CN115874943A - Pressurizing and resistance reducing device for coiled tubing drilling - Google Patents

Abstract

The invention provides a pressurizing resistance-reducing device for continuous pipe drilling, which comprises a resistance-reducing unit, wherein the resistance-reducing unit comprises an oscillating element and a jet element connected to the oscillating element; the pressurizing unit comprises a cylinder barrel which is connected to the resistance reducing unit and provided with an inner cavity, a piston rod is arranged in the inner cavity, a piston is sleeved on the piston rod, and the drilling tool assembly is connected to the bottom of the pressurizing unit. The jet element can generate jet flow so as to enable fluid flowing through the resistance reducing unit to vibrate, and the piston rod can axially move along the cylinder under the action of pressure difference on two sides of the outer wall of the cylinder, so that flexible bit weight is applied to the bottom hole assembly. The pressurizing and resistance reducing device for continuous pipe drilling can improve the drilling pressure of the continuous pipe drilling and reduce the well wall friction force on the continuous pipe.

Description

Pressurizing and resistance reducing device for coiled tubing drilling

Technical Field

The invention relates to the field of oilfield exploitation, in particular to a pressurizing and resistance reducing device for coiled tubing drilling.

Background

In the process of oil well drilling, the coiled tubing drilling technology is more and more widely applied due to the advantages of small occupied area, small pollution, high tripping speed and the like. Especially, under the condition that most of old oil fields in China are in the middle and later stages of development, the coiled tubing drilling technology can be adopted to realize the effective development of oil and gas resources which are difficult to use. Therefore, the coiled tubing drilling technology has very wide application prospect.

In the process of continuous pipe drilling, due to the fact that a bottom hole assembly is not provided with a drill collar, the downward force of an injection head is limited, and sufficient drilling pressure cannot be provided. Therefore, the coiled tubing drilling technology has the problems of serious pressure supporting, difficult horizontal section extension and the like.

In addition, due to the characteristics of no rotation, light weight and low rigidity of the coiled tubing, the coiled tubing is easy to cause instability of the tubing string and form spiral locking when being subjected to well wall friction, so that the coiled tubing drilling technology is difficult to apply to deep wells.

Disclosure of Invention

In view of the technical problems described above, the present invention aims to provide a pressurized resistance reducing device for coiled tubing drilling. The pressurizing and resistance reducing device for continuous pipe drilling can improve the drilling pressure of the continuous pipe drilling and reduce the well wall friction force on the continuous pipe.

According to the present invention there is provided a pressurised drag reduction device for coiled tubing drilling comprising: the resistance reducing unit comprises an oscillation element and a jet element connected to the oscillation element; the pressurizing unit comprises a cylinder barrel which is connected to the resistance reducing unit and provided with an inner cavity, a piston rod is arranged in the inner cavity, a piston is sleeved on the piston rod, and the pressurizing unit is connected to a drilling tool assembly at the bottom of the pressurizing unit.

The jet element can generate jet flow so as to enable fluid flowing through the resistance reducing unit to vibrate, and the piston rod can axially move along the cylinder under the action of pressure difference on two sides of the outer wall of the cylinder, so that flexible bit weight is applied to the bottom hole assembly.

In a preferred embodiment, a first vortex cavity and a second vortex cavity which are annular are arranged in the fluidic element, and a reversing flow passage and a feedback flow passage which are respectively communicated with the first vortex cavity and the second vortex cavity.

In a preferred embodiment, the reversing flow channel is configured in a substantially "V" shape, and the feedback flow channel is arranged along a common tangential direction of the first and second vortex chambers.

In a preferred embodiment, the piston rod is tubular, a liquid chamber is formed between the piston rod and the inner wall of the cylinder, and the piston is arranged in the liquid chamber.

In a preferred embodiment, at least one breathing hole communicated with the liquid cavity is further arranged on the outer wall of the cylinder barrel.

In a preferred embodiment, a scraping ring is arranged on the outer wall of the piston rod, and the scraping ring is sleeved on a groove of the outer wall of the piston rod.

In a preferred embodiment, a spline joint connected with the bottom drilling tool is further arranged at the end part of one side of the cylinder barrel, which is far away from the resistance reducing unit, and the spline joint comprises a spline shaft and a spline barrel.

In a preferred embodiment, the spline shaft is also sleeved with a falling-proof half ring.

In a preferred embodiment, a plurality of sets of pressure units are provided within the barrel.

In a preferred embodiment, the bottom of the piston rod is provided with a liquid passing groove, so that drilling fluid flowing through the piston rod is allowed to enter between the piston rod and the spline shaft, and the spline shaft and the piston rod are pushed to move together.

Drawings

The present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a schematic diagram of a pressurized drawdown apparatus for coiled tubing drilling according to one embodiment of the present invention.

FIG. 2 is a schematic view of the fluidic elements of the pressurized drawdown apparatus of FIG. 1 for coiled tubing drilling.

Fig. 3 shows a schematic view of a cylinder barrel in a pressurizing unit according to the invention.

FIG. 4 is a schematic view of a piston rod of the pressurized friction reducing device for coiled tubing drilling of FIG. 1.

In the present application, the drawings are all schematic and are used only for illustrating the principles of the invention and are not drawn to scale.

Detailed Description

The invention is described below with reference to the accompanying drawings.

FIG. 1 shows a pressurized drawdown apparatus 100 for coiled tubing drilling according to one embodiment of the present invention. As shown in fig. 1, the pressurized drag reduction device 100 for coiled tubing drilling comprises a drag reduction unit 1 connected to a drill string (not shown). The impedance reduction unit 1 includes an oscillation element 10 and a fluidic element 20 inserted into the oscillation element 10. The fluidic element 20 can generate a periodically-changing jet flow for the high-pressure fluid flowing through the fluidic element 20, so as to drive the oscillation element 10 to oscillate. Therefore, the oscillating element 10 generates periodic vibration along the axial direction, so as to drive a downhole drill string (not shown) to vibrate along the axial direction, thereby reducing the friction force between the drill string and the well wall and achieving the functions of reducing friction and resistance.

Fig. 2 is a schematic view of the fluidic element 20 of the pressurized flow reducing device 100 for coiled tubing drilling shown in fig. 1. As shown in fig. 2, a first swirl chamber 22 and a second swirl chamber 24, which are designed in the form of rings, are arranged in the interior of the flow element 20. A liquid inlet 225 and a liquid outlet 245 are respectively arranged on the first vortex cavity 22 and the second vortex cavity 24. A reversing flow channel 25 and a feedback flow channel 26 which are respectively communicated with the first vortex cavity 22 and the second vortex cavity 24 are also arranged between the first vortex cavity 22 and the second vortex cavity 24.

As shown in fig. 2, the diverting flow passage 25 is constructed in a substantially "V" shape having a first flow passage 251 communicating with the first vortex chamber 22, and a second flow passage 252 and a third flow passage 253 communicating with the first vortex chamber 24 at the same time. The feedback flow passages 26 are provided in two, which are respectively arranged along a common tangential direction of the first vortex chamber 22 and the second vortex chamber 24.

When the high-pressure liquid flows from the oscillation element 10, the high-pressure liquid passes through the liquid inlet 225 to reach the inside of the fluidic element 20 and forms a jet at the liquid inlet 225. The jet will then pass through the first flow channel 251 and the second flow channel 252, respectively, to the second vortex chamber 24. In this process, since the high-pressure fluid is turbulent and unstable, the flow rate of the high-pressure fluid entering the second flow passage 252 and the third flow passage 253 is different, so that two flows respectively passing through the second flow passage 252 and the third flow passage 253 can impact each other and flow out of the second vortex chamber 24. However, according to the coanda effect, the final jet flows from only one of the first flow passage 251 or the second flow passage 252 into the second vortex chamber 24 and forms a vortex in the second vortex chamber 24.

As the swirl in the second vortex chamber 24 increases, the fluid flow and velocity in the feedback channel 26 increases as the swirl in the second vortex chamber 24 increases to a certain threshold value. The fluid in the feedback flow passage 26 impacts the fluid in the second flow passage 252 or the third flow passage 253 to change the direction of the fluid until the vortex in the second vortex chamber 24 is disturbed and gradually dissipated, and a reverse vortex flow is formed. Through such a periodic switching, an oscillation effect can be generated, so that the oscillation element 10 generates an axial force that changes periodically, thereby driving the oscillation element 10 to generate a periodic vibration along the axial direction.

As shown in fig. 1, the pressurized drag reduction device 100 for coiled tubing drilling further includes a pressurizing unit 2. Wherein, the pressurizing unit 2 is arranged at the downstream of the resistance reducing unit 1 and can receive the periodically switched high-pressure fluid flowing out of the resistance reducing unit 1. The bottom of the pressurizing unit 2 far away from the resistance reducing unit 1 is connected with a drilling assembly (not shown). In the present invention, the oscillating mechanism 10 can generate an oscillating effect to the high-pressure fluid in the well, so that the high-pressure fluid with the oscillating effect acts on the pressurizing unit 2. In this way, the high and low pressure differences formed between the high pressure fluid having an oscillating effect and the bottom hole assembly act on the pressurizing unit 2, thereby applying a flexible weight on bit to the bottom hole assembly by the pressurizing unit 2.

As shown in fig. 1, the pressurizing unit 2 includes a cylinder 30 having an inner chamber 35. The cylinder 30 is connected to the resistance reducing unit 1 by a joint 31, so that fluid can flow into the inner cavity 35 after passing through the resistance reducing unit 1. A piston rod 32 is further arranged in the cylinder 30, and a piston 321 is sleeved on the outer wall of the piston rod 32. The piston rod 32 can move along the axial direction of the cylinder barrel 30 under the action of the difference between the internal pressure and the external pressure on the end face of the piston 321. Meanwhile, the piston rod 32 is configured in a tubular shape, and a passage 351 for fluid communication is defined in the piston rod 32, so that the fluid flowing into the inner chamber 35 can flow out of the cylinder 30 through the passage 351.

A liquid chamber 31 is formed between the piston rod 32 and the cylinder tube 30 provided outside thereof. The fluid chamber 31 can provide a temporary storage space for drilling fluid.

It will be readily appreciated that when the fluid pressure in the internal chamber 35 is greater than the fluid pressure in the space 38 outside the cylinder barrel 30, this pressure differential will act on the end faces on either side of the piston 321, thereby urging the piston rod 32 to move away from the fluidic element 20.

Fig. 3 shows a schematic view of a cylinder 30 in a pressurizing unit 2 according to the invention. As shown in fig. 3, the cylinder tube 30 is provided with two breathing holes 60 communicating with the liquid chamber 31. The two breathing holes 60 are preferably radially symmetrical in order to ensure that the liquid chamber 31 communicates with the outer annulus. Thus, during the free axial reciprocation of the combination of the piston 321 and the piston rod 32 in the cylinder 30, downhole fluid can be repeatedly sucked or discharged through the fluid chamber 31.

During well drilling, the drilling fluid will first pass through the drill string to the drill bit (not shown) at the bottom of the well, through the drill bit to the space between the drill string and the wall of the well, and then back up the well head through the space between the drill string and the wall of the well, completing the circulation. During this cycle, the pressure of the drilling fluid returning to the wellhead from the space 38 between the drill string and the borehole wall is always less than the pressure of the drilling fluid in the drill string, due to the throttling pressure differential between the drill bit and the bottom motor.

Therefore, when the pressurized drag reduction device 100 for coiled tubing drilling of the present invention is installed on a drill string to participate in the circulation of drilling fluid, the fluid pressure outside the bore 30 will always be less than the fluid pressure in the inner chamber 35. Under this pressure differential, the piston rod 32 will move away from the fluidic element 20. This pressure is transmitted to the lower drill assembly.

Fig. 4 is a schematic view of the piston rod 32 of the pressurized drag reduction device 100 for coiled tubing drilling shown in fig. 1. As shown in fig. 4, a locking groove 42 is further provided on the outer wall of the piston rod 32. The clamping groove is used for sleeving a scraping ring. The scraping ring is a circular ring protruding out of the clamping groove 42 and can abut against the inner wall of the cylinder barrel 30. Thus, when the piston rod 32 moves along the axial direction of the cylinder 30, the scraping ring 47 can clean the inner wall of the cylinder 30, and prevent drilling fluid or other solid impurities from remaining on the inner wall of the cylinder 30.

As shown in fig. 1, a spline joint 50 is further provided at an end of the piston rod 32 remote from the oscillating element 10. The pressurized drag reduction device 100 is connected to the drill string via a spline joint 50. Specifically, the spline joint 50 includes a spline shaft 52 and a spline barrel 54 that are sleeved together. The spline joint 50 can ensure that the pressurizing and resistance reducing device 100 for continuous pipe drilling always rotates synchronously with the drill string during the rotary drilling process of the underground drill string.

Meanwhile, the outer wall of the spline shaft 52 is provided with a drop-proof half ring, and the drop-proof half ring 56 can be embedded into a clamping groove (not shown) formed on the spline shaft, so that the spline shaft 52 is prevented from slipping into the bottom of the well and causing downhole accidents.

It is easily understood that in the present invention, two-stage pressurization is realized by the piston rod 32 and the spline shaft 52. With this arrangement, the pressurization effect of the pressurization drag reduction device 100 for coiled tubing drilling of the present invention can be further improved. Meanwhile, a liquid passing groove 322 is provided at the bottom of the piston rod 32. Due to the liquid passing groove 322, the drilling fluid flowing through the first group of piston rods 32 can enter the shaft end of the spline shaft 52, and the problem of the flow resistance of the drilling fluid can be effectively solved.

It should be noted that, the worker may also set a plurality of sets of piston rods 32 according to the actual working conditions on site and the tensile and torsional strength of the whole tool, so as to determine the actual pressurizing stage number, which is not limited herein.

The operation of the pressurized drag reduction device 100 for coiled tubing drilling according to the present invention is briefly described as follows.

The pressurized drag reduction device 100 for coiled tubing drilling of the present invention is adapted to be attached to a drill string and lowered into a well with the drill string. In the drilling process, the resistance reducing unit 1 can generate periodically-changed hydraulic oscillation, so that the pressurizing resistance reducing device 100 periodically shakes along the axial direction to drive the underground drill string to periodically shake. Therefore, the friction force between the drill string and the well wall is reduced, and the function of friction reduction and resistance is achieved.

Meanwhile, in the process of drilling fluid circulation, because the pressure of the drilling fluid in the cylinder barrel 30 is always higher than the pressure of the drilling fluid between the cylinder barrel 30 and the well wall, a pressure difference is generated at two radial sides of the cylinder barrel 30, the piston rod 32 and the piston 321 on the piston rod 32 are pushed to move towards the direction far away from the oscillation element 10, and thus the pressure is transmitted to the drilling tool assembly at the side of the piston rod 32 far away from the oscillation element 10, so that a pressurization effect is generated.

Finally, it should be noted that the above-mentioned embodiments are only preferred embodiments of the present invention, and do not limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described in the foregoing examples, or that equivalents may be substituted for elements thereof. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A pressurized drag reduction device (100) for coiled tubing drilling, comprising:

the device comprises a resistance reducing unit (1) and a control unit, wherein the resistance reducing unit comprises an oscillating element (10) and a jet element (20) connected to the oscillating element;

a pressurizing unit (2) comprising a cylinder (30) connected to the resistance-reducing unit and having an inner chamber (35) in which a piston rod (32) is disposed, a piston (321) being sleeved on the piston rod,

a drilling assembly connected to the bottom of the pressurizing unit,

the jet element can generate jet flow so as to enable fluid flowing through the resistance reducing unit to vibrate, and the piston rod can axially move along the cylinder under the action of pressure difference on two sides of the outer wall of the cylinder, so that flexible bit weight is applied to the bottom hole assembly.

2. The pressure drag reduction device (100) for coiled tubing drilling according to claim 1, wherein a first swirl chamber (22) and a second swirl chamber (24) are provided in the fluidic element in annular form, and a diverting flow channel (25) and a feedback flow channel (26) communicating the first swirl chamber and the second swirl chamber, respectively.

3. The pressure drag reduction device (100) for coiled tubing drilling as claimed in claim 2, wherein said reversing flow channel is configured in a substantially "V" shape, said feedback flow channel being arranged along a common tangential direction of said first and second vortex chambers.

4. The pressurized drag reduction device (100) for coiled tubing drilling as claimed in claim 3, wherein said piston rod is configured as a tube, a fluid chamber (31) is formed between said piston rod and the inner wall of said cylinder, and said piston is disposed in said fluid chamber.

5. The pressurized drag reduction device (100) for coiled tubing drilling as claimed in claim 4, wherein at least one breathing hole (60) communicating with the fluid chamber is further provided on the outer wall of the cylinder.

6. The pressurized drag reduction device (100) for coiled tubing drilling as claimed in claim 5, wherein a scraping ring (47) is provided on the outer wall of the piston rod, said scraping ring being fitted at a groove (42) of the outer wall of the piston rod.

7. A pressurized drag reduction device (100) for coiled tubing drilling according to any of claims 1-6, wherein a spline joint for connecting the bottom hole tool is further provided at the end of the cylinder on the side away from the drag reduction unit, said spline joint comprising a spline shaft and a spline barrel.

8. The pressurized drag reduction device (100) for coiled tubing drilling as claimed in claim 7, wherein a drop-proof half ring is further sleeved on the spline shaft.

9. A pressurized drag reduction device (100) for coiled tubing drilling according to any of claims 1-6, wherein multiple sets of pressurizing units are provided within the cylinder.

10. The pressurized drag reduction device (100) for coiled tubing drilling as claimed in any of claims 1-6, wherein the bottom of the piston rod has a fluid through slot, thereby allowing drilling fluid flowing through the piston rod to enter between the piston rod and the splined shaft, thereby pushing the splined shaft and piston rod together.

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