CN114622857B

CN114622857B - Pressure regulating circulation switching device and method suitable for continuous circulation drilling of gas

Info

Publication number: CN114622857B
Application number: CN202110805035.2A
Authority: CN
Inventors: 李宬晓; 周长虹; 杨超; 徐忠祥; 蒲克勇; 廖兵; 颜海; 吴琦; 肖洲; 刘云
Original assignee: China National Petroleum Corp; CNPC Chuanqing Drilling Engineering Co Ltd
Current assignee: China National Petroleum Corp; CNPC Chuanqing Drilling Engineering Co Ltd
Priority date: 2021-07-16
Filing date: 2021-07-16
Publication date: 2024-05-14
Anticipated expiration: 2041-07-16
Also published as: CN114622857A

Abstract

The invention provides a pressure regulating circulation switching device and a method suitable for continuous circulation drilling of gas. The pressure regulating circulation switching method suitable for the gas continuous circulation drilling is realized by the pressure regulating circulation switching device, and the method comprises the steps of controlling a positive circulation process, a side circulation process, a positive circulation rotating side circulation process and a side circulation rotating positive circulation process of dry gas and atomization continuous circulation drilling. The beneficial effects of the invention can include: the pressure regulating circulation switching device and the switching method are suitable for gas continuous circulation drilling, and underground complex conditions caused by circulation interruption and large pressure fluctuation are avoided.

Description

Pressure regulating circulation switching device and method suitable for continuous circulation drilling of gas

Technical Field

The invention relates to the technical field of petroleum drilling devices, in particular to a pressure regulating circulation switching device and method suitable for continuous circulation drilling of gas.

Background

At present, in the process of connecting a single joint (upright post) or tripping in petroleum drilling, the circulation of drilling fluid is stopped, negative pressure is excited to the bottom of the well, and the bottom of the well is possibly lower than the pore pressure of the stratum, so that accidents such as well kick, gas invasion, well wall collapse, blocking and burying drilling tools and the like are possibly caused. The pump is restarted after the single joint (upright post) is completed, positive pressure excitation is caused to enable the bottom hole pressure to be higher than the pressure in normal circulation, even the pressure exceeds the formation fracture pressure, so that the problems of fracturing leakage, differential pressure sticking and the like are caused, well quality is reduced, and a plurality of potential difficulties are brought to subsequent operations, particularly casing and well cementation.

In the dry gas and atomization drilling process, the gas is quickly flushed, the well wall is irregular, the large belly well holes are more, and after the circulation is interrupted, rock scraps quickly settle, accidents such as drilling tool burying and drilling sticking can be caused, and particularly in the stratum with more sand setting, the damage is more serious. After the middle section of the stratum is circulated, stratum water gathers and soaks the well wall, so that the well wall is seriously unstable, and gas drilling failure is caused. After the middle section circulates in the deep well section atomization well drilling, the stable time for establishing the circulating pressure is longer, and the ageing is reduced.

The continuous circulation drilling technology breaks through the traditional mode, keeps the drilling medium continuously circulated in the process of connecting a single column and tripping, continuously cleans the bottom of the well, keeps the bottom pressure relatively stable, and can avoid all underground complex and accidents caused by circulation interruption. Particularly, under the conditions of dry gas and an atomization drilling process, a circulating medium is kept to circulate continuously, rock scraps are suspended continuously, complex accidents such as drilling tool burying and drilling sticking caused by sand setting and sedimentation are avoided, and meanwhile, the process can effectively prolong the air drilling footage of a stratum with more sand setting and trace water outlet.

The continuous circulation drilling technology mainly adopts two modes of a continuous circulation system and a continuous circulation valve. The continuous circulation valve is arranged at the top end of a single column in advance in a continuous circulation valve control mode, the single column with the continuous circulation valve is drilled, a side circulation pipeline is connected to the side valve of the continuous circulation valve, lateral circulation channel switching is carried out, forward switching is carried out after the single column is connected and disconnected, and a drilling process that circulation mediums are not interrupted in the process of tripping and connecting the single column is realized. However, after the single (upright post) is connected, the tap and the water hole connected with the single (upright post) are not filled with the circulating medium, when the lateral circulation is switched to the forward circulation, a certain time is needed to fill the forward circulation pipeline (the tap and the connected upright post), so that the pressure balance can be achieved, the continuous circulation can be interrupted as a final result, the bottom hole pressure fluctuation is large, and the underground complexity can be caused as well; similarly, when the forward circulation and the reverse side circulation are performed, a certain time is required for the side circulation pipeline to be filled with the circulation medium.

Disclosure of Invention

The present invention is directed to solving one or more of the problems of the prior art, including the shortcomings of the prior art. For example, it is an object of the present invention to provide a pressure regulating circulation switching device suitable for gas continuous circulation drilling. Another object of the present invention is to provide a pressure regulating circulation switching method suitable for gas continuous circulation drilling.

In one aspect, the invention provides a pressure regulating circulation switching device suitable for continuous circulation drilling of gas. The pressure regulating circulation switching device comprises a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline, a first control valve, a second control valve, a third control valve, a fourth control valve, a first pressure regulating valve, a second pressure regulating valve, a circulating medium inlet, a positive circulation joint, a side circulation joint and a pressure relief joint, wherein one end of the first pipeline is connected with the circulating medium inlet, and the other end of the first pipeline is connected with the positive circulation joint; one end of the second pipeline is connected with the circulating medium inlet, and the other end of the second pipeline is connected with the side circulating joint; one end of the third pipeline is connected with the positive circulation joint, and the other end of the third pipeline is connected with the pressure relief joint; one end of the fourth pipeline is connected with the side circulation joint, and the other end of the fourth pipeline is connected with the pressure relief joint; the first control valve is arranged on the first pipeline, the second control valve is arranged on the second pipeline, the third control valve is arranged on the third pipeline, and the fourth control valve is arranged on the fourth pipeline; one end of the fifth pipeline is communicated with a part of the pipeline of the second pipeline, which is positioned between the circulating medium inlet and the second control valve, and the other end of the fifth pipeline is communicated with a part of the pipeline of the third pipeline, which is positioned between the positive circulating joint and the third control valve; the first pressure regulating valve is arranged on a fifth pipeline; one end of the sixth pipeline is communicated with a part of the fifth pipeline between the second pipeline and the first pressure regulating valve, and the other end of the sixth pipeline is communicated with a part of the fourth pipeline between the side circulation joint and the fourth control valve; the second pressure regulating valve is arranged on the sixth pipeline.

In an exemplary embodiment of an aspect of the present invention, the circulation switching device may further include a first pressure gauge provided on the positive circulation joint to display the pressure in the first line, and a second pressure gauge provided on the lateral circulation joint to display the pressure in the second line.

In an exemplary embodiment of an aspect of the present invention, the first and second control valves may be flat gate valves, the third and fourth control valves may be throttle valves, and the first and second pressure regulating valves may be throttle valves.

In an exemplary embodiment of an aspect of the present invention, the first control valve, the second control valve, the third control valve, the fourth control valve, the first pressure regulating valve and the second pressure regulating valve may have two modes of hydraulic control and mechanical control, and may be opened by adopting a manual control mode in case of hydraulic control failure.

In an exemplary embodiment of an aspect of the present invention, the pressure-regulating circulation switching device may further include an uninterrupted circulation joint, where the uninterrupted circulation joint includes a shorting unit and a movable docking unit, the shorting unit includes an upper connector, a lower connector, a clutch device, a first inlet check valve and a second inlet check valve, the upper connector and the lower connector are rotationally connected from top to bottom, and both have hollow axial cavities, the axial cavities of the two are interconnected, and a through side connection port is further opened on a side wall of the upper connector; the clutch device is sleeved on the upper connector and/or the lower connector, and can enable the upper connector and the lower connector to keep relative rotation or synchronous rotation; the first inlet check valve is arranged in the upward opening of the upper connector, and the second inlet check valve is arranged in the lateral connecting port of the upper connector; the movable butt joint unit comprises a side connection mechanism, the side connection mechanism comprises a side connector, the front end of the side connector is matched with the side connector and can be inserted into the side connector, the rear end of the side connector is provided with an interface for butt joint with a drilling circulation medium pipeline, and the side connector is also provided with a hollow cavity for communicating the front end with the rear end; the positive circulation joint is connected with the first inlet check valve through a pipeline, and the side circulation joint is connected with the second inlet check valve through a pipeline.

In an exemplary embodiment of an aspect of the present invention, the mobile docking unit may further include a mobile seat, and the lateral connection mechanism is located on the mobile seat; the side connecting mechanism comprises a hollow motor and a fastening sleeve, a rotation output hole of the hollow motor is kept horizontal, the fastening sleeve is fixed in the rotation output hole of the hollow motor, the fastening sleeve is sleeved on the side connecting head, and the front end of the fastening sleeve is located outside the hollow motor.

In an exemplary embodiment of an aspect of the present invention, the lateral connection mechanism may further include a torsion limiter, a rotary table, and a lifting structure, wherein the torsion limiter is fixed in a rotation output hole of the hollow motor, the fastening sleeve is connected with an inner cavity of the torsion limiter in an adaptive manner, the fastening sleeve is sleeved on the lateral connection head, and a front end of the fastening sleeve is located outside the hollow motor; the front end of the fastening sleeve is matched with the side connecting port and can be screwed into the side connecting port; the rotary table can rotate on a horizontal plane, and the hollow motor is fixed on the table top of the rotary table; the lifting structure is positioned between the rotary table and the movable seat, and can adjust the vertical distance between the rotary table and the movable seat.

In an exemplary embodiment of an aspect of the present invention, the clutch device may include a spline housing, a portion of the upper connector contacting the spline housing is a first spline shaft, a portion of the lower connector contacting the spline housing is a second spline shaft, the first spline shaft and the second spline shaft are both matched with the spline housing, the spline housing can slide back and forth on the first spline shaft and the second spline shaft, and the shorting unit further includes a first fixing member capable of fixing the spline housing with the first spline shaft; the upper connecting body comprises a connecting shaft, a clutch shaft, a limiting shaft and a rotating shaft which are sequentially connected from top to bottom, wherein the upper end of the connecting shaft can also be connected with a drilling tool, a first inlet one-way valve is arranged in an upward opening of the connecting shaft, and a second inlet one-way valve is arranged on the side wall of the connecting shaft; the clutch shaft is a spline shaft, and the radial dimension of the clutch shaft is smaller than that of the connecting shaft; the radial dimension of the limiting shaft is smaller than the radial dimension of the lower end of the clutch shaft and the upper end of the rotating shaft; the lower connector is provided with an upper cavity and a lower cavity which are communicated up and down, the radial size of the upper cavity is larger than that of the lower cavity, and the rotating shaft can be placed in the upper cavity and connected between the upper cavity and the lower cavity in a rotating way.

The invention further provides a pressure regulating circulation switching method suitable for gas continuous circulation drilling, which is suitable for gas continuous circulation drilling. The method is realized by the pressure regulating circulation switching device suitable for gas continuous circulation drilling, and the method comprises the following steps: positive cycle process: opening a first control valve, closing a second control valve, a third control valve, a fourth control valve, a first pressure regulating valve and a second pressure regulating valve, wherein medium fluid enters from a circulating medium inlet, passes through a first pipeline and flows out from a positive circulation joint; side circulation process: opening a second control valve, closing a first control valve, a third control valve, a fourth control valve, a first pressure regulating valve and a second pressure regulating valve, wherein medium fluid enters from a circulating medium inlet, passes through a second pipeline and flows out from a side circulating joint; forward cycle-to-side cycle process: after the side circulation joint is connected with the side circulation pipeline, a second pressure regulating valve is opened, circulation medium is pumped into the second pipeline until the second pipeline and the side circulation pipeline are filled with the circulation medium, the pressure in the second pipeline rises to be close to the pressure in the first pipeline, a second control valve is opened, the second pressure regulating valve is closed, and a side circulation channel is established; closing the first control valve to cut off the positive circulation channel, opening the third control valve to release pressure, closing the third control valve after the pressure release, and completing the operation of positive circulation and lateral circulation; side circulation to forward circulation process: after the positive circulation joint is connected with the positive circulation pipeline, a first pressure regulating valve is opened, circulation medium is pumped into the first pipeline until the first pipeline and the positive circulation pipeline are filled with the circulation medium, the pressure in the first pipeline rises to be close to the pressure in the second pipeline, a first control valve is opened, the first pressure regulating valve is closed, and a positive circulation channel is established; closing the second control valve to cut off the side circulation channel, opening the fourth control valve to release pressure, closing the fourth control valve after releasing pressure, and completing the operation of side circulation to forward circulation.

In an exemplary embodiment of another aspect of the present invention, the pressure regulating ranges of the first and second pressure regulating valves may be0 to 15Mpa.

In an exemplary embodiment of another aspect of the present invention, the increase in the second in-line pressure to approximately the first in-line pressure may be at a value of greater than or equal to 95% of the second in-line pressure.

In an exemplary embodiment of another aspect of the present invention, the increase in the pressure in the first pipeline to approximately the pressure in the second pipeline may be a value of the pressure in the first pipeline that is greater than or equal to 95% of the pressure in the second pipeline.

In an exemplary embodiment of another aspect of the present invention, the positive cycle side cycle or the side cycle positive cycle may have a pressure fluctuation range of 0 to 0.5Mpa.

In an exemplary embodiment of another aspect of the present invention, the opening the fourth control valve to release the pressure may include closing the fourth control valve after the pressure of the second line drops to zero for 10 seconds.

Compared with the prior art, the invention has the beneficial effects that: the invention provides a pressure regulating circulation switching device and a method suitable for continuous circulation drilling of gas. In the continuous circulation drilling process, the circulation medium is ensured not to be interrupted, the problem of large pressure fluctuation in the switching process is solved, and the underground complex condition caused by circulation interruption and large pressure fluctuation is avoided.

Drawings

The foregoing and other objects and features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 illustrates a schematic diagram of a pressure regulating circulation switching device suitable for use in gas continuous circulation drilling in accordance with an exemplary embodiment of the present invention;

FIG. 2 illustrates a schematic diagram of an uninterrupted looping connection according to an exemplary embodiment of the invention;

figure 3 shows a schematic structural diagram of the shorting unit of the present invention;

Figure 4 shows a schematic assembly of the shorting unit of the present invention;

FIG. 5 shows a partial enlarged view at A in FIG. 2;

FIG. 6 shows a schematic structural view of the first side joint of the present invention;

Fig. 7 shows a schematic structural view of the second side joint of the present invention.

The reference numerals are as follows:

1-first pipeline, 2-second pipeline, 3-third pipeline, 4-fourth pipeline, 5-fifth pipeline, 6-sixth pipeline, 7-first control valve, 8-second control valve, 9-third control valve, 10-fourth control valve, 11-first pressure regulating valve, 12-second pressure regulating valve, A01-circulating medium inlet, A02-positive circulating joint, A03-pressure relief joint, A04-side circulating joint, 16-upper connector, 161-connecting shaft, 1611-side connecting port, 162-clutch shaft, 163-limiting shaft, 1631-limiting sleeve and 164-rotating shaft; 17-lower connector, 171-upper cavity, 172-lower cavity, 173-rotor mounting hole, 174-blocking pin; 18-a clutch device; 191-first inlet check valve, 192-second inlet check valve; 20-rotating member; 21-a seal; 221-first fixing piece, 222-second fixing piece; 23-rolling wheels; 24-supporting legs; 25-a mobile seat; 401-a hollow motor, 402-a torsion limiter, 403-a fastening sleeve, 404-a side connector, 405-a rotary table and 406-a lifting structure; 50-a control cabinet; 60-a gate valve manifold pry body; 70-an integrated box; 80-pipe.

Detailed Description

Hereinafter, the pressure regulating circulation switching device and method for gas continuous circulation drilling according to the present invention will be described in detail with reference to exemplary embodiments and accompanying drawings. It should be noted that the terms "first," "second," "third," "fourth," "fifth," "sixth," "seventh," "eighth," and the like are merely for convenience of description and convenience of distinction and are not to be construed as indicating or implying relative importance. The terms "upper," "lower," "left," "right," and "left" are merely used for convenience of description and to construct a relative orientation or positional relationship, and do not indicate or imply that the components in question must have that particular orientation or position.

In one aspect, the invention provides a pressure regulating circulation switching device suitable for continuous circulation drilling of gas.

Fig. 1 shows a schematic structure of a pressure regulating circulation switching device suitable for gas continuous circulation drilling according to an exemplary embodiment of the present invention.

In the first exemplary embodiment of the present invention, as shown in fig. 1, the pressure-regulating circulation switching device suitable for gas continuous circulation drilling is mainly composed of a first line 1, a second line 2, a third line 3, a fourth line 4, a fifth line 5, a sixth line 6, a first control valve 7, a second control valve 8, a third control valve 9, a fourth control valve 10, a first pressure regulating valve 11, a second pressure regulating valve 12, a circulation medium inlet a01, a positive circulation joint a02, a side circulation joint a04, and a pressure relief joint a 03.

One end of the first pipeline 1 is connected with the circulating medium inlet A01, and the other end of the first pipeline 1 is connected with the positive circulating joint A02. The first line 1 is further provided with a first control valve 7, and the medium fluid passing through the first line 1 is controlled by opening and closing the first control valve 7. Here, the first control valve 7 may be a flat valve. One end of the second pipeline 2 is connected with the circulating medium inlet A01, and the other end of the second pipeline 2 is connected with the side circulating joint A04. The second line 2 is further provided with a second control valve 8, the medium fluid passing through the second line 2 being controlled by opening and closing of the second control valve 8. Here, the second control valve 8 may be a flat valve. The first control valve and the second control valve are arranged as the flat valve, because the first control valve and the second control valve mainly play a role of stopping and closing, the flat valve has small flow resistance, the sealing surface of the flat gate valve can be automatically positioned, and the sealing surface of the valve seat is not damaged by the thermal deformation of the valve body; and even if the valve is closed in a cold state, the thermal elongation of the valve stem does not overload the sealing surface. As shown in fig. 1, the first line 1, the second line 2 and the circulating medium inlet a01 may be connected by a first rectangular cavity. The first rectangular cavity is a three-way joint connected by adopting a flange, and the arrangement is used for enhancing the high pressure resistance.

One end of the third pipeline 3 is connected with the positive circulation joint A02, and the other end of the third pipeline 3 is connected with the pressure relief joint A03. The third pipeline 3 is also provided with a third control valve 9, and the circulating medium fluid in the first pipeline 1 is decompressed by opening and closing the third control valve 9. One end of the fourth pipeline 4 is connected with the side circulation joint A04, and the other end of the fourth pipeline 4 is connected with the pressure relief joint A03. The fourth pipeline 4 is also provided with a fourth control valve 10, and the circulating medium fluid in the second pipeline 2 is decompressed by opening and closing the fourth control valve 10. As shown in fig. 1, the first line 1, the third line 3 and the positive circulation joint a02 may be connected by a second rectangular cavity; the third pipeline 3, the fourth pipeline 4 and the pressure relief joint A03 can be connected through a third rectangular cavity; the second line 2, the fourth line 4 and the side circulation connection a04 may be connected by a fourth rectangular cavity. Here, the third control valve 9 and the fourth control valve 10 may be throttle valves. The third control valve 9 and the fourth control valve 10 are arranged as throttle valves, and the speed of pressure relief can be controlled by using the throttle valves because the two valves are pressure relief valves, so that the safety of pressure relief ports is ensured. One end of the fifth line 5 communicates with a portion of the second line 2 of the pipe between the circulation medium inlet a01 and the second control valve 8, and the other end of the fifth line 5 communicates with a portion of the third line 3 between the positive circulation joint a02 and the third control valve 9. A first pressure regulating valve 11 is also provided in the fifth line 5, and the flow of medium through the fifth line 5 is controlled by opening and closing the first pressure regulating valve 11. As shown in fig. 1, the second line 2 is connected to the left end of the fifth line 5 through a fifth rectangular cavity, and the third line 3 is connected to the right end of the fifth line 5 through a sixth rectangular cavity. One end of the sixth line 6 communicates with a portion of the fifth line 5 located between the second line 2 and the first pressure regulating valve 11, and the other end of the fifth line 5 communicates with a portion of the fourth line 4 located between the side circulation joint a04 and the fourth control valve 10, of the fourth line 4. A second pressure regulating valve 12 is also provided in the sixth line 6, the flow of medium through the sixth line 6 being controlled by the opening and closing of the second pressure regulating valve 12. As shown in fig. 1, the upper end of the sixth pipeline 6 communicates with the fifth pipeline through a seventh rectangular cavity, and the lower end of the sixth pipeline 6 communicates with the fourth pipeline 4 through an eighth rectangular cavity. Here, the first pressure regulating valve 11 and the second pressure regulating valve 12 may be throttle valves. Here, the first pressure regulating valve 11 and the second pressure regulating valve 12 are provided as throttle valves because both valves are on-off valves of the pressure regulating passage, and the speed of pressure regulation can be controlled using the throttle valves, so that pressure fluctuation can be ensured in the range of 0 to 0.5 MPa. In the present exemplary embodiment, as shown in fig. 1, the circulation switching device may further include a first pressure gauge provided on the positive circulation joint a02 to display the pressure in the first line 1 and a second pressure gauge (not shown in fig. 1) provided on the side circulation joint a04 to display the pressure in the second line 2. Of course, the first pressure gauge may also be arranged on the second rectangular cavity or on a part of the first line 1, a part of the third line 3 or a part of the fifth line 5 communicating with the positive-cycle connection a 02. The second pressure gauge may also be arranged on the fourth rectangular cavity or on a part of the second line 2, a part of the fourth line 4 or a part of the sixth line 6 communicating with the side circulation connection a 04.

In this exemplary embodiment, the first control valve, the second control valve, the third control valve, the fourth control valve, the first pressure regulating valve and the second pressure regulating valve may have both hydraulic control and mechanical control, and may be opened and closed in a mechanical control manner after the automatic or manual hydraulic control fails.

In a second exemplary embodiment of the present invention, the voltage regulation cycle switching device may further include an uninterrupted cycle connection including a shorting unit and a mobile docking unit. In addition, the uninterrupted circulating joint can further comprise a gate valve manifold prying body and a control cabinet, wherein the gate valve manifold prying body is connected with the rear end of the side joint through a pipeline. For example, further, the control cabinet and the gate valve manifold pry can be arranged in the integrated box together, so that the working space is effectively saved. In addition, the uninterrupted looping connection may also include a drilling platform on which part or all of the connection may be placed.

The short circuit unit includes connector, lower connector, clutch, first entry check valve and second entry check valve, goes up connector and lower connector top-down and rotates to be connected, and both have hollow axial cavity, and the axial cavity of both is interconnected, has still offered the side connector that link up on the lateral wall of last connector. For example, the shorting unit may further include a plurality of sets of rotating members, the number of sets of rotating members being the same as and corresponding to the number of rotating grooves, each set of rotating members being capable of being mounted in a corresponding rotating groove. For example, the rotating member may include a number of steel balls, etc. For example, the shorting unit may also include a number of seals (e.g., sealing rings) mounted on the rotating shaft to effect a seal between the upper and lower connectors. For example, the upper connector may be provided with a plurality of mounting holes to fix different relative positions between the upper connector and the clutch device. For example, the upper end of the rotating shaft may be connected to a drilling tool, such as a drill rod. For example, further, the rotating shaft may be provided with a plurality of first annular grooves, the inner wall of the upper cavity is provided with a plurality of second annular grooves, the first annular grooves and the second annular grooves are the same in number and correspond to each other one by one, and the first annular grooves and the second annular grooves which are in corresponding relation form a rotating groove together.

The clutch device is sleeved on the upper connector and/or the lower connector, and can enable the upper connector and the lower connector to keep relative rotation or synchronous rotation. The first inlet check valve is arranged in the upward opening of the upper connector, and the second inlet check valve is arranged in the lateral connecting port of the upper connector. For example, the clutch device may include a spline housing, the portion of the upper connector that contacts the spline housing is a first spline shaft, the portion of the lower connector that contacts the spline housing is a second spline shaft, both the first spline shaft and the second spline shaft are mated with the spline housing, the spline housing is capable of sliding back and forth on the first and second spline shafts, and the shorting unit further includes a first fixing member (e.g., a dowel) that is capable of fixing the spline housing to the first spline shaft. For example, the upper connector may include a connecting shaft, a clutch shaft, a limiting shaft and a rotating shaft sequentially connected from top to bottom, wherein the upper end of the connecting shaft may also be connected to a drilling tool, the first inlet check valve is installed in an opening of the connecting shaft facing upwards, and the second inlet check valve is installed on a side wall of the connecting shaft; the clutch shaft is a spline shaft, and the radial dimension of the clutch shaft is smaller than that of the connecting shaft; the radial dimension of the limiting shaft is smaller than the radial dimension of the lower end of the clutch shaft and the upper end of the rotating shaft; the lower connector is provided with an upper cavity and a lower cavity which are communicated up and down, the radial size of the upper cavity is larger than that of the lower cavity, and the rotating shaft can be placed in the upper cavity and is rotationally connected between the upper cavity and the lower cavity.

The movable butt joint unit comprises a side connecting mechanism, the side connecting mechanism comprises a side connector, the front end of the side connector is matched with the side connector and can be inserted into the side connector, the rear end of the side connector is provided with an interface for butt joint with a drilling circulation medium pipeline, and the side connector is also provided with a hollow cavity for communicating the front end with the rear end of the side connector. For example, the mobile docking unit may further include a mobile base, and the lateral connection mechanism is located on the mobile base. For example, further, a roller is directly or indirectly connected to the bottom of the movable seat, so that the movable seat can move in all directions.

In this embodiment, the side connection mechanism may further include a hollow motor, a torsion limiter, and a fastening sleeve, wherein a rotation output hole of the hollow motor is kept horizontal; the torsion limiter is fixed in the rotary output hole of the hollow motor; the fastening sleeve is connected with the inner cavity of the torsion limiter in an adapting way; the fastening sleeve is sleeved on the lateral connecting head, and the front end of the fastening sleeve is positioned outside the hollow motor. In this case, the torque limiter is connected to the rotation output opening of the hollow motor in a rotationally fixed manner, so that the torque limiter can be rotated by the rotation of the hollow motor. Here, for example, the tip of the fastening sleeve can be further adapted to the side connection opening and screwed into the side connection opening. For example, the front end of the fastening sleeve is provided with external threads adapted to the lateral connection openings. For example, the tightness degree of the tightening sleeve matched with the tightening sleeve can be controlled through the torsion limiter, when the output torsion exceeds the highest output torsion of the torsion limiter, the inner ring of the tightening sleeve slips, the mechanical transmission efficiency is reduced, and the tightening sleeve gradually stops rotating. Here, when the torsion limiter drives the tightening sleeve to rotate, the lateral connectors are not or little affected and can remain substantially stationary. Here, through the adaptation of cavity motor, adapter sleeve and side connector, simplified the butt joint flow of side circulation pipeline greatly, reduced operating personnel's quantity, showing and promoted work efficiency. For example, further, the side connection mechanism may further include a rotary table and a lifting structure, wherein the rotary table can rotate on a horizontal plane, and a hollow motor is fixed on a table top of the rotary table; the lifting structure is positioned between the rotating table and the movable seat, and can adjust the vertical distance between the rotating table and the movable seat. For example, further, the lifting device may be a threaded screw structure, one end of the screw is movably connected with the rotary table, and the other end of the screw is adapted to a threaded hole configured on the movable seat, so that the rotary table can be lifted.

In the embodiment, the movable butt joint unit and the short circuit unit can be in butt joint through the hollow motor to drive the fastening sleeve to be screwed in, so that the working efficiency is remarkably improved. Meanwhile, the alignment of the height and the angle can be realized by matching the rotating table and the lifting structure, the butt joint procedure is effectively simplified, the consumed time is short, and the efficiency is high.

In this embodiment, the positive circulation joint is connected to the first inlet check valve through a pipe, and the lateral circulation joint is connected to the second inlet check valve through a pipe.

FIG. 2 illustrates a schematic diagram of an uninterrupted looping connection according to an exemplary embodiment of the invention; figure 3 shows a schematic structural diagram of the shorting unit of the present invention; figure 4 shows a schematic assembly of the shorting unit of the present invention; FIG. 5 shows a partial enlarged view at A in FIG. 2; FIG. 6 shows a schematic structural view of the first side joint of the present invention; fig. 7 shows a schematic structural view of the second side joint of the present invention. The following specific embodiments will be described in detail with reference to fig. 2 to 7.

As shown in fig. 2, in the present exemplary embodiment, the drill rotatable continuous circulation drilling system includes a shorting unit, a mobile docking unit, a control cabinet 50, a gate valve manifold sled 60, an integration box 70, and a pipe 80. The control cabinet 50 and the gate valve manifold sled 60 are located inside the manifold 70.

As shown in fig. 3 and 4, the shorting unit includes an upper connector 16, a lower connector 17, a clutch device 18, a first inlet check valve 191 and a second inlet check valve 192, and the axial cavities of the upper connector 16 and the lower connector 17 are interconnected. The upper link 16 includes, from top to bottom: a connecting shaft 161, a clutch shaft 162, a limiting shaft 163, and a rotating shaft 164. The wall of the connecting shaft 161 is also provided with a side connecting port 1611. The upper end of the rotary shaft 164 may be connected to a drilling tool, such as a drill rod. The clutch shaft 162 may be a spline shaft and the clutch shaft 162 may be adapted to the clutch device 18. The outer diameter of the clutch shaft 162 may be smaller than the outer diameter of the connecting shaft 161, the limiting shaft 163 may be sleeved with a limiting sleeve 1631, and the outer diameter of the limiting shaft 163 may be smaller than the outer diameter of the clutch shaft 162 and the outer diameter of the rotating shaft 164.

The lower connection body 17 may have an upper cavity 171 and a lower cavity 172 that are communicated with each other, and a radial dimension of the lower cavity 172 is smaller than a radial dimension of the upper cavity 171. The portion of the lower connecting body 17 in contact with the clutch device 18 may be a spline shaft.

The clutch device 18 is sleeved on the upper connector 16 and the lower connector 17, so that the upper connector 16 and the lower connector 17 can keep synchronous rotation. The clutch device 18 can be sleeved on the upper connecting body 16, so that the upper connecting body 16 and the lower connecting body 17 can keep relative rotation. The clutch 18 may include a spline housing, and changing the state of the clutch 18 enables different rotational modes.

The first inlet check valve 191 and the second inlet check valve 192 may be mounted at different positions on the upper connector 16; the first inlet check valve 191 may be mounted in an opening in the upper axial cavity of the upper connector 16 and the second inlet check valve 192 may be mounted in the side connection port 1611.

The outer wall of the rotating shaft is provided with a plurality of first annular grooves, the inner wall of the upper cavity of the lower connecting body can be provided with a plurality of second annular grooves, the number of the two annular grooves is equal and corresponds to each other one by one, and the rotating groove is formed by two annular grooves which correspond to each other. A plurality of sealing members 21 may be installed on the rotation shaft to achieve sealing between the upper and lower connection bodies. The seal 21 may comprise a sealing ring.

The shorting unit may further include a plurality of sets of rotating members 20, the number of rotating members 20 being equal to the number of rotating slots, one set of rotating members 20 being mounted in each rotating slot. The rotating member 20 may include a number of steel balls, etc.

The lower connector is also provided with a plurality of rotor mounting holes 173 and a plurality of blocking pins 174. Wherein, the quantity of rotating member mounting holes 173 is the same and the one-to-one correspondence with the quantity of second ring grooves, and each rotating member mounting hole 173 is mutually communicated with the corresponding second ring groove, and the quantity of shutoff pins 174 is the same and the one-to-one correspondence with the quantity of rotating member mounting holes 173, and the shutoff pins 174 can be used for plugging the corresponding rotating member mounting holes 173.

The stop collar 1631 may be a double-layer structure, and may include, from inside to outside, a graphite bearing sleeve and a housing, fixedly connected to each other, and fixedly connected to the lower connector.

The upper connector can be provided with a plurality of mounting holes so as to fix different relative positions between the upper connector and the clutch device. The upper coupling body 16 and the clutch 18 may be coupled by a first fixing member 221. The limit sleeve 1631 may be secured to the lower link 17 by the second securing member 222. The first fixing member 221 and the second fixing member 222 may each include a bolt, a screw, a dowel, or the like.

As shown in fig. 2, 5, 6, and 7, the movable docking unit includes a roller 23, a leg 24, a movable seat 25, and a side connection mechanism, which are disposed in this order from bottom to top. The bottom of the movable seat 25 is fixedly connected with a roller 23 through a support leg 24, and the roller 23 is a movable roller and can move in all directions without dead angles.

The side connection mechanism includes a hollow motor 401, a torque limiter 402, a tightening sleeve 403, a side connector 404, a rotary table 405, and a lifting structure 406. The lifting structure 406 is a threaded screw structure, threads matched with the screw are arranged on the movable seat 25, and a counter bore is arranged at the center of the bottom of the rotary table 405, so that the rotary table 405 is movably connected with the screw. The rotary table 405 is placed on the screw of the lifting structure 406 so that it can freely rotate around the screw. The hollow motor 401 is fixedly connected to the rotary table 405, and the torque limiter 402 is coaxial with the hollow motor 401 and connected to an output hole of the hollow motor 401. The fastening sleeve 403 is connected with the inner cavity of the torsion limiter 402 in a matching way, and the right end is provided with external threads which are in butt joint with the shorting unit. The hollow side connector 404 is sleeved in the inner cavity of the fastening sleeve 403, and the left end is provided with an interface for being abutted with the pipeline 80.

The positive circulation joint is connected with the first inlet check valve through a pipeline, and the side circulation joint is connected with the second inlet check valve through a pipeline, so that circulation switching operation can be performed.

In this exemplary embodiment, the method of using the uninterrupted looping connection includes the steps of:

during working, when drilling normally, the spline housing is matched with the upper connector and the lower connector, the upper connector and the lower connector synchronously rotate, and drilling circulating medium enters from the first inlet one-way valve;

when the drill rod needs to be disassembled, fastened, unfastened and tripped, the rotation of the drill rod is stopped. The installed movable butt joint unit is pushed to the vicinity of the short circuit unit, the height of the rotary table is adjusted through the lifting structure, and the angle is adjusted by utilizing the rotatability of the movable butt joint unit, so that the side connector is aligned to the side connector. And starting the hollow motor, and butting the hollow motor with the lateral connecting port through the external thread of the fastening sleeve. When the torsion reaches the maximum torsion stress of the torsion limiter, the fastening sleeve is gradually stopped from being screwed in to finish butt joint, so that the drilling circulation medium enters from the second inlet one-way valve, and the drilling circulation medium entering from the first inlet one-way valve is closed.

And moving the spline housing in a direction away from the lower connector, only meshing the spline housing with the clutch shaft of the upper connector, and fixing the spline housing at the position on the upper connector by using a positioning nail. The slips are arranged on the drill rod, the drill rod is driven to rotate by the rotary table, and the upper connector and the lower connector are in a clutch state and can mutually rotate, so that the drill string positioned in the well hole can rotate under the drive of the rotary table, and meanwhile drilling media can be circulated normally. And under the condition that the drill rod is required to be disassembled, the drill rod connected with the upper connector is directly disassembled, or the drill rod is connected with the upper connector.

When the rotary table drives the drill rod to rotate, the upper connecting body is required to be fixed by a fixed supporting frame, the fixed supporting frame can be designed into a V-shaped iron type support, a V-shaped support matched with the outer circle of the upper connecting body is fixedly arranged on the supporting seat, a V-shaped cover plate buckled with the V-shaped support is arranged on the V-shaped support, one end of the V-shaped support is hinged with the V-shaped cover plate, and the other end of the V-shaped support is provided with a screw which is detachably connected with the V-shaped cover plate.

The invention further provides a pressure regulating circulation switching method suitable for gas continuous circulation drilling.

In a third exemplary embodiment of the present invention, a pressure-regulating circulation switching method applicable to gas continuous circulation drilling may be implemented by the pressure-regulating circulation switching device for gas continuous circulation drilling of the above first exemplary embodiment, and the method includes the steps of:

Positive cycle process: and opening the first control valve, closing the second control valve, the third control valve, the fourth control valve, the first pressure regulating valve and the second pressure regulating valve, and allowing the medium fluid to enter from the circulating medium inlet, pass through the first pipeline and flow out from the positive circulation joint. Specifically, as shown in fig. 1, when the positive cycle is performed, the first control valve 7 is opened, the second control valve 8, the third control valve 9, the fourth control valve 10, the first pressure regulating valve 11, and the second pressure regulating valve 12 are closed, and a circulation medium such as dry gas or atomized gas flows in from the circulation medium inlet a01, passes through the first line 1 and the second rectangular cavity, flows out from the positive cycle joint a02, and flows into the positive cycle line to perform the positive cycle.

Side circulation process: and opening the second control valve, closing the first control valve, the third control valve, the fourth control valve, the first pressure regulating valve and the second pressure regulating valve, and allowing the medium fluid to enter from the circulating medium inlet, pass through the second pipeline and then flow out from the side circulating joint. Specifically, as shown in fig. 1, when the side circulation is performed, the second control valve 8 is opened, the first control valve 7, the third control valve 9, the fourth control valve 10, the first pressure regulating valve 11, and the second pressure regulating valve 12 are closed, and a circulation medium such as dry gas or atomized gas flows in from the circulation medium inlet a01, passes through the second line 2 and the fourth rectangular cavity, flows out from the side circulation joint a04, and enters the side circulation line to perform the side circulation operation.

Forward cycle-to-side cycle process: after the side circulation joint is connected with the side circulation pipeline, a second pressure regulating valve is opened, circulation medium is pumped into the second pipeline until the second pipeline and the side circulation pipeline are filled with the circulation medium, the pressure in the second pipeline rises to be close to the pressure in the first pipeline, a second control valve is opened, the second pressure regulating valve is closed, and a side circulation channel is established. And closing the first control valve to cut off the positive circulation channel, opening the third control valve to release pressure, and closing the third control valve after the pressure release to finish the operation of positive circulation and lateral circulation. For example, the pressure regulating ranges of the first pressure regulating valve and the second pressure regulating valve may be 0 to 15Mpa. Specifically, as shown in fig. 1, after one end of the side circulation line is connected to the side circulation joint a04, and the other end is connected to a drill side circulation joint (for example, a second control valve of an uninterrupted circulation short circuit device), the first pressure regulating valve 11 is opened, circulation medium is pumped into the second line 2 and the side circulation line until the side circulation line is filled, the pressure values (i.e., the readings of the first pressure gauge) of the first line 1 and the second line 2 are observed in the pressure regulating process, and when the pressure in the second line 2 rises to approach the pressure in the first line 1, the second control valve 8 and the second pressure regulating valve 12 are opened to establish a side circulation channel. Here, the pressure in the second pipeline 2 increases to be close to the pressure in the first pipeline 1, and the pressure in the second pipeline may be equal to or greater than 95% of the pressure in the first pipeline. Here, the opening degree of the second pressure regulating valve 12 needs to be delayed differently depending on the pressure value of the first line. The relationship between the different positive cycle pressure ranges for the second regulator valve opening and the time delay is given in table 1.

TABLE 1 different positive cycle pressure ranges correspond to the second pressure regulating valve opening and delay

As can be seen from Table 1, when the positive circulation pressure (i.e., the pressure in the first pipeline) P is less than or equal to 2.5MPa, the second pressure regulating valve can be directly opened; when the positive circulation pressure (i.e. the pressure in the first pipeline) is 2.5 < P.ltoreq.5 MPa, the opening degree (i.e. the valve port area) of the second pressure regulating valve is respectively 20%, 40%, 70% and 100%, and the corresponding delay waiting time is respectively 5s, 3s, 2s and 2s. Similarly, when the positive cycle pressure is 5 < P.ltoreq.10 and P > 10, the corresponding opening degree and delay time are shown in Table 1. Here, the sudden and complete opening of the pressure regulating valve causes a large pressure fluctuation, so that a delay is set to be reserved, the pressure fluctuation is reduced, and meanwhile, the pressure impact is reduced. After the second pressure regulating valve 12 is closed, the second control valve 8 is opened, the opening process of the second control valve 8 is identical to the opening process of the second pressure regulating valve 12 in table 1, and when the second control valve 8 is completely opened for 2s, the first control valve 7 is closed (directly closed without delay).

And opening the third control valve 9, discharging the pressure in the positive circulation pipeline, wherein the opening process of the third control valve 9 is consistent with the opening process of the second pressure regulating valve 12 in table 1, and after the pressure in the positive circulation pipeline is reduced to zero for 10 seconds, closing the third control valve 9.

At this time, the circulating medium enters the pressure regulating switching device from the circulating medium inlet A01, flows out from the side circulating joint A04 and enters the continuous circulating valve, so that the circulating medium enters the water hole of the drilling tool, and the positive circulation and the side circulation are completed.

Side circulation to forward circulation process: after the positive circulation joint is connected with the positive circulation pipeline, a first pressure regulating valve is opened, circulation medium is pumped into the first pipeline until the first pipeline and the positive circulation pipeline are filled with the circulation medium, the pressure in the first pipeline rises to be close to the pressure in the second pipeline, a first control valve is opened, the first pressure regulating valve is closed, and a positive circulation channel is established. Closing the second control valve to cut off the side circulation channel, opening the fourth control valve to release pressure, closing the fourth control valve after releasing pressure, and completing the operation of side circulation to forward circulation. Here, the pressure in the first pipeline increases to approximately the pressure in the second pipeline, which may be a value of the pressure in the first pipeline that is greater than or equal to 95% of the pressure in the second pipeline. Specifically, as shown in fig. 1, after the positive circulation line and the positive circulation joint a02 are connected to each other at the drill floor, the first pressure regulating valve 11 is opened to pump the circulation medium into the first line 1 and the positive circulation line, the pressure values of the first line 1 (i.e., the reading of the first pressure gauge) and the second line 2 (i.e., the reading of the second pressure gauge) are observed during pumping, and when the pressure of the first line 1 rises to approximately 95% or more of the pressure of the second line 2, the first pressure regulating valve 11 is closed, and the first control valve 7 is opened to establish a positive circulation passage. Here, the positive circulation line includes a tap (top drive) and a single piece (upright). The opening of the first pressure regulating valve 11 needs to be delayed differently according to the pressure value of the second line. The relationship between the different side circulation pressure ranges corresponding to the opening degree of the first pressure regulating valve and the time delay is shown in table 2.

TABLE 2 different side cycle pressure ranges correspond to the first pressure regulating valve opening and delay

As can be seen from table 2, when the side circulation pressure (i.e., the pressure in the second pipeline) P is less than or equal to 2.5MPa, the first pressure regulating valve can be directly opened; when the side circulation pressure (i.e. the pressure in the second pipeline) is 2.5 < P.ltoreq.5 MPa, the opening degree (i.e. the valve port area) of the first pressure regulating valve is respectively 20%, 40%, 70% and 100%, and the corresponding delay waiting time is respectively 5s, 3s, 2s and 2s. Similarly, when the side circulation pressure is 5 < P.ltoreq.10 and P > 10, the corresponding opening degree and delay time are shown in Table 2.

After the first pressure regulating valve 11 was closed, the first control valve 7 was opened, the opening process of the first control valve 7 was identical to the opening process of the first pressure regulating valve 11 in table 1, and after the first control valve 7 was completely opened for 2 seconds, the second control valve 8 was closed (directly closed, without delay).

The fourth control valve 10 is opened, the pressure in the side circulation pipeline is released, the opening process of the fourth control valve 10 is consistent with the opening process of the first pressure regulating valve in table 2, and after the pressure in the side circulation pipeline is reduced to zero for 10 seconds, the fourth control valve 10 is closed.

At this time, the circulating medium enters the pressure regulating switching device from the circulating medium inlet A01, flows out from the positive circulation joint A02 and enters the continuous circulation valve, so that the circulating medium enters the water hole of the drilling tool, and the side circulation is completed.

In the present exemplary embodiment, the circulation medium may include at least one of dry gas, atomized gas, foam, and slurry.

In the present exemplary embodiment, the positive cycle side cycle or the side cycle positive cycle may have a pressure fluctuation range of 0 to 0.5Mpa. Here, the pressure fluctuation range of the conventional cycle switching device for forward cycle side cycle or side cycle forward cycle is usually 3-10 Mpa, while the pressure fluctuation range of the conventional cycle switching device for forward cycle side cycle or side cycle forward cycle is only 0-0.5 Mpa, and the pressure fluctuation range is obviously reduced, so that the probability of complex underground situations is greatly reduced.

In summary, the pressure regulating circulation switching device and method for gas continuous circulation drilling of the present invention may have the following advantages:

(1) The pressure regulating circulation switching device for the continuous circulation well drilling is simple in structure and convenient to manufacture and maintain;

(2) The pressure regulating circulation switching device for continuous circulation drilling does not need to additionally increase a pressure compensation device, saves cost and improves economic benefit;

(3) The pressure regulating circulation switching device for continuous circulation drilling can ensure that a circulation medium is not interrupted, reduce pressure fluctuation in the switching process, and avoid underground complex conditions caused by circulation interruption and large pressure fluctuation.

Although the present invention has been described above by way of the combination of the exemplary embodiments, it should be apparent to those skilled in the art that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined in the appended claims.

Claims

1. The pressure regulating circulation switching device suitable for gas continuous circulation drilling is characterized by comprising a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a fifth pipeline, a sixth pipeline, a first control valve, a second control valve, a third control valve, a fourth control valve, a first pressure regulating valve, a second pressure regulating valve, a circulation medium inlet, a positive circulation joint, a side circulation joint and a pressure relief joint, wherein,

One end of the first pipeline is connected with the circulating medium inlet, and the other end of the first pipeline is connected with the positive circulating joint;

One end of the second pipeline is connected with the circulating medium inlet, and the other end of the second pipeline is connected with the side circulating joint;

one end of the third pipeline is connected with the positive circulation joint, and the other end of the third pipeline is connected with the pressure relief joint; one end of the fourth pipeline is connected with the side circulation joint, and the other end of the fourth pipeline is connected with the pressure relief joint;

The first control valve is arranged on the first pipeline, the second control valve is arranged on the second pipeline, the third control valve is arranged on the third pipeline, and the fourth control valve is arranged on the fourth pipeline;

one end of the fifth pipeline is communicated with a part of the pipeline of the second pipeline, which is positioned between the circulating medium inlet and the second control valve, and the other end of the fifth pipeline is communicated with a part of the pipeline of the third pipeline, which is positioned between the positive circulating joint and the third control valve;

The first pressure regulating valve is arranged on a fifth pipeline;

one end of the sixth pipeline is communicated with a part of the fifth pipeline between the second pipeline and the first pressure regulating valve, and the other end of the sixth pipeline is communicated with a part of the fourth pipeline between the side circulation joint and the fourth control valve;

the second pressure regulating valve is arranged on a sixth pipeline;

The pressure regulating circulation switching device also comprises an uninterrupted circulation joint, the uninterrupted circulation joint comprises a short circuit unit and a movable butt joint unit, wherein,

The short circuit unit comprises an upper connector, a lower connector, a clutch device, a first inlet one-way valve and a second inlet one-way valve, wherein the upper connector and the lower connector are rotationally connected from top to bottom and are provided with hollow axial cavities, the axial cavities of the upper connector and the lower connector are communicated with each other, and a through side connecting port is formed in the side wall of the upper connector; the clutch device is sleeved on the upper connector and/or the lower connector, and can enable the upper connector and the lower connector to keep relative rotation or synchronous rotation; the first inlet check valve is arranged in the upward opening of the upper connector, and the second inlet check valve is arranged in the lateral connecting port of the upper connector;

The movable butt joint unit comprises a side connection mechanism, the side connection mechanism comprises a side connector, the front end of the side connector is matched with the side connector and can be inserted into the side connector, the rear end of the side connector is provided with an interface for butt joint with a drilling circulation medium pipeline, and the side connector is also provided with a hollow cavity for communicating the front end with the rear end;

The positive circulation joint is connected with the first inlet check valve through a pipeline, and the side circulation joint is connected with the second inlet check valve through a pipeline;

The movable docking unit further comprises a movable seat, and the lateral connecting mechanism is positioned on the movable seat;

The side connecting mechanism comprises a hollow motor and a fastening sleeve, a rotation output hole of the hollow motor is kept horizontal, the fastening sleeve is fixed in the rotation output hole of the hollow motor, the fastening sleeve is sleeved on the side connecting head, and the front end of the fastening sleeve is positioned outside the hollow motor;

the side connecting mechanism also comprises a torsion limiter, a rotary table and a lifting structure,

The torque limiter is fixed in a rotation output hole of the hollow motor, the fastening sleeve is connected with an inner cavity of the torque limiter in an adapting mode, the fastening sleeve is sleeved on the lateral connecting head, and the front end of the fastening sleeve is located outside the hollow motor;

the front end of the fastening sleeve is matched with the side connecting port and can be screwed into the side connecting port;

the rotary table can rotate on a horizontal plane, and the hollow motor is fixed on the table top of the rotary table; the lifting structure is positioned between the rotary table and the movable seat, and can adjust the vertical distance between the rotary table and the movable seat.

2. The pressure regulating circulation switching device suitable for use in gas continuous circulation drilling of claim 1, further comprising a first pressure gauge disposed on the positive circulation joint to display the pressure in the first line and a second pressure gauge disposed on the lateral circulation joint to display the pressure in the second line.

3. The pressure regulating circulation switching device for continuous circulation drilling of gas according to claim 1, wherein the first control valve and the second control valve are flat gate valves, the third control valve and the fourth control valve are throttle valves, and the first pressure regulating valve and the second pressure regulating valve are throttle valves.

4. The pressure regulating circulation switching device suitable for continuous circulation drilling of gas according to claim 1, wherein the first control valve, the second control valve, the third control valve, the fourth control valve, the first pressure regulating valve and the second pressure regulating valve are in two modes of hydraulic control and mechanical control, and can be opened and closed in a manual control mode under the condition of hydraulic control failure.

5. The pressure regulating circulation switching device suitable for continuous circulation drilling of gas according to claim 1, wherein the clutch device comprises a spline housing, the part of the upper connecting body contacted with the spline housing is a first spline shaft, the part of the lower connecting body contacted with the spline housing is a second spline shaft, the first spline shaft and the second spline shaft are matched with the spline housing, the spline housing can slide back and forth on the first spline shaft and the second spline shaft, and the shorting unit further comprises a first fixing piece capable of fixing the spline housing with the first spline shaft;

the upper connector comprises a connecting shaft, a clutch shaft, a limiting shaft and a rotating shaft which are sequentially connected from top to bottom,

The upper end of the connecting shaft can be connected with a drilling tool, the first inlet one-way valve is arranged in the upward opening of the connecting shaft, and the second inlet one-way valve is arranged on the side wall of the connecting shaft;

The clutch shaft is a spline shaft, and the radial dimension of the clutch shaft is smaller than that of the connecting shaft;

The radial dimension of the limiting shaft is smaller than the radial dimension of the lower end of the clutch shaft and the upper end of the rotating shaft;

The lower connector is provided with an upper cavity and a lower cavity which are communicated up and down, the radial size of the upper cavity is larger than that of the lower cavity, and the rotating shaft can be placed in the upper cavity and connected between the upper cavity and the lower cavity in a rotating way.

6. A pressure regulating circulation switching method suitable for gas continuous circulation drilling, characterized in that the method is realized by the pressure regulating circulation switching device suitable for gas continuous circulation drilling according to any one of claims 1-5, and the method comprises the steps of:

positive cycle process: opening a first control valve, closing a second control valve, a third control valve, a fourth control valve, a first pressure regulating valve and a second pressure regulating valve, wherein medium fluid enters from a circulating medium inlet, passes through a first pipeline and flows out from a positive circulation joint;

side circulation process: opening a second control valve, closing a first control valve, a third control valve, a fourth control valve, a first pressure regulating valve and a second pressure regulating valve, wherein medium fluid enters from a circulating medium inlet, passes through a second pipeline and flows out from a side circulating joint;

Forward cycle-to-side cycle process: after the side circulation joint is connected with the side circulation pipeline, a second pressure regulating valve is opened, circulation medium is pumped into the second pipeline until the second pipeline and the side circulation pipeline are filled with the circulation medium, the pressure in the second pipeline rises to be close to the pressure in the first pipeline, a second control valve is opened, the second pressure regulating valve is closed, and a side circulation channel is established;

Closing the first control valve to cut off the positive circulation channel, opening the third control valve to release pressure, closing the third control valve after the pressure release, and completing the operation of positive circulation and lateral circulation;

Side circulation to forward circulation process: after the positive circulation joint is connected with the positive circulation pipeline, a first pressure regulating valve is opened, circulation medium is pumped into the first pipeline until the first pipeline and the positive circulation pipeline are filled with the circulation medium, the pressure in the first pipeline rises to be close to the pressure in the second pipeline, a first control valve is opened, the first pressure regulating valve is closed, and a positive circulation channel is established;

closing the second control valve to cut off the side circulation channel, opening the fourth control valve to release pressure, closing the fourth control valve after releasing the pressure, and completing the operation of side circulation to forward circulation;

the pressure in the second pipeline rises to be close to the pressure in the first pipeline, wherein the pressure value in the second pipeline is more than or equal to 95% of the pressure value in the first pipeline;

The pressure in the first pipeline rises to be close to the pressure in the second pipeline, wherein the pressure in the first pipeline is equal to or more than 95% of the pressure in the second pipeline.

7. The pressure regulating circulation switching method suitable for continuous circulation drilling of gas according to claim 6, wherein the pressure regulating range of the first pressure regulating valve and the second pressure regulating valve is 0-15 mpa.

8. The pressure regulating circulation switching method suitable for continuous circulation drilling of gas according to claim 6, wherein the pressure fluctuation range of the forward circulation side circulation or side circulation forward circulation is 0-0.5 mpa.

9. The method of claim 6, wherein opening the fourth control valve to release pressure, closing the fourth control valve after releasing pressure comprises closing the fourth control valve after the second line pressure drops to zero for 10 seconds.