Process method for pressure-controlled forced drilling in drilling water gushing process and application of process method

Abstract

The invention relates to a process method for pressure-controlled forced drilling in a drilling water gushing process, which comprises the following steps of: mounting a wellhead water gushing control device at a drilling wellhead, enabling a drill rod to touch gushing water in the drilling process, enabling the gushing water to rise along the drill rod to enter a middle pressure-bearing buffer bin, buffering the gushing water by the middle pressure-bearing buffer bin, and then entering a pressure-bearing buffer bin; the method comprises the following steps: discharging water from a water outlet of a lower variable-diameter three-way assembly, forcibly drilling to a water-bearing stratum to penetrate, continuously drilling under the protection of a wellhead water gushing control device until the water-bearing stratum is completely penetrated, stopping drilling after the water-bearing stratum is drilled, putting a sleeve to a target depth, sealing an outer annulus of an annulus surface sleeve by adopting a cementing process, isolating the water-bearing stratum, and stopping drilling after the water-bearing stratum is completely penetrated. In conclusion, the well mouth water burst control device has the advantages of being good in sealing effect, capable of reducing friction loss, long in service life, high in construction efficiency, low in price and cost and suitable for large-scale popularization.

Description

Technical Field

[0001] The present invention belongs to the technical field of coal mine production equipment, and in particular relates to a process method for pressure-controlled forced drilling during water gushing during drilling and an application thereof. Background Art

[0002] In coal mine production activities, since there are often aquifers in the surrounding rocks of coal seams, as the coal seams are mined, the formation pressure changes, which will cause the pressurized water in the surrounding rock aquifers to penetrate into the coal seams. In severe cases, it may cause mine water inrush accidents, resulting in heavy casualties and huge economic losses. In order to ensure the safe production of coal mines and reduce the risk of water inrush, we follow the principle of "prediction and forecast, exploration when in doubt, exploration before excavation, and treatment before mining". Regional water hazard control is carried out on the planned mining working face before mining. The control method is mainly to first drill and explore the corresponding fracture zones and water conduction zones, collect formation data, evaluate hydrogeological conditions, and then reinforce the upper and lower aquicludes of the coal seam through ground directional horizontal drilling and grouting to enhance its water-isolating capacity, thereby reducing the risk of pressurized water intrusion into the coal seam and effectively achieving the effect of regional water hazard control.

[0003] However, there are still many problems. First of all, during the drilling construction process, affected by mining activities and geological structures, the borehole is very likely to encounter a broken zone, resulting in water gushing. Water gushing not only threatens the safety of drilling construction, but also affects the grouting effect. The current solution in the industry is usually to use high-density mud to balance the wellbore pressure or cement sealing to deal with the water gushing problem. Although these methods can alleviate the impact of water gushing on construction to a certain extent, there are the following defects: 1. Affecting the judgment of aquifers. High-density mud or cement sealing may cover up the true situation of the aquifer, resulting in the inability to accurately identify the aquifer and the aquiclude, thereby affecting the subsequent treatment effect; 2. Limited treatment effect: If the aquifer is not effectively sealed, the grouting treatment project may fail and the risk of water inrush cannot be truly reduced; 3. Low construction efficiency: Traditional methods require frequent drilling stops to deal with water gushing, which seriously affects the construction progress.

[0004] To address the above issues, the existing technology lacks a device that can effectively control water inflow while ensuring drilling safety and treatment effectiveness. In particular, when the water inflow is less than 60m³ / h, the water pressure is less than 1.5MPa, and there is no other overflow, there is an urgent need for a process method and application for pressure-controlled drilling during water inflow. This method can effectively control water inflow while ensuring drilling safety and treatment effectiveness, and solve the problems existing in the existing technology, such as the inability to monitor water pressure in real time, poor construction continuity, low construction efficiency, poor flood control results, and the inability to ensure the safety of coal mine water hazard treatment. Summary of the Invention

[0005] In view of this, the present invention proposes a process method for controlling pressure and forcing drilling during water gushing during drilling and its application, and applies the technical field of coal mine production equipment to solve the technical problems of being unable to monitor water pressure in real time, poor construction continuity, low construction efficiency, poor flood control effect and inability to ensure the safety of coal mine water hazard control projects during the drilling process. It has high application and promotion value.

[0006] In order to achieve the above technical objectives, the specific technical solutions adopted by the present invention are: A process for pressure-controlled forced drilling during water gushing in a well, comprising: S1. Install the wellhead water inflow control device at the drilling wellhead. The wellhead water inflow control device includes an upper sealing assembly, a middle pressure buffer chamber, and a lower reducing tee assembly. Install them in sequence from bottom to top. Pass the drill pipe through the wellhead from top to bottom to install the water inflow control device. S2. During the drilling process, the drill pipe encounters gushing water, which rises along the drill pipe and enters the middle pressure buffer chamber. After being buffered by the middle pressure buffer chamber, the water is discharged from the outlet of the lower reducing tee assembly. S3. Drilling is performed forcefully until the aquifer is penetrated. Drilling is continued under the protection of the wellhead water inflow control device until the aquifer is completely penetrated. During the penetration of the aquifer, the flow control valve provided inside the lower reducing tee assembly is used to control the water inflow pressure inside the wellhead water inflow control device to prevent wellbore instability. S4. After drilling through the aquifer, stop drilling, lower the casing to the target depth, and use cementing technology to seal the annulus outside the annulus casing to isolate the aquifer and prevent pressurized water from seeping into the coal seam during subsequent mining; S5. After confirming that the cement has solidified and reached the required strength, remove the wellhead water inrush control device and continue drilling or grouting treatment operations to ensure the reinforcement effect of the coal seam roof and floor aquifers.

[0007] Furthermore, before installing the wellhead water inflow control device at the wellhead in step S1, a preliminary estimate of the water inflow problem encountered during the drilling process is made. If the water inflow volume is less than 60m³ / h and the water inflow pressure is less than 1.5MPa, subsequent installation work is carried out.

[0008] Furthermore, two tapered hollow rubber plugs are provided in the upper sealing assembly in step S2, and the hollow rubber plugs include a hollow upper plug and a hollow lower plug. An elastic side edge is provided between the hollow upper capsule and the hollow lower capsule, which are connected to the top of the middle pressure buffer chamber through the elastic side edge and the flange provided on the hollow rubber plug to ensure that the hollow upper plug and the hollow lower plug are tightly attached to the drill pipe under pressure, thereby achieving dynamic sealing and preventing wellhead gushing.

[0009] Furthermore, a pressure-bearing bearing flange is provided on the top of the middle pressure buffer chamber in step S2, and the pressure-bearing bearing flange is connected to the flange plate in the upper sealing assembly by bolts, so that the hollow upper rubber plug and the hollow lower rubber plug can rotate with the drill rod, reduce wear and extend service life.

[0010] Furthermore, the lower reducing tee assembly in step S3 includes a reducing tee pipe, the bottom of the reducing tee pipe is connected to an annular meter sleeve, the flow control valve is arranged at the water outlet position on one side of the bottom of the reducing tee pipe, and a pressure gauge is arranged on the top of the reducing tee pipe for real-time monitoring of water pressure to ensure construction safety.

[0011] Furthermore, the inner diameter of the reducing tee pipe gradually changes from 400 mm to the inner diameter length of the annulus sleeve, and the height difference between the outlet and the bottom end of the reducing tee pipe is 133 mm.

[0012] Furthermore, the reducing tee pipe is connected to the annulus sleeve through a tee pipe flange arranged on the outer ring of the bottom of the reducing tee pipe and a wellhead flange arranged on the top of the annulus sleeve. The drill pipe passes through the upper sealing assembly, the middle pressure buffer chamber, the reducing tee pipe and the annulus sleeve from top to bottom in sequence, and extends out from the bottom of the annulus sleeve.

[0013] Furthermore, the upper part of the drill pipe passes through the areas covered by the hollow upper rubber plug and the hollow lower rubber plug respectively during the process of passing through the upper sealing assembly, and the drill pipe is sealed by the hollow rubber plug. The diameters of the tee pipe flange and the wellhead flange are both 273 mm.

[0014] Furthermore, the middle pressure buffer bin adopts a steel structure with a length of 640 mm, an inner diameter of 405 mm and a wall thickness of 12 mm, and the pressure bearing flange is arranged at a height of 40 mm at the top of the middle pressure buffer bin.

[0015] A process for controlling pressure and forcing drilling during water gushing during drilling as described above is applied in coal seam drilling and mining.

[0016] By adopting the above technical solution, the present invention can also bring the following beneficial effects: 1. The present invention mentions a process method for controlling pressure and forcing drilling during water gushing in drilling and its application. Dynamic adaptive sealing is achieved under the rotating state of the drill pipe through a double-rubber plug-bearing flange collaborative sealing structure. The hollow rubber plug is tightly fitted to the drill pipe through elastic deformation to form a pressure-enhanced sealing surface. The hollow rubber plug is supported by a pressure-bearing bearing flange to rotate synchronously with the drill pipe, thereby reducing friction loss, extending the life of the seal, and completely solving the leakage problem of traditional static seals caused by drill pipe vibration. The sealing reliability is significantly improved, and the method has the advantages of good sealing effect, reduced friction loss, long service life and very convenient operation.

[0017] 2. The present invention mentions a process method for controlling pressure and forcing drilling during drilling water gushing and its application. An active pressure balance mechanism is constructed by a pressure gauge and a flow control valve. The pressure gauge feeds back water pressure data in real time, and the flow control valve is combined to dynamically adjust the drainage volume to control the wellbore pressure fluctuation within the range of ±0.1MPa, avoiding well wall collapse or aggravated water gushing caused by pressure imbalance. It not only reduces the consumption of plugging materials, but also does not interfere with the permeability identification of the aquifer. It has the advantages of being able to monitor water pressure in real time, low construction risk and high water control safety performance.

[0018] 3. The present invention mentions a process method for controlling pressure and forcing drilling during water gushing during drilling and its application. Through the middle pressure-bearing buffer chamber and the lower reducer tee assembly, drilling and water gushing control are carried out simultaneously while ensuring safety. It can not only effectively reduce the cost of stopping drilling, but also effectively shorten the cycle. By reducing the pressure change of water gushing, the risk of drill sticking is reduced. Moreover, subsequent continuous drilling does not affect the judgment of the aquifer, ensuring the accuracy of subsequent grouting and plugging. It has the advantages of continuous construction, high construction efficiency, low price cost and suitability for large-scale promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0020] Figure 1 This is a flowchart of a process method for pressure-controlled forced drilling during water gushing in a well according to the present invention; Figure 2 Schematic diagram of the structure of the wellhead water inrush control device in Example 1 of the present invention; 1. Upper sealing assembly; 2. Middle pressure buffer chamber; 3. Flow control valve; 4. Hollow upper rubber plug; 5. Hollow lower rubber plug; 6. Flange; 7. Pressure bearing flange; 8. Drill pipe; 9. Reducer tee pipe; 10. Annular gauge sleeve; 11. Pressure gauge; 12. Water outlet; 13. T-pipe flange; 14. Wellhead flange. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] The following describes the embodiments of the present invention through specific examples. Those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on the present invention, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.

[0024] It should also be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. The illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0025] Additionally, in the following description, specific details are provided to provide a thorough understanding of the examples. However, one skilled in the art will appreciate that the aspects described can be practiced without these specific details. Example

[0026] like Figure 1 and Figure 2 As shown, a process for pressure-controlled forced drilling during water gushing in a well, comprising: S1. Install the wellhead water inflow control device at the drilling wellhead. The wellhead water inflow control device includes an upper sealing assembly, a middle pressure buffer chamber, and a lower reducing tee assembly. Install them in sequence from bottom to top. Pass the drill pipe through the wellhead from top to bottom to install the water inflow control device. S2. During the drilling process, the drill pipe encounters gushing water, which rises along the drill pipe and enters the middle pressure buffer chamber. After being buffered by the middle pressure buffer chamber, the water is discharged from the outlet of the lower reducing tee assembly. S3. Drilling is performed forcefully until the aquifer is penetrated. Drilling is continued under the protection of the wellhead water inflow control device until the aquifer is completely penetrated. During the penetration of the aquifer, the flow control valve provided inside the lower reducing tee assembly is used to control the water inflow pressure inside the wellhead water inflow control device to prevent wellbore instability. S4. After drilling through the aquifer, stop drilling, lower the casing to the target depth, and use cementing technology to seal the annulus outside the annulus casing to isolate the aquifer and prevent pressurized water from seeping into the coal seam during subsequent mining; S5. After confirming that the cement has solidified and reached the required strength, remove the wellhead water inrush control device and continue drilling or grouting treatment operations to ensure the reinforcement effect of the coal seam roof and floor aquifers.

[0027] In step S1, before installing the wellhead water inflow control device at the wellhead, a preliminary estimate of the water inflow problem encountered during the drilling process is made. If the water inflow is less than 60m³ / h and the water inflow pressure is less than 1.5MPa, subsequent installation work is carried out.

[0028] Two tapered hollow rubber plugs are provided in the upper sealing assembly in step S2. The hollow rubber plugs include a hollow upper plug and a hollow lower plug. An elastic side edge is provided between the hollow upper capsule and the hollow lower capsule. The elastic side edge and the flange provided on the hollow rubber plug are connected to the top of the middle pressure buffer chamber to ensure that the hollow upper plug and the hollow lower plug are tightly attached to the drill pipe under pressure to achieve dynamic sealing and prevent wellhead gushing.

[0029] A pressure-bearing bearing flange is provided at the top of the middle pressure-bearing buffer bin in step S2, and the pressure-bearing bearing flange is connected to the flange plate in the upper sealing assembly by bolts, so that the hollow upper rubber plug and the hollow lower rubber plug can rotate with the drill pipe, reduce wear and extend service life. The drill pipe rotates, reduces wear and extends service life. The middle pressure-bearing buffer bin adopts a steel structure with a length of 640mm, an inner diameter of 405mm and a wall thickness of 12mm. The pressure-bearing bearing flange is arranged at a height of 40mm at the top of the middle pressure-bearing buffer bin.

[0030] The lower reducing tee assembly in step S3 includes a reducing tee pipe, the bottom of which is connected to an annulus cover, a flow control valve is provided at the water outlet position on one side of the bottom of the reducing tee pipe, and a pressure gauge is provided at the top of the reducing tee pipe for real-time monitoring of water pressure to ensure construction safety. The inner diameter of the reducing tee pipe gradually changes from 400mm to the inner diameter length of the annulus cover, and the height difference between the water outlet and the bottom end of the reducing tee pipe is 133mm. The reducing tee pipe is connected to the annulus cover through a tee pipe flange provided on the outer ring of the bottom of the reducing tee pipe and a wellhead flange provided on the top of the annulus cover. The drill pipe passes through the upper sealing assembly, the middle pressure buffer chamber, the reducing tee pipe and the annulus cover from top to bottom, and extends from the bottom of the annulus cover. The upper part of the drill pipe passes through the areas covered by the hollow upper rubber plug and the hollow lower rubber plug in the process of passing through the upper sealing assembly, and the drill pipe is sealed by the hollow rubber plug. The diameters of the tee pipe flange and the wellhead flange are both 273mm.

[0031] The present invention also relates to a process method for controlling pressure and forcing drilling during drilling water gushing, and its application in coal seam drilling and mining. In short, the present invention has the advantages of good sealing effect, reduced friction loss, long service life, high construction efficiency, low price cost and suitability for large-scale promotion.

[0032] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included in the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A process for pressure-controlled forced drilling during water gushing in a well, characterized in that: include: S1. Install a wellhead water inflow control device at the wellhead. The wellhead water inflow control device includes an upper sealing assembly, a middle pressure buffer chamber, and a lower reducing tee assembly. The devices are installed sequentially from bottom to top. The drill pipe is passed through the wellhead from top to bottom to install the water inflow control device. S2. During the drilling process, the drill pipe encounters gushing water, which rises along the drill pipe and enters the middle pressure buffer chamber. After being buffered by the middle pressure buffer chamber, the water is discharged from the outlet of the lower reducing tee assembly. S3. Drilling is performed forcefully until the aquifer is penetrated. Drilling is continued under the protection of the wellhead water inflow control device until the aquifer is completely penetrated. During the penetration of the aquifer, the flow control valve provided inside the lower reducing tee assembly is used to control the water inflow pressure inside the wellhead water inflow control device to prevent wellbore instability. S4. After drilling through the aquifer, stop drilling, lower the casing to the target depth, and use cementing technology to seal the annulus outside the casing to isolate the aquifer and prevent pressurized water from seeping into the coal seam during subsequent mining; S5. After confirming that the cement has solidified and reached the required strength, remove the wellhead water inrush control device and continue drilling or grouting treatment operations to ensure the reinforcement effect of the coal seam roof and floor aquifers.

2. The process for pressure-controlled forced drilling during water gushing during drilling according to claim 1, characterized in that: In step S1, before installing the wellhead water inflow control device at the wellhead, a preliminary estimate of the water inflow problem encountered during the drilling process is made. If the water inflow is less than 60m³ / h and the water inflow pressure is less than 1.5MPa, subsequent installation work is carried out.

3. The process for pressure-controlled forced drilling during water gushing in a well according to claim 2, characterized in that: Two tapered hollow rubber plugs are provided in the upper sealing assembly in step S2. The hollow rubber plugs include a hollow upper plug and a hollow lower plug. An elastic side edge is provided between the hollow upper capsule and the hollow lower capsule. The elastic side edge and the flange provided on the hollow rubber plug are connected to the top of the middle pressure buffer chamber to ensure that the hollow upper plug and the hollow lower plug are tightly attached to the drill pipe under pressure to achieve dynamic sealing and prevent wellhead gushing.

4. The process for pressure-controlled forced drilling during water gushing in a well according to claim 3, characterized in that: A pressure-bearing bearing flange is provided on the top of the middle pressure-bearing buffer bin in step S2, and the pressure-bearing bearing flange is connected to the flange plate in the upper sealing assembly by bolts, so that the hollow upper rubber plug and the hollow lower rubber plug can rotate with the drill rod, reduce wear and extend service life.

5. The process for pressure-controlled forced drilling during water gushing in a well according to claim 3, characterized in that: The lower reducing tee assembly in step S3 includes a reducing tee pipe, the bottom of which is connected to an annular meter sleeve, the flow control valve is arranged at the water outlet position on one side of the bottom of the reducing tee pipe, and a pressure gauge is arranged on the top of the reducing tee pipe for real-time monitoring of water pressure to ensure construction safety.

6. The process for pressure-controlled forced drilling during water gushing in a well according to claim 1, characterized in that: The inner diameter of the reducing tee pipe gradually changes from 400 mm to the inner diameter length of the annular sleeve, and the height difference between the water outlet and the bottom end of the reducing tee pipe is 133 mm.

7. The process for pressure-controlled forced drilling during water gushing in a well according to claim 6, characterized in that: The reducing tee pipe is connected to the annulus sleeve through a tee pipe flange arranged on the outer ring of the bottom of the reducing tee pipe and a wellhead flange arranged on the top of the annulus sleeve. The drill pipe passes through the upper sealing assembly, the middle pressure buffer chamber, the reducing tee pipe and the annulus sleeve from top to bottom in sequence and extends out from the bottom of the annulus sleeve.

8. The process for pressure-controlled forced drilling during water gushing in a well according to claim 7, characterized in that: The upper part of the drill pipe passes through the areas covered by the hollow upper rubber plug and the hollow lower rubber plug respectively during the process of passing through the upper sealing assembly, and the drill pipe is sealed by the hollow rubber plug. The diameters of the three-way pipe flange and the wellhead flange are both 273 mm.

9. The process for pressure-controlled forced drilling during water gushing during drilling according to claim 8, characterized in that: The middle pressure-bearing buffer bin adopts a steel structure with a length of 640 mm, an inner diameter of 405 mm and a wall thickness of 12 mm. The pressure-bearing bearing flange is arranged at a height of 40 mm at the top of the middle pressure-bearing buffer bin.

10. Application of the process method for pressure-controlled forced drilling during water gushing during drilling as claimed in claim 1 in coal seam drilling and mining.

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