Shale gas drilling nozzle drill bit with double flow channels capable of being switched

Abstract

The invention discloses a double-channel switchable shale gas drilling nozzle drill bit. The double-channel switchable shale gas drilling nozzle drill bit comprises a drill bit body, an embedded body and a cone, the drill bit body is provided with an external thread connector, a shaft hole which is coaxial with the external thread connector and used for conveying drilling fluid, and three seat blocks used for installing cones. The embedded body comprises a triangular body, and the triangular body is provided with a drilling fluid spraying channel, a sand-carrying fluid spraying channel communicated with the shaft pipe, a spraying channel conduction switching mechanism and an outlet adjusting mechanism. The device has the function of spraying drilling fluid into the shaft to clean the well wall and also has the function of spraying sand-carrying fluid into the shaft to enhance the stability of the well wall, well drilling requirements can be better met, well drilling efficiency can be better improved, and construction cost is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of drilling, and in particular to a drill bit. Background Art

[0002] In oil drilling projects, the drill bit is the most important rock-breaking tool. Shale reservoirs are relatively soft, so roller bits are often used for drilling operations. The roller bit consists of a drill body, a cutting structure, a bearing structure, a nozzle, etc. During the drilling process, the drilling fluid is injected into the bottom of the well through one or more nozzles inside the drill bit to achieve the purpose of cleaning and supporting the well wall. The nozzles of existing drill bits are all fixed inside the drill bit, and the smaller the diameter of the nozzle water hole, the faster the drilling fluid flow rate and the higher the cleaning efficiency.

[0003] As an emerging unconventional natural gas resource, shale gas is a new energy source with great development value. However, shale reservoirs have different geological characteristics from general oil and gas reservoirs. Shale reservoirs often have developed stratification, and serious wellbore instability problems often occur during drilling. In addition, shale reservoirs have variable occurrence, hard and brittle rock properties, and high content of water-sensitive minerals. It is easy to have problems such as well leakage and collapse. Wellbore collapse will not only affect the drilling period, but more importantly, the irregular wellbore will reduce the cementing quality, affect the casing pressure bearing capacity, and threaten the safety of subsequent fracturing. In order to prevent wellbore collapse, the conventional horizontal well sand filling idea can be used to inject sand-carrying fluid into the shale gas well to improve the wellbore stability. However, since the diameter of the nozzle water hole inside the drill bit is too small, the sand-carrying fluid is prone to blockage if it passes directly through the water hole. Therefore, the commonly used sand filling process requires the special sand filling tool to be lowered after the drill is lifted, which greatly increases the drilling and completion construction time, and may cause wellbore instability or collapse during the drill lifting process, increasing the economic cost. In the prior art, the diameter of the water hole of the nozzle on the drill bit cannot be adjusted. If the water flow rate is too high, the well wall may be damaged, while if the water flow rate is insufficient, the well wall may not be cleaned properly. If the well wall is not cleaned properly, the mud and cuttings on the well wall will affect the subsequent cementing operation. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a dual-channel switchable shale gas drilling nozzle drill bit to solve the technical problem that the existing drilling roller drill bit does not have a channel function for injecting sand-carrying fluid, and to solve the technical problem that the size of the channel outlet for injecting drilling fluid in the roller drill bit cannot be adjusted.

[0005] The dual-flow-channel switchable shale gas drilling nozzle drill bit of the present invention comprises a drill bit body, an inlay and a cone;

[0006] The drill bit body is provided with an external threaded joint, an axial hole coaxially arranged with the external threaded joint for conveying drilling fluid, and three seats for mounting the cone;

[0007] The inlay comprises a triangular body, on which an annular groove connected to the axial hole on the drill bit body, an axial tube located in the annular groove for conveying sand-carrying fluid, a drilling fluid spray channel connected to the annular groove, and a sand-carrying fluid spray channel connected to the axial tube are arranged; the triangular body is embedded in the drill bit body, and the axial tube is passed through the axial hole;

[0008] The inlay is provided with a spray channel conduction switching mechanism for selectively conducting a drilling fluid spray channel and a sand-carrying fluid spray channel;

[0009] The embedded body is also provided with an outlet regulating mechanism for regulating the size of the sand-carrying liquid spray channel outlet.

[0010] Furthermore, the jet conduction switching mechanism includes a first electric push rod fixed in the triangle and a radial hole set on the telescopic rod section of the first electric push rod; in a state where the lower end of the telescopic rod section of the first electric push rod extends into the sand-carrying fluid channel to block it, the radial hole is directly connected to the drilling fluid jet channel; in a state where the lower end of the telescopic rod section of the first electric push rod rises and exits the sand-carrying fluid channel to connect it, the radial hole is dislocated and disconnected from the drilling fluid jet channel.

[0011] Furthermore, the outlet adjustment mechanism includes a second electric push rod fixed in the triangle and an adjustment block connected to the lower end of the second electric push rod, and the adjustment block enters or exits the outlet of the drilling fluid spray channel under the drive of the second electric push rod.

[0012] Furthermore, the drill head body is provided with a wire groove for allowing the wires of the first electric push rod and the second electric push rod to enter the shaft hole.

[0013] Furthermore, the triangle and the drill bit body are fixedly connected by screws.

[0014] Beneficial effects of the present invention:

[0015] 1. The dual-channel switchable shale gas drilling nozzle drill bit of the present invention has a drilling fluid spray channel and a sand-carrying fluid spray channel that can be switched through a spray channel conduction switching mechanism, so that the drill bit has the function of spraying drilling fluid into the wellbore to clean the well wall, and also has the function of spraying sand-carrying fluid into the wellbore to enhance the stability of the well wall, which can better meet the drilling needs, is conducive to improving drilling efficiency and reducing construction costs.

[0016] 2. The dual-channel switchable shale gas drilling nozzle drill bit of the present invention has an outlet size of the drilling fluid channel that can be adjusted by an outlet adjustment mechanism. When encountering soft formations, the outlet of the drilling fluid channel can be enlarged to reduce the outlet flow rate, thereby avoiding damage to the well wall during flushing; when encountering hard formations, the outlet of the drilling fluid channel can be reduced to increase the outlet flow rate, thereby improving the flushing effect on the well wall.

[0017] 3. The dual-channel switchable shale gas drilling nozzle drill bit of the present invention adopts a split combination structure of a drill bit body and an inlay, and the drilling fluid spray channel, the sand-carrying fluid spray channel, the spray channel conduction switching mechanism and the outlet regulating mechanism are arranged in the inlay, so that the drilling fluid spray channel and the sand-carrying fluid spray channel can be conveniently processed on the inlay, which also facilitates the installation and arrangement of the spray channel conduction switching mechanism and the outlet regulating mechanism. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the three-dimensional structure of a dual-channel switchable shale gas drilling nozzle drill bit.

[0019] Figure 2 It is a cross-sectional view of a dual-flow channel switchable shale gas drilling nozzle drill bit.

[0020] Figure 3 It is a schematic diagram of the three-dimensional structure of the inlay. DETAILED DESCRIPTION

[0021] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0022] As shown in the figure, the dual-flow-channel switchable shale gas drilling nozzle drill bit of this embodiment includes a drill bit body 1 , an inlay 2 and a cone 3 .

[0023] The drill bit body is provided with an external threaded joint 4, an axial hole 5 coaxially arranged with the external threaded joint for conveying drilling fluid, and three seats 6 for mounting the cone. In a specific implementation, the drill bit body is connected to the outer tube of the double-wall drill pipe through the external threaded joint 4, and the axial hole 5 is connected to the inner hole of the outer tube of the double-wall drill pipe.

[0024] The inlay 2 includes a triangular body 21, on which an annular groove 22 connected to the axial hole on the drill bit body, an axial tube 23 located in the annular groove for conveying sand-carrying fluid, a drilling fluid spray channel 24 connected to the annular groove, and a sand-carrying fluid spray channel 25 connected to the axial tube; the triangular body 21 is embedded in the drill bit body 1, and the axial tube 23 is inserted into the axial hole 5. In a specific implementation, the axial tube 23 is connected to the inner tube of the double-wall drill pipe.

[0025] The embedded body is provided with a jet conduction switching mechanism for selectively conducting the drilling fluid jet and the sand-carrying fluid jet. In this embodiment, the jet conduction switching mechanism comprises a first electric push rod 7 fixed in the triangle and a radial hole 8 provided on the telescopic rod section of the first electric push rod; in a state where the lower end of the telescopic rod section of the first electric push rod extends into the sand-carrying fluid channel to block it, the radial hole is directly connected to the drilling fluid jet; in a state where the lower end of the telescopic rod section of the first electric push rod rises and exits the sand-carrying fluid channel to conduct it, the radial hole is dislocated and disconnected from the drilling fluid jet.

[0026] The embedded body is also provided with an outlet adjustment mechanism for adjusting the size of the sand-carrying fluid spray channel outlet. In this embodiment, the outlet adjustment mechanism includes a second electric push rod 9 fixed in the triangle and an adjustment block 10 connected to the lower end of the second electric push rod, and the adjustment block enters or exits the outlet of the drilling fluid spray channel under the drive of the second electric push rod.

[0027] In this embodiment, the drill bit body is provided with a wire groove 11 for the wires of the first electric push rod and the second electric push rod to enter the shaft hole. The wires for supplying power to the first electric push rod and the second electric push rod can reach the ground through the wire groove 11, the shaft hole 5 and the outer sleeve of the double-wall drill pipe.

[0028] In this embodiment, the triangular body and the drill bit body are fixedly connected by screws 12. The triangular body and the drill bit body are easy to disassemble and assemble.

[0029] In the present embodiment, the dual-channel switchable shale gas drilling nozzle drill bit has a drilling fluid spray channel and a sand-carrying fluid spray channel that can be switched through a spray channel conduction switching mechanism, so that the drill bit has both the function of spraying drilling fluid into the wellbore to clean the well wall and the function of spraying sand-carrying fluid into the wellbore to enhance the stability of the well wall. It can better meet drilling needs, help improve drilling efficiency, and reduce construction costs.

[0030] In the present embodiment, the dual-channel switchable shale gas drilling nozzle drill bit has an outlet size of the drilling fluid channel that can be adjusted by an outlet adjustment mechanism. When encountering soft formations, the outlet of the drilling fluid channel can be increased to reduce the outlet flow rate, thereby avoiding damage to the well wall during flushing; when encountering hard formations, the outlet of the drilling fluid channel can be reduced to increase the outlet flow rate, thereby improving the flushing effect on the well wall.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A dual-channel switchable shale gas drilling nozzle drill bit, characterized in that: It includes a drill body, an inlay and a cone; The drill bit body is provided with an external threaded joint, an axial hole coaxially arranged with the external threaded joint for conveying drilling fluid, and three seats for mounting the cone; The inlay comprises a triangular body, on which an annular groove connected to the axial hole on the drill bit body, an axial tube located in the annular groove for conveying sand-carrying fluid, a drilling fluid spray channel connected to the annular groove, and a sand-carrying fluid spray channel connected to the axial tube are arranged; the triangular body is embedded in the drill bit body, and the axial tube is passed through the axial hole; The inlay is provided with a spray channel conduction switching mechanism for selectively conducting a drilling fluid spray channel and a sand-carrying fluid spray channel; The embedded body is also provided with an outlet regulating mechanism for regulating the size of the sand-carrying liquid spray channel outlet.

2. The dual-flow channel switchable shale gas drilling nozzle drill bit according to claim 1, characterized in that: The jet conduction switching mechanism includes a first electric push rod fixed in the triangle and a radial hole set on the telescopic rod section of the first electric push rod; when the lower end of the telescopic rod section of the first electric push rod extends into the sand-carrying fluid channel to block it, the radial hole is directly connected to the drilling fluid jet path; when the lower end of the telescopic rod section of the first electric push rod rises and exits the sand-carrying fluid channel to connect it, the radial hole is dislocated and disconnected from the drilling fluid jet path.

3. The dual-flow channel switchable shale gas drilling nozzle drill bit according to claim 1 or 2, characterized in that: The outlet regulating mechanism comprises a second electric push rod fixed in the triangle and an regulating block connected to the lower end of the second electric push rod. The regulating block enters or exits the outlet of the drilling fluid spray channel under the drive of the second electric push rod.

4. The dual-flow channel switchable shale gas drilling nozzle drill bit according to claim 3, characterized in that: The drill body is provided with a wire groove for the wires of the first electric push rod and the second electric push rod to enter the shaft hole.

5. The dual-flow channel switchable shale gas drilling nozzle drill bit according to claim 1, characterized in that: The triangle body and the drill bit body are fixedly connected by screws.

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