Method and apparatus to vibrate a downhole component

(74) Author (54) Designation Device and method for generating vibrations in a well pipe string (56) Published publications Dl: US 4807709 (57) Abstract

A device for use in a wellbore (10) comprises a housing (200,300,400) having a longitudinal axis X and a mechanism including one or more supporting elements (602, 604) constructed to move along the longitudinal axis in an oscillating manner to create a forward axis. and reverse force against the housing (200, 300, 400) to vibrate the housing (200, 300,400). In another embodiment, a device for use in a wellbore (10) comprises a housing (200, 300, 400) and at least one supporting member (602,604) rotatably mounted in the housing (200,300,400). The at least one supporting element (602, 604) can be rotated in such a way that it oscillates back and forth and transmits a vibratory force to the housing.

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The present invention relates to a method and apparatus for vibrating a downhole component.

In order to create a well for hydrocarbon production, a number of operations are carried out, including drilling and completion operations. While drilling a well, a drill bit is inserted at the end of a drill pipe. During the completion of a well, a variety of operations can be performed where tools are brought down on a pipe string (for example, coiled tubing or extension pipe). In this application, the term pipe string is used for a rigid guide mechanism or construction, such as coiled tubing or drill pipe, which can be used to guide tools or fluids into a well.

In recent times, many wells or long wells have been drilled to improve the recovery of hydrocarbons. Long wells have been shown to make it possible to increase the hydrocarbon recovery volume while reducing operating costs. In general, the financial gain will increase by how deep a long well can be drilled or renovated. Despite many technical innovations in the long-well technology, a number of challenges remain in connection with drilling or renovation of long-wells.

For a given long well or auxiliary well, the range of a tool carried on a pipe string is limited by the tendency of the pipe string to be wedged. When a pipe string is introduced into a well, it must overcome the frictional forces between the pipe string and the well wall. The longer the pipe string introduced into the well, the greater the frictional force between the pipe string and the well wall. When the frictional force becomes large enough, it will cause cracking of the pipe string, first to a sinusoidal bending form and then to a helical bending shape. After the occurrence of helical cracking, continued insertion of the tube string into the well will eventually end in a situation where further inward pressure against the tube string will not result in the tube string moving further inward. Such a situation is termed pipe string arrest. The depth at which this pipe string residue occurs defines the maximum depth at which it is possible to introduce a tool or fluid into a well.

Various factors affect (directly or indirectly) the maximum depth to which a pipe string can be inserted into a well. One factor is the coefficient of friction between the pipe string and the well. Another factor is the normal force transmitted in the contact between the pipe string and the well, which depends on the weight and stiffness of the pipe. Generally, a lower coefficient of friction or a lower weight means that the pipe string can be inserted deeper into the well. A high bending stiffness also tends to delay cracking, which increases the range of the pipe string in the well.

Various solutions have been tried or implemented to increase the reach of a pipe string in a well. One is to reduce the contact force between the pipe string and the well, for example by using different fluids inside and outside the pipe string to reduce the buoyancy of the pipe string or by making the pipe string a lighter material. Another technique is to delay or prevent the initiation of the helical cracking, which can be achieved by using a larger diameter pipe string. However, this increases the weight of the pipe string and reduces flexibility during operation. Yet another technique is to use a tractor to pull the pipe string into the well by applying a pulling force at the lower end of the pipe string. Other techniques use vibration to reduce friction.

From US 4,807,709, there is shown hydraulically controlled drill string impact pipe, in which oscillating impact elements in a housing vibrate the housing by providing forward and reverse force to the housing.

However, despite the various solutions that have been proposed or implemented, there is still a need for an improved method and apparatus for increasing the range of a strand in a well.

In general, according to one embodiment, the invention comprises a device for generating vibrations in a well pipe string for the purpose of reducing the friction between pipe string and well wall. The device comprises a housing with a longitudinal axis and a mechanism including one or more supporting elements designed for movement along the longitudinal axis in an oscillating manner to provide a forward and reverse force against the housing to vibrate the housing. The mechanism comprises a pressure-activated mechanism comprising a first support member, a second support member and a pressure chamber under an elevated pressure which drives the first and second support members of the housing.

In general, according to one embodiment, a device for use in a well comprises a housing having a longitudinal axis and a mechanism including one or more supporting elements designed to move along the longitudinal axis in an oscillating manner to create a forward and reverse direction against the house that vibrates the house.

In general, according to another embodiment, a device for use in a well comprises a housing and at least one support member rotatably mounted in the housing. The at least one supporting element can be rotated in such a way that it oscillates back and forth and creates a vibratory force against the housing.

Other or alternative features will be apparent from the following description, the figures and the claims.

Figure 1 illustrates an embodiment of a tool attached to a guide or support structure in a well, wherein the guide or carrier structure includes one or more vibration devices.

Figures 2A-2C illustrate the effect of longitudinal vibration caused by the vibration device according to one embodiment.

Figure 3 generally illustrates a vibration device for generating a bidirectional longitudinal vibration.

Figures 4A-4B are a longitudinal sectional section of a vibration device for generating a longitudinal bidirectional vibration according to one embodiment.

Figures 5A-5C are longitudinal sectional views of a vibration device for creating a bidirectional vibration according to another embodiment.

Figure 6 illustrates a valve mechanism used in the vibration device of Figures 5A-5C.

Figures 7-10 illustrate a device for generating a rotational or torsional vibration in the tube string of Figure 1, according to another embodiment.

The following description describes a number of details to provide an understanding of the present invention. However, those skilled in the art will appreciate that the present invention may be practiced without these details and that a variety of variations and modifications of the described embodiments may be possible. Although described embodiments refer to vibration methods and devices to aid the drilling of or other work in long wells or auxiliary wells, the same or a modified vibration method and device may be used in connection with other applications, such as releasing a stuck tube , installing an extension tube, installing sand control filters, activating downhole mechanisms (e.g., valves, nipples, etc.) and other uses.

Designations such as "up" and "down"; “Up and down”; upstream and downstream; and other similar designations indicating relative positions above or below a given point or element are used in this specification to clarify certain embodiments of the invention. However, when used for equipment and methods of use in well sloping or horizontal wells, such designations may refer to a "left to right" or "right to left" or other relationship as appropriate.

With reference to Figure 1, a string includes a tool 18 which is passed on a pipeline or pipe 14 (hereinafter referred to as a "pipe string", a "pipe duct" or a tubular structure ") into a well 10.1 another embodiment needs not the structure which guides the tool 18 into the well to be tubular, but may have any other configuration suitable for use in the well as a rigid guide structure. In this application, a guide structure is considered rigid "if a compressive force can be used at one end of the guide structure to move it inwardly into the well. A rigid guide structure contrasts with non-rigid guide structures such as cables and cast lines.

The well 10 is positioned with a casing 12 and has a substantially vertical section and a sloping or horizontal section 20.1 In other embodiments, the well 10 may be a substantially vertical well, a sloping well or a horizontal well.

According to some embodiments of the invention, one or more vibration devices 16 are mounted on the string. In the example of Figure 1, two vibration devices 16A and 16B are shown. In other examples, a single vibration device or more than two vibration devices may be used.

In one embodiment, the vibration device includes one or more impact members which can oscillate back and forth along the longitudinal axis of the string to apply a forward and backward force to the string. The forward and reverse forces transmitted by one or more of the supporting elements of the vibration device create a vibration along other parts of the string. Alternatively, instead of bidirectional, repetitive strokes, the strokes can be directed only in one direction. In another embodiment, instead of the longitudinal impact elements oscillating in the vibration device 16, one or more of the supporting elements may be mounted for rotation in a housing of the vibration device to oscillate back and forth in a rotational manner and employ a rotational or torsional vibration force against the pipe string.

Thus, in the first embodiment, a longitudinal vibration (due to bidirectional or unidirectional stroke) is created in the pipe string, while in the second embodiment, rotational or torsional vibrations (due to bidirectional or unidirectional torsional stroke) are created in the pipe string. Longitudinal and torsional vibrations reduce the frictional force between the pipe string and the well wall. In yet another embodiment, both longitudinal and torsional vibration devices can be used in conjunction with a single tube string.

According to some embodiments of the invention, the bidirectional or unidirectional stroke oscillation can be obtained without having to stretch or compress the tube string. In other words, it is not necessary to apply an upward force on the tube string or a compressive force on the tube string 20 for operation of the vibration device 16.1 In one embodiment, the energy required to activate the axial reciprocal oscillation of the fluid pressure is provided. In other embodiments, other forms of energy, such as electrical energy, may be used. According to some embodiments, the mechanism for activating the vibration device 16 operates independently of any tensile or compressive forces applied to the pipe string.

In general, the mechanism for operating the vibration device activates at least one impact member to repeatedly create a longitudinal or torsional shaking force (with an approximately fixed frequency) against a housing of the vibration device. The shaking force may be bidirectional or unidirectional.

Although no stretching or compression is required in the pipe string to operate the vibration device in some embodiments, other embodiments may use tensile or compression forces to enable activation of the vibration device, particularly to generate unidirectional oscillatory impact forces.

When a longitudinal vibration is generated in a tube string, the rate of vibration can be superposed at the translational rate (the rate at which the tube string is introduced into the well). As long as the velocity of vibration is greater than the insertion rate of the pipe string, at any moment, some parts of the pipe string will have a velocity in one direction while other parts of the pipe string will have a velocity in the opposite direction. As a result, the frictional force on the pipe string will be directed in one direction for some parts of the pipe string and in the opposite direction for other parts io of the string. Accordingly, the net frictional force between the pipe string and the firewall will be reduced, so that the pipe string can be fed further into the well. In addition to the benefits of the vibration with respect to the frictional forces, the movement created by the vibration device also contributes to increasing the range of the pipe string in the well.

The vibration frequency can be selected on the basis of the characteristics of the tube string and the well 10. For example, the length of the inclined or horizontal section 20 of the well and the corresponding tube string may dictate the vibration frequency and the maximum amplitude of the impact forces created by the vibration devices 16.1. it

2o the inclined or horizontal section 20 is, the greater the vibrational forces needed to increase the range of the pipe string. The vibrational frequency and amplitude can be controlled to provide useful extended range properties while avoiding excessive vibrations that could result in damage to instruments and / or other tools attached to the pipe string. The frequency of the oscillation 25 of the support element or elements of the vibration device may be chosen to coincide with the resonant frequency and / or maximize the transmissibility of the tube string or to maximize the transmissibility of the vibrations along the tube string.

Shock absorbers 20A, 20B (FIG. 1) may be provided to protect 10 instruments or other tools in the pipe string which may otherwise be damaged by the vibration caused by the vibration devices 16.

The effect of the longitudinal vibration in a pipe string is illustrated in Figures 2A-2C. Figure 2A illustrates a structure 100 which is introduced into the well at a rate V. The structure 100 may be represented as a number (5 in the illustrated example) of masses 102A, 102B, 102C, 102D and 102E connected via respective springs 104A, 104B, 104C and 104D. In the absence of vibrations, the velocity of each of the masses is approximately the same (with the velocity represented as V). The frictional force on each mass 102 is also approximately the same (with the frictional force represented as f). As a result, the net frictional force on the structure 100 in the example of Figure 2 + 5f, acting in the opposite direction of the speed V.

Using longitudinal vibrations, the velocity at 10 different masses 102A-102E will be different. Figure 2B illustrates the velocity pattern of each mass at a given time. The velocity of the mass 102A is -5V, the velocity of the mass 102B is -3V, the velocity of the mass 102C is 0V, the velocity of the mass 102D is + 3V and the velocity of the mass 102E is + 5V. The longitudinal vibration is used at the same time as the tube string is introduced at a velocity V, as shown in Figure 2A. The resulting velocity pattern in the tube string is the sum of the translational velocity V (Fig. 2A) and the instantaneous vibrational velocity (Fig. 2B), to be discussed below.

As can be seen from Figure 2C, by superimposing the velocity patterns of Figures 2A and 2B, the net velocity of the mass 102A is -4V, the net velocity 20 of the mass 102B -2V, the net velocity of the mass 102C + 1V, the net velocity of the mass 102D + 4V, and the net velocity of the mass 102E + 6V. At the masses where the velocity points in the negative direction, the friction velocities are also negative (from left to right in the diagram). Thus, at 102A and 102B the frictional force is -f. At the masses where the velocity points in the positive direction, the resulting friction velocities are positive (from right to left in the diagram).

The frictional force on each mass is shown in Figure 2C. As a result, the net frictional force in this configuration is approximately + 1f, compared to + 5f without the use of longitudinal vibration (Figure 2A).

As can be seen from Figures 2A-2C, for the longitudinal vibration to occur

3o reduce the frictional force, the maximum vibrational speed should be higher than the translational speed of the pipe string during insertion into the well. The greater the maximum vibrational velocity relative to the translational velocity, the greater the reduction of the friction.

Figure 3 illustrates a vibration device 16 according to one embodiment for creating longitudinal vibrations. The vibration device 16 generally includes a housing 200 defining a chamber 202. A projectile 204 (a supporting member) is provided in the chamber 202.1 Instead of a single projectile, several projectiles can be provided in the chamber 202 in other embodiments. Two pressure control ports 206 and 208 are provided in housing 200. The first control port 206 communicates or releases fluid (gas, liquid or a combination thereof) pressure to or from the chamber 202 on the first side 210 of the projectile 204, while the second control port 208 communicates or releases the fluid pressure to or from the second side 212 of the projectile 204.

The projectile 204 is driven by the pressure difference in the fluid between the two sides of the projectile 204. One side of the projectile 204 may thus be in communication with the hydrostatic pressure in the well fluid, while the other side of the projectile 204 is in communication with an elevated pressure. The pressure difference accelerates the projectile 204 to a speed before it hits the wall (which is one example of a target) of the chamber 202. The length of the chamber 202 is adapted so that the projectile 204 achieves a velocity greater than a predetermined value before striking the target in the housing 200. During the impact, a shock wave is generated in the housing 200 which is transmitted to the pipe string. By reversing the pressure difference across projectile 204, this can be accelerated in the other direction after the impact. By repeatedly reversing the pressure difference across projectile 204, projectile 204 is oscillated back and forth in chamber 202 and applies an oscillating force to housing 200. When the shock wave is repeatedly generated by the blows and transmitted to the pipe string, the pipe string vibrates so that the friction between the pipe string and the the well is reduced.

The efficiency of a vibration tool is generally directly related to the maximum energy the vibrator can generate. The output energy (E) of a vibrator is proportional to the mass (M) and the square of the vibrator speed (V) (E and MV²). Unlike some other vibrators (hereinafter referred to as "mass-based vibrators"), which employ a heavy mass (M) to generate the vibrational energy, some embodiments of the present invention employ a more efficient means of generating vibrational energy using high impact velocity (hereinafter referred to as speed-based vibrators ”). For mass-based vibrators, the mass can be relatively large (from several hundred kilos to several thousand kilos) to generate sufficient vibrational energy for oilfield applications. This can create handling problems for operators in bringing heavy pulp into the wells, and mass-based vibrator can create problems (for example, by jamming downhole). The speed-based vibrator, on the other hand, uses a much lighter mass (from tens of pounds to hundreds of pounds). To create a comparable vibrational energy, the velocity-based vibrator needs only a fraction of the mass needed for the mass-based vibrator. Instead of relying on a heavy mass to obtain a desired output energy, the velocity-based vibrator creates a high velocity in a lighter mass to generate the desired output energy. As used herein, the term "high speed" means an instantaneous velocity greater than or equal to about 2 meters per minute. second (m / s) before the impact. An interval that can be used for the support element is between about 2 m / s and 50 m / s. Furthermore, a frequency of more than about 2 beats per minute can second to be sufficient to generate the desired output energy. An interval that can be used is between about 2 strokes per minute. per second and 60 beats per second. second. The significant reduction in mass for speed-based vibrators provides improved operational efficiency and safety as they are easier to handle and less likely to be fixed. Although use of a heavy mass is not desirable in some cases, other embodiments may use the velocity-based vibrator in combination with a mass-based vibrator.

In the embodiment of Figure 3, and also in the embodiments described below, the repeated blows from a projectile to the target in the vibration device generate significant amounts of heat energy. This may raise the temperature to a level (especially in deep boreholes where the temperature may be relatively high) which may adversely affect the vibration device performance. One method of reducing the possible negative effects of high temperatures is to make certain components of the vibration device of a material having a low temperature expansion coefficient, especially components within the vibration device. A further issue associated with the increased temperature is the build-up of fluid pressure within the vibration device, which may cause the fluid to become more viscous. Pressure compensating devices may be provided in the vibration device to vent any high pressures.

The impact forces from the vibration device can be made independently of an applied heavy mass and / or the weight of the pipe string. In the embodiment of Figure 3, the impact forces of the projectile 204 are created in response to differences in fluid pressure, and 5 is thus independent of the weight of the pipe string. By adjusting the impact member stroke length or the differences in fluid pressure, one can adjust the required weight of the impact member (in other words, the weight needed to generate a given impact force is reduced as the stroke length or pressure differences increase). Furthermore, according to some embodiments, an io external anchorage is not required to provide the desired vibration.

In some embodiments, the impact member, such as projectile 204, is made of impact-resistant and corrosion-resistant material. Examples include tungsten carbide, Monell K500, Inconell 718 and the like. In addition, in some embodiments, the support member and a housing or container in which the support member is ice are arranged made of materials with corresponding thermal expansion coefficients.

One embodiment of the device 16 shown in Figure 3 is illustrated in more detail in Figures 4A and 4B. In the embodiment of Figures 4A and 4B, the vibration device 16 includes a housing 300 defining a chamber within which an upper annular piston 304 and a lower annular piston 312 are provided.

As described below, the upper and lower pistons are used as projectiles to create longitudinal vibration in the housing 300.

The outer surface 311 of the upper piston 304 is in sealing contact with a protruding portion 318 of the housing 300 via an O-ring seal 316. The inner portion 309 of the upper piston 304 is in sealing contact 25 with a sleeve 308 via one or more seals. O-ring seals 320. The upper portion of piston 304 resides within a chamber 305 which may be in communication with well fluids under hydrostatic pressure.

The sleeve 308 may be moved along the longitudinal axis of the device 16 (indicated by arrow X). Although not shown in Figures 4A and 4B, the sleeve 308 30 is operatively coupled to an actuator designed to move the sleeve 308 back and forth along the longitudinal axis X. The actuator may be a mechanical, electrical or hydraulic actuator.

The lower portion of the upper piston 304 is formed as an annular cylinder 322 defining a compartment 324 within which a valve mechanism 310 is positioned. The valve mechanism 310 is essentially a circular block which includes a vent mechanism including an upper vent port 380. lower vent port 382 and a side vent port 384. A chamber in the block contains an upper ball 386, a lower ball 388, and a spring 390. The spring 390 binds the balls 386 and 388 to the respective upper and lower vent ports 380 and 382 and blocks flow through the vent ports. However, if the pressure on one or the other side is greater than the pressure in chamber 394, the current among the balls 386 and 388 will be pushed away from the associated vent port so that the fluid pressure is vented.

The outer surface of the circular block 310 is in sealing contact with the inner surface of the cylinder 322 via an O-ring seal 326. The inner surface of the circular block 310 is in sealing contact with the sleeve 308 via O-ring seals 330 and 332. Further For example, the valve mechanism 310 is fixedly attached to the sleeve 308 via a fastening element 334 (for example, a screw, a pin, etc.). Thus, as the sleeve 308 is moved, the valve mechanism 310 is moved therewith.

In the position illustrated in Figure 4A, a chamber 306 is defined between the valve mechanism 310 and a surface 368. The space 306 is initially filled with atmospheric pressure. The atmospheric chamber 306 is sealed by the seals 326,332 and 320.

A chamber 314 below the valve mechanism 310 is filled with fluid under pressure. For example, the fluid can be pumped down a channel 338 in the housing 300. The fluid can be provided from a source at the well surface to create an elevated pressure 25 which activates the vibration device 16. The fluid in the chamber 314 is also in communication with a shoulder 340 of the upper piston 304. below the projecting portion 318 of the housing 300. Thus, if an elevated pressure is created in the chamber 314, a pressure difference is developed over the upper piston 304 (the difference between the pressure against the shoulder 340 and the atmospheric pressure in the chamber 306) which creates a downward force against the upper piston 304. If the sleeve 308 is held tight of the actuator, however, this pressure difference will not move the upper piston 304.

In a similar embodiment, an outer surface of the lower piston 312 is in sealing contact with a protruding portion 344 of the housing 300 via an O-ring seal 346. Further, the inner surface of the lower piston 312 is in sealing contact with the sleeve 308 through 0. ring seals 348. The lower portion of piston 312 is in a chamber 315 which communicates with well fluids under hydrostatic pressure.

The upper portion of the piston 312 defines a cylinder 350 which defines a chamber 356 which can receive the valve mechanism 310 as it is moved downward.

In operation, to activate the vibration device 16, the actuator is actuated to move the sleeve 308 downward, which also moves the valve mechanism 310 downward. Due to the downward force applied to the shoulder 340 by the upper piston 304, the upper piston 304 moves downwardly with the valve mechanism 310. When the sleeve 308 is moved sufficiently far, the valve mechanism 310 enters the chamber 356 in the cylinder 350 of the lower piston 312. When the lower end 364 of the cylinder 322 of the upper piston 304 is brought into contact with the upper end 366 of the cylinder 350 of the lower piston 312, further downward movement of the upper piston 304 is blocked even as the sleeve 308 continues its downward movement. The sleeve 308 is further moved downwardly until the lower end 360 of the valve mechanism 310 contacts the bottom 362 of the cylinder 350.

Continued downward movement of the valve mechanism 310 when the cylinder 322 has stopped will cause the valve mechanism 310 to guide the ring seal 326 past the lower end 364 of the cylinder 322. This communicates fluid pressure in the chamber 314 to the upper surface 368 of the cylinder 322 and creates an abruptly acting force. against the upper piston 304. The pressure in the chamber 314 is brought to a level higher than the pressure in the chamber 305 (for example, at hydrostatic well pressure), so as to create a pressure difference and thus an upwardly directed force against the upper piston 304 when the pressure in the chamber 314 is communicated to the upper the surface 368 of the cylinder 322. The transmitted force causes the upper piston 304 to accelerate upwardly until its upper end 370 abuts a target surface 372 on the housing 300. More generally, the target may be any other object permanently tested to the housing 300. During the impact, a compressional wave is generated which is transmitted to the pipe string and creates a vibrational movement in the pipe string.

As the valve mechanism 310 enters the chamber 356 and the seal 326 of the valve mechanism 310 engages the interior wall of the cylinder 350, the buildup of the pressure in the chamber 356 is vented through the check valve provided by the ball 388 and the vent port 382.

The valve mechanism 310 is now in the chamber 356. The actuator is then actuated to move the sleeve 308 upwards, causing the valve mechanism 310 to move upwardly with the sleeve 308. As a result, a pressure difference is developed over the lower piston 312 (between the elevated pressure in the chamber 314 and the pressure in the well fluid in the region of the chamber 356 between the valve mechanism 310 and the bottom surface 362). This pressure differential creates a net upward force against a shoulder 374 on the lower piston 312. As the valve mechanism 310 moves upward, the lower piston 312 follows because of the force applied to the shoulder 374. The upward movement of the valve mechanism 310 and the lower piston 312 continues until the upper end 366 of the cylinder 350 is contacted with the lower end 364 of the upper cylinder 322, which stops further upward movement of the lower piston 312. The valve mechanism 310 continues however, its upward movement until the seal 326 goes clear of the upper end 366 of the lower cylinder 350. Again, any pressure built up in chamber 306 will be vented through the check valve provided by ball 386 and vent port 380.

As the seal 326 clears the upper end 366 of the lower cylinder 350, the elevated fluid pressure in the chamber 314 is communicated into the chamber 356 of the lower cylinder 350 and applies a downward compressive force to the bottom surface 362. A pressure differential is created over the lower piston 312 ( the difference between the pressure against the surface 362 and the pressure in the well fluid against the lower piston 312 in the chamber 315). As a result, the downward force accelerates the lower piston 312 downwardly until the lower end 376 of the lower piston 312 beats against a target surface 378 attached to the housing 300. As a result of this collision, a tensile wave is created in the housing 300. The stretching wave propagates to the tube string to create a vibrational movement in the tube string.

Continued upward and downward movement of the sleeve 308 caused by the actuator causes the upper and lower pistons to accelerate in the opposite direction to create oscillating forward and reverse directions which provide the desired longitudinal bidirectional vibration.

The effectiveness of the impact-induced vibration is directly related to the frequency spectrum of the impact forces. In order to maximize the stroke-induced vibration, the frequency spectrum of the stroke forces must be adjusted according to the length of the pipe string and downhole conditions. The length of the pipe string and downhole conditions affect the transmissibility of the pipe string into the well. There are many methods for changing the frequency spectrum of the impact force. For example, the frequency spectrum of the impact force can be changed by changing the counterpressure in the chamber 314 of Figure 4A. An increase in the counter pressure in the chamber 314 will result in lower frequency components in the frequency spectrum of the impact force, which is favorable for achieving better transmissibility. Another method of changing the frequency spectrum is to adjust the movement of the sleeve 308. Adaptations of the movement to the sleeve 308 which will change the frequency spectrum include adjusting the speed of the up and downward movement of the sleeve 308 as well as introducing a time delay at the end of the upward or downward movement of the sleeve 308 (for example, the sleeve 308 at the end of it). upward movement is stopped for a given period of time before moving downwards). Another method of changing the frequency spectrum of the impact force is to adjust the stroke length of the impact members, for example by adjusting the length of the chamber 314. Yet another method of changing the frequency spectrum of the impact force is a suitable choice of materials in the impact surfaces.

It should be noted that all of the above methods (except material selection) for changing the frequency spectrum can be used dynamically according to downhole conditions.

Figures 5A-5C illustrate another embodiment of the vibration device 16 which provides longitudinal bidirectional vibrations. In this embodiment, an upper spring 402 (Figure 5A) and a lower spring 406 (Figure 5C) provide the force to accelerate an upper hammer 404 and a lower hammer 408, respectively, to create a collision between the hammer 404 and 408 and a corresponding one. target fixedly attached to a housing 400 by the vibration device 16.

The upper hammer 404 includes a sleeve 472 extending downwardly within the housing 400. An inwardly projecting portion is provided on the sleeve 472. The lower end of the sleeve 472 is integral, with a stroke portion 475 including a impact surface 422. The impact surface 422 is designed to strike against a shoulder 423 of the housing 400. The space between the impact surface 422 and the shoulder 423 communicates with the pressure of the well fluid through one or more side ports 424.

The lower hammer 408 also includes a stroke shoulder 480 which is designed to strike against a shoulder 482 of the housing 400. The space between the stroke shoulder 480 and shoulder 482 is also in communication with the pressure in the well fluid. A sleeve portion 481 of the lower hammer 408 extends upwardly in housing 400 to an upper end portion 434.

The vibration device 16 also includes a stem 410 and a valve mechanism 412. An annular piston 430, the upper end of which includes a flanged portion 432, is provided around the stem 410.

An annular chamber 418 is defined between the lower surface of a shoulder 419 by the upper hammer 404 and the upper end 417 of the valve mechanism 412. Another chamber 420 is defined between the upper end portion 434 of the lower hammer 408 and the lower end 421 of the valve mechanism 412. The valve mechanism 412 selectively controls the flow of fluid from the inner bore 411 of the stem 410 to one of the chambers 418 and 420.

In the inner bore 411 of the stem 410, a ball seat 436 is provided which is designed to receive a ball released from the surface. When the ball is placed in the ball seat 436, the fluid pressure in the bore 411 of the stem can be increased to initiate the movement of the hammer 404 and 408 (described more fully below).

The valve mechanism 412 is illustrated in more detail in Figure 6. The valve mechanism 412 includes a channel 442 that communicates with the stem bore 411 through a port 440 in the stem 410. When ball is placed in the ball seat 436, the fluid in the stem bore 411 flows through the port 440 and the channel 442 to a longitudinal direction. channel 452 having an expanded compartment 444 which can receive an expanded portion 450 (constituting a sealing element) of a rod 446. The lower end of the rod 446 is an integral part of or fixedly attached to the flange portion 432 of the piston 430.

In the position illustrated in Figure 6, fluid entering chamber 444 flows upwardly through channel 452 and into chamber 418.1 in its lower position, the sealing element 450 of rod 446 seals in contact with the lower surface defining space 444 and blocks flow of fluid down channel 452. The seal may be provided in the form of an O-ring seal or coating of the seal member 450 with a suitable material. If the sealing element 450 of the rod 446 moves upwardly to seal contact with an upper surface defining the space 444, the fluid flows downwardly through the channel 452 and into the chamber 420.

Another part of valve mechanism 412 includes a spring 454 which is. provided in a chamber 456. The spring 454 is biased to ensure that the valve mechanism 412 in pressure balanced state (before the ball is dropped) is in a position such that fluid entering the port 440 is in communication with the chamber 418 while fluid in chamber 420 communicates with the well through port 464. The plate 460 is provided with a sealing member in such a way that when the plate 460 is in contact with the upper surface 417 of the valve mechanism

412, there is no communication of fluid between the chamber 418 and the duct

462. Likewise, the flange portion 432 is also provided with a sealing member to ensure that when in contact with the lower surface 421 of the valve mechanism 412, there is no communication of fluid between the lower chamber 420 and the channel 462.

A rod 458 is attached to the flange portion 432 of the piston 430. The upper end of the rod 458 is connected to a plate 460. The plate 460, the rod 458, and the flange portion 432 may be a single integral or integral member, or they may alternatively be separate portions. are firmly attached to each other. The rod 458 can be moved up and down in a channel 462 in the valve mechanism 412.

During operation, a ball is placed, which is dropped into the stem bore

411, in the ball set 436, creating a seal. Thereafter, fluid is pumped down the stem bore 411 which flows through the port 440 (Figure 6) and into the duct 442 and the longitudinal duct 452 and out into the upper chamber 418.

The increase in pressure in chamber 418 creates a pressure differential relative to the pressure in the well fluid in chamber 414, which causes upper hammer 404 to move upwardly relative to stem 410. As upper hammer 404 moves upwardly, spring 402 is compressed which precursors under the upper hammer 404 include the inwardly extending jib 470. When the upper hammer 404 is moved a predetermined length upwardly, a shoulder 474 on the projecting portion 470 is contacted with the flange portion 432 of the piston 430. Further upward movement of the hammer 404 causes the piston 430 to move upward as well.

In upward movement of the hammer 404, the rod 458 and plate 460 (FIG. 6) move upwardly so that fluid in upper chamber 418 can flow through channel 462 and port 464 and into stem bore 411 below ball seat 436. This flow of fluid from the upper chamber 418 causes a sudden drop in pressure in upper chamber 418, so that compressed upper ice spring 402 can drive upper hammer 404 downwardly relative to stem 410. The spring 402 drives the upper hammer 404 downwardly until the lower surface 422 of the hammer 404 strikes against a shoulder 423 in the housing 400. This impact creates an tensile wave in the housing 400 which propagates upwardly and transmits to the tool string.

When the sealing element 450 in the chamber 444 is in its upper position, the fluid flow through the stem bore 411 is above the ball seat 464 Isolated from the upper chamber 418. The fluid in the bore of the stem flows through the port 440, the channel 442 and the channel 452 and into the lower chamber 420. . of the pressure in chamber 420 creates a downward force toward the upper end portion 434 of the lower hammer 408. This causes the lower hammer 408 to move downwardly, which compresses the spring 406. When the lower hammer 408 is moved a predetermined length down one is brought. shoulder 476 on the lower surface of the portion 434 of the lower stem 408 in contact with a shoulder 478 on a lower portion of the piston 430. Further

3o downward movement of the lower hammer 408 causes the piston 430 to be pulled down as well.

The downward movement of the piston 430 pulls on the rods 458 and 446. As a result, the flow of fluid into the lower chamber 420 ceases, while re-establishing fluid communication between the lower chamber 420 and the channel 462 in the valve mechanism 412. The fluid flows from the lower chamber 420 through the channel 462 and the port 464 and into the stem bore 411. This creates a sudden pressure drop from the lower chamber 420 and into the stem bore 411 below the ball seat 436. As a result, the spring 406 can drive the lower hammer 408 upwards. As the lower hammer 408 is moved upward for a predetermined length, the impact shoulder 480 of the hammer 408 (Figure 5C) strikes the shoulder 482 in the housing 400. This impact creates a compressional wave in the housing 400 which propagates upwardly and is transmitted to the pipe string.

The above-described process is repeated as long as an increased pressure is caused by fluid flow down the stem bore 411 above the ball placed in the ball seat 436. This allows oscillation of the upper and lower hammer and the respective clashes between the ice upper hammer 404 and housing 400 and lower hammer 408 and housing 400.

In another embodiment, the vibration devices 16A and 16B used in the tube string of Figure 1 create rotational or torsional vibrations in the tube string. Figure 7 shows a cross section of a rotational or torsional vibration device (with reference number 600). The rotation vibration is caused by

2o collision between a pair of support members 602,604 connected to a spindle mandrel 610 and a pair of connector members 606,608. The support members 602, 604 are fixedly mounted to the spindle stem 610, which can be rotated relative to an outer housing 612 and an inner housing 614 of the rotational vibration device 600. The connector elements 606,608 connect the inner and outer housings 614 and 612.

In response to a pressure gradient in the fluid in a first direction, the stem 610 rotates in a first direction of rotation and beats against the connector elements 606,608. Then, in response to a pressure gradient in the fluid in the opposite direction, the stem 610 is rotated in the opposite direction of rotation so that.

the impact members 602, 604 strike against the connector elements 606, 608.

The connector elements 606 and 608 extend along the longitudinal axis of the vibration device 600. The connector elements 606 and 608 thus define two chambers 616 and 618.1 additionally, the support member 602 divides the chamber 616 into two portions: a first portion 616A and a second portion 616B. Similarly, support member 604 divides chamber 618 into two portions: a first portion 618A and a second portion 618B.

Four gates lead into the respective chamber sections. A first port 620 enters the chamber 616A, a second port 622 enters the chamber portion 616B, a third port 624 enters the chamber portion 618A, and a fourth port 626 leads into the chamber portion 618B. As described below, an upper set of ports 620,622,624 and 626 is provided at the upper end of vibration device 600, while a lower set of ports 620,622,624 and 626 is provided at the lower end of vibration device 600.

Ports 620, 622, 624 and 626 are selectively opened and closed to allow fluid pressure communication into respective chambers 616A, 616B, 618A and 618B. By controlling which gates are open and which are closed, a pressure gradient can be created over the supporting members 602, 604 in the desired direction of rotation to cause a desired rotational movement of the stem stem 610. By continuously rotating the supporting elements 602, 604 back and forth so that they strike against the connector elements 606, 608, a rotational vibration is created in the pipe string connected to the vibration device 600.

Ports 622 and 626 are opened, and ports 620 and 624 are closed to enable communication of an elevated fluid pressure into chambers 616B and 618B while chambers 616A and 618A remain at a lower pressure (e.g., the hydrostatic well pressure). The pressure difference created between the chambers 616B and 616A and between the chambers 618B and 618A in this case causes the stem stem 610 and the supporting members 602,604 to rotate in the direction indicated by the arrows R1.

To rotate the support members 602,604 in the opposite direction (indicated by arrows R2), gates 620 and 624 are opened while gates 622 and 626 are closed. An elevated pressure can then be pumped into the chambers 616A and 618A to create the pressure differences that move the impact members 602,604 in the direction R2.

Figure 8 illustrates a perspective view of the stem 610 and the supporting members 602 and 604. The supporting members 602 and 604 are attached to the stem 610 via respective connectors 630 and 632. The connectors 630 and 632 may be in the form of pins or other fastening mechanisms.

Figure 9 illustrates a longitudinal sectional view of the vibration device 600 in which a portion of the components is pulled apart. The inner housing 614 of the rotary vibration device 600 includes a longitudinal bore 615 in which the stem 610 can be positioned. The pins 630 5 and 632 which secure the stem 610 to the respective supporting members 602 and 604 are connected through openings 640 and 642 in the inner housing 614. As shown in Figure 9, the impact members 602 and 604 are designed to fit into the space between the inner and outer housings 614 and 612.

Sliders 650 and 652 are provided at one end of the vibration device 16, while sliders 654 and 656 are provided at the other end of the vibration device 16. The sliders have a generally semi-circular configuration so that each pair of sliders is placed in approximately the same plane. Each glider extends less than a 180 ° semicircle (for example, 170 °), creating space for the sliders to slide in the same plane. The sliders 650, 652, 654 and 656 ice provide each set of gates 620,622, 624 and 626 at the upper and lower ends of the vibration device 600. The gates 620,622, 624 and 626 are opened and closed based on the position of the sliders.

In addition, a first valve mechanism 658 interacts with the sliders 650 and 552 to communicate fluid through the slides 650 and 652 and into the first 20 end of the vibration device 16, while a second valve mechanism 660 interacts with the sliders 654 and 656 to communicate fluid into the the other end of the vibration device 16.

Together with the valve mechanism 658, the rotary slide 652 controls the selective opening and closing of the fluid communication between the chamber.

616A and the pipe string and between the chamber 616B and the pipe string. Similarly, the rotary slide 650 controls the selective opening and closing of the fluid communication between the chamber 618B and the pipe string and between the chamber 618A and the pipe string.

The valve mechanism 658 includes a ball seat 662 made to receive a 30 ball. The valve mechanism 658 also includes a first channel 664 and a second channel 666. The sliders 650 and 652 are provided with openings (Figure 10) which are selectively aligned with the channels 664 and 666 to allow communication of fluid through the valve mechanism 658 and through the openings in the slides of one. of chambers 616A, 616B, 618A or 618B.

In cooperation with the valve mechanism 660, the rotary slide 656 controls the selective opening and closing of the fluid communication between the chamber 616A and a region below the vibration device 600 (for example, a tool connected below the device 600 or an annulus below the device 600). The slider 656 also controls the selective opening and closing of the fluid communication between the chamber 616B and the area below the vibration device 600. Similarly, the rotary slide 654 controls the selective opening and closing of the fluid communication between the chamber 618B and the area below the vibration device 600 and the fluid communication between the chamber 618A and the lower region.

The valve mechanism 660 includes a first channel 668 and a second channel 670 which can be selectively aligned with the ports of slides 654 and 656. Slides 650,652,654 and 656 can be rotated respectively by actuating pins 680,682, 684 and 686. Actuating pins 680,682, 684 and 686 can be engaged2. and 604 when rotated ..

As shown in Figure 10, each slide 700 (corresponding to each of the slides 650,652,654 and 656) has a substantially subcircular configuration (somewhat smaller than a semicircle). As a result, two rotary slides can be placed side by side to form an approximate circle. Each slider 700 includes a first port 702 and a second port 704.1 In addition, the slider 700 includes an actuating pin 706 (corresponding to one of the pins 680, 682,684 and 686) which, when engaged by the impact member 602 or 604, causes the rotary slide 700 to rotate at a predetermined angle. The rotation of the slider 700 causes the ports 702 and 704 to move, and thereby allows the ports 702 and 704 to move relative to the channels of the valve mechanism 658 or 660.

During normal operation, when no torsional vibration is required, the vibration device 600 is used as a fluid channel. The fluid flows from the tubing string through the centered bore 601 into the hollow spindle stem 610. When torsional vibration is needed, a ball is released into the string for abutment in the ball seat 662 of the valve mechanism 658. The initial position of the rotary slides 650 and 652 is such that the tops of the chambers 616A and 6.18A are in communication with the fluid from the pipe string through the valve mechanism 658.

However, the chambers 616A and 618A are isolated from the area below the vibration device 600 by the rotary slides 654 and 656.

The chambers 616B and 618B, on the other hand, are in fluid communication with the area below the vibration device 600, while the chambers 616B and 618B s are isolated from the tube string by the rotary slides 654 and 656.

As the pressure in the pipe string increases, a pressure difference is created between the chambers 616Å and 616B and between the chambers 618A and 618B. As a result of this pressure difference, the stem stem 610 accelerates the direction indicated by arrows R2 (Figure 7).

io The support members 602, 604 are rotated until a collision occurs between the support members 602, 604 and the connector members 606, 608. However, just before a clockwise impact, the support members 602,604 engage the actuating pins 680, 682,684 and 686 of the respective rotary slides 65 and 650 change their rotation positions. As a result of this ice, a different set of slots in the slides are aligned with the channels of valve mechanisms 658 and 660, thus opening and closing another combination of gates 620, 622, 624 and 626. In this second position, the increased pressure in the pipe string causes the stem stem 610 to rotate in the opposite direction (indicated by arrows R1 as shown in Figure 7). This causes the impact members 602,604 to strike

2o to the connector elements 606,608 in the opposite direction. Just before the impact, the impact members 602,604 engage the actuating pins on the rotary slides 650,652, 654 and 656 to again bring the rotary slides to the initial position. Thus, by maintaining the pressure in the pipe string at an elevated level, the stem 610 is rotated back and forth, causing reciprocal collisions between the support members 602,604 and the connector members 606,608. As a result, a relatively continuous rotational vibration is created in the pipe string.