RU2354801C2 - Method for creation of tractive force in well and oilwell tractor (versions) - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention is related to works in well, namely, to method and versions of device for items transportation, in particular, instruments on cable in horizontal wells. Method for creation of tractive force in well, in which well tractor is used with supports that interact with well walls, and vibration exciter, well tractor body vibrations are created along well, vibrations are sent to wheel and/or lever supports pressed to wheel walls. Supports are arranged so that they prevent displacements of well tractor in direction opposite to required direction of motion in well. Wheel-support well tractor includes body, mechanisms for wheels pressing/release to well walls, wheels pressed to well walls, at least one vibration exciter, at least one unit of elastic mechanical and elastic electric connection to transported devices. Wheels are equipped with mechanisms that block rotation of wheels to the side that does not correspond direction of motion in well. Lever-support well tractor includes body, mechanisms for opening/closure of lever supports and lever supports, at least, one vibration exciter. Lever supports are arranged so that with their one end they are hingedly fixed to body, and with their other end they rest against well walls during opening in spring manner. All supports form sharp angles with body axis - angles of supports opening directed with their tops to one side, or tractor has two sets of supports with opening angles directed with their tops in opposite sides. Tractor also comprises at least one unit of elastic mechanical and elastic electric connection with transported devices.

EFFECT: expansion of technical facilities arsenal for instruments delivery to wells, increased efficiency and reduced technical complexity of well tractors.

4 cl

Description

The invention relates to work in wells and can be used to create traction and movement of objects, in particular devices on a cable in horizontal wells.

Horizontal are called wells in which at least part of the trunk has an anti-aircraft angle of more than 60-70 °. To move, for example, instruments on a cable through horizontal wells, a device called a downhole tractor is used. The downhole tractor generates traction by relying on the walls of the well with supports of various designs.

Known used in downhole tractors is a method of creating traction in wells using wheel bearings: the wheels are pressed against the walls of the well and transmit torque to them from the axes of the electric motors [1, 2, 3, 4]. The method does not guarantee the creation of the necessary traction in wells with uneven walls due to slipping of the wheels.

There is a known method used in downhole tractors to create traction force with the help of fixing supports, in which one part of the tractor is alternately fixed in the well with the help of the supports, while at the same time moving the other part along the shaft using a special drive [5, 6, 7]. The disadvantage of this method is, in particular, the technical complexity of the implementation.

In all downhole tractors, either a wheel drive or a drive for fixing supports is used. The prior art does not know a method of creating traction in wells, in which vibration is used instead of a drive.

The objective of the invention is to develop a vibrational method of creating traction in wells.

The problem is solved in that in the claimed method, the downhole tractor is provided with a vibration exciter, vibrations of the downhole tractor body are generated along the well, vibrations are transmitted to the supports pressed against the walls of the well, such that they prevent displacement of the downhole tractor in the direction opposite to the desired direction of movement along the well.

A downhole tractor, in which traction is created by vibration, will be called a vibro-tractor, omitting the definition of “downhole” for brevity.

The source of vibrations of the vibro-tractor body is the vibration exciter [8, p. 44-45]. The most common are unbalanced vibration exciters, in which the inertia force arising from the rotation of an unbalanced inertial element is used to generate oscillations. For the vibrotractor, oscillations directed along the axis of the well are useful. There are unbalanced vibration exciters in which, thanks to the use of several unbalanced inertial elements rotating synchronously in different directions, oscillations are generated along the straight line - such vibration exciters can be used in a vibration tractor. Can also be applied electromagnetic or electrodynamic vibration exciters [9, p. 507, 257-258]. In electromagnetic vibration exciters, forces that excite oscillations are created as a result of the action of a time-varying magnetic field on ferromagnetic bodies. For example, an electromagnetic vibration exciter may contain a solenoid laid in the stator through which alternating current is passed, and a spring-fixed iron core as an inertial element that performs translational-reverse motions under the action of the alternating magnetic field of the solenoid — vibrations. The stator is rigidly fixed in the vibrotractor housing and also vibrates with the housing.

To implement the method, the presence of a vibration exciter is essential, and not its device.

The technical result is achieved by converting the longitudinal vibrations of the vibro-tractor body into translational motion, i.e. the vibrotractor is a vibrating mover [8, p. 47-48]. The traction force is created at the ends of the supports fixed to the vibrotractor body as follows. The displacements of the vibro-tractor body directed towards the desired direction of movement are called direct displacements, and displacements directed in the opposite direction are called reverse displacements. Direct displacements occur unhindered. Reverse displacements are hindered by the action of friction forces from the side of the well walls on the supports. These forces are transmitted to the vibrotractor body. Thus, the traction force of the vibrotractor is created as the time-average friction force between the supports and the walls of the well.

Distinctive features of the method are the use of vibrations and hindering the reverse displacement of the supports, the absence of drive mechanisms on the supports. The method simplifies the design and increases the efficiency of the downhole tractor.

The method can be implemented using supports of various designs, such as wheeled or lever.

The wheel supports of the vibrotractor are wheels pressed against the walls of the well using mechanisms similar to those used in known wheeled tractors. For example, a mechanism providing clamping of wheels similarly to [1] may contain levers with wheels pivotally attached to the housing and pivotally connected to levers connected to the driving nuts. In this case, the spindle nuts are mounted on the spindles driven into rotation by an electric motor. The rotation of the spindles in one direction leads to the pressing of the wheels to the walls of the borehole, the rotation in the other moves the wheels away from the borehole wall. In order to ensure the pressure of the wheels in uneven borehole walls, the pressure should be spring. For this, for example, levers are connected that are connected to the driving nuts as a spring link [8, p. 354], which has mobility in the longitudinal direction.

To implement the method using the wheel supports, the presence of mechanisms for pressing the wheels is essential, and not their device.

In order for the wheel bearings pressed against the walls of the well to prevent the reverse displacements of the vibrotractor, they are equipped with a mechanism that blocks the rotation of the wheels in one direction. An example of a suitable mechanism is the ratchet mechanism [8, p. 504-505], which includes, in the simplest embodiment, a ratchet wheel and a spring-loaded dog. Many varieties of ratchets are known. In particular, the ratchet mechanism can be made in the form of a sleeve with internal teeth and a dog located inside the sleeve. Known ratchet mechanisms with several dogs and a variable pitch of the gear wheel - in this case, the angle of rotation of the wheel decreases, at which the reverse rotation is blocked, because at the slightest turn one of the dogs is triggered. Reversible ratchet mechanisms are known, i.e. those in which the direction of rotation is switched, for example, using a double-acting dog.

To implement the proposed method using wheel bearings, the presence of a mechanism blocking the rotation of the wheels in one direction, and not its device, is essential.

Lever supports are levers pivotally mounted on the housing, the free ends of which are spring-loaded against the walls of the well. With a reverse bias between the support and the borehole wall, a friction force arises that is greater than with a forward bias, because with reverse bias, a wedging effect occurs. The effectiveness of the lever supports increase, for example, making their ends sharp or toothed. Also, to increase the efficiency of the lever supports, the free ends of the levers can be bent so as to provide contact with the wall of the well and a wedging effect when changing the diameter of the well. At the same time, supports of different lengths and shapes can be used. Lever supports can be opened, i.e. cling to the walls of the well, and fold, i.e. press against the vibrotractor body. The mechanism of opening / closing of the lever supports can be performed in various ways, for example, levers connected to the spindle nuts mounted on the spindles driven by the rotation of the electric motor can be pivotally connected to the supports. The spring pressure of the lever supports can be provided, for example, by the implementation of levers connected to supports and running nuts in the form of spring links [8, p. 354], which have mobility in the longitudinal direction. The magnitude of the pressing force of the lever supports is not significant, since resistance to reverse displacements is provided by a wedging effect.

Known wheel-supporting downhole tractor [3] (analog 1), consisting of modules, each of which includes electric motors, mechanisms for extending and pressing wheel supports to the walls of the wells, mechanisms for transmitting torque to the wheels. Electric motors convert electrical energy into mechanical work, while traction is created by transmitting torque from the axis of the electric motor to the wheels. The wheel support tractor is mainly used in cased wells, since it does not guarantee the creation of traction if the walls of the well are uneven and the diameter of the well changes with depth.

The technical task of the invention is to simplify the design and increase the efficiency of the downhole tractor by creating a wheel-supporting vibrotractor.

The technical result is achieved by the fact that the device, a wheel support downhole tractor, including a housing, mechanisms for pressing / squeezing the wheels against the walls of the well, wheels pressed against the walls of the well, contains at least one vibration exciter, and the wheels are equipped with mechanisms that block rotation wheels in a direction that does not correspond to the direction of movement along the well, as well as at least one node of elastic mechanical and elastic electrical connection with transported devices.

The technical result is ensured by the fact that due to the blocking of the rotation of the wheels on one side between the wheels and the walls of the borehole, a friction force arises, which is the traction force, and it does not require transmission of torque to the wheels. It is assumed that greater efficiency in wells with uneven walls compared to the analogue, because direct displacements of a wheel borehole vibrotractor occur due to inertia. In addition, the design of the downhole tractor is simplified.

The wheel-supporting well vibrotractor may include mechanisms that switch the direction of possible rotation of the wheels and, accordingly, the direction of movement of the tractor along the well, for example, reversible ratchet mechanisms.

A well-known tractor without wheels [7] (analogue 2), in which the traction is provided using two axially symmetrically mounted locking legs that can be moved along the section body — three supports in each section, while the supports of one of the sections are supported alternately during the movement of the downhole tractor on the walls of the well and moving the tractor along the well, at this time, another section of the supports, moving along the tractor, takes its initial position. The device has two electric motors, hydraulic and mechanical systems. Electric motors convert electrical energy into mechanical work, and traction is created by a mechanical drive that moves the support sections along the downhole tractor. The main disadvantage of the device is its technical complexity.

The technical task of the invention is to simplify the design and increase the efficiency of the downhole tractor by creating a lever-supporting vibrotractor.

The technical result is achieved in that the device, the lever-supporting downhole tractor, including the housing, mechanisms for opening / closing the lever supports and lever supports, contains at least one vibration exciter, and the lever supports are made so that one end is pivotally attached to the body, and when opening, they spring against the walls of the well, while all the supports form sharp angles with the axis of the body — the opening angles of the supports directed by the vertices in one direction, as well as at least one elastic and mechanical unit adic electrical connection with transportable devices.

The technical result is ensured by the fact that the friction force between the ends of the supports and the walls of the well depends on the direction of displacement: if the displacement is such that the friction force tends to increase the opening angles of the supports, then due to the wedging effect, friction force is greater than when displaced in the opposite direction . If the ends of the supports have a small area, then, clinging to the walls of the well, they are positioned in irregularities, abut against them. In addition, the supports can be sharp, serrated, made of solid materials and stuck into the walls of the well at reverse displacements. Also, the supports can be made curved so as to provide contact with the wall of the well and a wedging effect when changing the diameter of the well. Thus, the supports are locking at reverse and sliding at forward displacements. It is assumed that, in comparison with the analogue, the efficiency of the lever-support vibrotractor in wells with uneven walls and variable diameter is large. In addition, the design of the downhole tractor is simplified.

In order for the lever-support vibrotractor to create traction force both in the constrictions and in the extensions of the well, it can contain supports of different lengths: in the constrictions, they are pressed at the optimal angle to the wall of the well and provide traction short, and in extensions, long supports.

The lever-supporting vibrotractor may have two sets of supports, differing in the direction of the opening angles. In this case, you can switch the direction of the traction force of the vibrotractor and the direction of movement along the well, revealing the supports of only one of the sets.

Both wheel-supporting and lever-supporting vibrotractors must transmit traction to the transported device, but not transmit vibration. For this, the vibrotractor includes an elastic mechanical connection, for example, a spring vibration isolator, which provides transmission of traction and isolation of the transported device from vibrations, while at the same time allowing the vibrotractor body to vibrate. The elastic electrical connection provides the transmission of electrical energy and control signals and can be carried out, for example, using a cable having sufficient "slack".

Between the vibrotractor and the transported device, an vibration damper in the form of a massive body with an elastic mechanical and elastic electrical connection can additionally be located.

The vibrotractor may contain not one, but several not necessarily the same blocks described above, including wheel support blocks and lever support blocks, elastomechanically and electrically interconnected directly or via transportable devices.

The invention is explained below using schematically depicted in the accompanying drawings examples of implementation.

The drawings show:

figure 1: schematic diagram - an example implementation of a wheel-supporting vibrotractor;

figure 2: schematic diagram - an example implementation of the lever-supporting vibrotractor;

figure 3: schematic diagram - an example implementation of a mechanism for folding lever supports.

Figure 1 shows: the body of the vibration tractor 1, the exciter V, the motor D, the lead screw 2, the lead nut 3, the swivel joints A, B, C, the lever 4 with a spring link 5, the lever 6, the wheel 7 with a ratchet mechanism 8, electromechanical connector 9 with spring 10. The cable coming from the electromechanical connector 9 to the vibro-tractor housing is not shown. The elements that are symmetrically located relative to the axis of the vibrotractor to those indicated are not marked, but when describing one element, we will keep in mind the symmetrical one. During the descent / ascent into the well, the axis of the wheel 7 is in position B '(the axis of the second wheel is in position B "), the spindle 2 occupies the leftmost position (not shown). The planes of the wheels are offset relative to each other, so the wheels do not interfere with each other In order to create traction, engine D rotates the spindle 2, the spindle nut 3 moves, and thanks to the levers 4 and 6, the wheel 7 is pressed against the borehole wall. Vibration exciter V creates longitudinal vibrations of the housing 1 and the elements attached to it. , caused by vibration, the force on the wheel 7 pressed against the borehole wall tends to rotate around axis B. According to the drawing, the wheel 7 rotates freely counterclockwise, but cannot rotate clockwise due to the ratchet mechanism 8. Thus Thus, when vibrations from the side of the walls of the borehole arise, the friction force F directed to the right appears in Fig. 1, to simplify the drawing, only one pair of wheel supports is shown. As a rule, at least two pairs of wheel supports are used. The sum of the friction forces acting on all the supports that are part of the vibrotractor is the traction force of the vibrotractor. The traction force is transmitted through the spring 10 and the electromechanical connector 9 to the transported device.

Figure 2 shows: the body of the vibration tractor 1, the exciter V, the electric motor D, the lead screw 2, the lead nut 3, the swivel joints A, E, C, the lever 4 with the spring link 5, the lever 6, the shoe of the lever support 11, the electromechanical connector 9 with spring 10. Not shown cable coming from the electromechanical connector 9 to the body of the vibrotractor. The elements that are symmetrically located relative to the axis of the vibrotractor to those indicated are not marked, but when describing one element, we will keep in mind the symmetrical one. When lowering / raising into the well, the lever supports are in the folded position: the swivel joint E is in the E position, the spindle 2 is in the leftmost position (not shown). The plane of the lever supports are offset relative to each other, therefore, do not interfere with each other when folded. To create a traction force, the engine D rotates the lead screw 2, while the lead nut 3 moves, and thanks to the levers 4 and 6, the shoe of the lever support 11 is pressed against the borehole wall. The vibration exciter V creates longitudinal vibrations of the housing 1 and the elements attached to it. With displacements to the right caused by vibration, the shoe 11 slides along the wall of the well, since the spring link 5 does not create a significant pressure. With displacements to the left, a wedging effect occurs and a greater friction force between the shoe and the wall of the well than with displacements to the right. Thus, with vibrations from the side of the borehole walls, a frictional force F arises to the right. In figure 2, to simplify the drawing, only one pair of supports is shown. It is advisable to use a larger number of supports for guaranteed creation of force F. The sum of the friction forces acting on all the supports that are part of the vibrotractor is the traction force of the vibrotractor. The traction force is transmitted through the spring 10 and the electromechanical connector 9 to the transported device.

Figure 3 shows: the lever supports 12, the axis of attachment of the supports O, P, Q and H, a curved rail R, a line indicating the edge of the housing of the vibrotractor MN. Due to the symmetry of the drawing, notation is not indicated on its lower part. The lever supports 12 are spring-loaded (not shown) and, under the action of the springs, tend to open, i.e. occupy the position shown in the drawing. The curved rail R can only be moved along the axis of the vibrotractor, for example, by means of a running clutch (not shown) connected to the rail, driven by a lead screw (not shown). During the descent / ascent of the vibrotractor into the well, the rail R is shifted to the right by half the distance between the adjacent axes of the supports with respect to the position shown in the drawing. In this case, the supports 12 are rotated so that their long ends extend beyond the edge of the housing of the vibrotractor MN. To bring the supports 12 to the working position, the rail is shifted to the left, to the position shown in the drawing. In this position, the ends of the supports interact with the walls of the well and, when vibrated, create a traction force F.

Information sources

1. RF patent RU 2236549 C2.

2. Downhole deliveryman DS-2 (DS-3). A system for delivering geophysical instruments to horizontal sections of wells. NGO Taris, www.taris.rn.

3. Downhole Tractor (MDT). Sondex. www.sondex.com.

4. US patent US 6,273,189 B1.

5. RF patent RU 2175374 C1.

6. US patent US 5,794,703.

7. Alden M., Arif F., Billingham M., Gronnerod, N., Harvey, S., Richards, M. and West, C., "Advancing Downhole Conveyance", Schlumberger Oilfield Rewiew, Vol.16, No. 3, p.30-43.

8. Krainev A.F. Dictionary reference to mechanisms. M .: Engineering, 1987.

9. Vibration in technology: a reference. In 6 volumes - M .: Mechanical Engineering, 1981. - Volume 4. Vibration processes and machines. / Ed. E.E. Lavendela. 1981. 509 p.

Claims (4)

1. A method of generating traction in a well, in which a downhole tractor is used with supports interacting with the walls of the well, characterized in that the downhole tractor is equipped with a vibration exciter, the body of the downhole tractor is created along the well, vibrations are transmitted to the wheel and / or pressed against the walls of the well lever supports, while the supports are such that they prevent the displacement of the downhole tractor in the direction opposite to the desired direction of movement along the well. 2. Wheel-supporting downhole tractor, comprising a housing, mechanisms for pressing / pressing wheels against the walls of the well, wheels pressed against the walls of the well, characterized in that it contains at least one vibration exciter, and the wheels are equipped with mechanisms that block the rotation of the wheels in a side that does not correspond to the direction of movement along the well, as well as at least one node of an elastic mechanical and elastic electrical connection with transported devices. 3. Wheel support well tractor according to claim 2, characterized in that it has mechanisms for switching the direction of rotation of the wheels. 4. Lever-supporting downhole tractor, comprising a housing, mechanisms for opening / closing the lever supports and lever supports, characterized in that it contains at least one vibration exciter, and the lever supports are made so that one end is pivotally attached to the body, and when opening, they spring against the walls of the well, while all the supports form sharp angles with the axis of the body — the opening angles of the supports directed by the vertices in one direction, or the tractor has two sets of supports with the opening angles directed by the vertices in the opposite direction s side, as well as at least one elastic mechanical assembly and electrical connection to a flexible transportable devices.

Images