Hybrid bit for shale gas development

Abstract

The present application relates to energy-saving equipment technical field, specifically relates to a kind of shale gas exploitation mixed drill bit, including main unit, including drill bit stem, PDC component for cutting and breaking shale formation being arranged on drill bit stem, and cone component for impacting pre-breaking hard interlayer and inhibiting stick-slip vibration being arranged on drill bit stem, hydraulic jet unit, including jet mechanism for high-pressure jet cooling and flushing of chip and well bottom being arranged on drill bit stem;By PDC cutting structure and cone impact structure compound arrangement, reduce cutting tooth impact wear, extend drill bit service life, utilize downhole regulation jet pressure, improve the adaptability and reliability of cooling and chip removal, and through hydraulic, gas pressure linkage control jet spray posture, further improve the chip removal efficiency, avoid tooth surface mud cake, guarantee drilling continuous and stable, greatly improve shale gas drilling efficiency, reduce construction cost, better meet the use demand of long-term stable drilling under complex geological conditions.

Description

Technical Field

[0001] This invention relates to the field of energy-saving equipment technology, specifically to a hybrid drill bit for shale gas development. Background Technology

[0002] Shale gas is an important unconventional natural gas resource. Shale gas extraction is mostly carried out through drilling. The drill bit is used to efficiently break and drill through the shale formation in order to build the well and connect the gas layer. The drill bit is the core execution component of shale gas drilling and directly determines the drilling efficiency, construction cost and extraction safety.

[0003] Currently, the drill bits commonly used in shale gas extraction mainly include two types: PDC drill bits and roller cone drill bits. PDC drill bits rely on the shearing action of polycrystalline diamond composite plates to achieve continuous rock breaking, with fast drilling speed and high efficiency. However, when dealing with hard interlayers and highly abrasive formations, the cutting teeth are prone to impact overload and breakage and wear. At the same time, the accumulation of rock cuttings can easily cause mud clogging on the tooth surface. Roller cone drill bits break hard rock through the impact and crushing action of cemented carbide teeth, with strong impact resistance and wide adaptability. However, their continuous cutting ability is relatively weak, and their drilling efficiency is relatively low. In addition, drill bits mostly rely on external water supply equipment for cooling and cuttings removal. However, under the high confining pressure conditions of deep wells, this may affect the jet impact force, resulting in poor cooling effect and failure to remove rock cuttings in time, which further affects the normal operation of the drill bit.

[0004] In view of this, we propose a hybrid drill bit for shale gas development. Summary of the Invention

[0005] To address the aforementioned shortcomings of existing technologies, this invention provides a hybrid drill bit for shale gas development. This effectively solves the problems of limited rock-breaking performance and insufficient adaptability of both PDC and roller cone drill bits used in shale gas development. Furthermore, the cooling and cuttings removal jets used in these drill bits are difficult to adapt to the high confining pressure conditions in deep wells, which can easily lead to cooling failure and cuttings accumulation, thus affecting the efficient and stable drilling of the drill bit in complex formations.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] The present invention provides a hybrid drill bit for shale gas development, comprising a main unit including a drill bit body, a PDC assembly disposed on the drill bit body for cutting and breaking shale formations, and a roller cone assembly disposed on the drill bit body for impacting and pre-breaking hard interlayers and suppressing stick-slip vibrations;

[0008] The hydraulic jetting unit includes a jetting mechanism mounted on the drill bit rod for high-pressure jet cooling, chip removal, and bottom flushing; an adjustment mechanism one mounted on the drill bit rod for regulating jet pressure and flow rate; and an adjustment mechanism two mounted on the drill bit rod for regulating nozzle opening angle and jetting attitude.

[0009] Furthermore, the PDC assembly includes a cutter blade base fixedly connected to the drilling end of the drill bit body, and the cutter blade base is fixedly connected with cutting teeth for cutting and breaking shale formations through tooth sockets opened on its surface.

[0010] Furthermore, the roller assembly includes a roller shaft fixedly connected to the drilling end of the drill bit body, and a conical roller gear ring rotatably connected to the end of the roller shaft away from the drill bit body. The conical roller gear ring is fixedly connected to alloy inserts for impact pre-breaking of hard interlayers and suppression of stick-slip vibration through tooth sockets opened on its surface.

[0011] Furthermore, the jetting mechanism includes a main water inlet cylinder fixedly connected to the inner wall of the drill bit rod, and a connecting pipe for connecting to an external water supply device is fixedly connected to the input end of the main water inlet cylinder.

[0012] Furthermore, the main water inlet cylinder output end is fixedly connected to a pressure deformation outer layer and a fluid guiding inner layer via a connecting pipe. The pressure deformation outer layer is sleeved on the outside of the fluid guiding inner layer. The two are a double-layer isolation structure that is independently sealed to each other, forming independent air passages and water passages.

[0013] Furthermore, a nozzle is fixedly connected to one end of the outer layer of air pressure deformation and the inner layer of fluid flow guidance away from the second connecting pipe. The input end of the nozzle is connected to the output end of the inner layer of fluid flow guidance. A protective frame is provided outside the nozzle to protect and block the outer layer of air pressure deformation, the inner layer of fluid flow guidance and the nozzle, and the protective frame is fixedly connected to the surface of the main water inlet cylinder.

[0014] Furthermore, the adjustment mechanism includes a pressure boosting cylinder fixedly connected to the inner wall of the drill bit rod, the bottom of the pressure boosting cylinder being connected to the top of the main water inlet cylinder, a piston being sleeved on the inner wall of the pressure boosting cylinder, and a piston rod being fixedly connected to the top of the piston, which slides through the pressure boosting cylinder.

[0015] Furthermore, a push-pull block is fixedly connected to the top of the piston rod, and a lead screw is threadedly connected to the inner wall of the push-pull block. The top of the lead screw is rotatably connected to the inner wall of the drill bit rod, and a motor is fixedly connected to the inner wall of the drill bit rod at the bottom of the lead screw. The motor is fixedly connected to the bottom of the lead screw through an output shaft.

[0016] Furthermore, the second adjustment mechanism includes an oil storage tank fixedly connected to the inner wall of the drill bit body. An oil pump is fixedly connected to the bidirectional flow end of the oil storage tank. The surface of the oil pump is fixedly connected to the inner wall of the drill bit body. An oil-gas control cylinder is fixedly connected to the bidirectional flow end of the oil pump through a connecting pipe three. The surface of the oil-gas control cylinder is fixedly connected to the inner wall of the protective frame. The bidirectional flow end of the oil-gas control cylinder is fixedly connected to the bidirectional flow end of the outer layer of the gas pressure deformation through a connecting pipe four. This mechanism is used to supply or exhaust gas to the gas passage formed by the outer layer of the gas pressure deformation and the inner layer of the fluid guide.

[0017] Furthermore, a piston two is sleeved on the inner wall of the oil and gas control cylinder, and a spring is fixedly connected to the bottom of the piston two. The end of the spring away from the piston two is fixedly connected to the inner wall of the oil and gas control cylinder. The hydraulic oil chamber located below the piston two inside the oil and gas control cylinder is connected to the connecting pipe three. The air chamber located above the piston two inside the oil and gas control cylinder is connected to the connecting pipe four.

[0018] The technical solution provided by this invention has the following advantages compared with known public technologies:

[0019] This invention combines a PDC cutting structure with a roller cone impact structure, enabling the PDC assembly to continuously shear and break rock, while the roller cone assembly pre-breaks and buffers the load on hard interlayers. The two work together to achieve highly efficient rock breaking adaptable to both soft and hard formations. Mechanically, it significantly suppresses stick-slip vibration, reduces cutting tooth impact wear, and extends drill bit life. By adjusting the downhole jet pressure, the injection intensity can be changed according to well depth, confining pressure, and formation hardness. This ensures sufficient jet impact force under high confining pressure in deep wells and avoids excessive wellbore erosion in soft formations, stabilizing drill bit load and improving the adaptability and reliability of cooling and cuttings removal. Furthermore, through hydraulic and pneumatic linkage control of the nozzle's injection posture, the injection angle and coverage can be freely adjusted to achieve uniform cooling and cuttings removal across the entire working face or targeted enhanced erosion. This ensures precise matching of hydraulic action with the rock-breaking area, further improving cuttings removal efficiency, preventing mud buildup on the tooth surface, ensuring continuous and stable drilling, significantly improving shale gas drilling efficiency, reducing construction costs, and better meeting the needs of long-term stable drilling under complex geological conditions. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0021] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2This is a schematic diagram of the main body unit and the hydraulic jet unit of the present invention;

[0023] Figure 3 This is a cross-sectional view of the drill bit body of the present invention;

[0024] Figure 4 For the present invention Figure 1 Enlarged schematic diagram of the structure at point A;

[0025] Figure 5 This is a schematic diagram of the hydraulic jetting unit structure of the present invention;

[0026] Figure 6 This is a schematic diagram of the adjustment mechanism of the present invention;

[0027] Figure 7 This is a schematic diagram of the two structures of the injection mechanism and the adjustment mechanism of the present invention;

[0028] Figure 8 This is a schematic diagram of the second adjustment mechanism of the present invention;

[0029] Figure 9 This is a cross-sectional view of the oil and gas regulating cylinder of the present invention;

[0030] Figure 10 This is a schematic diagram of the spray mechanism of the present invention.

[0031] The labels in the diagram represent: 100, main unit; 101, drill rod body; 102, PDC assembly; 1021, cutter blade base; 1022, cutting teeth; 103, roller cone assembly; 1031, roller cone shaft; 1032, conical roller cone gear ring; 1033, alloy insert teeth;

[0032] 200. Hydraulic jet unit; 201. Jet mechanism; 2011. Main water inlet cylinder; 2012. Protective frame; 2013. Connecting pipe one; 2014. Connecting pipe two; 2015. Outer layer of air pressure deformation; 2016. Inner layer of fluid guide; 2017. Nozzle; 202. Adjusting mechanism one; 2021. Pressure booster cylinder; 2022. Piston one; 2023. Lead screw; 2024. Piston rod; 2025. Push-pull block; 2026. Motor; 203. Adjusting mechanism two; 2031. Oil storage tank; 2032. Oil pump; 2033. Connecting pipe three; 2034. Oil and gas control cylinder; 2035. Piston two; 2036. Spring; 2037. Connecting pipe four. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0034] The present invention will be further described below with reference to embodiments.

[0035] like Figures 1 to 10 As shown, a hybrid drill bit for shale gas development includes a main unit 100, comprising a drill bit body 101, a PDC assembly 102 mounted on the drill bit body 101 for cutting and breaking shale formations, and a roller cone assembly 103 mounted on the drill bit body 101 for impacting and pre-breaking hard interlayers and suppressing stick-slip vibrations. A hydraulic jetting unit 200 includes a jetting mechanism 201 mounted on the drill bit body 101 for high-pressure jet cooling, cuttings removal, and bottom hole flushing, and a regulating mechanism mounted on the drill bit body 101 for controlling jet pressure and flow rate. The system includes a PDC assembly 102 and an adjustment mechanism 203 mounted on the drill bit body 101 to control the opening angle and jetting posture of the nozzle 2017. The PDC assembly 102 is used to cut and break shale formations, the roller cone assembly 103 is used to impact and pre-break hard interlayers and suppress stick-slip vibration, and the jetting mechanism 201 is used for high-pressure jet cooling, cuttings removal and bottom hole flushing. The adjustment mechanism 202 is used to control the jet pressure and flow rate, and the adjustment mechanism 203 is used to control the opening angle and jetting posture of the nozzle 2017. The various units cooperate with each other to achieve efficient and stable drilling.

[0036] Specifically, refer to Figure 3 and Figure 4The PDC assembly 102 includes a cutter blade base 1021 fixedly connected to the drilling end of the drill bit body 101. The cutter blade base 1021 has cutting teeth 1022 fixedly connected to it via toothed recesses on its surface for cutting and breaking shale formations. The roller cone assembly 103 includes a roller cone shaft 1031 fixedly connected to the drilling end of the drill bit body 101. A conical roller cone gear ring 1032 is rotatably connected to the end of the roller cone shaft 1031 away from the drill bit body 101. The conical roller cone gear ring 1032 has alloy inserts 1033 fixedly connected to it via toothed recesses on its surface for impact pre-breaking of hard interlayers and suppressing stick-slip vibrations. The cutter blade base 1021, fixed to the drilling end of the drill bit body 101, is made of high-strength wear-resistant alloy steel and has toothed recesses on its surface for cutting... The tooth 1022 is made of polycrystalline diamond composite material and is fixed by tooth socket inlay. It has high hardness, high wear resistance and high shear rock breaking ability. The cutter blade base 1021 and the conical roller cone tooth ring 1032 are arranged alternately and evenly along the circumference of the drill bit rod 101 to form a composite rock breaking structure of cutting and impact. The two do not interfere with each other and work together at the drilling end. The roller cone shaft 1031 is also fixed to the drilling end of the drill bit rod 101. The conical roller cone tooth ring 1032 is rotatably connected to the end of the roller cone shaft 1031 away from the drill bit rod 101. The surface is opened with tooth sockets. The alloy insert tooth 1033 is made of hard alloy material and is embedded and fixed in the tooth socket. It is used for impact and crushing to break hard interlayers, and works with the PDC component 102 to break rocks and reduce stick-slip vibration.

[0037] Specifically, refer to Figure 5 , Figures 7 to 10The spraying mechanism 201 includes a main water inlet cylinder 2011 fixedly connected to the inner wall of the drill bit body 101. A connecting pipe 2013 for connecting to an external water supply device is fixedly connected to the input end of the main water inlet cylinder 2011. An air pressure deformation outer layer 2015 and a fluid guiding inner layer 2016 are fixedly connected to the output end of the main water inlet cylinder 2011 via a connecting pipe 2014. The air pressure deformation outer layer 2015 is sleeved on the outside of the fluid guiding inner layer 2016, forming an independent, sealed double-layer isolation structure, constituting independent air and water passages. A nozzle 2017 is fixedly connected to the end of the air pressure deformation outer layer 2015 and the fluid guiding inner layer 2016 away from the connecting pipe 2014. The input end of the nozzle 2017 communicates with the output end of the fluid guiding inner layer 2016. An external device is provided on the nozzle 2017 for spraying air pressure deformation outer layer 2015 and fluid guiding inner layer 2016. The protective frame 2012 protects and blocks the nozzle 2017, and the protective frame 2012 is fixedly connected to the surface of the main water inlet cylinder 2011; the main water inlet cylinder 2011 is fixed to the inner wall of the drill bit rod 101, and the connecting pipe 2013 is used to connect with the external water supply equipment to realize the entry of drilling fluid. The gas pressure deformation outer layer 2015 is made of polyurethane elastomer material, which has high elasticity, high wear resistance, oil resistance, drilling fluid corrosion resistance, tear resistance and pressure sealing characteristics. It can generate controllable expansion and contraction deformation under gas pressure drive, and adapt to the exposed wear environment downhole. The fluid guide inner layer 2016 is made of high pressure wear-resistant flexible rubber or nylon composite hose material, which is used to guide high pressure water flow. It has strong sealing and pressure resistance. The gas pressure deformation outer layer 2015 is sleeved on the outside of the fluid guide inner layer 2016 to form a double-layer isolation structure with independent sealing, forming separate gas passage and water passage.

[0038] It should be noted that the protective frame 2012 is a frame structure, which is cage-shaped or arc-shaped and fixed to the outside of the main water inlet cylinder 2011. It is used to protect and block the outer layer 2015 of air pressure deformation, the inner layer 2016 of fluid flow guidance and the nozzle 2017 to avoid collision damage to the well wall. The nozzle 2017 is fixed to the end of the double-layer structure and is connected to the inner layer 2016 of fluid flow guidance to spray high-pressure water in a directional manner.

[0039] Specifically, refer to Figure 5 and Figure 6The adjusting mechanism 202 includes a pressure boosting cylinder 2021 fixedly connected to the inner wall of the drill bit rod 101. The bottom of the pressure boosting cylinder 2021 is connected to the top of the main water inlet cylinder 2011. A piston 2022 is sleeved on the inner wall of the pressure boosting cylinder 2021. A piston rod 2024 that slides through the pressure boosting cylinder 2021 is fixedly connected to the top of the piston 2022. A push-pull block 2025 is fixedly connected to the top of the piston rod 2024. A lead screw 2023 is threadedly connected to the inner wall of the push-pull block 2025. The top of the lead screw 2023 is rotatably connected to the drill bit rod. On the inner wall of drill bit body 101, a motor 2026 is fixedly connected to the bottom of the lead screw 2023. The motor 2026 is fixedly connected to the bottom of the lead screw 2023 through an output shaft. The booster cylinder 2021 is fixed on the inner wall of drill bit body 101, and its bottom is connected to the main water inlet cylinder 2011. The piston 2022 is sleeved inside the booster cylinder 2021 and can slide axially along the inner wall. The piston rod 2024 is fixed on the top of the piston 2022 and extends upward through the booster cylinder 2021. Its upper end is fixed to the push-pull block 2025.

[0040] It should be noted that the lead screw 2023 is threadedly engaged with the push-pull block 2025 and is driven to rotate by the motor 2026, which in turn drives the push-pull block 2025, piston rod 2024 and piston 2022 to move up and down, changing the effective volume inside the pressure booster cylinder 2021, and realizing the active adjustment of water pressure and flow rate in the main water inlet cylinder 2011.

[0041] Specifically, refer to Figures 7 to 10The regulating mechanism 203 includes an oil storage tank 2031 fixedly connected to the inner wall of the drill bit body 101. An oil pump 2032 is fixedly connected to the bidirectional flow end of the oil storage tank 2031. The surface of the oil pump 2032 is fixedly connected to the inner wall of the drill bit body 101. An oil-gas regulating cylinder 2034 is fixedly connected to the bidirectional flow end of the oil pump 2032 via a connecting pipe 3 2033. The surface of the oil-gas regulating cylinder 2034 is fixedly connected to the inner wall of the protective frame 2012. The bidirectional flow end of the oil-gas regulating cylinder 2034 is fixedly connected to the bidirectional flow end of the pressure deformation outer layer 2015 via a connecting pipe 4 2037, used to supply or exhaust gas to the gas passage formed by the pressure deformation outer layer 2015 and the fluid guiding inner layer 2016. A piston 2035 is sleeved on the inner wall of the oil-gas regulating cylinder 2034. A spring 2036 is fixedly connected to the bottom of the piston 2035. The end of spring 2036 away from piston 2035 is fixedly connected to the inner wall of oil and gas control cylinder 2034. The hydraulic oil chamber located below piston 2035 is located inside oil and gas control cylinder 2034 and is connected to connecting pipe 3 2033. The air chamber located above piston 2035 is located inside oil and gas control cylinder 2034 and is connected to connecting pipe 4 2037. Oil storage tank 2031 and oil pump 2032 are both fixed to the inner wall of drill rod 101. The two are connected through a bidirectional flow end, which can realize the delivery and return of hydraulic oil. Oil pump 2032 is connected to oil and gas control cylinder 2034 through connecting pipe 3 2033. Oil and gas control cylinder 2034 is fixed to the inner wall of protective frame 2012 and piston 2035 is sleeved inside. The bottom of piston 2035 is fixed to spring 2036, and the other end of spring 2036 is fixed to the inner wall of oil and gas control cylinder 2034. The oil and gas control cylinder 2034 is divided into upper and lower chambers by piston 2035. The lower chamber is the hydraulic oil chamber, which is connected to connecting pipe 3 2033. The upper chamber is the gas chamber, which is connected to connecting pipe 4 2037. Connecting pipe 4 2037 is connected to the outer layer 2015 of gas pressure deformation, forming a closed gas passage.

[0042] It should be noted that the oil pump 2032 pumps the hydraulic oil in the oil storage tank 2031 into or out of the hydraulic oil chamber, and in conjunction with the spring 2036, pushes the piston 2035 to move up and down, thereby changing the volume of the air chamber and realizing the inflation or deflation of the outer layer 2015 of the air pressure deformation, thereby controlling the opening angle and spray posture of the nozzle 2017.

[0043] The working principle of the present invention is as follows: During the drilling process, the PDC component 102 and the roller cone component 103 of the main unit 100 are arranged alternately and evenly along the circumference of the drill bit rod 101 to form a composite rock breaking mode of shearing and cutting and impact crushing.

[0044] The cutter blade base 1021 of the PDC assembly 102 rotates synchronously with the drill bit rod 101. The cutting teeth 1022 on the surface continuously shear and crush the main body of the shale formation with the high hardness and high wear resistance of the polycrystalline diamond composite sheet, undertaking the main rock breaking and footage function. Meanwhile, the conical roller gear ring 1032 of the roller assembly 103 rotates freely around the roller shaft 1031. The alloy insert teeth 1033 impact, crush and pre-crush the hard interlayers, dense nodules and heterogeneous rock layers in the formation as the roller rolls, thus reducing the impact load of the high-strength rock layer on the cutting teeth 1022 in advance. This avoids the PDC assembly 102 from violent jumping, vibration and rapid wear due to local overload. The two do not interfere with each other and work together at the drilling end, so that the drill bit maintains a balanced load in the soft and hard formation. From the mechanical structure level, this significantly reduces the generation of stick-slip vibration and improves drilling stability and rock breaking efficiency.

[0045] At the same time, the hydraulic jetting unit 200 is started simultaneously, and the external water supply equipment continuously inputs high-pressure drilling fluid into the main water inlet cylinder 2011 through the connecting pipe 2013. The drilling fluid is stably transported to the nozzle 2017 along the fluid guide inner layer 2016 and sprayed out in the form of a high-speed jet, which forcibly cools the cutting teeth 1022 and the alloy insert teeth 1033 to prevent the cutting teeth 1022 from failing due to high temperature. At the same time, it quickly flushes away the rock cuttings generated by the bottom of the well from the working face, preventing repeated rock cuttings, mud buildup on the tooth surface and repeated grinding at the bottom of the well. It also weakens the formation strength through auxiliary flushing, further reducing the difficulty of mechanical rock breaking.

[0046] To adapt to different well depths, changes in bottom hole confining pressure, and differences in formation hardness, the regulating mechanism 202 can adjust the jet pressure and flow rate in real time downhole. The motor 2026 drives the lead screw 2023 to rotate in the forward or reverse direction. The lead screw 2023 drives the push-pull block 2025 to move axially through the threaded engagement. The push-pull block 2025 then drives the piston 2022 to slide up and down inside the pressure booster cylinder 2021 through the piston rod 2024.

[0047] When piston 2022 moves downward, the effective fluid volume formed by booster cylinder 2021 and main water inlet cylinder 2011 decreases, the internal drilling fluid is compressed, and the injection pressure and jet velocity of nozzle 2017 are significantly increased, forming a high-impact jet, which is suitable for hard formations and deep wells with high confining pressure. It can enhance cooling, powerfully remove cuttings, and prevent rock cuttings accumulation and overheating of cutting teeth 1022.

[0048] When piston 2022 moves upward, the effective fluid volume increases, the injection pressure decreases, and the flow rate relatively increases, forming a large-flow, gentle jet. This is suitable for soft formations and shallow well conditions, avoiding excessive jet flow from scouring the well wall and causing well wall collapse. By precisely matching the formation conditions and adjusting the water pressure, the jet can always be in the optimal working state, further stabilizing the drill bit load and suppressing stick-slip vibration.

[0049] While regulating the water pressure, the regulating mechanism 203 independently controls the spray posture, opening angle and coverage of the nozzle 2017 using hydraulic and pneumatic linkage to achieve precise matching between hydraulic action and mechanical rock breaking area.

[0050] When the oil pump 2032 is running in the forward direction, the hydraulic oil in the oil storage tank 2031 is pumped into the hydraulic oil chamber at the bottom of the oil-gas control cylinder 2034 through the connecting pipe three 2033. The hydraulic oil pushes the piston two 2035 to move upward and stretches the spring 2036. The volume of the air chamber at the top of the oil-gas control cylinder 2034 decreases, the internal gas is pressurized and forced into the pressure deformation outer layer 2015 through the connecting pipe four 2037, so that the pressure deformation outer layer 2015 expands evenly, driving the nozzle 2017 to expand outward, increasing the spray angle and expanding the coverage area. It can simultaneously and completely cover the entire working area of ​​the PDC cutting tooth 1022 and the alloy insert tooth 1033, realizing uniform cooling and chip removal of the entire working surface.

[0051] When the oil pump 2032 operates in reverse, the hydraulic oil is drawn back from the hydraulic oil chamber of the oil-gas control cylinder 2034 to the oil storage tank 2031. The spring 2036 pulls the piston 2035 downward through its own elastic force, increasing the volume of the air chamber. The outer layer 2015 of the air pressure deformation contracts and resets under its own elasticity. The nozzle 2017 can retract inward, reducing the spray angle and making the jet more concentrated. It can be aimed at the tooth surface of the cutting tooth 1022 and the rock breaking point for enhanced cooling and chip removal, improving the local effect.

[0052] The outer layer 2015 for air pressure deformation and the inner layer 2016 for fluid flow are independent and sealed double-layer isolation structures. The air path attitude adjustment and the water path jet delivery do not interfere with each other and work independently, ensuring that the adjustment process is stable and reliable. The protective frame 2012 has a cage-like frame structure, which can continuously protect the nozzle 2017, the outer layer 2015 for air pressure deformation and the inner layer 2016 for fluid flow, avoiding collision damage with the well wall and rock blocks during drilling, drilling and tripping, and does not affect the attitude adjustment of the nozzle 2017.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A hybrid drill bit for shale gas extraction, characterized in that, It includes a main unit (100), including a drill bit rod body (101), a PDC assembly (102) disposed on the drill bit rod body (101) for cutting and breaking shale formations, and a roller cone assembly (103) disposed on the drill bit rod body (101) for impact pre-breaking of hard interlayers and suppressing stick-slip vibration. The hydraulic jetting unit (200) includes a jetting mechanism (201) mounted on the drill bit rod (101) for high-pressure jet cooling and chip removal and bottom flushing, an adjustment mechanism one (202) mounted on the drill bit rod (101) for regulating jet pressure and flow rate, and an adjustment mechanism two (203) mounted on the drill bit rod (101) for regulating nozzle (2017) opening angle and jetting attitude.

2. The hybrid drill bit for shale gas extraction according to claim 1, characterized in that, The PDC assembly (102) includes a cutter blade base (1021) fixedly connected to the drilling end of the drill bit body (101), and the cutter blade base (1021) is fixedly connected with cutting teeth (1022) for cutting and breaking shale formations through tooth sockets opened on its surface.

3. A hybrid drill bit for shale gas extraction according to claim 1, characterized in that, The roller assembly (103) includes a roller shaft (1031) fixedly connected to the drilling end of the drill rod (101). A conical roller gear ring (1032) is rotatably connected to the end of the roller shaft (1031) away from the drill rod (101). The conical roller gear ring (1032) is fixedly connected to an alloy insert (1033) for impact pre-breaking of hard interlayers and suppression of stick-slip vibration through a tooth socket on its surface.

4. A hybrid drill bit for shale gas extraction according to claim 1, characterized in that, The jetting mechanism (201) includes a main water inlet cylinder (2011) fixedly connected to the inner wall of the drill bit rod body (101), and a connecting pipe (2013) for connecting to an external water supply device is fixedly connected to the input end of the main water inlet cylinder (2011).

5. A hybrid drill bit for shale gas extraction according to claim 4, characterized in that, The main water inlet cylinder (2011) output end is fixedly connected to a pressure deformation outer layer (2015) and a fluid guiding inner layer (2016) through a connecting pipe two (2014). The pressure deformation outer layer (2015) is sleeved on the outside of the fluid guiding inner layer (2016). The two are a double-layer isolation structure that is independently sealed to each other, forming an independent air passage and water passage.

6. A hybrid drill bit for shale gas extraction according to claim 5, characterized in that, A nozzle (2017) is fixedly connected to one end of the outer layer (2015) and the inner layer (2016) away from the second connecting pipe (2014). The input end of the nozzle (2017) is connected to the output end of the inner layer (2016). A protective frame (2012) is provided on the outside of the nozzle (2017) to protect and block the outer layer (2015), the inner layer (2016) and the nozzle (2017). The protective frame (2012) is fixedly connected to the surface of the main water inlet cylinder (2011).

7. A hybrid drill bit for shale gas extraction according to claim 1, characterized in that, The adjustment mechanism 1 (202) includes a pressure boosting cylinder (2021) fixedly connected to the inner wall of the drill bit rod body (101). The bottom of the pressure boosting cylinder (2021) is connected to the top of the main water inlet cylinder (2011). A piston 1 (2022) is sleeved on the inner wall of the pressure boosting cylinder (2021). A piston rod 1 (2024) that slides through the pressure boosting cylinder (2021) is fixedly connected to the top of the piston 1 (2022).

8. A hybrid drill bit for shale gas extraction according to claim 7, characterized in that, The piston rod (2024) is fixedly connected to the top of a push-pull block (2025), and the inner wall of the push-pull block (2025) is threadedly connected to a lead screw (2023). The top of the lead screw (2023) is rotatably connected to the inner wall of the drill bit rod body (101), and the bottom of the lead screw (2023) is provided with a motor (2026) fixedly connected to the inner wall of the drill bit rod body (101). The motor (2026) is fixedly connected to the bottom of the lead screw (2023) through an output shaft.

9. A hybrid drill bit for shale gas extraction according to claim 1, characterized in that, The second regulating mechanism (203) includes an oil storage tank (2031) fixedly connected to the inner wall of the drill rod (101). An oil pump (2032) is fixedly connected to the bidirectional flow end of the oil storage tank (2031). The surface of the oil pump (2032) is fixedly connected to the inner wall of the drill rod (101). An oil and gas control cylinder (2034) is fixedly connected to the bidirectional flow end of the oil pump (2032) through a connecting pipe (2033). The surface of the oil and gas control cylinder (2034) is fixedly connected to the inner wall of the protective frame (2012). The bidirectional flow end of the oil and gas control cylinder (2034) is fixedly connected to the bidirectional flow end of the pressure deformation outer layer (2015) through a connecting pipe (2037). It is used to supply or exhaust gas to the gas passage formed by the pressure deformation outer layer (2015) and the fluid guiding inner layer (2016).

10. A hybrid drill bit for shale gas extraction according to claim 9, characterized in that, The inner wall of the oil and gas control cylinder (2034) is fitted with piston two (2035). A spring (2036) is fixedly connected to the bottom of piston two (2035). The end of spring (2036) away from piston two (2035) is fixedly connected to the inner wall of the oil and gas control cylinder (2034). The hydraulic oil chamber located below piston two (2035) in the oil and gas control cylinder (2034) is connected to connecting pipe three (2033). The air chamber located above piston two (2035) in the oil and gas control cylinder (2034) is connected to connecting pipe four (2037).

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