Jet flow speed increasing tool for reducing well bottom pressure difference in well drilling process

Abstract

The invention discloses a jet flow speed increasing tool used for reducing the well bottom pressure difference in the drilling process, and relates to the technical field of drilling, the jet flow speed increasing tool comprises a shell provided with an in-pipe channel, a mixing chamber is formed in the shell, the in-pipe channel is communicated with the mixing chamber through a supply channel, and the shell is further provided with a backflow channel communicated with the mixing chamber; the supply channel can achieve acceleration of fluid, so that jet flow is formed in the mixing chamber, a low-pressure area is formed in the mixing chamber, suction force to the fluid below the shell is formed in the backflow channel, and the fluid mixed in the mixing chamber is sprayed obliquely and upwards. The jet action of the device occurs in the gap between the side cylindrical surface of the shell and the well wall, and the well bottom pressure difference can be correspondingly reduced due to the jet action, so that the mechanical drilling speed is increased.

Description

Technical Field

[0001] The invention relates to the technical field of drilling, and in particular to a jet speed-increasing tool for reducing the bottom hole pressure difference during the drilling process. Background Art

[0002] Discovering oil and gas in deep hard formations and complex geological conditions is an important task in current exploration and development. During the drilling process, the formation hardness and drilling difficulty increase with the increase of well depth, so improving the drilling speed in hard formations is one of the recognized difficulties. As the drilling depth increases, the mechanical drilling speed drops sharply. The bottom hole pressure difference is one of the main factors that determine the drilling speed.

[0003] At present, the technologies for reducing the pressure difference include reducing the density of the drilling fluid, such as balanced drilling and underbalanced drilling, and reducing the viscosity of the drilling fluid, such as reducing the circulating pressure loss. However, reducing the density of the drilling fluid will bring about well control problems, and the use of controlled pressure drilling is not suitable for all drilling conditions; reducing the viscosity of the drilling fluid will bring about problems such as difficulty in controlling water loss and difficulty in carrying cuttings. Especially with the large-scale application of oil-based drilling fluid, its high viscosity and high lubricity require a larger pump displacement and higher pump pressure to maintain a clean bottom of the well, which further reduces the drilling speed. Summary of the invention

[0004] In order to solve the above problems in the prior art, a jet speed-up tool for reducing the bottom hole pressure difference during drilling is provided.

[0005] The technical solution adopted by the present invention to solve its technical problem is: The present invention provides a jet speed-up tool for reducing the bottom hole pressure difference during drilling, comprising a shell with an inner tube passage, a mixing chamber is provided in the shell, the inner tube passage is connected to the mixing chamber through a supply passage, and the shell is further provided with a return passage connected to the mixing chamber; The supply channel can accelerate the fluid to form a jet in the mixing chamber, forming a low-pressure area in the mixing chamber, and then the reflux channel forms suction on the fluid below the shell, and the mixed fluid in the mixing chamber is sprayed obliquely upward.

[0006] Preferably, one end of the shell is an upper conical head detachably connected to the drill tool, and the connection end between the upper conical head and the shell is wider than the connection end between the upper conical head and the drill tool.

[0007] Preferably, the inclined surface of the upper conical head is provided with a jet port connected to the mixing chamber, and the jet port is oriented so that the mixed fluid is jetted obliquely upward.

[0008] Preferably, the other end of the shell is a lower conical head detachably connected to the drill bit, the connection end between the lower conical head and the shell is wider than the connection end between the lower conical head and the drill bit, and the ratio of the outer diameter of the shell to the drill bit diameter is (0.55-0.96):1.

[0009] Preferably, the inclined surface of the lower conical head is provided with a suction port connected to the reflux channel, and the suction port opened obliquely downward allows the fluid below the shell to be sucked into the reflux channel.

[0010] Preferably, the central axis of the mixing chamber is coaxial with the central axis of the supply channel, and the angle between the central axis of the mixing chamber and the central axis of the shell is 10-40°.

[0011] Preferably, a nozzle capable of forming a jet is provided at the connection between the supply channel and the mixing chamber, the central axis of the mixing chamber, the central axis of the nozzle and the central axis of the reflux channel intersect in the same plane, and the ratio of the outlet cross-sectional diameter of the nozzle to the diameter of the supply channel is 1:(1-6).

[0012] Preferably, the ratio of the diameter of the reflow channel to that of the mixing chamber is (0.4-1.0):1, and the ratio of the outlet cross-sectional diameter of the nozzle to the diameter of the reflow channel is 1:(0.16-0.38).

[0013] Preferably, the shell is evenly spaced with a plurality of supply channels communicating with the channel in the tube, and each supply channel is correspondingly provided with a mixing chamber and a reflux channel.

[0014] Preferably, the cross-sections of the supply channel and the return channel are both cylindrical.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The supply channel provided in the present application can increase the speed of the fluid, thereby forming a low-pressure area in the mixing chamber, so that the fluid below the shell is sucked into the mixing chamber through the reflux channel, and then sprayed obliquely upward by the mixing chamber. When the jet is ejected from the mixing chamber into the top of the shell, the injection action occurs in the gap between the side cylindrical surface of the shell and the well wall. Due to the jet action, the bottom hole pressure difference can be reduced accordingly, thereby achieving an increase in mechanical drilling speed. The structure is reasonable, the installation is convenient, the maintenance is simple, and the drilling cost is effectively reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 It is an overall schematic diagram of the present invention; Figure 2 It is an overall schematic diagram of the second embodiment; Figure 3 It is an overall schematic diagram in Embodiment 3; Figure 4 It is an overall schematic diagram of the fourth embodiment; Figure 5 It is an overall schematic diagram of the fifth embodiment.

[0017] Description of reference numerals: 1 shell; 2 channel in the tube; 3 supply channel; 4 nozzle; 5 mixing chamber; 6 reflux channel; 7 lower conical head; 8 injection port; 9 suction port; 10 upper conical head; 11 drill bit; 12 drilling tool; 13 drill bit channel. DETAILED DESCRIPTION

[0018] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0019] Embodiment 1 like Figure 1 As shown, this embodiment proposes a jet speed-up tool for reducing the bottom hole pressure difference during drilling, including a shell 1 with an inner tube channel 2, the inner tube channel 2 is opened in a vertical direction, a drill bit 11 is opened with a drill bit channel 13, the lower end of the inner tube channel 2 is connected to the drill bit channel 13, and the upper end of the inner tube channel 2 is connected to the drill tool 12, so that the drilling fluid flows from the drill tool 12 into the inner tube channel 2 and then is ejected from the drill bit channel 13.

[0020] A mixing chamber 5 is provided in the shell 1, and the tube channel 2 is connected to the mixing chamber 5 through the supply channel 3. The shell 1 also has a reflux channel 6 connected to the mixing chamber 5. The supply channel 3 and the mixing chamber 5 are both opened in an inclined direction. The drilling fluid enters the supply channel 3 through the tube channel 2, and then flows into the mixing chamber 5, and is mixed with the fluid below the shell 1 in the mixing chamber 5.

[0021] The supply channel 3 can accelerate the fluid to form a jet in the mixing chamber 5, so that the mixing chamber 5 forms a low-pressure area, and then the reflux channel 6 forms a suction force on the fluid below the shell 1, and then mixes it in the mixing chamber 5. The mixed fluid in the mixing chamber 5 is sprayed obliquely upward.

[0022] One end of the shell 1 is an upper conical head 10 detachably connected to the drill tool 12. The upper conical head 10 is detachably connected to the drill tool 12 by a threaded connection. The connection end of the upper conical head 10 and the shell 1 is wider than the connection end of the upper conical head 10 and the drill tool 12.

[0023] The inclined surface of the upper conical head 10 is provided with a jet port 8 connected to the mixing chamber 5. There are a plurality of jet ports 8, and all of the jet ports 8 are opened obliquely upward. The central axes of the jet ports 8 have the same height, and the orientation of the jet ports 8 allows the mixed fluid to be sprayed obliquely upward.

[0024] The other end of the shell 1 is a lower conical head 7 which is detachably connected to the drill bit 11. The lower conical head 7 is detachably connected to the drill bit 11 by a threaded connection. The connection end between the lower conical head 7 and the shell 1 is wider than the connection end between the lower conical head 7 and the drill bit 11. The outer diameter of the shell 1 is always smaller than the diameter of the drill bit 11. The ratio of the outer diameter of the shell 1 to the drill bit diameter is (0.55-0.96):1.

[0025] The inclined surface of the lower conical head 7 is provided with a suction port 9 connected to the reflux channel 6. There are several suction ports 9, and the several suction ports 9 are all opened obliquely downward. The central axes of the several suction ports 9 have the same height. Each suction port 9 is provided with a corresponding injection port 8. The suction ports 9 opened obliquely downward allow the fluid below the shell 1 to be sucked into the reflux channel 6.

[0026] The shell 1 includes two settings. In mode 1, the upper end of the shell 1 is connected to the drill 12, and the lower end is connected to the drill bit 11. In mode 2, the shell 1 can also be connected above a power drill, such as a screw drill or a turbine drill.

[0027] The shell 1 is evenly spaced with multiple supply channels 3 connected to the tube channel 2. The inner diameters of the several supply channels 3 are the same and are evenly distributed in the shell 1. Each supply channel 3 is correspondingly provided with a mixing chamber 5 and a reflux channel 6. There should be at least two supply channels 3. More supply channels 3 can be provided according to the diameter of the drill bit 11.

[0028] The supply channel 3, the return channel 6 and the mixing chamber 5 are all cylindrical in cross section, and the straight shape ensures that the loss due to hydraulic resistance is minimized.

[0029] The central axis of the mixing chamber 5 is coaxial with the central axis of the supply channel 3 , and the angle between the central axis of the mixing chamber 5 and the central axis of the housing 1 is 10-40°.

[0030] The ratio of the outlet cross-sectional diameter of the nozzle 4 to the diameter of the supply channel 3 is 1:(1-6), and the diameter of the supply channel 3 is larger than the outlet cross-sectional diameter of the nozzle 4 .

[0031] A nozzle 4 capable of forming a jet is provided at the connection point between the supply channel 3 and the mixing chamber 5. The outlet cross-sectional diameters of several nozzles 4 are the same, and the outlet cross-sectional diameter of the nozzle 4 is smaller than the diameter of the supply channel 3. The setting of the nozzle 4 can realize the acceleration of the drilling fluid, and then under the action of the nozzle 4, a jet is formed to enter the mixing chamber 5. The nozzle 4 is a circular hole, and the circular hole makes the jet have a more symmetrical shape in the initial stage.

[0032] The central axis of the mixing chamber 5 is coaxial with the central axis of the nozzle 4, and the central axis of the mixing chamber 5, the central axis of the nozzle 4 and the central axis of the reflow channel 6 intersect in the same plane, the ratio of the diameter of the reflow channel 6 to the mixing chamber 5 is (0.4-1.0):1, and the ratio of the outlet cross-sectional diameter of the nozzle 4 to the diameter of the reflow channel 6 is 1:(0.16-0.38), wherein the outlet cross-sectional diameter of the nozzle 4 is fixed.

[0033] The diameter of the mixing chamber 5 is larger than the diameter of the reflow channel 6. This arrangement can play the following role: deceleration effect. According to the fluid continuity equation, when the fluid flows from a smaller channel into a larger space, the speed of the fluid will decrease.

[0034] Turbulence dissipation: When the fluid flows from the smaller reflux channel 6 into the larger mixing chamber 5, the turbulence that may have existed will gradually dissipate due to the expansion of the space, and the fluid flow will become smoother.

[0035] Mixing promotion: The fluid in the reflux channel 6 is drilling fluid containing drill cuttings. The reduction in fluid velocity and the stabilization of the flow in the reflux channel 6 help the fluid to mix more fully with the drilling fluid in the mixing chamber 5, while reducing the impact of the fluid on the inner wall of the mixing chamber 5 and reducing wear.

[0036] A method for using a jet speed-up tool for reducing the bottom hole pressure difference during drilling, using the above-mentioned jet speed-up tool for reducing the bottom hole pressure difference during drilling, comprising the following steps: The upper conical head 10 of the housing 1 is threadedly connected to the drill tool 12, and the drill bit 11 is threadedly connected to the lower conical head 7 of the housing 1. At this time, the drill tool 12, the inner tube channel 2 and the drill bit channel 13 form a flow state. The drill tool 12 supplies the drilling fluid to the drill bit 11 through the inner tube channel 2. Part of the drilling fluid passes through the supply channel 3 and the speed increasing effect of the nozzle 4 to form a jet in the mixing chamber 5, so that a low pressure area is formed in the mixing chamber 5, and the drilling fluid containing drill cuttings is transported from the bottom of the well to the mixing chamber 5 through the return channel 6. The straight shape of the supply channel 3 and the return channel 6 ensures that the loss caused by hydraulic resistance is minimized. When the jet is ejected from the mixing chamber 5 into the top of the housing 1, the injection action occurs in the gap between the side cylindrical surface of the housing 1 and the well wall. Due to the jet action, the bottom hole pressure difference is correspondingly reduced, and the mechanical drilling speed is increased.

[0037] During the drilling process, the drilling fluid containing drill cuttings is jetted in an oblique upward manner, which can improve the efficiency of cuttings cleaning. During the process of rock crushing by the drill bit 11, the crushed cuttings are held at the bottom of the well due to a large pressure difference, resulting in the cuttings being unable to leave the bottom of the well in time. This phenomenon is called the cuttings "holding effect". The bottom hole impact pressure wave and bottom hole flow formed by the high-pressure water jet at the bottom of the well improve the bottom hole purification effect, reduce the holding effect of the rock, and avoid repeated damage to the drill bit 11. At the same time, the cuttings can also replace the steel particles to a certain extent, forming a particle jet, or the cuttings can be used as part of the particle jet.

[0038] Embodiment 2 like Figure 2 As shown, this embodiment proposes a jet speed-up tool for reducing the bottom hole pressure difference during drilling. In this embodiment, the inclination angle of the axis of the mixing chamber 5 is 10°, the ratio of the outlet cross-sectional diameter of the nozzle 4 to the diameter of the reflow channel 6 is 1:0.18, and the ratio of the diameter of the reflow channel 6 to the mixing chamber 5 is 1:1.

[0039] Embodiment 3 like Figure 3 As shown, this embodiment proposes a jet speed-up tool for reducing the bottom hole pressure difference during drilling. In this embodiment, the inclination angle of the axis of the mixing chamber 5 is 40°, the ratio of the outlet cross-sectional diameter of the nozzle 4 to the diameter of the reflow channel 6 is 1:0.35, and the ratio of the diameter of the reflow channel 6 to the mixing chamber 5 is 0.4:1.

[0040] Embodiment 4 like Figure 4 As shown, this embodiment proposes a jet speed-up tool for reducing the bottom hole pressure difference during drilling. In this embodiment, the inclination angle of the axis of the mixing chamber 5 is 20°, the ratio of the outlet cross-sectional diameter of the nozzle 4 to the diameter of the reflow channel 6 is 1:0.24, and the ratio of the diameter of the reflow channel 6 to the mixing chamber 5 is 0.8:1.

[0041] Embodiment 5 like Figure 5 As shown, this embodiment proposes a jet speed-up tool for reducing the bottom hole pressure difference during drilling. In this embodiment, the inclination angle of the axis of the mixing chamber 5 is 30°, the ratio of the outlet cross-sectional diameter of the nozzle 4 to the diameter of the reflow channel 6 is 1:0.3, and the ratio of the diameter of the reflow channel 6 to the mixing chamber 5 is 0.6:1.

[0042] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A jet speed-up tool for reducing the bottom hole pressure difference during drilling, comprising a housing (1) having an inner tube passage (2), characterized in that: A mixing chamber (5) is provided in the housing (1), the in-tube channel (2) is connected to the mixing chamber (5) via a supply channel (3), and the housing (1) is further provided with a reflux channel (6) connected to the mixing chamber (5); The supply channel (3) can accelerate the fluid and thereby form a jet in the mixing chamber (5), so that the mixing chamber (5) forms a low-pressure area, thereby causing the reflux channel (6) to form a suction force on the fluid below the shell (1), and the mixed fluid in the mixing chamber (5) is ejected obliquely upward.

2. A jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 1, characterized in that: One end of the housing (1) is an upper conical head (10) detachably connected to a drilling tool (12); the connection end between the upper conical head (10) and the housing (1) is wider than the connection end between the upper conical head (10) and the drilling tool (12).

3. A jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 2, characterized in that: The inclined surface of the upper conical head (10) is provided with a spray port (8) which is in communication with the mixing chamber (5), and the spray port (8) is oriented so that the mixed fluid is sprayed obliquely upward.

4. The jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 1, characterized in that: The other end of the housing (1) is a lower conical head (7) detachably connected to the drill bit (11); the connection end between the lower conical head (7) and the housing (1) is wider than the connection end between the lower conical head (7) and the drill bit (11); and the ratio of the outer diameter of the housing (1) to the diameter of the drill bit is (0.55-0.96):

1.

5. A jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 4, characterized in that: The inclined surface of the lower conical head (7) is provided with a suction port (9) connected to the reflux channel (6). The suction port (9) opened obliquely downward allows the fluid below the shell (1) to be sucked into the reflux channel (6).

6. The jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 1, characterized in that: The central axis of the mixing chamber (5) is coaxial with the central axis of the supply channel (3), and the angle between the central axis of the mixing chamber (5) and the central axis of the housing (1) is 10-40°.

7. The jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 1, characterized in that: A nozzle (4) capable of forming a jet is provided at the connection point between the supply channel (3) and the mixing chamber (5); the central axis of the mixing chamber (5), the central axis of the nozzle (4) and the central axis of the return channel (6) intersect in the same plane; and the ratio of the outlet cross-sectional diameter of the nozzle (4) to the diameter of the supply channel (3) is 1:(1-6).

8. The jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 7, characterized in that: The ratio of the diameter of the reflow channel (6) to that of the mixing chamber (5) is (0.4-1.0):1, and the ratio of the outlet cross-sectional diameter of the nozzle (4) to the diameter of the reflow channel (6) is 1:(0.16-0.38).

9. The jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 1, characterized in that: The shell (1) is evenly spaced with a plurality of supply channels (3) in communication with the channel (2) in the tube, and each supply channel (3) is correspondingly provided with a mixing chamber (5) and a reflux channel (6).

10. The jet speed-up tool for reducing the bottom hole pressure difference during drilling according to claim 1, characterized in that: The cross sections of the supply channel (3) and the return channel (6) are both cylindrical.

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