Casing drilling tool and casing drilling and completion method

Abstract

The invention belongs to the technical field of oil and gas drilling, and particularly relates to a casing drilling tool and a drilling and completion method. The casing drilling tool comprises a casing string, a bypass short section, a drilling tool and a drill bit which are sequentially connected from top to bottom, and in a first state, the bypass short section is constructed to be axially communicated, so that fluid in the casing string can sequentially pass through the bypass short section, the drilling tool and the drill bit in the axial direction to enter a well wall annulus; and in the second state, the bypass short section is configured to be communicated in the radial direction, so that fluid in the casing string can flow into the well wall annulus in the radial direction through the bypass short section. After well drilling is finished, cement paste can be pumped to implement well cementation operation without drilling off a drill bit.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas drilling, and specifically, relates to a casing drilling tool and a casing drilling and completion method. Background Art

[0002] Casing drilling technology can complete drilling, casing running, and cementing operations simultaneously in one drilling process. It can not only greatly reduce the drilling cost and speed up the completion speed, but also significantly reduce the potential accident hazards existing in conventional drilling technology, such as wellbore collapse and wellbore wall erosion. It can also reduce the drilling time wasted due to reaming and handling well kicks during tripping. In addition, the drilling fluid can continuously circulate during casing drilling, so it is safer than conventional drilling technology where the drilling fluid does not circulate during tripping. As an effective means to reduce the non - productive time of traditional drilling, the use of casing drilling has obvious economic benefits. More importantly, it can meet the requirements of safety and the environment and has broad application prospects.

[0003] Casing drilling technology is mainly divided into two categories: retrievable bottom hole assembly casing drilling technology and non - retrievable casing drilling technology.

[0004] The retrievable casing drilling system includes the bottom hole assembly at the bottom of the casing string, the pilot bit and the reamer, as well as the wire rope for retrieving and replacing the bottom hole assembly and the bit. Applying this system can drill not only vertical wells but also directional wells.

[0005] The non - retrievable casing drilling system uses a drillable bit connected to the bottom of the casing string to drill a vertical wellbore. Since the channel for circulating the drilling fluid in the drillable bit is too small to be used for pumping cement slurry, after the drilling is completed, the non - retrievable casing drilling system needs to trip in again to drill through the drillable bit at the bottom of the casing string before it can pump cement slurry to complete the cementing operation.

[0006] The present invention provides a new non - retrievable casing drilling and completion tool system and a drilling and completion method, which can save the time for drilling out the bit. Summary of the Invention

[0007] Aiming at the above - mentioned technical problems, the present invention aims to provide a casing drilling tool that can pump cement slurry for cementing operation without drilling out the bit after the drilling is completed.

[0008] The present invention also proposes a casing drilling and completion method, which can pump cement slurry without drilling out the bit after the drilling is completed to implement the cementing operation, thereby saving construction time and accelerating the construction progress.

[0009] According to the present invention, a casing drilling tool is provided, which includes a casing string, a bypass sub, a drill string, and a drill bit connected in sequence from top to bottom. In the first state, the bypass sub is configured to be axially connected, so that the fluid in the casing string can axially pass through the bypass sub, the drill string, and the drill bit in sequence and enter the wellbore annulus; in the second state, the bypass sub is configured to be radially connected, so that the fluid in the casing string can radially flow into the wellbore annulus through the bypass sub.

[0010] In a specific embodiment, the bypass sub includes:

[0011] a housing, on the side wall of which a bypass hole is provided; and

[0012] a sliding sleeve arranged in the housing through a pin, and the sliding sleeve closes the bypass hole;

[0013] the sliding sleeve is configured to be able to move downward relative to the housing after a ball is dropped and pressure is applied, so as to open the bypass hole.

[0014] In a specific embodiment, a check and setting key tool is arranged between the casing string and the bypass sub. In the first state, a measurement-while-drilling instrument is arranged in the check and setting key tool. In the second state, a check valve is arranged in the check and setting key tool.

[0015] In a specific embodiment, the check and setting key tool includes a body, a positioning cylinder is arranged inside the body, and a plurality of grooves are arranged along the axial direction on the inner wall of the body, and the grooves are arranged above the positioning cylinder.

[0016] In a specific embodiment, the check valve includes:

[0017] a valve body, an internal flow channel is arranged axially in the valve body, and a blocking ball is arranged in the internal flow channel;

[0018] a valve seat arranged at the lower end of the valve body, and a spring is arranged between the valve seat and the blocking ball;

[0019] The fluid flowing downward in the internal flow channel can push the blocking ball downward, so as to open the internal flow channel. The fluid flowing upward in the internal flow channel cannot push the blocking ball, so the internal flow channel cannot be opened.

[0020] In a specific embodiment, at least one first valve through hole is arranged on the side surface of the valve body, and the first valve through hole is located below the blocking ball.

[0021] In a specific embodiment, a nut, a sliding seat, and a rubber cylinder are sequentially arranged from top to bottom on the outside of the valve body. The nut is fixedly arranged at the upper end of the valve body. The upper end of the sliding seat abuts against the nut. The upper end of the rubber cylinder abuts against the sliding seat. A slider is arranged on the outside of the sliding seat, and the upper end of the slider abuts against the nut.

[0022] In a specific embodiment, the outer wall of the sliding seat and the inner wall of the slider are arranged as mutually adapted inclined surfaces, and a plurality of teeth are arranged on the outer wall of the slider.

[0023] According to the present invention, a casing drilling and completion method is also provided. Using the casing drilling tool provided by the present invention, after the drilling is completed, an opening ball is put into the bypass sub and pressured, so that the bypass sub is radially communicated with the annulus between the wellbore wall and the casing. Cement slurry is pumped into the annulus between the wellbore wall and the casing through the bypass sub to complete well cementing.

[0024] In a specific embodiment, after the drilling is completed, the measurement-while-drilling instrument in the check valve setting tool is salvaged. An opening ball is put into the bypass sub and pressured. After the bypass sub is radially communicated, a check valve is put into the check valve setting tool, and cement slurry is pumped and left to set to complete well cementing.

[0025] Compared with the prior art, the advantages of the present application are as follows.

[0026] The casing drilling tool of the present invention includes a casing string, a bypass sub, a drill string, and a drill bit that are sequentially arranged from top to bottom. During the drilling process, the casing string, the bypass sub, the drill string, and the drill bit are axially communicated, so that the drilling fluid can circulate normally. After the drilling is completed, the bypass sub can be radially communicated with the annulus between the wellbore wall and the casing, thereby providing a channel for pumping cement slurry and saving the time for drilling out the drill bit.

[0027] In addition, compared with the prior art method of drilling out the drill bit, the present invention only needs to complete the radial communication between the bypass sub and the annulus between the wellbore wall and the casing by the method of putting a ball and pressurizing. The operation is simple, the safety is high, and it is not easy to have downhole accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be described below with reference to the accompanying drawings.

[0029] Figure 1 Shows a schematic diagram of an embodiment of the casing drilling tool according to the present invention in the first state;

[0030] Figure 2 Shows a schematic diagram of an embodiment of the casing drilling tool according to the present invention in the second state;

[0031] Figure 3A schematic diagram showing an embodiment of a non-return key tool according to the present invention is shown;

[0032] Figure 4 Shows Figure 3 A partial enlarged schematic diagram of point Ⅰ in the middle;

[0033] Figure 5 A schematic diagram showing an embodiment of a check valve according to the present invention;

[0034] Figure 6 Shows Figure 5 Cross-sectional view at AA in the middle;

[0035] Figure 7 Shows Figure 5 A partial enlarged schematic diagram of point II in the middle;

[0036] Figure 8 A schematic diagram showing an embodiment of a bypass sub according to the present invention is shown.

[0037] 20. Casing string; 1. Coupling; 2. First casing;

[0038] 3. Straighten the short joint;

[0039] 4. Check key tool; 41. Main body; 411. Second cylindrical section; 412. Second joint section; 413. First cylindrical surface; 414. Second cylindrical surface; 415. Limiting conical surface; 42. Positioning cylinder; 421. Helical surface; 422. First hole; 423. Second hole; 43. Groove;

[0040] 5. Second casing;

[0041] 6. Bypass sub; 61. Sliding sleeve; 62. Bypass hole; 63. Housing; 631. First cylinder section; 632. First joint section; 64. Opening ball;

[0042] 7. Back pressure valve; 8. Drilling tools; 9. Drill bit;

[0043] 10. Check valve; 101. Nut; 102. Slider; 103. Sliding seat; 104. Rubber cartridge; 105. Valve body; 1051. First valve section; 1052. Second valve section; 106. Sealing ball; 107. Spring; 108. Valve seat; 109. Conical surface; 110. First valve through hole; 111. Second valve through hole; 112. Internal flow channel;

[0044] 11. Measurement while drilling instrument;

[0045] 100. Casing drilling tools.

[0046] In this application, all drawings are schematic drawings, which are only used to illustrate the principles of the present invention and are not drawn to scale. Detailed implementation manners

[0047] The present invention will be introduced below with reference to the accompanying drawings.

[0048] It should be noted that in this application, the direction close to the bottom of the well after the casing drilling tool of the present invention enters the well is described as "down" or similar terms, and the direction away from the bottom of the well after the casing drilling tool enters the well is described as "up" or similar terms.

[0049] Figure 1 The structure of the casing drilling tool 100 according to the present invention is shown. As Figure 1 shown, the casing drilling tool 100 includes a casing string 20, a centralizer sub 3, a check and setting key tool 4, a second casing 5, a bypass sub 6, a backpressure valve 7, a drill string 8 and a drill bit 9 that are coaxially connected in sequence from top to bottom. Among them, the casing string 20 can apply torque and downward pressure to the drill bit 9, so as to drill the formation. In a preferred embodiment, the drill string 8 is a positive displacement motor.

[0050] In the first state, the bypass sub 6 is configured to be axially connected. Specifically, as Figure 1 shown, the inner cavities of the casing string 20, the bypass sub 6, the drill string 8 and the drill bit 9 are axially connected to each other. During the drilling process, the drilling fluid on the ground can flow downward along the casing string 20, the bypass sub 6, the drill string 8 and the drill bit 9 in sequence, and then enter the annulus between the casing drilling tool 100 and the wellbore through the drill bit 9 and return to the ground, taking the debris generated by the drill bit drilling out of the well.

[0051] In the second state, the bypass sub 6 is configured to be radially connected. Specifically, as Figure 2 shown, the bypass sub 6 is radially connected to the annulus. At this time, when the fluid flows from the casing drilling tool 100 to the annulus, the fluid does not need to pass through the drill string 8 and the drill bit 9 anymore, and only needs to pass through the bypass sub 6 to radially flow to the annulus.

[0052] With this setting of the present invention, during the drilling process, the bypass sub 6 is in the first state for circulating the drilling fluid. After the drilling is completed, during the cementing process, the bypass sub 6 is in the second state for pumping the cement slurry. In this way, when using the casing drilling tool 100 provided by the present invention for cementing, it is not necessary to lower the drill again to drill out the drill bit 9, but to open a bypass hole 62 that can be used for the cement slurry to flow to the annulus at the bypass sub 6, thereby saving construction time.

[0053] In this embodiment, as Figure 8As shown, the bypass sub 6 includes a housing 63 and a sliding sleeve 61. Among them, the housing 63 is set to be generally cylindrical in shape, and at least one bypass hole 62 is provided on the side of the housing 63. There is no specific requirement for the size of the bypass hole 62, as long as the cement slurry can flow smoothly under a certain pumping pressure. The sliding sleeve 61 is set to be generally cylindrical in shape. In the first state, the sliding sleeve 61 is coaxially fixedly sleeved inside the housing 63 by shear pins or other means, thereby blocking the bypass hole 62. When cementing is required after drilling is completed, the bypass sub 6 can be converted to the second state. Specifically, as Figure 2 shown, an opening ball 64 is dropped above the sliding sleeve 61. The opening ball 64 blocks the sliding sleeve 61. At this time, when pressure is pumped from the wellhead to the casing drilling tool 100, it can push the sliding sleeve 61 to move downward, thereby opening the bypass hole 62 and converting the bypass sub 6 to the second state. The opened bypass hole 62 can be used for the flow of cement slurry during the cementing process.

[0054] In a specific embodiment, as Figure 8 shown, the housing 63 includes a first cylinder section 631 and a first joint section 632 that are coaxially fixedly connected. Among them, the outer diameter of the first cylinder section 631 is larger than the outer diameter of the first joint section 632, and an external thread for connecting to the downhole tool below is provided on the outer wall of the first joint section 632. The inner diameter of the first cylinder section 631 is larger than the inner diameter of the first joint section 632, and the sliding sleeve 61 is arranged inside the first cylinder section 631. That is to say, the outer diameter of the sliding sleeve 61 is adapted to the inner diameter of the first cylinder section 631. When a ball is dropped onto the sliding sleeve 61 and pressure is applied, the sliding sleeve 61 can move downward relative to the first cylinder section 631. When the sliding sleeve 61 moves to the first joint section 632, the lower end face of the sliding sleeve 61 axially abuts against the upper end face of the first joint section 632.

[0055] In a preferred embodiment, the upper end portion of the inner cavity of the sliding sleeve 61 is set to be a conical surface, so as to better seal and cooperate with the opening ball 64.

[0056] According to the present invention, in a specific embodiment, the casing string 20 includes a first casing 2 and a coupling 1. Among them, the first casing 2 is a drilling-type casing, and the coupling 1 is a drilling-type coupling. The casing string 20 can provide torque and downward pressure to the drill bit 9 below. Further, the casing string 20 includes a plurality of first casings 2, and adjacent first casings 2 are connected by couplings 1. By providing a plurality of first casings 2, the length of the casing string 20 can be increased, so as to adapt to different drilling depths.

[0057] In a preferred embodiment, the casing drilling tool 100 further includes a centralizer sub 3, and the centralizer sub 3 is coaxially fixed at the lower end of the casing string 20. In this embodiment, as Figure 1As shown, an internal thread is provided at the upper end of the centralizing sub 3, and an external thread is provided at the lower end of the first casing 2. The centralizing sub 3 and the first casing 2 are fixedly connected by means of threaded connection. By providing the centralizing sub 3, the casing drilling tool 100 can always be kept in the central position in the well.

[0058] In a preferred embodiment, the casing drilling tool 100 further includes a check and setting key tool 4, and the check and setting key tool 4 is coaxially and fixedly arranged at the lower end of the centralizing sub 3. In this embodiment, as Figure 1 shown, an external thread is provided at the lower end of the centralizing sub 3, and an internal thread is provided at the upper end of the check and setting key tool 4. The centralizing sub 3 and the check and setting key tool 4 are fixedly connected by means of threaded connection. The check and setting key tool 4 can provide an installation space for the measurement-while-drilling instrument 11 and the check valve 10, and facilitate the installation of the measurement-while-drilling instrument 11 and the check valve 10. In the first state, as Figure 1 shown, the measurement-while-drilling instrument 11 is arranged in the check and setting key tool 4. In the second state, as Figure 2 shown, the check valve 10 is arranged in the check and setting key tool 4.

[0059] The structure of the check and setting key tool 4 in this embodiment is as Figure 3 shown. The check and setting key tool 4 includes a body 41 and a positioning cylinder 42.

[0060] Among them, the body 41 is integrally in the shape of a cylindrical barrel, and the body 41 includes a second barrel section 411 and a second joint section 412 that are coaxially and fixedly connected. The outer diameter of the second barrel section 411 is larger than the outer diameter of the second joint section 412, and an external thread for connecting with the downhole tool below is provided on the outer wall of the second joint section 412. The inner diameter of the second barrel section 411 is larger than the inner diameter of the second joint section 412. The positioning cylinder 42 is arranged in the second barrel section 411, and the lower end surface of the positioning cylinder 42 axially abuts against the upper end surface of the second joint section 412. A spiral surface 421 is provided at the upper end of the positioning cylinder 42, and the spiral surface 421 can play a role in orienting the downhole tool adapted to the positioning cylinder 42. In the first state, the measurement-while-drilling instrument 11 is arranged in the check and setting key tool 4 and is oriented through the spiral surface 421 of the positioning cylinder 42, and then the measurement work is carried out.

[0061] In a preferred embodiment, the inner cavity of the positioning cylinder 42 includes a first hole 422 and a second hole 423 that are coaxially communicated. The first hole 422 is arranged above the second hole 423, the aperture of the first hole 422 is larger than the aperture of the second hole 423, and the first hole 422 and the second hole 423 are connected by a tapered surface in a transitional manner. During the drilling process, the first hole 422 and the second hole 423 are used to place the measurement-while-drilling instrument 11, and during the pumping of the cement slurry for well cementing, the first hole 422 and the second hole 423 provide a channel for the cement slurry for well cementing.

[0062] A plurality of grooves 43 are sequentially arranged along the axial direction on the inner wall of the second cylinder section 411. The grooves 43 are arranged above the positioning cylinder 42 and are used to be adapted to the slider 102 of the check valve 10. The specific structure of the check valve 10 is described in detail below. In this embodiment, the groove 43 is arranged as a triangular groove, and the adjacent grooves 43 are arranged at equal intervals.

[0063] In a preferred embodiment, the inner wall of the second cylinder section 411 includes a first cylindrical surface 413 at the upper part, a limiting conical surface 415, and a second cylindrical surface 414 at the lower part. The diameter of the first cylindrical surface 413 is larger than that of the second cylindrical surface 414. Among them, the groove 43 is arranged on the first cylindrical surface 413, and the positioning cylinder 42 is arranged within the range of the second cylindrical surface 414. In the second state, the limiting conical surface 415 is used to limit the further downward movement of the check valve 10.

[0064] In this embodiment, an internal thread for connecting with the centralizer sub 3 is arranged at the upper end of the second cylinder section 411.

[0065] It is easy to understand that the structure of the measurement-while-drilling instrument 11 is well-known to those skilled in the art and will not be described in detail here.

[0066] As Figure 5 shown, in this embodiment, the check valve 10 includes a valve body 105, a plugging ball 106, a spring 107, and a valve seat 108.

[0067] In this embodiment, an internal flow channel 112 is arranged along the axial direction in the valve body 105, and the plugging ball 106 is located in the internal flow channel 112. Specifically, the valve body of the valve body includes a first valve section 1051 and a second valve section 1052. The first valve section 1051 is located above the second valve section 1052, and the inner diameter of the first valve section 1051 is smaller than that of the second valve section 1052. The inner cavities of the first valve section 1051 and the second valve section 1052 are both part of the internal flow channel 112. The plugging ball 106 is axially movably arranged in the second valve section 1052, and the diameter of the plugging ball 106 is larger than the inner diameter of the first valve section 1051. The valve seat 108 is fixedly arranged at the lower end of the valve body 105. A second valve through hole 111 communicating with the inner cavity of the second valve section 1052 is arranged in the valve seat 108. The spring 107 is arranged between the valve seat 108 and the plugging ball 106. In the absence of external force, the spring 107 radially abuts against the plugging ball 106, so that the plugging ball 106 is sealed with the lower end of the first valve section 1051. Through this setting, the check valve 10 only allows the fluid to flow from top to bottom and cannot flow from bottom to top.

[0068] The outer shape of the valve body 105 is configured to be insertable into the check valve seating key tool 4. Specifically, the outer diameter of the first valve section 1051 is larger than that of the second valve section 1052, and the outer walls of the first valve section 1051 and the second valve section 1052 are transitionally connected through a conical surface 109. In this setting, after the check valve 10 is in place in the check valve seating key tool 4, the second valve section 1052 enters the range of the second cylindrical surface 414, and the first valve section 1051 is located within the range of the first cylindrical surface 413. The conical surface 109 contacts the limiting conical surface 415, and the limiting conical surface 415 restricts the further downward movement of the check valve 10.

[0069] In a preferred embodiment, at least one first valve through-hole 110 is provided on the side surface of the second valve section 1052, and the first valve through-hole 110 is located below the plug ball 106. When the plug ball 106 moves downward to open the lower end of the inner cavity of the first valve section 1051, the first valve through-hole 110 communicates with the inner cavity of the first valve section 1051. Since the plug ball 106 is always located above the second valve through-hole 111, the flow area of the second valve through-hole 111 is relatively small. Therefore, in this embodiment, the first valve through-hole 110 is provided on the side surface of the second valve section 1052. When the plug ball 106 is pushed downward by the fluid, the plug ball 106 can move below the first valve through-hole 110, thereby increasing the flow area of the fluid. During well cementing, the fluid mainly flows through the first valve through-hole 110.

[0070] In a preferred embodiment, a nut 101, a sliding seat 103, a sliding block 102, and a rubber cylinder 104 are sequentially arranged on the outside of the valve body 105 from top to bottom.

[0071] Specifically, a step is provided on the outside of the first valve section 1051, that is, the outer diameter of the upper part of the first valve section 1051 is smaller than that of the lower part. A nut 101 is fixedly arranged at the upper end of the first valve section 1051, and the outer diameter of the nut 101 is equal to the outer diameter of the lower part of the first valve section 1051. The sliding seat 103 and the rubber cylinder 104 are sequentially sleeved on the outside of the step of the first valve section 1051 from top to bottom, and the upper end of the sliding seat 103 abuts against the lower end of the nut 101, the lower end of the sliding seat 103 abuts against the upper end of the rubber cylinder 104, and the lower end of the rubber cylinder 104 abuts against the step end of the first valve section 1051.

[0072] A T-shaped groove for installing the sliding block 102 is provided on the outer wall of the sliding seat 103. The T-shaped groove forms an angle of 7° with the axis of the sliding seat 103, and the outer diameter of the upper part of the outer wall of the sliding seat 103 is smaller than that of the lower part. The upper end of the sliding block 102 abuts against the nut 101, and the inner wall of the sliding block 102 is provided with an inclined surface adapted to the T-shaped groove of the sliding seat 103. As Figure 7As shown, a plurality of triangular teeth are provided on the outer wall of the slider 102. The slider 102 is engaged with the groove 43 of the check seat key tool 4 through the teeth, so that the slider 102 can only move downward relative to the check seat key tool 4, preventing the slider 102 from moving upward relative to the check seat key tool 4.

[0073] By providing the slide base 103, the slider 102 and the rubber cylinder 104, the check valve 10 can strengthen the seal with the check seat key tool 4 after the cement slurry displacement is completed during pumping. After the displacement, due to the pump shutdown, the wellhead pressure is zero, and the pressure of the cement slurry column that has entered the wellbore annulus is greater than the pressure of the liquid column in the casing string 20. This pressure difference acts on the plugging ball 106, causing the check valve 10 to move upward. The teeth of the slider 102 enter the groove 43 of the check seat key tool 4, restricting the upward movement of the slider 102, so that the valve body 105 moves upward relative to the slider 102. During the upward movement of the valve body 105, it pushes the rubber cylinder 104 and the slide base 103 upward, causing the rubber cylinder 104 to be compressed, sealing the gap between the check valve 10 and the check seat key tool 4. Subsequently, the slide base 103 moves upward relative to the slider 102, causing the slider 102 to expand, strengthening the anchoring of the slider 102 to the check seat key tool 4. The greater the pressure difference between the cement slurry column and the liquid column in the casing string 20, the better the sealing effect, thereby preventing the cement slurry that has entered the wellbore annulus from flowing back into the casing string 20 through the bypass hole 62 of the bypass nipple 6 and the check valve 10.

[0074] In a specific embodiment, as Figure 6 shown, four sliders 102 are uniformly arranged on the outer wall of the slide base 103 along the circumferential direction.

[0075] In a preferred embodiment, the casing drilling tool 100 further includes a second casing 5, and the second casing 5 is coaxially fixed between the check seat key tool 4 and the bypass nipple 6. The logging-while-drilling tool 11 is relatively long, and it is suspended in the check seat key tool 4 from the upper part through the positioning cylinder 42 and extends all the way into the second casing 5. The second casing 5 is made of non-magnetic material because the probe of the logging-while-drilling tool 11 needs to work in a non-magnetic environment. Further, the wall thickness of the second casing 5 is greater than the wall thickness of the first casing 2 to protect the logging-while-drilling tool 11.

[0076] In a preferred embodiment, the casing drilling tool 100 further includes a backpressure valve 7, and the backpressure valve 7 is coaxially fixed between the bypass nipple 6 and the drill string 8. The backpressure valve 7 functions as a check valve, that is, the fluid can flow from top to bottom and cannot flow from bottom to top. Its main function is to prevent the cement slurry from flowing back to the drill floor when the wellhead is connected to the casing.

[0077] According to the present invention, there is also provided a casing drilling and completion method. Using the casing drilling tool 100 provided by the present invention, after the drilling is completed, an opening ball 64 is put into the bypass sub 6 and pressured, so that the bypass sub 6 is radially communicated with the annulus between the wellbore wall, and cement slurry is pumped into the annulus between the wellbore wall through the bypass sub 6 to complete cementing.

[0078] In a specific embodiment, the method for drilling and completion using the casing drilling tool 100 provided by the present invention includes the following steps.

[0079] (1) Connect the check valve and setting key tool 4, the second casing 5, the bypass sub 6, the back pressure valve 7, the drill string 8 and the drill bit 9 in sequence at the wellhead to form a pipe string, and hang the pipe string on the wellhead.

[0080] (2) Put the measurement-while-drilling instrument 11 into the pipe string hung on the wellhead in step (1), and hang it on the positioning cylinder 42 of the check valve and setting key tool 4.

[0081] (3) Connect the centralizing sub 3 to the upper end of the check valve and setting key tool 4.

[0082] (4) Connect the first casing 2 according to the need of the drilling depth at the upper end of the centralizing sub 3:

[0083] Specifically, connect the coupling 1 with the first casing 2 in advance, clamp the coupling 1 with a casing gripper, connect the lower end of the first casing 2 with the centralizing sub 3. After the connection is completed, release the hanging slips at the wellhead, establish the drilling fluid circulation, and start drilling. When one joint of the first casing 2 is drilled and the length needs to be increased, hang the pipe string on the wellhead, loosen the casing gripper, clamp another first casing 2 (the coupling 1 has been connected to its upper end) with the casing gripper, connect the lower end of the first casing 2 clamped by the casing gripper with the coupling 1 hung on the wellhead, then release the hanging slips at the wellhead, establish the drilling fluid circulation, and start drilling again. Connect and lower several first casings 2 to the completion depth in sequence according to the above sequence. During this process, the surface drilling fluid passes through the inner cavity of the casing drilling tool, enters the annulus between the wellbore wall through the nozzles of the drill bit 9, and then returns to the surface.

[0084] (5) Fish out the measurement-while-drilling instrument 11:

[0085] Hang the pipe string in the well on the wellhead, loosen the casing gripper, and lift it by more than 3 meters. Use a cable winch to lower the fishing tool for the measurement-while-drilling instrument 11 into the pipe string hung on the wellhead, and lower it to the depth where the measurement-while-drilling instrument 11 is located. Control the cable winch to lift the instrument fishing tool to the wellhead, and fish out the measurement-while-drilling instrument 11 from the pipe.

[0086] (6) Put in the opening ball 64 to open the bypass sub 6:

[0087] Put the opening ball 64 into the wellhead string, connect the casing gripper to the wellhead string, start the pump at a low pump stroke. Under the action of gravity and hydraulic force, the opening ball 64 falls onto the sliding sleeve 61. Observe the change of the standpipe pressure. When the standpipe pressure rises to 8 - 12 MPa and then suddenly drops, and the circulation pressure loss under the same displacement and the same conditions is smaller than that of the normal drilling circulation, it indicates that the opening ball 64 pushes the sliding sleeve 61 downward to open the bypass hole 62. At this time, the surface drilling fluid passes through the casing drilling tool 100, enters the wellbore annulus through the bypass hole 62, and then returns to the surface.

[0088] (7) Insert the check valve 10 and pump the check valve 10 into the check valve setting tool 4 by starting the pump:

[0089] Hang the wellbore string on the wellhead, loosen the casing gripper, and hoist it by more than 3 meters. Put the check valve 10 into the wellhead string, connect the casing gripper to the wellhead string, start the pump at a low pump stroke, and observe the change of the standpipe pressure. When the pressure rises to 2 - 3 MPa, it indicates that the check valve 10 is in place.

[0090] (8) Cementing and waiting for setting:

[0091] Hang the wellbore string in the casing head, loosen the casing gripper, and hoist it by more than 5 meters. Connect the cement head and conduct the cementing operation. At this time, the surface cement slurry passes through the cement head, enters the casing drilling tool 100, and then enters the internal flow path 112 of the check valve 10. Under the action of the pressure difference, the plugging ball 106 and the spring 107 move downward together, and the first valve through-hole 110 and the second valve through-hole 111 open. Then the cement slurry flows downward to the bypass nipple 6 and enters the wellbore annulus through the bypass hole 62. After pumping the cement slurry, release the cementing plug, pump the plug to the upper end of the check valve 10 to achieve a bump pressure, stop the pump, and the spring 107 and the plugging ball 106 reset. Due to stopping the pump, the wellhead pressure is zero, and the pressure of the cement slurry column that has entered the wellbore annulus is greater than the pressure of the liquid column in the casing string 20. This pressure difference acts on the plugging ball 106, causing the check valve 10 to move upward, and the teeth of the slider 102 enter the groove 43 of the check valve setting tool 4, restricting the upward movement of the slider 102, so that the valve body 105 moves upward relative to the slider 102. During the upward movement of the valve body 105, it pushes the rubber barrel 104 and the sliding seat 103 upward, causing the rubber barrel 104 to be compressed, sealing the gap between the check valve 10 and the check valve setting tool 4. Subsequently, the sliding seat 103 moves upward relative to the slider 102, causing the slider 102 to expand, strengthening the anchoring of the slider 102 and the check valve setting tool 4. The greater the pressure difference between the cement slurry column and the liquid column in the casing string 20, the better the sealing effect, thus preventing the cement slurry that has entered the wellbore annulus from flowing back into the casing string 20 through the bypass hole 62 of the bypass nipple 6 and the check valve 10.

[0092] In the description of the present invention, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0093] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed" and other terms shall be construed in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0094] In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0095] Finally, it should be noted that the above are only the preferred implementation schemes of the present invention and do not constitute any limitation to the present invention. Although the present invention has been described in detail with reference to the foregoing implementation schemes, for those skilled in the art, it is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A casing drilling tool, characterized in that, It includes a casing string (20), a bypass sub (6), a drill string (8), and a drill bit (9) connected in sequence from top to bottom. In the first state, the bypass sub (6) is configured to be axially connected, so that the fluid in the casing string (20) can axially pass through the bypass sub (6), the drill string (8), and the drill bit (9) in sequence and enter the wellbore annulus. In the second state, the bypass sub (6) is configured to be radially connected, so that the fluid in the casing string (20) can radially flow into the wellbore annulus through the bypass sub (6).

2. The casing drilling tool according to claim 1, wherein, The bypass sub (6) includes: A housing (63) with a bypass hole (62) provided on the side wall of the housing (63); and A sliding sleeve (61) arranged in the housing (63) by pins, and the sliding sleeve (61) closes the bypass hole (62); The sliding sleeve (61) is configured to be able to move downward relative to the housing (63) after a ball is dropped and pressure is applied, thereby opening the bypass hole (62).

3. The casing drilling tool according to claim 1 or 2, characterized in that, A check and setting key tool (4) is arranged between the casing string (20) and the bypass sub (6). In the first state, a measurement-while-drilling instrument (11) is arranged in the check and setting key tool (4). In the second state, a check valve (10) is arranged in the check and setting key tool (4).

4. The casing drilling tool according to claim 3, wherein The check and setting key tool (4) includes a body (41). A positioning cylinder (42) is arranged inside the body (41). A plurality of grooves (43) are arranged axially in sequence along the inner wall of the body (41), and the grooves (43) are arranged above the positioning cylinder (42).

5. The casing drilling tool according to claim 3, characterized in that, The check valve (10) includes: A valve body (105) with an internal flow passage (112) arranged axially inside the valve body (105), and a blocking ball (106) is arranged in the internal flow passage (112); A valve seat (108) arranged at the lower end of the valve body (105), and a spring (107) is arranged between the valve seat (108) and the blocking ball (106); The fluid flowing downward in the internal flow passage (112) can push the blocking ball (106) downward, thereby opening the internal flow passage (112). The fluid flowing upward in the internal flow passage (112) cannot push the blocking ball (106), so the internal flow passage (112) cannot be opened.

6. The casing drilling tool according to claim 5, wherein, At least one first valve through-hole (110) is arranged on the side of the valve body (105), and the first valve through-hole (110) is located below the blocking ball (106).

7. The casing drilling tool according to claim 6, characterized in that, A nut (101), a sliding seat (103), and a rubber cylinder (104) are arranged on the outside of the valve body (105) in sequence from top to bottom. The nut (101) is fixedly arranged at the upper end of the valve body (105). The upper end of the sliding seat (103) abuts against the nut (101). The upper end of the rubber cylinder (104) abuts against the sliding seat (103). A slider (102) is arranged on the outside of the sliding seat (103), and the upper end of the slider (102) abuts against the nut (101).

8. The casing drilling tool according to claim 7, wherein The outer wall of the sliding seat (103) and the inner wall of the sliding block (102) are provided with mutually adapted inclined surfaces, and a plurality of teeth are provided on the outer wall of the sliding block (102).

9. A casing drilling and completion method, characterized in that, When using the casing drilling tool according to any one of claims 1 to 8, after the drilling is completed, an opening ball (64) is put into the bypass sub (6) and pressured to make the bypass sub (6) radially communicate with the annulus between the wellbore and the wall, and cement slurry is pumped into the annulus between the wellbore and the wall through the bypass sub (6) to complete well cementing.

10. The casing drilling and completion method according to claim 9, characterized in that After the drilling is completed, the measurement-while-drilling instrument in the check valve setting tool is salvaged. An opening ball (64) is put into the bypass sub (6) and pressured. After the bypass sub (6) is radially communicated, a check valve is put into the check valve setting tool. The cement slurry is pumped and left to set to complete well cementing.

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