Patent Grant
7628213
This patent application claims priority from PCT/GB03/005714, having an international filing date of 30 Dec. 2003, and a priority date of 30 Jan. 2003.
Not Applicable
Not Applicable
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The present invention relates to downhole tools as used in the oil and gas industry and in particular, though not exclusively, to a downhole tool which includes a lock bar to allow movement of a sleeve within the tool over a predefined range.
While many downhole tools operate continuously through a well bore e.g. scrapers and brushes as disclosed in U.S. Pat. No. 6,227,291, it is more desirable to provide a tool which performs a function only when it has reached a preferred location within a well bore. An example of such a tool would be a circulation tool as disclosed in WO 02/061236. The tool provides a cleaning action on the walls of the casing or lining of the well bore. The cleaning action is only required after the casing has been brushed or scraped and thus the tool is designed to be selectively actuated in the well bore. Such tools provide the advantage of allowing an operator to mount a number of tools on a single work string and operate them individually on a single trip in to the well bore. This saves significant time in making the well operational.
Tools which are selectively actuable in a well bore commonly operate by having an element which can be moved relative to the tool when in the well bore. In the circulation tool of WO 02/061236, the element is a sleeve located in the cylindrical body of the tool. When run in the well, the sleeve is held in a first position by one or more shear screws. To actuate the tool, a drop ball is released from the surface of the well through the work string. On reaching the sleeve, the ball blocks the flow of fluid through the tool and consequently pressure builds up until the shear screws shear and the sleeve is forced downwards. The movement of the sleeve is then stopped when a lower ledge of the sleeve contacts a shoulder on the internal surface of the tool body.
Such tools have a number of disadvantages. The tools are generally limited to one actuable movement. If two sleeves are incorporated to overcome this, the shear screws of the second sleeve can operate prematurely under the shock created to shear the shear screws of the first sleeve. Additionally, it is difficult to machine a circumferential shoulder into the central bore of a tool. To overcome this, the body is generally provided in two parts with different bore diameters, so that when they are screwed together a shoulder is created. This two part construction is expensive and is prone to weakness at the point where the parts meet. The reduced bore diameter of the lower part also effects the flow rate achievable through the tool.
It is an object of the present invention to provide a downhole tool which obviates or mitigates at least some of the disadvantages of the prior art.
It is a further object of at least one embodiment of the present invention to provide a downhole tool in which movement of a sleeve is controlled within a well bore.
It is yet further object of at least one embodiment of the present invention to provide a downhole tool in which hydraulic damping occurs to prevent premature shearing within the tool following a shock.
According to a first aspect of the present invention there is provided a downhole tool, the tool comprising:
a substantially cylindrical body having a central bore running axially therethrough,
a sleeve located within the bore, the sleeve including a recess on an outer surface,
at least one locking bar, the locking bar being an elongate member having a first and a second end,
the at least one locking bar being located through the body and substantially perpendicular to the central bore,
the first end of the at least one locking bar being located in the recess, and
wherein the body and the sleeve move relative to each other by virtue of the bar moving within the recess.
Thus the tool of the present invention allows a sleeve within the tool to move over a distance defined by the recess. As the bar moves within the recess there is no requirement for a shoulder in the central bore.
Preferably the cylindrical body includes a first and a second end for connection in a work string. More preferably the cylindrical body is of unitary construction.
Preferably the recess is dimensioned to allow movement of the sleeve axially relative to the body. Thus the recess may comprise an elongate channel having a width substantially similar to the width of the first end of the bar.
Alternatively the recess is dimensioned to allow movement of the sleeve circumferentially with respect to the body. Thus the recess may comprise a circumferential groove on the outer surface of the sleeve.
Preferably one or more shear screws are located between the sleeve and the body. Shearing of the shear screws free the sleeve to move relative to the bar.
Preferably the/each locking bar includes a port for venting fluid within the recess to an outer surface of the body. Fluid within the recess provides hydraulic damping when the sleeve moves. Thus a hydraulic break is provided when the shear screws shear and prevent premature shearing of any other shear screws provided in the tool.
Advantageously a magnet is located on the first end of the/each lock bar. The magnet ensures a sealing contact between the bar and the recess.
Preferably the sleeve includes one or more ports located between an inner surface of the sleeve and an outer surface of the sleeve. The ports may be transverse to the central bore or they may be at an angle relative to the central bore. Preferably also, the body includes one or more ports arranged between the central bore and the outer surface of the body. The ports may be transverse to the central bore or they may be at an angle relative to the central bore. When the tool is in an actuated position the ports of the sleeve may align with the ports of the body to provide for the passage of fluid from the central bore to a casing or liner of the well bore. Thus the tool could be a jetting tool.
The tool may further comprise an outer sleeve arranged circumferentially around the body. The outer sleeve may include raised portions which act to stabilise the tool when in a well bore. Thus the tool may act as a stabiliser and replace a conventional stabiliser in a BHA (Bottom Hole Assembly). The outer sleeve may include one or more radial ports through which fluid may pass. More preferably the one or more radial ports include one or more nozzles to provide a jetting action to the fluid. Advantageously channels may be provided on the outer surface of the body to connect the ports of the body with the radial ports of the outer sleeve and thus fluid is jetted from the central bore, through the sleeve, the body and the outer sleeve to the well bore casing or liner. Preferably the nozzles are located on the raised portions to improve the cleaning action of the tool.
Preferably the sleeve includes a first shoulder, the first shoulder being located circumferentially on the inner surface of the sleeve. The shoulder provides a contact point for a drop ball or the like to seal the central bore and provide sufficient pressure increase to shear the shear pins holding the sleeve in place.
Preferably also the sleeve includes a second shoulder, the second shoulder also being located circumferentially on the inner surface of the sleeve above the first shoulder. The second shoulder provides a contact point for a drop ball or the like to seal the central bore and provide sufficient pressure increase to shear a second shear pins holding the sleeve in place. Advantageously an inner diameter of the second shoulder is greater than an inner diameter of the first shoulder. In this way a first drop ball can fall through the second shoulder to contact the first shoulder.
In a preferred embodiment the sleeve comprises a first circumferential portion and a second circumferential portion, the second circumferential portion arranged inside the first circumferential portion. Each portion includes at least one recess for at least one locking bar. Preferably first locking bars are located between the body and the first circumferential portion and second locking bar(s) are located between the first and second circumferential portions. Shear pins preferably hold the portions together and to the tool body. The shoulders are preferably located on the second circumferential portion. Thus the portions can move together or independently on shearing of the pins, with their distance of movement controlled by the locking bars in the recesses.
Preferably the first circumferential portion includes at least bypass recess on an inner surface. The bypass recess, provides for the passage of fluid around the shoulder when a drop ball is in contact with the shoulder and the sleeve has moved as a result of the action of the drop ball.
Preferably the tool includes two sleeves and thus operates as a double jetting sub. In this embodiment four drop balls actuate the tool to provide two jetting actions. The diameter of each ball is progressively larger to contact the progressively larger shoulder diameters.
According to a second aspect of the present invention there is provided a method of moving a sleeve mounted in a cylindrical body of a downhole tool in a well bore, the method comprising the steps:
(a) locating a locking bar through the body and in to a recess on the outer surface of the sleeve;
(b) locating a shear screw through a portion of the body and the sleeve;
(c) releasing a drop ball to contact a shoulder of the sleeve and block fluid flow through the tool;
(d) shearing the shear pin as a result of the build up of pressure behind the drop ball;
(e) moving the locking bar relative to the sleeve by the distance of the recess; and
(f) hydraulically braking the movement of the locking bar through the controlled release of fluid from the recess.
It will be appreciated that while a drop ball is described any other obturating projectile e.g. a dart could be used.
According to a third aspect of the present invention there is provided a method of performing multiple downhole operations on a single trip in a well bore, the method including the steps of:
(a) mounting a downhole tool on the work string, the tool comprising:
a tubular body having an axial throughbore and adapted for connection within a work string;
a sleeve mounted around the body, the sleeve including one or more stabiliser blades, said stabiliser blades including one more jetting ports to direct fluid from the axial throughbore onto a surface of the well bore; and
one or more actuating means to selectively direct the fluid through the jetting ports and thereby circulate the fluid; and
(b) selectively performing a plurality of operations from a group comprising:
(i) stabilising the work string in the well bore by keeping the distance between the stabiliser blades and the surface of the well bore as relatively small;
(ii) pumping loss circulation material by circulating fluid through the tool;
(iii) jet cleaning the well bore;
(iv) using the downhole tool in conjunction with a mud motor to shut down a bit at a shoe in the well bore to minimize wear of a casing in the wellbore while pumping fluid;
(v) running the downhole tool with a near bit reamer, de-activating blades of the reamer at a shoe in the wellbore and bypassing the bit with all mud pumped; and
vi) retrieving a ‘drill ahead’ bore protector,
wherein the sleeve of the downhole tool further includes a recess on an outer surface, and the tool further includes at least one locking bar, the locking bar being an elongate member having a first and a second end, the at least one locking bar being located through the body and substantially perpendicular to the central bore the first end of the at least one locking bar being located in the recess, and wherein the body and the sleeve move relative to each other within a range limited by virtue of the bar moving within the recess.
Preferably, the downhole tool is according to the first aspect.
Preferably, the step of jet cleaning includes one or more of the following steps:
(a) jet cleaning a low pressure housing;
(b) jet cleaning a high pressure wellhead; and
(c) jet cleaning one or more downhole casing adapter profiles.
An embodiment of the invention will now be described, by way of example only, with reference to the following drawings of which:
a) is a cross-sectional view through a downhole tool according to an embodiment of the present invention with
a) to (e) show schematic illustrative diagrams of the operating positions of the tool of
Reference is initially made to
Tool 10 comprises a cylindrical body 12 of unitary construction having at an upper end 14, a conventional pin section 16 and at a lower end 18, a conventional box section 20 for connection of the tool in a work string (not shown). In the embodiment shown a saver sub 22 is attached to the pin section 16. This is optional and is generally used to protect the pin section 16 in mounting and demounting of the tool in the work string. Further the body 12 has a central bore 40 of uniform diameter, thus the body 12 can be easily manufactured from standard tubing with only machining required to be done on an outer surface 30 of the body 12. Body 12 includes twelve ports connecting an inner surface 28 of the body to the outer surface 30 of the body. The ports are arranged in two pairs 24, 26 of six ports. Each pair 24, 26 of ports is arranged equidistantly around the circumference of the body. A pair of opposed access ports, one of each pair being shown in
Located within the body 12 against the inner surface 2B are two sleeves 42, 44. Each sleeve 42, 44 comprises two cylindrical portions 46, 48 and 50, 52 (shown in
The inner cylindrical portions 46, 50 each have a conical entry port 86, 88 which funnels a drop ball towards the central bore 54,56 of the cylindrical portions 46,50. Conical exit ports 90, 92 are arranged are on the opposite end of the bores 54, 56 also. The diameter of the ports 86, 88, 90, 92 determines the size of drop ball which will seal the central bore 40 of the tool 10. Arranged in the wall 94, 96 of each of the inner cylindrical portions are three sets of six equidistantly spaced ports 98, 100, 102, 104, 106, 108. The ports are arranged at approximately 45 degrees to the central bore 54, 56. On the wall 94, 96 facing the body are two opposed slots 110, 112. The slots 110, 112 are arranged longitudinally and parallel with the central bore 54, 56. The slots 110, 112 provide a recess into which inner locking bars 36, 38 locate and define the movement of the bars 36, 38 with respect to the inner cylindrical portions 46, 50.
The inner cylindrical portions 46, 50 are held to the outer cylindrical portions 48, 52 by shear screws 114, 116. These same shear screws 114, 116 have a second shear face so that they additionally hold the outer cylindrical portions 48,52 to the body 12. Typically twelve shear screws are arranged circumferentially around the sleeves 42, 44. In this way the portions can be separated from each other at a lower force than that required to separate the sleeves from the body.
The arrangement of the locking bars 36, 38, 78, 80 is best seen with the aid of
Reference is now made to
In use, sleeves 42, 44 are located in the bore 40 and held in place by the locking bars 36, 38, 78, 80 and the shear screws 114, 116. The tool 10 is mounted on a work string using the pin section 16 and the box section 20. An optional saver sub 22 may be used with the tool 10. The tool can then be run in a casing or liner of a well bore. The raised portions 134 on the sleeve 118 will contact the casing or liner and stabilise the tool 10 in the well bore.
In this first position, illustrated in
Referring to
As the bar 80 moves in the slot 76, fluid is forced from the slot 76 through the escape port 124. The escaping fluid provides a hydraulic braking effect to the movement of the sleeve 44. By braking this movement, any shock created within the tool 10 is reduced and thus the remaining planes of the shear pins 114,116 are prevented from shearing prematurely.
On movement of the sleeve 44, as shown in
Referring to
As the bar 38 moves in the slot 112, fluid is forced from the slot 112 through the escape port 128 and the vent port 34. The escaping fluid provides a hydraulic braking effect to the movement of the inner portion 50. By braking this movement, any shock created within the tool 10 is reduced and thus the remaining planes of the shear pins 114 are prevented from shearing prematurely.
In this position, illustrated in
Movement of the inner portion 50 also causes misalignment of ports 68,104 to prevent any radial passage of fluid to the jets 150.
If a further jetting action is required a third drop ball 146 is released into the work string. This actuates sleeve 42 in an identical manner to sleeve 44 by virtue of the ball sticking in port 90. Ball 146 preferably has a diameter of 2½ inch. Jetting now occurs through ports 130 as shown by arrow D in
Similarly, when jetting is no longer required a fourth drop ball 148 is released into the work string to provide longitudinal passage of fluid through the work string again in an identical manner to the dropping of ball 144. Ball 148 preferably has a diameter of 2¾ inch and when actuated provides a tool 10 with a fluid flow through area of 6.28 square inches. This is illustrated in
A jetting and circulating tool as described hereinbefore, has a number of application areas as illustrated with the aid of
By circulating fluid through the ports, jet cleaning can be performed on the LP (low pressure housing) 216, the HP wellhead 218 and the downhole casing adapter profiles 220a,b,c. When the tool 200 is run in conjunction with a mud motor, used to shut down the bit at the shoe to minimise casing wear while pumping (to condition the mud and remove cuttings from the well bore 224. Additionally when the tool 200, is run in conjunction with a near bit reamer 222, it can be used to de-activate the reamer blades at the shoe and bypass the bit 226 with all mud pumped. Further it will be recognised that secondary recovery of the ‘drill ahead’ bore protector is achievable. Each of these operations can be selectively achieved on a single trip into the well bore.
Thus when the tool 200 is used in a drilling assembly, the tool is not actuated during the drilling operation, but acts as a stabiliser. On completion of drilling, the tool can be used to boost drill cuttings. Further as the tool is pulled out of the hole, cleaning can be performed without requiring a second trip into the well bore. By the angling of the jets, effective cleaning can be performed on the casing hangar areas on a high pressure tree system.
It will be appreciated that although the embodiment has been described as a jetting tool, the tool is more fully described as a stabiliser, jetting and circulating tool.
The principal advantage of the present invention is that it provides a tool in which movement of a sleeve is controlled within a well bore. A further advantage of an embodiment of the present invention is that it provides a tool in which hydraulic damping occurs to prevent premature shearing within the tool following a shock.
A yet further advantage to an embodiment of the present invention is that it provides a jetting tool having a dual or double action. Further this action does not limit the fluid flow through the tool after each jetting function occurs. Thus any number of actuable movements could be achieved within a tool, the limit being only on the minimum diameter of drop ball available.
A yet further advantage of the present invention is that it combines a number of functions on a single tool within a well bore. For example, it provides a large outer diameter jetting and circulating device that acts as a drilling stabiliser as well and can be activated by different means one or more times. Thus, specific areas within the well can be jetted at various times without retrieval of the string from the well. It can replace a conventional stabiliser used in a bottom hole assembly. Further, drilling can be performed with this tool mounted in the bottom hole assembly and the tool can be also used to pump mud while drilling. Alternatively, the tool can be used to jet clean the low pressure housing, the high pressure well head and downhole casing adapter profile, as it is more effective than using the bit and does not require an extra trip into the well. The tool can further be run in conjunction with a mud motor and can be used to shut down the bit at the shoe to minimise casing wear while pumping. It will also be appreciated that the tool may be run in conjunction with an under reamer and can be used to deactivate blades at a shoe. Thus it can be used in preference to dropping a dart.
It will be appreciated by those skilled in the art that various modifications may be made to the invention herein described without departing from the scope thereof. For example, while an embodiment of a jetting sub is illustrated the present invention could be applied to other circulation tools where selective access through a radial port is required within the well bore e.g. a cementing tool.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0302121.9 | Jan 2003 | GB | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/GB03/05714 | 12/30/2003 | WO | 00 | 1/19/2006 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2004/067908 | 8/12/2004 | WO | A |
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| Number | Date | Country | |
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| 20060124317 A1 | Jun 2006 | US |
