Information
-
Patent Grant
-
6367552
-
Patent Number
6,367,552
-
Date Filed
Tuesday, November 30, 199924 years ago
-
Date Issued
Tuesday, April 9, 200222 years ago
-
Inventors
-
Original Assignees
-
Examiners
- Bagnell; David
- Kreck; John
Agents
- Carstens; David W.
- Herman; Paul I.
-
CPC
-
US Classifications
Field of Search
US
- 166 355
- 166 2427
- 166 2426
- 166 377
- 285 1234
- 285 12313
- 285 900
-
International Classifications
-
Abstract
Initially, a set of locking lugs lock an inner mandrel is locked in position with respect to an outer mandrel. Unlocking the travel joint is accomplished by applying a constant vertical or downward force on the tubing string. That vertical force is transmitted through the tubing string to the outer mandrel, which causes hydraulic pressure with a hydraulic chamber to increase. When the hydraulic pressure exceeds a pressure threshold, a pressure sensitive valve opens, and the hydraulic fluid gradually flows into a reserve hydraulic chamber, allowing the outer mandrel to move with respect to the inner mandrel. A viscosity independent flow restrictor limits the transfer of hydraulic fluid to a preset flow rate. After sufficient hydraulic fluid has been received into the reserve chamber, the outer mandrel aligns with the locking lugs, which then move from the locked position to the unlocked position. The travel joint then releases, allowing the outer mandrel to telescope inward and outward.
Description
BACKGROUND OF THE INVENTION
1. Technical Field
The present invention relates to travel joints used in subterranean wells. More particularly, the present invention related to reusable travel joints. Still more particularly, the present invention relates to a reusable travel joint able to be reliably activated in highly deviated wellbores.
2. Description of the Related Art
Drilling rigs supported by floating drill ships or floating platforms are often used for offshore well development. These rigs present a problem for the rig operators in that ocean waves and tidal forces cause the drilling rig to rise and fall with respect to the sea floor and the subterranean well. This vertical motion must be either controlled or compensated while operating the well.
FIG. 1A
depicts a typical offshore rig operation involving ship
102
, which supports rig
104
. Without compensation, such vertical movement would transmit undesirable axial loads on a rigid tubing string within well casing string
106
, which is extended downwardly from ship
102
. This problem becomes particularly acute in well operations involving fixed bottom hole assemblies, such as the packers depicted in box
110
and further depicted in
FIGS. 1B and 1C
.
In the depicted example, packer
112
has been previously set in casing string
106
. As is known in the art, packer
112
includes a receiving orifice for connection with a packer stinger located at the bottom of tubing
114
. The connecting operation, or “stinging in” requires that tubing
114
apply an amount of force for makeup depending on the particular packer. Different mechanisms exist for stinging in, such as a “J-latch” connection, which requires rotational force to latch the “J” or a force actuated latch which uses vertical force from tubing
114
. When seals within the packer are in place against the stinger, the stinger is fixed in place.
Once the stinger is in place, any vertical movement from the ship or platform will create undesirable downward and upward forces on packer
112
or may cause premature failure of components or may sting out the stinger from packer
112
. What is needed is a means to compensate for the movement of the drilling ship or platform. Normally, the solution has been to place a travel joint in the tubing string, which compensates for the movement of rig
104
by axial telescoping action, as depicted in
FIGS. 1B and 1C
.
FIG. 1B
illustrates travel joint
116
in the latched or locked position, that is a position that allows the rig operators to apply the force needed to sting in packer
112
. Travel joint
116
is unlocked by different means, depending on the type of locking mechanism. One type of locking mechanism uses a shear pin that is forcibly sheared when the travel joint is unlocked. The shear pin is used to prevent the travel joint from inadvertently unlocking. One problem with this design is that the travel joint can only be unlocked once and then must be re-dressed with a new shear pin prior to subsequent use. Another type of locking mechanism uses a “J-latch” similar to that described above, is used for stinging into a packer. While this mechanism allows travel joint
112
to be locked and unlocked a number of times without re-dressing the travel joint, it has the disadvantage in that the type of packer must be considered prior to using a J-latch type travel joint. This is so because of the possibility of inadvertently stinging out of the J-latch packer that requires a similar rotational force as unlocking the travel joint. In a related packer consideration problem, certain packers allow the stinger to freely rotate within the packer, and those packers may not transmit the needed rotational resistance for unlocking or locking the J-latch on the travel joint. Therefore, the travel joint may not unlock, or worse, may not lock back in position. The benefits derived from having a travel joint in a tubing string can only be realized if the travel joint can be reliably unlocked from the surface.
FIG. 1C
illustrates travel joint
116
in the unlocked position with tubing
114
telescoping into both travel joint
116
and upper tubing
118
. After travel joint
116
is unlocked, the travel joint and upper tubing
118
may be telescoped over tubing
114
. Lower tubing
114
may be a lighter weight than upper tubing
118
and use flush joint connections
120
which do not increase the exterior diameter of tubing
114
, allowing travel joint
116
and tubing
118
to be telescoped over more than a single joint of tubing. However, as a general rule, the first joint of lower tubing
114
will be a machined joint custom manufactured for use with travel joint
116
.
Another problem common to both of the above-described locking mechanisms is premature unlocking in highly deviated wellbores. In offshore drilling operations it is routine to drill a number of wells from a single platform. Each well is directionally drilled to a target location in the zone of interest, which may be a lengthy horizontal distance from the platform itself. Therefore, during a trip into the well, the wellbore string slides, or is pushed, along the inner wall of casing
106
rather than merely being lowered in the center of casing
106
. Significant forces build up, which oppose the wellbore string's being lowered into the wellbore, which may unlock travel joint
116
prior to the stinger being seated in packer
112
. Once unlocked, it is virtually impossible to sting into packer
112
without re-locking the travel joint. This may require an additional trip out of the well to re-dress the travel joint.
Still another problem is the uncertainty as to whether a premature unlocking has taken place. Using a prior art type travel joint, no accurate means is available for gauging whether a travel joint has become unlocked. Often the first indication that the travel joint is in the unlocked position manifests itself when the stinger will not sting into the packer. At that point, the entire well string must be completely removed from the wellbore, reset or re-dressed, and then run in again with the hope that the travel joint will not unlock again. Therefore, a wireline collar locator is often run into the wellbore to confirm that the travel joint is locked and the lower tubing is in place.
Still another problem with prior art travel joints involves the hard release inherent in the shear pin locking means. Conventionally, after a bottom hole assembly is first stung into a packer, tubing weight is applied across the travel joint, severing the shear pin, and unlocking the travel joint. Prior art shear pin-type travel joints unlock hard due to the energy stored in the tubing being released when the shear pin severs. In highly deviated wells, or wells with known tight spots, higher shear pin strengths are necessary because of the possibility of premature pin breakage. The higher the shear rating on the pin, the more stored up energy in the tubing to be released when the pin shears. This may cause damage to the tubing hanger or seat if the two make contact when the travel joint unlocks. A collar locator is often run on wireline prior to stinging into the packer to conform tubing spacing and lessen the chance of hanger or seat damage.
Further, by eliminating the wireline intervention to verify the travel joint location there is a significant reduction in the risk associated with such operations, namely the breakage of the wireline, the risk of fishing in the wellbore, and damage to the seal bore, nipple seal, nipple bore, and other inner diameter restrictions in the wellbore.
It would be advantageous to provide a smooth release travel joint which eliminated the need for a wireline depth determination. It would be advantageous to provide a travel joint with a reliable re-locking means. It would also be advantageous to provide a travel joint with a reliable locking and unlocking means for highly deviated wells. It would be further advantageous to provide the operator with an indication that the travel joint has become unlocked.
SUMMARY OF THE INVENTION
In accordance with a preferred embodiment of the present invention, the travel joint disclosed within includes a hydraulically metered locking and unlocking mechanism for engaging and disengaging inner mandrel locking lugs. Initially, a set of locking lugs lock an inner mandrel in locked position with respect to an outer mandrel. Unlocking the travel joint is accomplished by applying a constant vertical or downward force on the tubing string at a predetermined downhole or vertical force. That vertical force is transmitted through the tubing string to the outer mandrel, which causes hydraulic pressure within a hydraulic chamber to increase. When the hydraulic pressure within the chamber exceeds a pressure threshold, a pressure sensitive valve opens, and the hydraulic fluid gradually flows into a reserve hydraulic chamber, allowing the outer mandrel to move with respect to the inner mandrel. A viscosity independent flow restrictor limits the transfer of hydraulic fluid to a preset flow rate. After sufficient hydraulic fluid has been received into the reserve chamber, the outer mandrel aligns with the locking lugs, which then move from the locked position to the unlocked position. The locking mechanism in the travel joint then releases, allowing the collapse of the travel joint, wherein the outer mandrel freely travels over the inner mandrel. Thereafter, the outer mandrel may freely and telescopically move in relation to the inner mandrel upon the application of compressional or torsional forces on the string. Additionally, the travel joint may be fully extended and re-locked upon the application of sufficient tension on the string. Accordingly, the travel joint may be repeatedly locked and re-locked as needed.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the invention are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objects and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
FIG. 1A
depicts a typical offshore rig operation involving a ship which supports a rig;
FIG. 1B
illustrates a travel joint in the locked position, that is a position that allows the rig operators to apply the force needed to sting in a packer;
FIG. 1C
illustrates a travel joint in the unlocked position with tubing telescoping into both the travel joint and the tubing;
FIGS. 2A through 2C
depict a hydraulically metered travel joint in accordance with a preferred embodiment of the present invention;
FIGS. 3A and 3B
depict a travel joint in the fully locked position;
FIGS. 4A through 4C
depict a travel joint in an intermediate unlocking position;
FIGS. 5A through 5D
depict a travel joint in another intermediate unlocking position;
FIGS. 6A through 6D
depict a travel joint in the process of releasing an inner mandrel;
FIGS. 7A through 7C
depict a travel joint in the unlocked position and an inner mandrel released;
FIGS. 8A through 8C
show a lug remaining positioned within a release slot as a travel joint is moved upward with respect to an inner mandrel;
FIGS. 9A through 9C
depict an intermediate locking position for a travel joint;
FIGS. 10A and 10B
illustrate a travel joint in the fully locked position;
FIG. 11A
is a are diagrams depicting the use of a drag block in combination with a hydraulically metered travel joint;
FIG. 11B
is a cutaway diagram of drag block
1100
;
FIG. 12
depicts a process for locking and unlocking a hydraulically metered travel joint in accordance with a preferred embodiment of the present invention; and
FIG. 13
depicts the process for re-locking the travel joint.
DETAILED DESCRIPTION
FIGS. 2A through 2C
depict a hydraulically metered travel joint in accordance with a preferred embodiment of the present invention. Unlike the predecessor travel joints discussed above with respect to the prior art, the preferred embodiment of the present invention depicted as travel joint
200
includes a hydraulic chamber for control of the locking and unlocking mechanism. Unlocking the travel joint is accomplished by applying a constant vertical or downward force on the tubing string. That vertical force is transmitted through the tubing string to the outer mandrel causing pressure to be applied across a hydraulic piston. The hydraulic pressure slowly bleeds off, allowing locking lugs situated between the outer mandrel and the inner mandrel to move from the locked position to the unlocked position. Once unlocked, the travel joint telescopes in and outward similarly to the travel joints discussed above in the prior art. Other benefits of the present invention will become apparent as the figures related to a hydraulically metered travel joint are discussed.
Travel joint
200
is positioned in the tubing string between upper tubing
246
and lower tubing
244
, as discussed above with respect to the prior art. In reference to the present invention, the terms “upper” and “lower” are reference terms, which indicate a component's relative position to travel joint with respect to the surface end of the string and its relative position to the travel joint with respect to the bottom assembly of the string, respectively. Lower tubing
244
joints may be connected by means of flush joint internal threads in order to be received within travel joint
200
, but generally there is no need to telescope more that the first joint within the travel joint. Therefore, the first joint of lower tubing
114
is a precision machined joint, which may be repeatedly telescoped within the body of travel joint
200
without damaging the travel joint's inner wall, seals, or locking/unlocking mechanism. Travel joint
200
itself consists of outer mandrel
202
, which is mechanically connected to upper tubing
246
by means of common pipe threads, through adapter subassemblies
256
and
258
. Seals
252
are provided between adapter
258
and inner mandrel
206
and between outer mandrel
202
and inner mandrel
206
for dampening shock during unlocking and for isolating the fluid within inner mandrel
202
from fluid external to outer mandrel
206
. From external appearances, outer mandrel
202
looks as if it consists of three components, upper outer mandrel
202
A, pressure block
218
and lower outer mandrel
202
B. However, for the purpose of describing the functionality of travel joint
200
, upper outer mandrel
202
A and lower outer mandrel
202
B will be referred to as outer mandrel
202
. Lower tubing
244
is threaded to the bottom end of inner mandrel
206
.
For ease of understanding a preferred embodiment of the present invention, travel joint
200
comprises four assemblies: outer mandrel
202
; inner mandrel
206
; a pressure block assembly; and an engaging/disengaging assembly. Outer mandrel
202
and inner mandrel
206
were described briefly above. The pressure block assembly controls the flow of hydraulic fluid between upper hydraulic chamber
240
and lower hydraulic chamber
242
. The pressure block assembly comprises pressure block
218
, pressure relief and restrictor valve
220
, unlock channel
234
, pressure relief port
236
, lock channel
235
, check valve
222
, and a plurality of o-rings
250
used for hydraulically isolating the pressure block assembly. In a preferred embodiment of the present invention, pressure relief and restrictor valve
220
is a viscosity independent, pressure activated restrictor valve such as currently available from the Lee Co., 2 Pettipaug Rd., PO Box 424, Westbrook, Conn. 06498-0424. Pressure relief and restrictor valve
220
comprises a pressure sensitive valve that requires a threshold pressure be overcome before hydraulic fluid will flow across the valve. Once threshold pressure is exceeded, a steady rate of flow is achieved regardless of the viscosity of the hydraulic fluid. A steady rate of flow translates into a steady and predictable rate of movement for outer mandrel
202
. The predictable rate of outer mandrel movement leads to a predictable time for unlocking the travel joint. A typical hydraulic fluid suitable for the purposes described herewithin is a high grade automatic transmission fluid (ATF) available at any automotive parts retailer. However other hydraulic fluids may be used, such as silicon fluids and the like, which are known and used by those of ordinary skill in the art.
The final assembly is the engaging/disengaging assembly whose primary function is to engage and disengage locking lugs
204
in the locked or unlocked positions. In addition to locking lugs
204
, the engaging assembly includes lug carrier
210
, which is threaded onto lug carrier connector
214
, which is in turn threaded to transfer piston
224
. Set screws may be included for securing the threaded components in position and ensuring that the connected components do not loosen during operation. Mechanically cooperating with lugs
204
and lug carrier
210
are lug support
208
and support spring
212
. Finally, the engaging assembly includes floating piston
216
and inner and outer o-rings
250
. Floating piston
216
is disposed in a radial cavity created laterally by the inner wall of outer mandrel
202
and the outer wall of transfer piston
224
, with the upper and lower extents defined by the lower portion of lug carrier connector
214
and the upper portion of pressure block
218
, respectively. It is important to note that the upper portion of floating piston
216
does not fill the entire void of the radial cavity and remains proximate to the lower portion of lug carrier connector
214
. Upper hydraulic chamber
240
is thereby formed from the unused portion of the radial cavity described above. Hydraulic fluid contained in upper hydraulic chamber
240
is hydraulically isolated by a plurality of o-rings
250
shown in FIG.
2
A. In a preferred embodiment of the present invention, floating piston
216
is not physically connected to either transfer piston
224
or lug carrier connector
214
. This allows floating piston
216
to move at a slightly different upward rate than transfer piston
224
and lug carrier connector
214
. The different rate of movement compensates for air in the hydraulic chambers and for matching the precise displacement of volume transferred from lower hydraulic chamber
242
. Lower hydraulic chamber
242
is defined laterally by the inner wall of outer mandrel
202
and the outer wall of transfer piston
224
, and its upper and lower extents are defined by the lower portion of pressure block
218
and an upper facing portion of transfer piston
224
, respectively. Hydraulic fluid contained in lower hydraulic chamber
242
is also hydraulically isolated by a plurality of o-rings
250
shown in FIG.
2
A.
The four assemblies discussed immediately above cooperate to lock and unlock inner mandrel
206
from the remainder of travel joint
200
. In the locked position, inner mandrel
206
is locked in position within the axial annular space of the inner wall of outer mandrel
202
. Hence, the interior diameter of outer mandrel
202
is sufficient to allow the exterior diameter of both inner mandrel
206
and lower tubing
244
to freely move in the vertical motion, telescoping, once travel joint
200
is unlocked. To prevent inner mandrel
206
from undesired telescoping within outer mandrel
202
, locking lugs
204
are radially spaced around the outer diameter of inner mandrel
206
and within the inner diameter of outer mandrel
202
. When travel joint
200
is in the locked position, lugs
204
are received within locking slot
232
.
In a preferred embodiment of the present invention, locking slot
232
is a chamfered channel or slot, radially machined within inner mandrel
206
. Locking slot
232
is of sufficient size to accept a portion of locking lugs
204
. In the unlocked position, locking lugs
204
are partially accepted within locking slot
232
. Release slot
230
is a chamfered channel or slot that is radially machined within the inner wall of outer mandrel
202
and of sufficient size to partially accept locking lugs
204
. Both locking slot
232
and release slot
230
are machined with forty-five degree chamfered edges at the bottom of the respective slots, rather than the slot walls directly meeting the slot bottoms at a ninety-degree angle.
Turning now to
FIG. 2C
, front, top, and side views of locking lug
204
are depicted. Note that each edge of locking lug
204
that contacts a forty five-degree chamfer, is itself beveled at a corresponding forty five-degree angle. The combination of the beveled lugs and chamfered slots allows for reliable engaging and disengaging of the lugs and slots with little tendency of hanging up during locking/unlocking operation. This configuration allows the shearing force on lugs
204
, caused by axial forces applied to outer mandrel
202
and inner mandrel
206
, to be redirected as a radially inward or radially outward force on lug
204
, sufficient to move lugs
204
from release slot
230
or locking slot
232
, respectively.
In a preferred embodiment of the present invention, three locking lugs are used for locking and unlocking travel joint
200
, as depicted in FIG.
2
B. However, any number of locking lugs may be used without unnecessarily restricting the operation of the present invention. Locking lugs
204
are positioned at regular angles around inner mandrel
206
and held in those precise radial angles by lug carrier
210
. Lug carrier
210
contains a number of lug grooves equal to the number of lugs employed in the travel joint. The purpose of the lug grooves in lug carrier
210
is to maintain the proper orientation of lugs
204
with respect to locking slot
232
and release slot
230
. Lug carrier
210
rides on inner mandrel
206
and lug support
208
.
FIG. 2B
is a diagram showing a radial cutaway view taken at section A-A′. Note that in the present locked position, lugs
204
are situated against the inner wall of outer mandrel
202
and within locking slot
232
machined into inner mandrel
206
. Lug carrier
210
is situated between the interior diameter of outer mandrel
202
and the exterior diameter of inner mandrel
206
. As will be seen by the following figures, the axial alignment of lugs
204
is provided by lug carrier
210
, while the radial position of lugs
204
is determined by the position of locking slot
232
and release slot
230
relative to lugs
204
.
The description of travel joint
200
is an exemplary preferred embodiment and not to be construed as the only embodiment. Those of ordinary skill in the art will readily understand that alternatives may be substituted for the components described above without departing from the scope of the invention.
In accordance with a preferred embodiment, radially expanding keys or lugs are provided for locking and unlocking. However, one of ordinary skill in the art would understand that locking could also be achieved by a series of collets, which are free to flex (or deflect) into similar locking recesses. The collets would also be supported and unsupported in the same manner as the locking keys in the preferred embodiment. Similarly, a snap ring system or series of snap rings could also be used, which would be free to flex (or deflect) into similar locking recesses. The snap rings would also be supported and unsupported in the same manner as the locking lugs in the preferred embodiment.
Also in accordance with a preferred embodiment of the present invention, hydraulic metering (delay) is accomplished by using a pressure relief and restrictor valve or a series of proprietary restricting valves, which allow restricted flow in one direction and virtual free flow in the opposite direction. These restrictions provide for the required ‘time delay’ during operation. Built into these proprietary restricting valves is a relief mechanism that will permit flow only when a predetermined threshold pressure is reached.
One of ordinary skill in the art would realize that time delay can also be provided by restricting single direction flow by providing an elastomeric seal designed to leak at a very slow rate can be provided for restricting fluid flow. In this case no restricting valves would be required. A second alternative is by using a series of accurately sized orifices of very small diameter placed in the fluid transfer block (typically, but not limited to, a radial orientation) designed to permit fluid bypass at a very slow rate would also serve as a fluid restrictor. In this case no restricting valves would be required. Finally, a very small annular bypass area that would allow fluid bypass at a very slow rate could be used. In this case no restricting valves or seals (preventing flow through the bypass section at least) would be required.
As to a free flow state, one of ordinary skill in the art would realize that free flow can also be accomplished (in one direction) by a commonly available, ball-style check-valve where the ball is typically biased against its seat with a form of spring. The ball can be metallic or thermoplastic. Another option for facilitating free flow in one direction is by proving a commonly available, poppet-style check-valve where the poppet is biased against its seat with a form of spring. The poppet can be metallic or thermoplastic. Another option is a commonly available, flap-style check-valve where the flap mechanism is biased against its seat with a form of spring. The flap mechanism can be metallic or thermoplastic.
Alternatives for a single direction relief valve threshold pressure are similar to those used for achieving free flow state, such as a ball-style check-valve; a poppet-style check-valve; or a flap style check-valve, each of which are described above.
In accordance with a preferred embodiment, the present invention utilizes a transfer chamber using a floating piston to maintain a hydrostatic pressure balance (in the transfer piston chambers) with the well pressure inside and outside the travel joint locking mechanism assembly. This floating piston also accommodates fluid thermal expansion, as well as fluid volume tolerance during loading of the chambers with hydraulic fluid. Other embodiments utilize a U-cup style piston seal. This single section seal would straddle the gap between the seal bore ID and seal shaft ID thus replacing the piston and O-rings currently shown in the preferred embodiment. Another alternative embodiment includes the use of V-packing piston seals. This single section multi-stack sealing arrangement would also straddle the gap between the seal bore ID and seal shaft ID thus replacing the piston and o-rings currently shown in the preferred embodiment.
The inner and outer housing (that make up the overall body of the travel joint) are fixed relative to one another by means of the locking mechanism and hydraulic time delay system. In a preferred embodiment, the maximum stroke of the travel joint is determined by the length of the outer tube above the outer housing of the travel joint mechanism and the length of the inner tube below the inner housing of the travel joint mechanism. The inner and outer connecting tubes are suitably sized joints of oilfield tubing/casing, which use a flush joint tubing thread to avoid undesirable upsets. Artisans skilled in the art would realize that other alternatives by which travel joint stroke can also be accomplished. For instance, suitably sized upset joints of tubing/casing above and below the travel joint mechanism, which use may be joined by straight, tapered, buttress, modified buttress, or proprietary premium thread joints. Also, suitably sized one-piece components (other than purchased oilfield tubulars) manufactured to lengths necessary for the desired travel joint stroke. Here connecting joints may or may not be required.
In the preferred embodiment, a temporary seal is achieved by use of several robust molded seals. This seal is bi-directional and is necessary for the purpose of a rudimentary pressure test prior to travel joint release and space-out. This seal mechanism may also be unidirectional, as required. The seal in the preferred embodiment is temporary. That is, once the locking mechanism has released the inner and outer housings, the seals no longer provide pressure containment. However, during stroke-out or space-out a continuous seal is also possible. Continuous or temporary. BI or unidirectional sealing can also be accomplished by: elastomeric or non-elastomeric o-rings; elastomeric or non-elastomeric multi-stack v-packing; elastomeric or non-elastomeric U-cups; and/or specialized premium seals (such as proprietary non-elastomeric brands and metal seals).
FIGS. 3 through 10
depict the cooperation of components comprising travel joint
200
during locking and unlocking operations.
FIGS. 3A and 3B
depict travel joint
200
in the fully locked position. In the fully locked position, lugs
204
are completely seated within locking slot
232
, as can be seen in
FIG. 3A
or in cutaway section A-A′ shown in FIG.
3
B. Lug carrier
210
is situated between the interior diameter of outer mandrel
202
and the exterior diameter of inner mandrel
206
, and lugs
204
are radially disposed between lug grooves formed in lug, carrier
210
. A lug support is pressed firmly against locking slot lower shoulder
233
due to support spring
212
being in the fully compressed position, which exerts the maximum upward force possible. Floating piston
216
is in the lowermost position possible, which reduces the volume of upper hydraulic chamber
240
to the minimum. Conversely, lower hydraulic chamber
242
has the maximum capacity possible. However, rather than completely filling lower chamber
242
with hydraulic fluid, the amount of hydraulic fluid is used in slightly less than the capacity of lower chamber
242
in order to compensate for thermal expansion in the wellbore. The lower extent of the chamber has been increased due to the position of transfer piston
224
being in the lowermost possible position.
In the fully locked position, hydraulic fluid in the upper and lower hydraulic chambers is static. Dynamic flow from lower hydraulic chamber
242
to upper hydraulic chamber
240
can only occur when the pressure inside the lower hydraulic chamber exceeds the pressure threshold of pressure relief and restrictor valve
220
. Pressure is increased within lower hydraulic chamber
242
by downward force on travel joint
200
being applied though the connected tubing. Such force causes outer mandrel
202
and pressure block
218
to move downward with respect to transfer piston
224
and the remaining components of travel joint
200
. Once the pressure within lower hydraulic chamber
242
exceeds the threshold pressure of pressure relief and restrictor valve
220
, flow occurs from the lower chamber to the upper chamber via unlock channel
234
.
The pressure threshold may be changed, thereby adjusting the force required to unlock the travel joint, by substituting pressure relief and restrictor valves. Pressure relief and restrictor valves vary depending on their preset pressure threshold. The operation of the pressure relief and restrictor valve can be checked by placing the entire travel joint between hydraulically operated rams and noting the pressure needed to actuate unlocking. Alternatively, the hydraulic pressure within lower hydraulic chamber
242
may be increased via an external hydraulic connection port (not shown) in lower chamber
242
. Flow is detected at a similar external hydraulic connection port (not shown) in upper chamber
240
when the pressure exceeds the threshold pressure for pressure relief and restrictor valve
220
. The external ports are also used for filling the hydraulic chambers with fluid.
FIG. 3B
is a diagram showing a radial cutaway view taken at section A-A′. Travel joint
200
is in the fully locked position. Lugs
204
are firmly between the inner wall of outer mandrel
202
and inner mandrel
206
, filling locking slot
232
. Lug carrier
210
is situated between the interior diameter of outer mandrel
202
and the exterior diameter of inner mandrel
206
.
FIGS. 4A through 4C
depict travel joint
200
in an intermediate unlocking position. After the downward force on travel joint
200
is sufficient to cause the hydraulic pressure within lower hydraulic chamber
242
to exceed the preset pressure threshold of pressure relief and restrictor valve
220
, outer mandrel
202
moves down with respect to its fully locked position. Once the threshold pressure is exceeded, the hydraulic fluid slowly flows into tipper chamber
240
at a predetermined steady rate, which is determined by the selection of pressure relief and restrictor valve. The steady rate of flow translates into a steady and predictable rate of movement for outer mandrel
202
, and a predictable time for unlocking the travel joint. The hydraulic section is contained in box
402
and magnified in FIG.
4
C.
The path of hydraulic fluid flow is depicted in
FIG. 4C
as arrows from lower hydraulic chamber
242
to upper hydraulic chamber
240
. As outer mandrel
202
and pressure block
218
move downward with respect to transfer piston
224
, fluid in lower hydraulic chamber
242
is forced through pressure relief and restrictor valve
220
into unlock channel
234
and finally into upper hydraulic chamber
240
. Note that in the process, pressure relief slot
238
in transfer piston
224
is brought closer to pressure relief port
236
in pressure block
218
. In the present position, however, pressure relief slot
238
is isolated from pressure relief port
236
by lower o-ring
251
. Floating piston
216
moves upward at a corresponding distance from pressure block
218
because floating piston
216
is not physically connected to either transfer piston
224
or lug carrier connector
214
. This allows floating piston
216
to move at a slightly different rate to compensate for air in the hydraulic chambers and for matching the precise displacement of fluid volume from lower hydraulic chamber
242
.
Returning to
FIG. 4A
, note that the position of lugs
204
is much closer to release slot
230
than in the previous figure, FIG.
3
A. However, support spring
212
remains fully compressed, thereby forcing lug support
208
solidly against locking slot lower shoulder
233
. As can be seen from cutaway section A-A′ depicted in
FIG. 4B
, travel joint
200
is still in the locked position, preventing inner mandrel
206
from telescoping into the upper tubing. Lugs
204
still remain firmly between the inner wall of outer mandrel
202
and inner mandrel
206
, filling locking slot
232
.
FIGS. 5A through 5D
depict travel joint
200
in another intermediate unlocking position. Outer mandrel
202
continues to move downward with respect to the other components in travel joint
200
. Hydraulic fluid flows into upper chamber
240
and remains at a steady rate, with the lower end of pressure block
218
moving closer to the lower end of transfer piston
224
, thereby continuing to reduce the volume of lower hydraulic chamber
242
. The hydraulic section is contained in box
504
and is magnified in FIG.
5
C.
Turning to
FIG. 5C
, the path of hydraulic fluid flow is again depicted as arrows from lower hydraulic chamber
242
to upper hydraulic chamber
240
. Outer mandrel
202
and pressure block
218
continue to move downward with respect to transfer piston
224
, and the volume of lower hydraulic chamber
242
continues to be reduced. Hydraulic fluid flows into upper hydraulic chamber
240
from lower hydraulic chamber
242
causing floating piston
216
to maintain its position relative to transfer piston
224
and lug carrier connector
214
. Note that pressure relief slot
238
is now positioned across the lowermost o-ring on pressure block
218
, but not yet across pressure relief port
236
. The seal provided by that o-ring has now lost some hydraulic fluid that may be escaping from lower hydraulic chamber
242
directly into relief port
236
, thereby circumventing the flow across pressure relief and restrictor valve
220
.
Returning to
FIG. 5A
, box
502
, including the engagement/disengagement mechanism (lug
204
, lug carrier
210
, lug carrier connector
214
, transfer piston
224
, and floating piston
216
), is magnified in FIG.
5
D. Turning to
FIG. 5D
, lug
204
is now partially positioned across release slot
230
; however, lug
204
remains firmly within locking slot
232
. With lug
204
still in locking slot
232
, locking slot lower shoulder
233
keeps lug support
208
from moving upward, and support spring
212
continues to be fully compressed.
FIG. 5B
depicts a cutaway representation of cross section A-A′. Travel joint
200
is still in the locked position, preventing inner mandrel
206
from telescoping into the upper tubing. Lugs
204
still remain firmly between the inner wall of outer mandrel
202
and inner mandrel
206
, filling locking slot
232
. However, release slot
230
is now visible around the outer diameter of both lugs
204
and lug carrier
210
.
FIGS. 6A through 6D
depict travel joint
200
in the process of releasing inner mandrel
206
. As can be seen from
FIG. 6A
, lug
204
has been completely received within release slot
230
, as will be described more completely with respect to FIG.
6
D. Additionally, outer mandrel
202
and pressure block
218
have completed their downward travel, reducing the volume of lower hydraulic chamber
242
to its minimum volume.
However, during the release mode and immediately before lugs
204
disengage from locking slot
232
(not shown in FIG.
6
A), hydraulic pressure in lower hydraulic chamber
242
may create an undesirable force between lugs
204
and locking slot
232
that prevents lugs
204
from properly disengaging from locking slot
232
. That force may prevent inner mandrel
206
from smoothly unlocking. A corresponding undesirable force occurs during locking mode immediately before lugs
204
disengage from release slot
230
and is also a result of hydraulic pressure in lower hydraulic chamber
242
.
To completely free lug
204
during engaging and disengaging and to facilitate locking and unlocking of the travel joint, pressure relief slot
238
is provided in transfer piston
224
and pressure relief port
236
is provided in pressure block
218
, as can be seen in FIG.
6
C. The hydraulic fluid flows from lower hydraulic chamber
242
through pressure relief slot
238
, through pressure relief port
236
, and into upper hydraulic chamber
240
. The placement of pressure relief slot
238
and pressure relief port
236
allows hydraulic fluid to bleed around pressure relief and restrictor valve
220
and directly into upper hydraulic chamber
240
(as shown by the arrows representing the fluid flow). In the intermediate unlocking position, pressure relief slot
238
is aligned across both pressure relief port
236
and the lowermost o-ring. The hydraulic fluid flows around pressure relief and restrictor value
220
and not across it. In so doing the pressure in lower hydraulic chamber
242
drops below the threshold pressure needed for overcoming pressure relief and restrictor value
220
. Therefore, immediately prior to lugs
204
being received into release slot
230
the pressure equalizes between the hydraulic chambers, and the force between lugs
204
and locking slot
232
is relieved. Lug
204
can then be received within release slot
230
as shown in FIG.
6
A.
FIG. 6D
depicts the engagement/disengagement mechanism depicted in box
602
of FIG.
6
A. Turning to
FIG. 6D
, the continued downward movement of outer mandrel
202
translates into an outward radial force due to the cooperation between the forty five-degree chamfer in locking slot
232
and the corresponding forty five-degree bevel on lug
204
. Locking slot lower shoulder
233
forces lug
204
completely into release slot
230
. Lug
204
is then held in position by locking slot lower shoulder
233
, as outer mandrel
202
continues to move down. The change in relative positions between inner mandrel
206
and lug
204
allows lug support
208
to move upward with respect to lug
204
, allowing support spring
212
to partially decompress.
The result of repositioning lugs
204
needed for unlocking is better shown in
FIG. 6B
, which is a cutaway representation of cross section A-A′ shown in FIG.
6
A. Travel joint
200
is now in releasing position and, as lugs
204
have been fully received within release slot
230
, inner mandrel
206
may now telescope into the upper tubing. Lugs
204
have moved radially outward from the center of travel joint
200
and now are firmly positioned between the outer wall of inner mandrel
206
and the inner wall of outer mandrel
202
, filling release slot
230
.
FIGS. 7A through 7C
depict travel joint
200
in the unlocked position and inner mandrel
206
released. Referring to
FIG. 7A
, outer mandrel
202
and pressure block
218
remain in their complete downward positions, having forced the transfer of the hydraulic fluid from lower hydraulic chamber
242
to upper hydraulic chamber
240
. The fluid flow was achieved by simultaneously reducing the volume of capacity of lower hydraulic chamber
242
while increasing the volume of upper hydraulic chamber
240
a corresponding amount. Because of the alignment of pressure relief slot
238
and pressure relief port
236
, pressure between the upper and lower hydraulic chambers has been equalized.
As can be seen in
FIG. 7A
, inner mandrel
202
is now free to telescope within travel joint
200
. Locking slot lower shoulder
233
has moved upward with respect to lug
204
, allowing lug support
208
to reposition itself under both lug
204
and lug carrier
210
, from upward force provided by the decompression of support spring
212
. The fully locked position of lug support
208
is better realized by viewing
FIGS. 7B and 7C
.
FIG. 7B
, which is a cutaway representation of cross section A-A′ shown in FIG.
7
A. Travel joint
200
is now in the fully released position and lugs
204
have been fully received within release slot
230
. Lugs
204
are extended radially outward and now are firmly positioned between the inner wall of outer mandrel
202
and the outer wall of lug support
208
, filling release slot
230
.
FIG. 7B
depicts a magnified view of block
702
shown in
FIG. 7A
showing a side view of release slot
230
fully receiving locking lug
204
. Inner mandrel
206
has been unlocked allowing inner mandrel
206
to slide free of locking lug
204
. Locking slot
232
and locking slot lower shoulder
233
has moved upward with respect to lug
204
, allowing lug support
208
under both lug
204
and lug carrier
210
.
In accordance with a preferred embodiment of the present invention, releasing travel joint
200
requires the well operator to apply a set compressive force across the traveling joint for a fixed time interval. This procedure ensures that travel joint
200
does not become prematurely unlocked while tripping into the wellbore. An equally important aspect of the present invention is that once unlocked, travel joint
200
can be re-locked with minimal tension applied across the travel joint. In most cases, the tension needed to lock travel joint
200
is a force only slightly higher than that needed to compress support spring
212
, overcome the friction of the internal seals, and overcome the minimal hydraulic resistance of the check valve.
FIGS. 8 through 10
depict the locking operation in accordance with a preferred embodiment of the present invention. The locking operation is largely the reverse of the unlocking operation described above with some exceptions. Those exceptions arc stressed below. Initially, the tubing string is pulled upward, causing a slight compressive force across travel joint
200
.
Referring now to
FIGS. 8A
, lug
204
remains positioned within release slot
230
as travel joint
200
is moved upward with respect to inner mandrel
206
. At some point, locking slot lower shoulder
233
contacts lug support
208
and stops lug support
208
from continuing its upward movement. Support spring
212
is then compressed between lug support
208
and transfer piston
224
, as the transfer piston continues to move up with outer mandrel
202
.
FIG. 8C
depicts the engagement/disengagement mechanism depicted in box
802
of FIG.
8
A. Lugs
204
remain on locking slot lower shoulder
233
until the alignment with locking slot
232
is completed.
The repositioning of locking slot lower shoulder
233
with respect to lugs
204
is shown in
FIG. 8B
, which is a cutaway representation of cross section A-A′ shown in FIG.
8
A. There the outer surfaces of lugs
204
remain firmly in release slot
230
, however, the inner surfaces are positioned over a portion of locking slot
232
. Once lugs
204
align completely with locking slot
232
, the lugs will disengage release slot
230
and re-engage locking slot
232
.
FIGS. 9A through 9C
depict an intermediate locking position for travel joint
200
. Eventually the upward movement of outer mandrel
202
moves lug
204
past lower shoulder
233
and lugs
204
align with locking slot
232
. The upward force is translated into an inward radial force on lugs
204
due to the cooperation between the forty five-degree chamfer in release slot
230
and the corresponding forty five-degree bevel on lug
204
. Lug
204
is received within locking slot
232
. Simultaneously, lug support
208
rides below locking slot lower shoulder
233
, fully compressing support spring
212
.
Once lugs
204
have seated into locking slot
232
, the force needed from completing the locking operation may be somewhat reduced because support spring
212
is fully compressed and locked in place. The entire upward force is then applied across the engaging/disengaging assembly (lug
204
, lug carrier
210
, lug carrier connector
214
, transfer piston
224
, and floating piston
216
).
The repositioning of locking slot lower shoulder
233
with respect to lugs
204
needed for re-locking is shown in
FIG. 9B
, which is a cutaway representation of cross section A-A′ shown in FIG.
9
A. Travel joint
200
is in another intermediate locked position where lugs
204
have been fully received within locking slot
232
, but traveling piston
224
has not been fully reset. Lugs
204
have moved radially inward from the circumference of travel joint
200
and now are firmly positioned between the outer wall of inner mandrel
206
and outer mandrel
202
, filling locking slot
232
.
Turning to
FIG. 9C
, the path of hydraulic fluid through pressure block
218
is depicted. As discussed above, the pressures within upper hydraulic chamber
240
and lower hydraulic chamber
242
is approximately equal, allowing for the hydraulic fluid to flow from the upper chamber to the lower chamber via check valve
222
and lock hydraulic channel
235
, as indicated by the arrows. Again, because the hydraulic fluid traverses check valve
222
, rather than a pressure relief and restrictor valve, locking travel joint
200
takes relatively little force. Equally important is the fact that, once any hydraulic fluid is transferred into lower hydraulic chamber
242
, travel joint
200
can only be unlocked by providing a sufficient force across the travel joint to overcome the threshold pressure associated with pressure relief and restrictor valve
220
(shown in FIG.
9
A). The threshold pressure is independent of the amount of fluid in the lower chamber or the position of the pistons, provided lug
204
is not aligned with release slot
230
.
FIGS. 10A and 10B
illustrate travel joint
200
in the fully locked position. At some point, outer mandrel
202
reaches its uppermost position with respect to the remaining components in travel joint
200
. At that point, floating piston
216
and transfer piston
224
are at their lowermost position with respect to outer mandrel
202
, and the flow of hydraulic fluid through check valve
222
and locking hydraulic channel
235
ceases. The pressures within upper hydraulic chamber
240
and lower hydraulic chamber
242
are approximately equal. Lower hydraulic chamber
242
now is fully expanded and contains the maximum possible volume of hydraulic fluid, while upper hydraulic chamber
240
is fully contracted and contains only the minimum possible volume of hydraulic fluid.
Lugs
204
are completely seated within locking slot
232
, as can be seen in
FIG. 10A
or in cutaway section A-A′ shown in FIG.
10
B. Lug carrier
210
is situated between the interior diameter of outer mandrel
202
and the exterior diameter of inner mandrel
206
, and lugs
204
are radially disposed between lug grooves formed in lug carrier
210
. Lug support
208
is pressed firmly against locking slot lower shoulder
233
due to support spring
212
being in the fully compressed position, which exerts the maximum upward force possible.
FIG. 10B
is a diagram showing a radial cutaway view taken at section A-A′. Travel joint
200
is in the fully locked position. Lugs
204
are firmly between the inner wall of outer mandrel
202
and outer wall of inner mandrel
206
, filling locking slot
232
.
As discussed above, the hydraulically metered travel joint disclosed herewithin has several distinct advantages over prior art travel joints, allowing the present travel joint to be used in even the most rigorous wellbore environments. An important feature of the present invention is that the unlocking or release mechanism is hydraulically metered. Force applied to the tubing is translated into hydraulic pressure, and the unlocking activation process commences when the hydraulic pressure exceeds a preset threshold. An important feature of the present invention is that the hydraulically metered travel joint is configurable to different wellbore environments. Both the threshold pressure and activation time interval can be preset. The process of locking the travel joint merely entails reversing the direction of movement and requires little force to be applied across the travel joint.
FIG. 11A
is a diagram depicting the use of a drag block in combination with a hydraulically metered travel joint. Here a bottom hole assembly includes upper tubing
246
, travel joint
200
, lower tubing
244
, and packer stinger
1110
. As discussed above, in this configuration a typical operation might involve stinging into a downhole packer with stinger
1110
and then applying sufficient compressional pressure across travel joint
200
such that the hydraulic pressure in the lower hydraulic chamber exceeds the threshold pressure needed for initiating the locking. The hydraulic fluid would then flow from the lower hydraulic chamber into the upper hydraulic chamber at a predetermined rate, eventually allowing the inner mandrel to smoothly unlock from the upper mandrel. The inner mandrel can then be telescoped into the outer mandrel, thereby spacing out the tubing length between the tubing hanger and stinger
1110
.
Also depicted in
FIG. 11A
is drag block
1100
, which may be included in the bottom hole assembly for increasing drag resistance for resetting travel joint
200
in highly deviated or horizontal wellbores. When running travel joint
200
through a tight spot or restriction in a wellbore, the tubing weight needed for traversing the restriction might increase the compressional pressure across travel joint
200
in excess of the force needed for initiates the unlocking process. While this condition would be catastrophic for prior art shear pin type travel joints, an important aspect of the present invention is that unlocking requires the application of a predetermined compressional pressure, over a preset time period. The preset time period is determined by metering the flow rate of hydraulic fluid. Therefore, a well operator has the option of working a tubing string past a tight spot by exceeding the tubing weight needed for unlocking travel joint
200
, provided the cumulative time that the tubing weight exceeds the unlocking pressure does not exceed the preset time period. However, once travel joint
200
has passed the tight spot, the travel joint should be reset, thereby resetting the time period needed for unlocking. The tension needed to reset travel joint
200
is a force only slightly higher than that needed to compress the support spring, overcome the friction of the internal seals, and overcome the minimal hydraulic resistance of the check valve. In many cases the tension needed for resetting travel joint
200
is less the combined weight of lower tubing
244
and stinger
1110
. However, in horizontal or highly deviated wellbores the tension created by the weight of the lower tubing and stinger is not sufficient to reset the travel joint. In that case, drag block
1100
is included in the string, which creates drag below travel joint
200
and enables the well operator to reset travel joint
200
by merely pulling tip on the tubing string. Note, however, that the inclusion of drag block
1100
reduces stroke length
1150
for travel joint
200
because drag block
1100
cannot be telescoped within travel joint
200
. Therefore, the placement of drag block
1100
should allow for stroke length
1150
sufficient for the well application.
FIG. 11B
is a cutaway diagram of drag block
1100
. Drag block
1100
is positioned between lower tubing
244
and stinger
1110
. Drag is created against the inner wall of a wellbore by frictional force created by a plurality of drag shoes
1120
held in position by outer housing
1130
. The frictional force created from drag shoes
1120
may be considerable, therefore drag shoes
1120
are composed of a hardened metal such as carbide steel or the like. The force needed for keeping drag shoes
1120
against the inner wellbore wall and creating the drag friction is provided by a plurality of high tension springs
1124
affixed between drag shoes
1120
and inner housing
1126
. While drag block
1100
is a preferred embodiment of a drag producing device, those skilled in the art would realize that other drag producing devices exist such as bow springs or drag spring and the like.
FIGS. 12 and 13
depict a process for locking and unlocking a hydraulically metered travel joint in accordance with a preferred embodiment of the present invention. The process begins by calculating the maximum force expected to be encountered while running the travel joint in the well (step
1202
). Generally, the higher the wellbore deviation, the deeper the wellbore; and the more corkscrews or doglegs, the more force will be needed in order to run the tubing in the well. By knowing how much force is needed for running the tubing past a tight spot in the well, an appropriate travel joint for the well can be selected. The appropriateness of the travel joint is based on the ratings of the pressure relief and restrictor valve. The valve ratings must correspond to both the required threshold pressure rating and the desired preset release time period necessary for successfully running the tubing in the well without prematurely unlocking (step
1204
). The tubing, including the travel joint, is then run into the wellbore (step
1206
). Next, as the tubing is being run into the wellbore, the force needed to get the tubing to the bottom is constantly monitored. A determination is made as to whether the maximum expected forces on the travel joint have been exceeded running in wellbore (step
1208
). If so, the tubing is immediately backed off, or pulled up slightly, allowing the hydraulic section of the travel joint to return to a fully locked position (step
1210
). Importantly, the present travel joint does not instantaneously unlock once the threshold pressure has been exceeded. Instead, the threshold pressure must be maintained for a preset time period, however, the time period is cumulative. Therefore, in extreme wellbore conditions, the threshold pressure may be exceeded any number of times without fear of pre-mature unlocking, as long as the cumulative time for exceeding the threshold pressure does not exceed the preset time period. Still more importantly, after the threshold pressure has been exceeded for a time period, the travel joint can be pulled up a short distance in the wellhore, which resets the cumulative time interval (in highly deviated wellbores a drag block may be needed for generating the force needed to reset the travel joint). Those of ordinary skill in the art will realize that an important benefit of the present invention allows a well operator the flexibility to “push” the tubing past a tight spot and, once having completely cleared the tight spot, pull up on the tubing, which re-starts the cumulative time interval. The travel joint is thus reset for the next tight spot and continues to be run into the wellbore (step
1208
). The iterations of pushing past tight spots and re-starting the cumulative time interval continue until the tubing nears the packer. The well operator then notes the normal tubing weight prior to stinging into the packer (step
1212
), stings into the packer (step
1214
), and calculates the normal tubing string weight at the travel joint (step
1216
). Next, downward force is exerted on the travel joint in excess of that needed to generate threshold pressure. The force is maintained for a cumulative time interval greater than the preset release time interval (step
1218
). From the surface weight indicator, the well operator should be able to see a slight increase in tubing weight, indicating that the inner mandrel is released from the travel joint (step
1220
). The tubing weight should be approximately equal to the calculated normal tubing string weight at the travel joint. Confirmation that the travel joint is unlocking is obtained by moving tubing downward without tubing weight loss (step
1222
).
FIG. 13
depicts the process for re-locking the travel joint. The process begins by calculating the normal tubing string weight at the travel joint (step
1302
). The well operator then pulls up on the tubing, which engages the locking lugs and resets the hydraulic section (step
1304
). The travel joint immediately locks, unlike unlocking, which is time-delayed. Confirmation that the travel joint is locking is obtained by the surface tubing weight dropping below the calculated normal tubing weight when tubing is slightly lowered (step
1306
).
Although preferred embodiments of the present invention have been described in the foregoing detailed description and illustrated in the accompanying drawings, it will be understood that the invention is not limited to the embodiments disclosed but is capable of numerous rearrangements, modifications, and substitutions of steps without departing from the spirit of the invention. Accordingly, the present invention is intended to encompass such rearrangements, modifications, and substitutions of steps as fall within the scope of the appended claims.
Claims
- 1. A hydraulically metered travel joint, comprising:an inner mandrel; an outer mandrel of sufficient size for partially enclosing the inner mandrel; an engagement assembly for locking and unlocking the inner mandrel to and from a fixed position, wherein: the fixed position is fixed relative to the position of the outer mandrel; and the inner and outer mandrel can be repeatedly unlocked and relocked without redressing the travel joint; and a hydraulic assembly for activating the engagement assembly.
- 2. The hydraulically metered travel joint recited in claim 1, wherein the hydraulic assembly further comprises:a pressure relief and restrictor valve wherein the pressure relief and restrictor valve restricts a flow of hydraulic fluid prior to hydraulic pressure exceeding a pressure threshold value, thereby pressure biasing the activation of the engagement assembly.
- 3. The hydraulically metered travel joint recited in claim 1, wherein the hydraulic assembly further comprises:a pressure relief and restrictor valve, wherein the pressure relief and restrictor valve restricts a rate of flow of hydraulic fluid subsequent to hydraulic pressure exceeding a pressure threshold value, thereby time biasing the activation of the engagement assembly.
- 4. The hydraulically metered travel joint recited in claim 1, wherein the hydraulic assembly further comprises:a first hydraulic chamber; a second hydraulic chamber; and a pressure block, wherein the pressure block further comprises: a pressure relief and restrictor valve disposed between the first and second hydraulic chambers, for restricting the flow of hydraulic fluid between the first and second hydraulic chambers during activation of the engagement assembly for unlocking the inner mandrel.
- 5. The hydraulically metered travel joint recited in claim 4, wherein the pressure block further comprises:a check valve disposed between the first and second hydraulic chambers, for allowing a relatively free flow of hydraulic fluid between the first and second hydraulic chambers during activation of the engagement assembly for locking the inner mandrel.
- 6. The hydraulically metered travel joint recited in claim 4, wherein the pressure block further comprises:a pressure relief port for relieving trapped pressure in one of the first and second hydraulic chambers subsequent to activating the engagement assembly for locking the inner mandrel.
- 7. The hydraulically metered travel joint recited in claim 4, wherein the hydraulic assembly further comprises:a floating piston for expanding a volume of the first hydraulic chamber prior to activating the engagement assembly for unlocking the inner mandrel.
- 8. The hydraulically metered travel joint recited in claim 4, wherein the hydraulic assembly further comprises:a transfer piston for contracting a volume of the second hydraulic chamber prior to activating the engagement assembly for unlocking the inner mandrel.
- 9. The hydraulically metered travel joint recited in claim 1, wherein the engagement assembly further comprises:a locking lug for locking and unlocking the inner mandrel.
- 10. The hydraulically metered travel joint recited in claim 9, wherein the engagement assembly further comprises:a lug carrier for maintaining an axial orientation of the locking lug.
- 11. The hydraulically metered travel joint recited in claim 10, wherein the engagement assembly further comprises:a lug support for supporting the locking lug while the inner mandrel is unlocked.
- 12. The hydraulically metered travel joint recited in claim 1, wherein the outer mandrel further comprises:a release slot for receiving a locking lug.
- 13. The hydraulically metered travel joint recited in claim 1, wherein the inner mandrel further comprises:a locking slot for receiving a locking lug.
- 14. A hydraulically metered travel joint, comprising:an inner mandrel; an outer mandrel of sufficient size for partially enclosing the inner mandrel; an engagement assembly for locking and unlocking the inner mandrel to a fixed position, wherein the fixed position is fixed relative to the position of the outer mandrel; and a hydraulic assembly for activating the engagement assembly, wherein said hydraulic assembly further comprises: a first hydraulic chamber; a second hydraulic chamber; and a pressure block, wherein said pressure block further comprises: a pressure relief and restrictor valve disposed between the first and second hydraulic chambers, for restricting the flow of hydraulic fluid between the first and second hydraulic chambers during activation of the engagement assembly for unlocking the inner mandrel; and a check valve disposed between the first and second hydraulic chambers, for allowing a relatively free flow of hydraulic fluid between the first and second hydraulic chambers during activation of the engagement assembly for locking the inner mandrel.
- 15. The hydraulically metered travel joint of claim 14, wherein said pressure relief and restrictor valve restricts a flow of hydraulic fluid prior to hydraulic pressure exceeding a pressure threshold value, thereby pressure biasing the activation of the engagement assembly.
- 16. The hydraulically metered travel joint of claim 14, wherein said pressure relief and restrictor restricts a rate of flow of hydraulic fluid subsequent to hydraulic pressure exceeding a pressure threshold value, thereby time biasing the activation of the engagement assembly.
- 17. The hydraulically metered travel joint of claim 14, wherein said pressure block further comprises:a pressure relief port for relieving trapped pressure in one of the first and second hydraulic chambers subsequent to activating the engagement assembly for locking the inner mandrel.
- 18. The hydraulically metered travel joint of claim 14, wherein said hydraulic assembly further comprises:a floating piston for expanding a volume of the first hydraulic chamber prior to activating the engagement assembly for unlocking the inner mandrel.
- 19. The hydraulically metered travel joint of claim 14, wherein said hydraulic assembly further comprises:a transfer piston for contracting a volume of the second hydraulic chamber prior to activating the engagement assembly for unlocking the inner mandrel.
- 20. The hydraulically metered travel joint of claim 14, wherein said engagement assembly further comprises:a locking lug for locking and unlocking the inner mandrel.
- 21. The hydraulically metered travel joint recited in claim 20, wherein the engagement assembly further comprises:a lug carrier for maintaining an axial orientation of the locking lug.
- 22. The hydraulically metered travel joint recited in claim 21, wherein the engagement assembly further comprises:a lug support for supporting the locking lug while the inner mandrel is unlocked.
- 23. The hydraulically metered travel joint recited in claim 14, wherein the outer mandrel further comprises:a release slot for receiving a locking lug.
- 24. The hydraulically metered travel joint recited in claim 14, wherein the inner mandrel further comprises:a locking slot for receiving a locking lug.
- 25. A hydraulically metered travel joint, comprising:an inner mandrel; an outer mandrel of sufficient size for partially enclosing the inner mandrel; an engagement assembly for locking and unlocking the inner mandrel to a fixed position, wherein the fixed position is fixed relative to the position of the outer mandrel; and a hydraulic assembly for activating the engagement assembly, wherein said hydraulic assembly further comprises: a first hydraulic chamber; a second hydraulic chamber; and a pressure block, wherein said pressure block further comprises: a pressure relief and restrictor valve disposed between the first and second hydraulic chambers, for restricting the flow of hydraulic fluid between the first and second hydraulic chambers during activation of the engagement assembly for unlocking the inner mandrel; and a pressure relief port for relieving trapped pressure in one of the first and second hydraulic chambers subsequent to activating the engagement assembly for locking the inner mandrel.
- 26. The hydraulically metered travel joint of claim 25, wherein said pressure relief and restrictor valve restricts a flow of hydraulic fluid prior to hydraulic pressure exceeding a pressure threshold value, thereby pressure biasing the activation of the engagement assembly.
- 27. The hydraulically metered travel joint of claim 25, wherein said pressure relief and restrictor valve restricts a rate of flow of hydraulic fluid subsequent to hydraulic pressure exceeding a pressure threshold value, thereby time biasing the activation of the engagement assembly.
- 28. The hydraulically metered travel joint of claim 25, wherein said pressure block further comprises:a check valve disposed between the first and second hydraulic chambers, for allowing a relatively free flow of hydraulic fluid between the first and second hydraulic chambers during activation of the engagement assembly for locking the inner mandrel.
- 29. The hydraulically metered travel joint of claim 25, wherein said hydraulic assembly further comprises:a floating piston for expanding a volume of the first hydraulic chamber prior to activating the engagement assembly for unlocking the inner mandrel.
- 30. The hydraulically metered travel joint of claim 25, wherein said hydraulic assembly further comprises:a transfer piston for contracting a volume of the second hydraulic chamber prior to activating the engagement assembly for unlocking the inner mandrel.
- 31. The hydraulically metered travel joint of claim 25, wherein said engagement assembly further comprises:a locking lug for locking and unlocking the inner mandrel.
- 32. The hydraulically metered travel joint recited in claim 31, wherein the engagement assembly further comprises:a lug carrier for maintaining an axial orientation of the locking lug.
- 33. The hydraulically metered travel joint recited in claim 32, wherein the engagement assembly further comprises:a lug support for supporting the locking lug while the inner mandrel is unlocked.
- 34. The hydraulically metered travel joint of claim 25, wherein the outer mandrel further comprises:a release slot for receiving a locking lug.
- 35. The hydraulically metered travel joint of claim 25, wherein the inner mandrel further comprises:a locking slot for receiving a locking lug.
US Referenced Citations (4)
Foreign Referenced Citations (3)
Number |
Date |
Country |
WO-9533912 |
Dec 1995 |
WO |
WO-9607009 |
Mar 1996 |
WO |
WO-9919599 |
Apr 1999 |
WO |