RU2420387C1 - Bench for assembly and disassembly of downhole motors - Google Patents

Abstract

FIELD: process engineering. ^ SUBSTANCE: invention relates to machine building, particularly, to devices intended for tightening and loosening of threaded joints. Proposed bench comprises torque generator including drive device with hollow shaft and disk chuck fitted on the shaft and provided with clamping hydraulic cylinders. Each of the latter comprises HP and LP chambers, delay device and hydraulic system. Hollow shaft of the drive device is provided with fixed sleeve. Two annular chambers are made on inner surface of said sleeve. Hollow shaft wall have channels to communicate one of said annular chambers with HP chambers of all clamping hydraulic cylinders and another annular chamber with LP chambers of said hydraulic cylinders. ^ EFFECT: easy, fast and low-cost assembly and disassembly of threaded joints. ^ 2 cl, 4 dwg

Description

The invention relates to the field of engineering, in particular to equipment for servicing hydraulic downhole motors, as well as other elements of the drill string used in telesystems, drill and casing pipes, jars, etc. More specifically, the invention relates to devices designed for screwing loosening threaded joints requiring high torque values.

A well-known stand for the assembly and disassembly of threaded joints (see book: V.A.Dobkin, G.M. Nikitin, A.A. Utrobin. Maintenance and repair of downhole hydraulic motors, M., Nedra, 1983, p. 83- 85). The stand contains a torque generating mechanism with a drive device including a hollow shaft mounted on its console part faceplate with clamping elements, a delay device with a faceplate secured from rotation and containing similar clamping elements. The clamping elements are made in the form of three cams eccentrically mounted with the possibility of rotation in the face plates, the outer surface of which is equipped with cracked crackers. Before making or unscrewing, cams with crackers are brought into contact with the cylindrical surface of the serviced downhole motors. When the drive device rotates due to friction of crackers with a notch along the surface of the engine, the cams with the teeth of the crackers are embedded in the surface of the engine, thereby creating the necessary coupling of the cam with screwed parts.

A disadvantage of the known design is the uncontrolled clamping force of three cams, since the friction force in the contact depends on many factors (sharpness or crushing of the teeth of the notch, contamination of the contacting surfaces, the value of the eccentricity of the cams). The radial forces arising in this case lead to the deformation of the hull products until they lose their cylindrical shape, and the cams slip leads to the milling of the body by the teeth of crackers. All this leads to accelerated wear and failure of expensive hull parts of downhole motors.

A known stand for screwing and unscrewing threaded joints of hydraulic downhole motors according to patent RU 2236535 (publ. September 20, 2004), which includes a mechanism for creating torque with a drive device and a delay with faceplates, and the delay device is designed so that the stand allows disassembly and assembly engines with skew axles.

However, a significant drawback of this stand is also the clamping of parts by eccentric cams, destroying screwed or unscrewed parts.

The stand for assembling and disassembling threaded joints of Torquemaster downhole motors manufactured by the American company National Oil Well Varco, information about which is published in the Composite Catalog (publ. 2000, pp. 111-113), as well as information about the stand is available on the website of National Oil Well (www.nov.com/Downhole/ServiceJEquipment/Make-UpJBreak-OutEquipment/TORQUEMASTER Mashine.aspx)

A stand for assembling and disassembling threaded joints of downhole motors contains a torque generating mechanism including a drive device with a hollow shaft, a faceplate with clamping hydraulic cylinders radially mounted on it, each of which contains a high and low pressure chamber, as well as a delay device and a hydraulic system, including an oil pump unit, reversible flow distributors and a flow divider.

The main disadvantage of the known design of the stand is low productivity when fixing and unfastening the threads of downhole motors.

Another disadvantage of the known design is the need for continuous operation of the pump and its engine throughout the entire make-up or unscrewing process, which leads to an excessive consumption of electricity and accelerated wear of the pump and motor.

The present invention solves the problem of increasing the productivity of the stand for the assembly and disassembly of threaded joints of downhole motors, as well as increasing the durability and reliability of the stand and reducing energy consumption.

To achieve the indicated technical result, in a stand for assembling and disassembling threaded joints of downhole motors containing a torque generating mechanism including a drive device with a hollow shaft, a face plate with clamping hydraulic cylinders radially mounted on it, each of which contains high and low pressure chambers, and also a delay device and a hydraulic system including an oil-bearing unit, reversible flow distributors and a flow divider, are installed on the hollow shaft of the drive unit A fixed sleeve is introduced, on the inner surface of which there are two annular chambers connected to one reversible flow distributor, channels connecting one of the annular chambers with high-pressure chambers of all hydraulic cylinders and the other annular chamber with low-pressure chambers of these hydraulic cylinders are made in the wall of the hollow shaft moreover, the flow divider is mounted on a rotating faceplate of the torque generating mechanism. The stand can be equipped with hydropneumatic accumulators.

Distinctive features of the proposed stand from the above known, closest to it, is that a fixed sleeve is installed on the hollow shaft of the drive device, on the inner surface of which there are two annular chambers connected to one reversible flow distributor, channels are made in the wall of the hollow shaft, connecting one of the annular chambers with high-pressure chambers of all hydraulic cylinders, and the other annular chamber - with low-pressure chambers of these hydraulic cylinders, and the flow divider is set connected to the rotating faceplate of the torque mechanism. The stand can be equipped with hydropneumatic accumulators. Due to the presence of these features, the stand of the proposed design allows the assembly and disassembly of threaded joints in a quality, quick and cheap manner.

The proposed design of the stand is illustrated by the drawings shown in figures 1-4.

Figure 1 shows a General view of the stand,

figure 2 is a longitudinal section of a mechanism for creating torque with a faceplate,

figure 3 is a view along arrow A of the mechanism for creating torque with a faceplate,

figure 4 is a hydraulic diagram of the stand.

A stand for assembling and disassembling threaded joints of downhole motors (Fig. 1) includes a torque generating mechanism I, a delay device II, and a hydraulic system III mounted on a common frame 1, which is a rigid welded structure.

The torque generating mechanism 1 (FIG. 2) includes an electric motor 2, a gearbox J with a reduction gear, a hollow shaft 4 mounted on two radial bearings 5. On the cantilever part of the hollow shaft 4, a faceplate 6 is mounted with clamping cylinders 7 radially mounted on it, each of which contains a high-pressure chamber 8 located on the periphery of the faceplate 6, a low-pressure chamber 9 located on the other side of the hydraulic cylinder 7. These chambers are separated by a piston 10 with a seal 11. The rod 12 of the piston 10 (Fig.3) is directed to the center the neutral axis of the faceplate 6 and the hollow shaft 4, on the end of the rod 12 is fixed cracker 13, made with high hardness and having a notch to improve adhesion to products subjected to screwing or unscrewing. The number of hydraulic cylinders 7 on the faceplate 6 is usually four or six, but there may be other options.

On the cantilever part of the shaft 4 (FIG. 2), a thick-walled bushing 14 is mounted with minimal gaps, which is fixed against rotation by means of the strut 15. Two annular grooves 16 are made on the inner surface of the bushing 14, each of which is sealed with O-rings 17. In the hollow wall of the shaft 4, channels 18 and 19 are made for connecting the annular grooves 16 with the high-pressure chambers 8 and low-pressure chambers 9 of the hydraulic cylinders 7. A flow divider 20 is also mounted on the faceplate 6, which is designed to equalize the fluid supply speed to cylinder 7 in order to ensure synchronous convergence of the rods 12. The dividers 20 can be of various designs, for example based on adjustable throttles installed on each hydraulic cylinder, or on the basis of identical volumetric hydraulic pumps whose shafts rotate synchronously. The figures conventionally show the last version of the divider.

Delay device II (FIG. 1) is a rigid frame 21 provided with wheels 22 for moving along frame 1, as well as a drive for moving and safety devices against tipping over at high torques (the drive and safety devices are not shown in the drawings). On the frame 21 of the delay device II is mounted coaxially with the faceplate 6 (Fig.1) faceplate 23, identical in design to the faceplate 6, but fixed from rotation. The washer 23 is also equipped with a flow divider 24.

To drive the hydraulic cylinders of the faceplates, the stand is equipped with a hydraulic system III, which includes an oil pump unit consisting of an electric motor 25 mounted on the oil tank 26 and driving the oil pump 27, which supplies oil under pressure to the control valves 28 and 29. Connection of the control valves 28 and 29 sec hydraulic cylinders are presented on a hydraulic circuit (figure 4). Hydropneumatic accumulators 30 and 31 are also integrated in the circuit and are associated with adjustable check valves 32 and 33, respectively.

The work of the stand is as follows. If necessary, make screwing on the thread of two parts, one of them is inserted into the faceplate 6 of the mechanism for creating torque L. The electric motor 25 is turned on, which drives the oil pump 27 of the oil pump unit. The oil is supplied by the oil pump 27 from the oil tank 26 through a reversible hydraulic distributor 29 through the oil pipes to the sleeve 4, from where through the channels 18 and the flow divider 20 it is sent in equal shares to the high-pressure chambers 8 of the hydraulic cylinders 7 of the rotating faceplate 6. Due to the uniform distribution of the flow between the cylinders, their pistons 10 move synchronously to the axis of the stand, while the rods 12 with crackers 13 clamp the screwed part coaxially with the faceplate 6. The pressure necessary to create sufficient clamping force of the part is set using oil pump unit (control hydraulic equipment on the hydraulic circuit is not shown). When the pressure in the high-pressure chambers 8 of the hydraulic cylinders 7 increases, the hydraulic accumulator 30 charged with nitrogen gas is also charged, but at the end of the oil supply, the zy directional control valve switches to the neutral position, the adjustable check valve 32 is closed and the pressure in the hydraulic cylinders 7 of the rotating faceplate 6 is maintained.

The second screw-in part is likewise installed in the faceplate 23 of the delay device II, while the oil is directed through the oil distributor 28 through the corresponding oil lines through the divider 24 into the pressure chambers of the hydraulic cylinders of the faceplate 23 of the delay device II. In this case, the hydraulic accumulator 31 is charged, the valve 28 is placed in the neutral position, the oil pump 27 is turned off. By moving the delay device II to the torque generating device, the threaded ends of the parts to be joined are joined.

The electric motor 2 through the gearbox 3 drives the hollow shaft 4 and the faceplate 6 mounted on it with the part clamped in it, and the second part, clamped in the faceplate 23 of the delay device II, is screwed with the first part when moving the latter to the faceplate 6. The make-up process is carried out until the moment of make-up reaches the value required for this type of thread. The equipment with which the torque is monitored and the engine 2 is turned off when the required moment is reached is well known and therefore is not considered in this description.

If it is necessary to disconnect the parts by thread, the engine is rotated back using the electric switch on the remote control 34 (Fig. 1) (the switch is not shown), the necessary torque is created, which is aimed at unscrewing. Screwing and unscrewing of parts, in contrast to the prototype, is carried out with a one-time capture of parts by the rods of the delay hydraulic cylinders and faceplates 6.

To release parts, the control valves 28 and 29 are switched to the position when the oil from the oil pump 27 is supplied to the low-pressure chambers 9 of the hydraulic cylinders 7, while the check valves 32 and 33 and the oil from the high-pressure chambers 8 of the hydraulic cylinders 7 are opened through flow dividers 20 and 24, check valves 32 and 33, control valves 28 and 29 are fed to the drain.

Thus, thanks to the improvements made according to the invention, a stand has been created for assembling and disassembling threaded joints, which allows to increase the productivity and convenience of the stand staff, increase the reliability and durability of the equipment serviced at the stand, and also reduce energy consumption due to the possibility of turning off the oil pump engine when make-up and unscrewing of the GZD threads. The stand according to the invention is designed, manufactured and put into operation at ZAO Gidrobur-service.

Claims (2)

1. A stand for assembling and disassembling threaded joints of hydraulic downhole motors, comprising a torque generating mechanism, including a drive device with a hollow shaft, a faceplate mounted on the shaft with radially mounted clamping cylinders, each of which contains high and low pressure chambers, and delay device and hydraulic system, including oil pump unit, reversible flow distributors and flow divider, characterized in that on the hollow shaft of the drive device a fixed sleeve is installed, on the inner surface of which there are two annular chambers connected to one reversible flow distributor, channels are connected in the wall of the hollow shaft connecting one of the annular chambers with high-pressure chambers of all clamping hydraulic cylinders, and the other annular chamber with low-pressure chambers of the aforementioned hydraulic cylinders, and the flow divider is mounted on a rotating faceplate of the torque generating mechanism. 2. The stand according to claim 1, characterized in that the torque generating mechanism and the delay device are equipped with hydropneumatic accumulators.

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