.

[0025] The standard drill string assembly was lowered in to resume normal drilling.

[0026] A further improvement of the present invention is that the spraying operation includes:

[0027] When well leakage occurs, the first circulation channel is closed by wellhead operation, the second fluid is pumped downhole through the second circulation channel, and the second fluid is injected through the plugging nozzle to plug the leakage.

[0028] A further improvement of the present invention is that the spraying operation includes:

[0029] When wellbore instability occurs, the first circulation channel is closed by wellhead operation, the third fluid is pumped downhole through the second circulation channel, and the third fluid is injected through the wall protection nozzle to enhance the sealing.

[0030] A further improvement of the present invention is that the first fluid is drilling fluid, the second fluid is a plugging fluid containing large-diameter bridging particles, and the third fluid is a solidifying fluid.

[0031] A further improvement of the present invention is that the solidifying liquid includes gel cement mixture, resin cement mixture, quick-drying cement or other solidifiable liquid.

[0032] Compared with the prior art, the advantages of the present invention are as follows:

[0033] The wellbore wall protection device and method for drilling spraying described in this invention can rapidly spray the wellbore wall while the wellbore is being formed, which helps to reduce the risk of wellbore instability and leakage.

[0034] The wellbore wall protection device and method for drilling spraying described in this invention utilizes the inner tube of the double-walled drill pipe to circulate drilling fluid, while the outer tube is injected with a solidifying liquid. The inner and outer tubes operate separately, thus avoiding the risk of slurry mixing.

[0035] The wellbore wall protection device and method for drilling spraying described in this invention have the following advantages: the plugging nozzle sprays liquid onto the wellbore wall in a jetting manner, which is beneficial for penetrating deep into the fractures and enhancing the sealing effect; the wall protection nozzle sprays liquid tangentially onto the wellbore wall, which is beneficial for forming a uniform consolidation coating on the surface of unstable formations.

[0036] The wellbore wall protection device and method for drilling spraying described in this invention, compared with conventional consolidation plugging or wellbore strengthening methods, can achieve drilling wall sealing without stopping drilling, and has the characteristics of convenient construction and safety and reliability. Attached Figure Description

[0037] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, in which:

[0038] Figure 1 The diagram shown is a schematic representation of a wellbore wall protection device for drilling spraying according to an embodiment of the present invention.

[0039] Figure 2 The diagram shown is a structural schematic of a double-walled drill pipe according to an embodiment of the present invention;

[0040] Figure 3 The diagram shown is a schematic representation of the spraying section according to an embodiment of the present invention, illustrating the structure for sealing the nozzle;

[0041] Figure 4 The diagram shown is a structural schematic of a spraying section according to an embodiment of the present invention, illustrating the structure of the protective nozzle;

[0042] The accompanying drawings are not drawn to scale.

[0043] The meanings of the reference numerals in the attached figures are as follows:

[0044] 1. Converter head; 2. Double-walled drill pipe; 3. Spraying sub; 4. Drill bit; 11. First connector; 12. Second connector; 21. Outer cylinder; 22. Inner cylinder; 23. First circulation channel; 24. Second circulation channel; 25. Rib; 31. Outer cylinder of spraying sub; 32. Inner cylinder of spraying sub; 33. Sealing nozzle; 34. Wall-protecting nozzle. Detailed Implementation

[0045] To make the technical solutions and advantages of the present invention clearer, exemplary embodiments of the present invention will be described in further detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not an exhaustive list of all embodiments. Furthermore, without conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0046] Under current drilling conditions, methods such as simplified drill string assembly for plugging while drilling, consolidation-specific plugging, and cement plug sealing are commonly used. However, if these methods are not addressed promptly, they can lead to loss of return, wellbore collapse, or even stuck pipe. In some high-stress concentration areas, after the drill bit breaks through the lower formation, the upper well section loses support, resulting in severe wellbore collapse and a high risk of blockage, stuck pipe, or even burying the drill string. To improve wellbore reinforcement and reduce complex downhole failures caused by fractured wellbore leakage and wellbore instability, it is necessary to explore new methods for maintaining wellbore stability.

[0047] This method proposes a wellbore wall protection device that is sprayed while drilling, which can solve the above problems.

[0048] In such Figure 1 In the embodiment shown, the wellbore wall protection device that utilizes the double-walled drill pipe 2 for drilling spraying,

[0049] include:

[0050] The double-walled drill rod 2 has an annular cross-section, including an inner cylinder 22 and an outer cylinder 21 that are sleeved together. The inner cylinder 22 is sleeved inside the outer cylinder 21. A first circulation channel 23 is formed inside the inner cylinder 22, and an annular second circulation channel 24 is formed between the inner cylinder 22 and the outer cylinder 21.

[0051] The upper end of the double-walled drill pipe 2 is provided with a conversion head 1 for connecting a dedicated circulation channel and a drilling faucet on the ground. The dedicated circulation channel is connected to the second circulation channel 24, and the drilling faucet is connected to the second circulation channel 24.

[0052] The lower end of the double-walled drill rod 2 is connected to a spraying short section 3, which is connected to the lower end of the second circulation channel 24.

[0053] The lower end of the double-walled drill rod 2 is also connected to a drill bit 4, which is located below the spraying short section 3, and the connecting drill bit 4.

[0054] During drilling, a first fluid for drilling flows through the first circulation channel 23 and the second circulation channel 24. The first fluid flows from the wellhead into the downhole through the first circulation channel 23 and flows back to the wellhead through the second circulation channel 24. A circulation is established through the first circulation channel 23 and the second circulation channel 24, which can cool the drill bit 4 and has the ability to carry sand.

[0055] In the event of well leakage, the first circulation channel 23 is closed, and the second circulation channel 24 is circulated with a second fluid for plugging the leakage.

[0056] In the event of wellbore instability, the first circulation channel 23 is closed, and a third fluid for reinforcing the wellbore flows through the second circulation channel 24.

[0057] In the wellbore wall protection device using spraying while drilling as described in this embodiment, the spraying method allows for rapid spraying of the wellbore wall during wellbore formation, which helps reduce the risk of wellbore instability and leakage. The drilling fluid is circulated in the inner tube of the double-wall drill pipe 2, while a solidifying liquid is injected into the outer tube. The inner and outer tubes 21 operate separately, avoiding the risk of slurry mixing. Compared with conventional solidification plugging or wellbore reinforcement methods, this method can achieve wellbore wall sealing while drilling without stopping drilling, and is characterized by convenient construction and high safety and reliability.

[0058] In one embodiment, the spraying sub 3 is disposed below the double-walled drill rod 2 and above the drill bit 4; the spraying sub 3 is provided with a plurality of nozzles, and the second liquid or the third fluid is sprayed out along the nozzles.

[0059] In this embodiment, the nozzle is capable of spraying a second liquid and a third liquid, used for plugging leaks and reinforcing the wellbore, respectively. The first fluid is drilling fluid, the second fluid is a plugging fluid containing large-diameter bridging particles, and the third fluid is a solidifying liquid.

[0060] In one embodiment, the spraying sub 3 includes a spraying sub outer cylinder 31, the upper end of which is connected to the lower end of the outer cylinder 21 of the double-walled drill rod 2, and the two are fixedly connected by threads or other means. An inner spraying sub cylinder 32 is disposed inside the outer cylinder 31, coaxially arranged with the outer cylinder 31, and the upper end of the inner cylinder 32 is connected to the inner cylinder 22 of the double-walled drill rod 2. Thus, the spraying sub 3 also forms an annular space.

[0061] The nozzle is provided on the outer cylinder 31 of the spraying section, and the nozzle is arranged circumferentially on the outer surface of the outer cylinder 31 of the spraying section.

[0062] In one embodiment, the nozzle includes a sealing nozzle 33, which is preferably conical. The sealing nozzle 33 has a nozzle tube disposed inside it along the radial direction of the spraying section 3, and the spraying direction is along the radial direction of the spraying section 3.

[0063] In another embodiment, the nozzle includes a wall-mounted nozzle 34, the interior of which is provided with a nozzle tube. The inner side of the nozzle tube is along the radial direction of the spraying section 3, and the outer side is at a certain angle to the radial direction of the spraying section 3. The spraying direction is also at a certain angle to the radial direction of the spraying section 3. Preferably, the spraying direction is along the tangent of the arc of the outer surface of the spraying section 3.

[0064] In the wellbore wall protection device for drilling spraying according to this embodiment, the plugging nozzles are arranged in the radial direction. During construction, the liquid is sprayed onto the well wall in a jetting manner, which is conducive to penetrating into the fractures and thus enhancing the sealing effect.

[0065] The wall-protecting nozzle 34 in this embodiment can spray liquid tangentially onto the well wall, which is beneficial for forming a uniform consolidation coating on the surface of unstable formations.

[0066] In one embodiment, a plurality of ribs 25 are provided between the inner cylinder 22 and the outer cylinder 21 of the double-walled drill rod 2. Preferably, there are four ribs 25, which are evenly arranged in the circumferential direction.

[0067] In one embodiment, the upper end of the double-walled drill pipe 2 is provided with a wellhead converter 1. The wellhead converter 1 includes a first interface 11 and a second interface 12 for connecting to a drilling hydrant. The first interface 11 is connected to the first circulation channel 23, and the second interface 12 is connected to the second circulation channel 24. The second interface 12 can serve as a circulation outlet for drilling fluid or can be connected to a dedicated circulation channel for pumping in a second and third fluid.

[0068] The wellbore wall protection device for drilling spraying described in this invention proposes a drilling spraying method that can rapidly spray the wellbore wall while the wellbore is being formed, which helps to reduce the risk of wellbore instability and leakage.

[0069] The wellbore wall protection device for drilling spraying described in this invention utilizes the inner tube of the double-walled drill pipe 2 to circulate drilling fluid, while the outer tube is injected with a solidifying liquid. The inner and outer cylinders 21 operate separately, thus avoiding the risk of slurry mixing.

[0070] The wellbore wall protection device for drilling spraying described in this invention has a plugging nozzle that sprays liquid onto the well wall in a jetting manner, which is beneficial for penetrating deep into the fractures and enhancing the sealing effect; and a wall protection nozzle 34 that sprays liquid tangentially onto the well wall, which is beneficial for forming a uniform consolidation coating on the surface of unstable formations.

[0071] The wellbore wall protection device sprayed while drilling described in this invention, compared with conventional consolidation plugging or wellbore reinforcement methods, can achieve wellbore wall sealing while drilling without stopping drilling, and has the characteristics of convenient construction and safety and reliability.

[0072] According to another aspect of the present invention, a wellbore wall protection method for drilling spraying is also proposed, which is implemented using the wellbore wall protection device for drilling spraying according to the above embodiments.

[0073] In one embodiment, the method includes:

[0074] Before drilling to the geologically predicted fault zone or fracture development section, the conventional drilling tool assembly in the well is pulled out;

[0075] The wellbore wall protection device, which is sprayed while drilling, is assembled on the ground and then drilled down to the bottom of the well.

[0076] Drilling begins, and the first fluid is circulated through the double-walled drill pipe 2.

[0077] Spraying operations are carried out when well leakage or wellbore instability occurs;

[0078] After the spraying operation is completed, continue drilling using the combination of two drill bits and two drill rods until the fracture zone or crack zone is penetrated. Once it is confirmed that a stable stratum has been entered, the drill string is pulled out.

[0079] The standard drill string assembly was lowered in to resume normal drilling.

[0080] In this embodiment, the spraying while drilling method can rapidly spray the wellbore while the wellbore is being formed, which helps reduce the risk of wellbore instability and leakage. The drilling fluid is circulated in the inner tube of the double-walled drill pipe 2, while a solidifying liquid is injected into the outer tube. The inner and outer tubes 21 operate separately, avoiding the risk of slurry mixing.

[0081] In one embodiment, the spraying operation includes:

[0082] When well leakage occurs, the first circulation channel 23 is closed by wellhead operation, the second fluid is pumped downhole through the second circulation channel 24, and the second fluid is injected through the plugging nozzle 33 to plug the leakage.

[0083] In one embodiment, the spraying operation includes:

[0084] When wellbore instability occurs, the first circulation channel 23 is closed by wellhead operation, the third fluid is pumped downhole through the second circulation channel 24, and the third fluid is sprayed through the wall protection nozzle 34 to enhance the sealing.

[0085] In one embodiment, the first fluid is drilling fluid, the second fluid is plugging fluid containing large-diameter bridging particles, and the third fluid is a solidifying fluid.

[0086] In one embodiment, the solidifying liquid includes gel, cement mixture, resin, cement mixture, quick-drying cement, or other solidifiable liquid (e.g., a mixture of gel, cement, resin, or other coagulant).

[0087] In one specific embodiment, the method addresses the problems of leakage in fractured and cavernous formations and wellbore instability and collapse in broken formations. The method includes the following steps:

[0088] Before drilling to the geologically predicted fault zone or fracture development section, the conventional drilling tool assembly in the well is pulled out;

[0089] The wellbore wall protection device for drilling spraying is assembled on the ground, connecting the wellhead conversion head 1, double wall drill pipe 2, spraying sub 3, and drill bit 4 together to form a drilling spraying tool assembly;

[0090] The double-walled drill pipe 2 is divided into an inner cylinder 22 and an outer cylinder 21, which are connected by a straight-through rib plate 25; the wellhead conversion head 1 has two inner and two outer circulation channels, which can be opened or closed by wellhead operation to achieve connection with the inner and outer cylinders 21 of the double-walled drill pipe 2;

[0091] The spraying section 3 body is equipped with multiple layers of nozzles, with each layer of nozzles arranged radially. The spray diameter and spray angle can be selected according to the required functions, with multiple sizes and angle series available. It is divided into sealing nozzles 33 for leaking layers and wall protection nozzles 34 for easily collapsible strata. The specific nozzle type is selected according to the predicted situation of the underlying strata.

[0092] Lower the drilling tool assembly with spray coating to the bottom of the well, start the top drive or rotary table to drill, connect the wellhead conversion joint to the drilling fluid pipeline, open the inner channel of the conversion joint, and use the inner cylinder 22 of the double-walled drill pipe 2 to circulate the drilling fluid, cool the drill bit 4 and carry the cuttings.

[0093] When well leakage occurs, the inner channel of the wellhead conversion joint is closed by wellhead operation, and the outer channel is opened. The plugging fluid with large-diameter bridging particles is pumped in by the outer cylinder 21 of the double-wall drill pipe 2. The plugging fluid is sprayed at a high injection pressure onto the newly formed well wall through the sealing nozzle 33 of the spraying tool at the bottom of the tubing string, and penetrates into the cracks and pores to enhance the sealing effect.

[0094] When wellbore instability occurs, the inner channel of the wellhead conversion joint is closed by wellhead operation, and the outer channel is opened. Various solidifying liquids such as gel, cement mixture, resin, cement mixture, and quick-drying cement are pumped into the outer cylinder 21 of the double-wall drill pipe 2. The liquids are then sprayed evenly onto the wellbore in a "brushing" manner along the tangential direction of the short section through the wall protection nozzle 34 of the spraying tool at the bottom of the tubing string, forming a film-like structure covering the surface and strengthening the wellbore.

[0095] After the spraying operation is completed, switch the circulation channel to the inner cylinder 22 and continue drilling using the double-wall drill rod 2 drill tool combination until the fracture zone or crack zone is drilled through. After confirming that a stable stratum has been entered, the drill is pulled out.

[0096] The standard drill string assembly was lowered in to resume normal drilling.

[0097] The method described in this invention, which involves spraying while drilling, enables rapid coating of the wellbore while the wellbore is being formed, thus reducing the risk of wellbore instability and leakage. By utilizing the inner tube of the double-walled drill pipe 2 to circulate drilling fluid and the outer tube to inject a solidifying liquid, the inner and outer tubes 21 operate separately, avoiding the risk of slurry mixing.

[0098] The method described in this invention involves the plugging nozzle spraying liquid onto the well wall in a jetting manner, which facilitates penetration into the fracture and enhances the sealing effect; and the wall protection nozzle 34 spraying liquid tangentially onto the well wall, which facilitates the formation of a uniform consolidation coating on the surface of unstable formations.

[0099] Compared with conventional consolidation plugging or wellbore reinforcement methods, the method described in this invention can achieve wellbore sealing while drilling without stopping drilling, and has the characteristics of convenient construction and safety and reliability.

[0100] It should be understood that the embodiments disclosed herein are not limited to the specific structures, processing steps, or materials disclosed herein, but should be extended to equivalent substitutions of these features as understood by those skilled in the art. It should also be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting.

[0101] In the description of this invention, unless otherwise stated, "a plurality of" means two or more; the terms "upper," "lower," "left," "right," "inner," "outer," "front end," "rear end," "head," "tail," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0102] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0103] Certain terms are used throughout this application to refer to specific system components. As those skilled in the art will recognize, the same components may often be referred to by different names, and therefore this application is not intended to distinguish components that differ only in name and not in function. The terms "an embodiment" or "embodiment" used in the specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. Therefore, the phrase "an embodiment" or "embodiment" appearing throughout the specification does not necessarily refer to the same embodiment.

[0104] The embodiments of the present invention are given for illustrative and descriptive purposes only, and are not intended to be exhaustive or to limit the invention to the forms disclosed. Many modifications and variations will be apparent to those skilled in the art. The embodiments were chosen and described in order to better illustrate the principles and practical application of the invention, and to enable those skilled in the art to understand the invention and to design various embodiments with various modifications suitable for a particular purpose.

[0105] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and / or modifications falling within the scope of the invention, and all changes and / or modifications made according to embodiments of the invention should be covered within the protection scope of the invention.

Claims

1. A wellbore wall protection device for spraying while drilling, characterized in that, include: A double-walled drill pipe (2) includes an inner cylinder (22) and an outer cylinder (21). A first circulation channel (23) is formed inside the inner cylinder (22), and a second circulation channel (24) is formed between the inner cylinder (22) and the outer cylinder (21). The lower end of the double-walled drill rod (2) is connected to a spraying short section (3) and a drill bit (4). The drill bit (4) is connected to the first circulation channel (23), and the spraying short section (3) is connected to the second circulation channel (24). During drilling, a first fluid for drilling flows through the first circulation channel (23) and the second circulation channel (24). The first fluid flows from the wellhead into the well via the first circulation channel (23) and flows back to the wellhead through the second circulation channel (24). In the event of well leakage, the first circulation channel (23) is closed, and the second circulation channel (24) circulates a second fluid for plugging the leakage; In the event of wellbore instability, the first circulation channel (23) is closed, and a third fluid for reinforcing the wellbore circulates in the second circulation channel (24).

2. The wellbore wall protection device for drilling spraying according to claim 1, characterized in that, The spraying section (3) is located below the double-walled drill rod (2) and above the drill bit (4); the spraying section (3) is provided with a plurality of nozzles, and the second liquid or the third fluid is sprayed out along the nozzles.

3. The wellbore wall protection device for drilling spraying according to claim 2, characterized in that, The spraying short section (3) includes a spraying short section outer cylinder (31), the upper end of which is connected to the outer cylinder (21) of the double-wall drill rod (2); the spraying short section outer cylinder (31) is provided with a spraying short section inner cylinder (32), the upper end of which is connected to the inner cylinder (22) of the double-wall drill rod (2); The nozzle is provided on the outer cylinder (31) of the spraying section.

4. The wellbore wall protection device for drilling spraying according to claim 3, characterized in that, The nozzle includes a sealing nozzle (33), and the sealing nozzle (33) has a nozzle tube arranged in the radial direction of the spraying section (3) inside, and the spraying direction is in the radial direction of the spraying section (3).

5. The wellbore wall protection device for drilling spraying according to claim 3 or 4, characterized in that, The nozzle includes a wall-protecting nozzle (34), and a nozzle tube is provided inside the wall-protecting nozzle (34). The inner side of the nozzle tube is along the radial direction of the spraying section (3), and the outer side is at a certain angle to the radial direction of the spraying section (3). The spraying direction is at a certain angle to the radial direction of the spraying section (3).

6. The wellbore wall protection device for drilling spraying according to claim 5, characterized in that, Several ribs (25) are provided between the inner cylinder (22) and the outer cylinder (21) of the double-walled drill rod (2).

7. The wellbore wall protection device for drilling spraying according to claim 6, characterized in that, The upper end of the double-walled drill pipe (2) is provided with a wellhead conversion head (1). The wellhead conversion head (1) includes a first interface (11) and a second interface (12) for connecting to the drilling faucet. The first interface (11) is connected to the first circulation channel (23), and the second interface (12) is connected to the second circulation channel (24).

8. A method for wellbore wall protection by spraying while drilling, characterized in that, This is achieved using a wellbore wall protection device that is sprayed while drilling according to any one of claims 1 to 7.

9. The method according to claim 8, characterized in that, include: Before drilling to the geologically predicted fault zone or fracture development section, the conventional drilling tool assembly in the well is pulled out; The wellbore wall protection device, which is sprayed while drilling, is assembled on the ground and then drilled down to the bottom of the well. Drilling begins and the first fluid is circulated through the double-walled drill pipe (2); Spraying operations are carried out when well leakage or wellbore instability occurs; After the spraying operation is completed, continue drilling using the double-wall drill rod (2) drill bit combination until the fracture zone or crack zone is drilled through. After confirming that the stable stratum has been entered, the drill bit is pulled out. The standard drill string assembly was lowered in to resume normal drilling.

10. The method according to claim 9, characterized in that, The spraying operation includes: When well leakage occurs, the first circulation channel (23) is closed by wellhead operation, the second fluid is pumped downhole through the second circulation channel (24), and the second fluid is injected through the plugging nozzle (33) to plug the leakage.

11. The method according to claim 9, characterized in that, The spraying operation includes: When wellbore instability occurs, the first circulation channel (23) is closed by wellhead operation, the third fluid is pumped downhole through the second circulation channel (24), and the third fluid is sprayed through the wall nozzle (34) to enhance the sealing.

12. The method according to claim 11, characterized in that, The first fluid is drilling fluid, the second fluid is plugging fluid containing large-diameter bridging particles, and the third fluid is a solidifying fluid.

13. The method according to claim 12, characterized in that, The solidifying liquid includes gel cement mixture, resin cement mixture, quick-drying cement, or other solidifiable liquids.

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