Controllable rotary screw drill string

Abstract

The application provides a controllable rotary screw drill tool, which comprises a shell, a power spindle concentrically arranged in the shell and capable of rotating relative to the shell, the power spindle being provided with a first central flow channel, and a spline groove extending along an axial part being arranged on an inner wall of a lower end of the power spindle; an output spindle for connecting a drill bit, the output spindle being arranged at a lower end of the power spindle and provided with a second central flow channel, and a spline capable of being matched with the spline groove being arranged on an outer wall of an upper end of the output spindle; wherein in a first state, the controllable rotary screw drill tool can be lifted off a bottom of a well, so that the output spindle is separated from the power spindle, and thus a power motor is separated from the drill bit to perform directional measurement; in a second state, the output spindle and the power spindle can be connected through the spline and the spline groove to form a connection, so that the power motor drives the drill bit to rotate, and thus drilling operation can be directly performed after directional measurement without drilling.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas drilling tool technology, and specifically relates to a controllable rotating screw drill bit. Background Technology

[0002] During the drilling of deep and ultra-deep wells, the deeper the well, the higher the temperature inside the well. Downhole instruments are limited by temperature resistance, so it is necessary to start the pump circulation in the casing before drilling to cool down the directional instruments and carry out directional measurements at the same time.

[0003] However, in existing technologies, in most cases after directional measurement, it is necessary to pull out the drill bit, connect the screw, and then continue drilling. This method is cumbersome and inefficient. If drilling proceeds directly after directional measurement and connection of the screw to the directional instrument, a problem arises: the screw motor will drive the drill bit to rotate during directional circulation, causing wear on the casing, which will seriously affect the service life of the casing. Summary of the Invention

[0004] To address the technical problems described above, this invention aims to provide a controllable rotating screw drill bit that can effectively avoid casing wear and can directly begin drilling after directional measurement without lifting the drill bit.

[0005] To address this, the present invention provides a controllable rotating screw drill bit, comprising: a cylindrical housing; a power spindle for connecting a power motor, the power spindle being concentrically arranged within the housing and rotatable relative to the housing, the power spindle having a first central flow channel and a spline groove extending axially on the inner wall of the lower end of the power spindle; and an output spindle for connecting a drill bit, the output spindle being disposed at the lower end of the power spindle and having a second central flow channel, and a spline on the outer wall of the upper end of the output spindle that is adapted to the spline groove; wherein, in a first state, the controllable rotating screw drill bit can be lifted off the bottom of the well, causing the output spindle to disengage from the power spindle, thereby separating the power motor from the drill bit for directional measurement; in a second state, the output spindle and the power spindle can be connected by the spline and the spline groove being adapted to each other, so that the power motor drives the drill bit to rotate, thereby enabling drilling operations to be performed directly without lifting the drill after directional measurement.

[0006] In one embodiment, the axial extension length of the spline is set to be in the range of 110-360 mm.

[0007] In one embodiment, the circumferential spacing of the spline is set to be in the range of 10-25 mm, and the thickness of the spline is set to be in the range of 5-15 mm.

[0008] In one embodiment, the number of spline heads is set to be in the range of 8-16mm.

[0009] In one embodiment, the lower end of the power spindle is provided with an inner chamfer, and the upper end of the spline is constructed as a guide slope.

[0010] In one embodiment, the housing is configured to include an upper housing, a middle stabilizer, and a lower housing that are fixedly connected from top to bottom.

[0011] In one embodiment, a bearing string is sleeved on the power spindle, and the bearing string is located between the upper housing and the power spindle.

[0012] In one embodiment, a first upper straightening and anti-wear component and a second upper straightening and anti-wear component are respectively provided at both ends of the bearing string.

[0013] In one embodiment, a limiting cylinder is fixedly connected to the lower end of the lower housing, and a lower straightening and anti-wear component is provided between the limiting cylinder and the output spindle.

[0014] In one embodiment, an anti-drop ring is fixed on the output spindle. The anti-drop ring is located axially inside the spline. In a first state, the lower end face of the anti-drop ring abuts against the upper end face of the limiting cylinder, thereby axially limiting the output spindle.

[0015] In one embodiment, a straightening device is installed between the output spindle and the lower housing.

[0016] Compared with the prior art, the advantages of this application are:

[0017] The controllable rotating screw drill of the present invention can disengage the power motor from the drill bit during circulation to avoid friction between the drill bit and the casing, thereby enabling directional measurement. This effectively avoids casing wear and significantly extends casing service life. Furthermore, the controllable rotating screw drill can commence drilling operations directly after directional measurement is completed without lifting the drill bit, simplifying operation and greatly improving construction efficiency. Attached Figure Description

[0018] The present invention will now be described with reference to the accompanying drawings.

[0019] Figure 1 This is a cross-sectional view of the controllable rotating screw drill according to the present invention.

[0020] Figure 2 yes Figure 1 A cross-sectional view of the power spindle in the controllable rotating screw drill shown.

[0021] Figure 3 schematically shown Figure 1 The structure of the output spindle in the controllable rotating screw drill shown.

[0022] In this application, all drawings are schematic and are used only to illustrate the principles of the invention, and are not drawn to scale. Detailed Implementation

[0023] The invention will now be described with reference to the accompanying drawings.

[0024] In this application, it should be noted that the end of the controllable rotating screw drill tool according to the present invention that is lowered into the wellbore near the wellhead is defined as the upper end or a similar term, and the end that is away from the wellhead is defined as the lower end or a similar term.

[0025] It should also be noted that the directional terms or qualifiers such as "up" and "down" used in this application are all specific to the referenced appendix. Figure 1 In other words, they are not used to define the absolute position of the components involved, but can vary depending on the specific circumstances.

[0026] Figure 1 This is a cross-sectional view of the controllable rotating screw drill 100 according to the present invention. Figure 1 As shown, the controllable rotary screw drill 100 includes a cylindrical housing 1, a power spindle 2 concentrically arranged within the housing 1, and an output spindle 4 for connecting the drill bit. The power spindle 2 is concentrically arranged inside the housing 1 and has a first axially extending central flow channel 21 for flowing drilling fluid. A bearing string 3 is fitted onto the power spindle 2, forming a rotatable connection between the power spindle 2 and the housing 1. The output spindle 4 is concentrically arranged inside the housing 1 and located at the lower end of the power spindle 2. The output spindle 4 has a second axially extending central flow channel 41. A spline groove 22 extending axially is provided on the inner wall of the lower end of the power spindle 2. Simultaneously, a spline 42 that mates with the spline groove 22 is provided on the outer wall of the upper end of the output spindle 4.

[0027] In practical applications, a directional instrument (not shown) is connected to the top of the controllable rotary screw drill 100 and is arranged inside the casing for directional measurement. Before drilling, a pump needs to be started inside the casing to circulate and cool the directional instrument while simultaneously performing directional measurements. During circulation, the controllable rotary screw drill 100 can be lifted off the bottom of the well, disengaging the output spindle 4 from the power spindle 2, thereby separating the power motor from the drill bit. The upper drill pipe rotates while the drill bit does not rotate to avoid friction between the drill bit and the casing, thus enabling directional measurement. At this time, the controllable rotary screw drill 100 is in its first state. After the directional measurement is completed, drilling pressure is applied, and circulation resumes. The output spindle 4 and the power spindle 2 can be connected via spline 42 and spline groove 22 to drive the drill bit to rotate, allowing drilling operations to proceed directly without lifting the drill bit after the directional measurement.

[0028] According to the present invention, such as Figure 1 As shown, the housing 1 is constructed to include an upper outer shell 11, a middle connector 12, and a lower outer shell 13, which are fixedly connected from top to bottom. The power spindle 2 is located within the upper outer shell 11 and the middle connector 12, and the output spindle 4 is located within the lower outer shell 13. The middle connector 12 can be a centralizer (a spiral centralizer or a straight-edged centralizer), which enables the central connector 12 to centralize the controllable rotating screw drill 100, greatly enhancing the performance of the controllable rotating screw drill 100.

[0029] In one embodiment, the upper housing 11, the middle connector 12, and the lower housing 13 are all fixedly connected by positive and negative tapered connectors. This connection method is convenient and quick to install, and can effectively ensure the stability of the connection.

[0030] like Figure 1 As shown, the bearing string 3 is disposed between the power spindle 2 and the upper housing 11. Preferably, the bearing string 3 is a TC bearing string, such as a cemented carbide bearing or a tungsten carbide bearing, where TC refers to tungsten carbide, which is the main raw material for producing cemented carbide. The inner ring of the bearing string 3 is fixedly connected to the power spindle 2 by an interference fit, and the outer ring of the bearing string 3 is fixedly connected to the inner wall of the upper housing 11. Thus, the power spindle 2 and the housing 1 are rotatably connected through the bearing string 3.

[0031] According to the present invention, a first upper straightening and anti-wear component 31 and a second upper straightening and anti-wear component 32 are respectively provided at the upper and lower ends of the bearing string 3. Figure 1 As shown, the first upper anti-wear assembly 31 is located radially between the power spindle 2 and the upper housing 11. The first upper anti-wear assembly 31 includes a first anti-wear stationary ring 311 and a first anti-wear moving ring 312. The first anti-wear stationary ring 311 is fixedly connected to the inner wall of the upper housing 11, and its lower end face abuts against the upper end face of the outer ring of the bearing string 3. In one embodiment, the inner wall of the upper housing 11 has a two-stage step with its end face facing downwards, and the outer wall of the first anti-wear stationary ring 311 has a two-stage step with its end face facing upwards. The first anti-wear stationary ring 311 and the upper housing 11 are axially limited by the two-stage step. The first anti-wear moving ring 312 is fixedly connected to the power spindle 2, and its lower end face abuts against the upper end face of the inner ring of the bearing string 3. The first upper anti-wear assembly 31 effectively prevents wear between the power spindle 2 and the upper housing 11.

[0032] like Figure 1As shown, a tightening nut 9 is provided at the upper end of the first upper straightening and anti-wear component 31, and the tightening nut 9 is fastened to the power spindle 2 by threads. The tightening nut 9 is used to lock the first anti-wear moving ring 312 of the first upper straightening and anti-wear component 31 onto the power spindle 2, so that the first anti-wear moving ring 312 is relatively stationary with respect to the power spindle 2, realizing the fixed connection between the first anti-wear moving ring 312 and the power spindle 2, thereby enhancing the stability of the controllable rotating screw drill 100.

[0033] Additionally, an adjusting shim can be installed on the upper end of the tightening nut 9 as an adjustment component during installation to facilitate installation.

[0034] like Figure 1 As shown, the second upper anti-wear assembly 32 is located radially inner to the central connector 12. The second upper anti-wear assembly 32 includes a second anti-wear stationary ring 321 and a second anti-wear moving ring 322. The second anti-wear stationary ring 321 is fixedly connected to the inner wall of the central connector 12, and its upper end face abuts against the lower end face of the outer ring of the bearing string 3. In one embodiment, the inner wall of the central connector 12 has an upward-facing step, and the lower end face of the second anti-wear stationary ring 321 abuts against this step to form an axial limit. The second anti-wear moving ring 322 is fixedly connected to the power spindle 2, and its upper end face abuts against the lower end face of the inner ring of the bearing string 3. The second upper anti-wear assembly 32 effectively prevents wear between the power spindle 2 and the central connector 12.

[0035] During operation, the first upper centering and anti-wear assembly 31 and the second upper centering and anti-wear assembly 32 can withstand the eccentric movement of the rotor in the downhole motor, as well as the radial force generated by the oscillation of the universal joint shaft and the fixed-axis rotation of the power spindle 2 itself. This improves the guiding capability of the controllable rotating screw drill 100 and the transmission performance of the power spindle 2.

[0036] According to the present invention, a clamping component may also be provided between the bearing string 3 and the second upper straightening and anti-wear component 32. For example... Figure 1 As shown, the clamping assembly is disposed axially between the bearing string 3 and the second upper straightening and anti-wear assembly 32. The clamping assembly includes an outer clamping sleeve 33 and an inner clamping sleeve 34. The outer clamping sleeve 33 is used to clamp the lower end face of the outer ring of the bearing string 3, and the inner clamping sleeve 34 is used to clamp the lower end face of the inner ring of the bearing string 3. In one embodiment, the inner clamping sleeve 34 is provided with an internal thread, which forms a fixed connection with the power spindle 2 through the internal thread, thereby clamping the inner ring of the bearing string 3 and thus axially limiting the bearing string 3.

[0037] According to the present invention, the axial extension length of the spline 42 on the output spindle 4 is set to be in the range of 110-360 mm. The number of spline 42 heads on the output spindle 4 is set to be in the range of 8-16, the circumferential spacing of the spline 42 is set to be in the range of 10-25 mm, and the thickness of the spline 42 is set to be in the range of 5-15 mm. Correspondingly, the spline groove 22 on the power spindle 2 is adapted to the spline 42. In order to facilitate the mating of the spline 42 and the spline groove 22, the width and depth of the spline groove 22 are both set to be slightly larger than the width and depth of the spline 42.

[0038] like Figure 2 and Figure 3 As shown, in order to facilitate the fit between the spline 42 and the spline groove 22, the lower end of the power spindle 2 is provided with an inner chamfer, while the upper end of the spline 42 is constructed as a guide slope 43.

[0039] In an embodiment not shown, a straightening device may be installed between the output spindle 4 and the lower housing 13 to ensure the coaxiality between the output spindle 4 and the power spindle 2, which is more conducive to the fit between the spline 42 and the spline groove 22.

[0040] like Figure 1 As shown, a limiting cylinder 6 is fixed to the lower end of the lower housing 13. In one embodiment, the limiting cylinder 6 is fixedly connected to the lower housing 13 by threads. A lower straightening and anti-wear assembly 7 is provided between the limiting cylinder 6 and the output spindle 4. The lower straightening and anti-wear assembly 7 includes a straightening and anti-wear moving ring and a straightening and anti-wear stationary ring formed on the inner wall of the limiting cylinder 7. The straightening and anti-wear moving ring is fixedly connected to the output spindle 4, for example, by threads. Thus, the lower straightening and anti-wear assembly 7 effectively prevents wear between the output spindle 4 and the lower housing 13.

[0041] According to the present invention, such as Figure 1 As shown, an anti-drop ring 5 is fixed on the output spindle 4. The anti-drop ring 5 is fixedly installed on the axial inner side of the spline 42. In the first state, the lower end face of the anti-drop ring 5 abuts against the upper end face of the limiting cylinder 6, thereby forming an axial limit on the output spindle 4 and preventing the output spindle 4 from falling.

[0042] In one embodiment, the output spindle 4 has an external thread on its outer wall, and the anti-drop ring 5 has an internal thread. The anti-drop ring 5 is fixedly connected to the output spindle 4 by the engagement of its internal thread with the external thread.

[0043] The working process of the controllable rotary screw drill 100 according to the present invention is briefly described below. First, the controllable rotary screw drill 100 is connected to the lower end of the downhole motor. After assembly, it is lowered into the wellbore. During the lowering process, the output spindle 4 is effectively prevented from falling off under the action of the anti-drop ring 5 and the limiting sleeve 7. An orientation instrument (not shown) is connected to the top of the controllable rotary screw drill 100 and is arranged in the casing for orientation measurement. Before drilling, the pump needs to be turned on in the casing to circulate and cool the orientation instrument, while simultaneously performing orientation measurement. During circulation, by lifting the controllable rotary screw drill 100 from the bottom of the well, the output spindle 4 is disengaged from the power spindle 2, thereby disengaging the power motor from the drill bit. The upper drill pipe rotates while the drill bit does not rotate, thus avoiding friction between the drill bit and the casing, thereby performing orientation measurement. At this time, the controllable rotary screw drill 100 is in the first state. After the directional measurement is completed, drilling pressure is applied through the wellhead and circulated, so that the output spindle 4 and the power spindle 2 are connected by the spline 42 and the spline groove 22. This allows the power motor to transmit torque through the power spindle 2 and the output spindle 4 in sequence to drive the drill bit to rotate, so that drilling can be carried out directly without lifting the drill after the directional measurement.

[0044] The controllable rotary screw drill 100 of the present invention can disengage the power motor from the drill bit during circulation to avoid friction between the drill bit and the casing, thereby enabling directional measurement. This effectively avoids casing wear and significantly extends the service life of the casing. The controllable rotary screw drill 100 can also directly commence drilling operations after directional measurement is completed without lifting the drill bit, simplifying operation and greatly improving construction efficiency.

[0045] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0046] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that the specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any suitable manner in one or more embodiments or examples.

[0047] Finally, it should be noted that the above description is merely a preferred embodiment of the present invention and does not constitute any limitation on the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A controllable rotating screw drill for deep or ultra-deep wells, comprising: The outer shell (1) is constructed in a cylindrical shape, and the outer shell is constructed to include an upper outer shell (11), a middle stabilizer (12) and a lower outer shell (13) that are fixedly connected from top to bottom. A power spindle (2) for connecting a power motor is arranged concentrically inside the housing and can rotate relative to the housing. The power spindle is provided with a first central flow channel (21) and a spline groove (22) extending axially on the inner wall of the lower end of the power spindle. The output spindle (4) is used to connect the drill bit. The output spindle is located at the lower end of the power spindle and has a second central flow channel (41). The upper outer wall of the output spindle has a spline (42) that can be adapted to the spline groove. In the first state, the controllable rotating screw drill bit can be lifted off the bottom of the well, causing the output spindle to disengage from the power spindle, thereby separating the power motor from the drill bit for directional measurement. In the second state, the output spindle and the power spindle can be connected by the spline and the spline groove, so that the power motor drives the drill bit to rotate, thereby enabling drilling operations to be carried out directly without drilling after directional measurement; A limiting cylinder (6) is fixedly connected to the lower end of the lower outer shell. A lower straightening and anti-wear component (7) is provided between the limiting cylinder and the output spindle. An anti-drop ring (5) is fixed on the output spindle. The anti-drop ring is located on the axial inner side of the spline. In the first state, the lower end face of the anti-drop ring abuts against the upper end face of the limiting cylinder, thereby forming an axial limit on the output spindle.

2. The controllable rotating screw drill according to claim 1, characterized in that, The axial extension length of the spline is set to be in the range of 110-360mm.

3. The controllable rotating screw drill according to claim 1 or 2, characterized in that, The circumferential spacing of the splines is set to be in the range of 10-25mm, and the thickness of the splines is set to be in the range of 5-15mm.

4. The controllable rotating screw drill according to claim 1 or 2, characterized in that, The number of spline heads is set to be in the range of 8-16.

5. The controllable rotating screw drill according to claim 1 or 2, characterized in that, The lower end of the power spindle is provided with an inner chamfer, and the upper end of the spline is constructed as a guide slope (43).

6. The controllable rotating screw drill according to claim 1 or 2, characterized in that, A bearing string (3) is sleeved on the power spindle, and the bearing string is located between the upper housing and the power spindle.

7. The controllable rotating screw drill according to claim 6, characterized in that, A first upper straightening and anti-wear component (31) and a second upper straightening and anti-wear component (32) are respectively provided at both ends of the bearing string.

8. The controllable rotating screw drill according to claim 1 or 2, characterized in that, A straightening device is installed between the output spindle and the lower housing.

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