Patent Application
20230279736
The present invention relates to a plug assembly for the temporary blocking of fluid flow through a downhole tubular. More specifically it relates to the shape of a plug and other components of the glass assembly in said plug assembly.
During the drilling, testing, completion, fracking, production and abandonment stages of hydrocarbon wells there are many uses for plugs assemblies that create a fluid barrier in the well. Some of these uses are not permanent such as plug and abandonment, but rather temporary, where it is desired to re-establish fluid flow at a later stage. Some examples of such temporary uses of plugs are for flotation, well testing during completion, packer setting and fluid loss devices. Temporary plugs may thus be installed in any kind of piping installed downhole, for example casing, liner, or other tubing. The only difference between these is the inner diameter of the pipe.
When flow through the well is to be established, the plug is broken. This preferably done without spearing, milling, or other mechanical intervention from the surface. Ways to achieve the desired breaking is through the use of pressure, pressure pulses, or explosives. When the plug is removed it allows for a nonrestricted fluid flow past the opened plug assembly, and for many applications after opening of the plug assembly this is required in order to pass various tools past the plug assembly.
Plugs can be made of various materials, such as metal, stone, or composites, or more frangible materials such as glass or ceramics. Frangible materials are often preferred as they have the advantage of being relatively insensitive to pressure, temperature and chemical corrosion, yet by their frangible nature they are relatively easy to destroy when used as the fluid blocking part of plug assemblies. Particularly glass, e.g. hardened glass, can be made to break into very small pieces that will not pose a problem in most wells. Frangible materials are therefore well suited for opening the plug assembly by constructing the plug assembly with a breaker of small amounts of explosives that will crush or shatter a glass disc, and open the plug assembly, but not damage the production tubing or casing the plug assembly is installed in. Plugs can also be opened by applying direct force thereto with a breaker. The breaker will then make contact with the plug on a relatively small area. Frangible materials will typically shatter, and this property of breaking under a large point pressure load is taken advantage of by employing a breaker object with a relatively small impact area, such as a thin edge like a knife blade, a point such as a pin, or even a small ball.
A problem with many frangible materials is that they can prematurely break where they contact a hard surface such as a metal surface. This can happen when the plug is being installed or even when changes in pressure in the well causes minute movements of the glass assembly. One way to overcome this issue is to put a bearing ring of a soft material (e.g. plastics such as polyether ether ketone; PEEK) between the frangible plug and any hard surface (e.g. steel) it abuts. This allows the force on the plug to be transferred to the bearing ring instead. The bearing ring will then compress and prevent the plug from coming in contact with a hard surface.
The plug should be installed in such a way that it is well secured, and will not break easily from fluctuating well pressures (i.e. from direct pressure rather than from a breaker). The plug should also be secured in such a way that it forms a as fluid tight seal as the specifications of the specific application require until it is removed. Leakage of fluid between the plug tubular and the surrounding area, such as the annulus, should be prevented as far as possible.
Loose parts in the wellbore can cause a lot of damage to equipment and even obstruct the well bore. Thus, the plug should preferably break into fragments small enough to not be a potential problem in the well. The various other parts of the plug assembly should preferably be prevented from entering the wellbore when breaking the plug, so they or pieces thereof will not be a potential problem in the well. These other parts should also preferably be prevented from moving once the plug assembly is opened. There should not be a possibility of a partial opening of the plug, i.e. the system should preferably only allow for the plug to be fully intact or fully broken, not partially broken. If partially broken, it would not be possible to open fully with pressure from above since a partially open plug assembly could not be pressurized, so different means to open it fully would have to be used.
The inner diameter of the tubing the plug assembly is installed in should preferably be fully restored upon opening of the plug assembly, i.e. the plug assembly should not have a smaller inner diameter than the inner diameter below and above the plug assembly. This allows for a nonrestricted fluid flow past the opened plug assembly, as well as unrestricted passing of tools up to the inner diameter of the pipe the plug sits in.
It is an object of the present invention to provide a plug assembly comprising a plug that can hold pressure while being used for its purpose, and then be safely and completely opened after it has served its purpose. Once open, the plug assembly parts should stay in place, and said parts or pieces thereof should not enter the wellbore.
It is an object of the present invention to provide a plug assembly comprising a plug that has an improved sealing of said plug before it is opened. Another object of the present invention is to provide a plug that is less likely to be prematurely broken during assembly, insertion into the well, or by movement of the plug tubular in the pipe (e.g. from movement or pressure changes in the pipe or formation). This is achieved by the geometries of the plug and/or stabilizer and/or glass assembly.
By the plug not having sharp corners, but rather rounded edges, it is less likely for said rounded edges to be chipped off during assembly, or when the plug experience relative movement against the surrounding components, such as when the plug is inserted into the well, or the plug housing shifts with the formation, or when the pressure applied from up hole or downhole or the formation changes.
Usually there is no bearing ring or stabilizer between a plug surface parallel with the plug housing and said housing or sleeve or whatever component the plug is to seal against. By adding the stabilizer, it helps stabilizing and centralizing the plug in place. If made of a softer material, similar to the materials the bearing rings are made of, it also helps cushion the side of the plug against any sideways impacts, and gives it a little extra play for movement. Rig operators are often concerned that frangible plugs are exposed to impacts and vibrations both during transport and operation, and therefore it is usually required that the plug assembly must be able to withstand shock and vibrations. Adding a stabilizer helps fill this requirement.
Not being bound to a specific theory, possible reasons for the improved sealing of the seals when on a surface not parallel to the plug housing but rather sloped is that the seals will receive less force than when on a surface parallel to the plug housing, such as at a parallel side of the plug. Such nonparallel surfaces may be better supported by the plug and housing. Thus, the seals may experience less force trying to push them out of the way. The seals would also have to move further, so it would take more force, to move them when on the sloped walls than when on a parallel, straight up and down wall. The pressure on the seals results in less of a risk of extrusion of said seals (e.g. O-rings), as the gap will be closed by the forces applied by the pressure. This may then lead to the seals being able to take higher pressure and leak less. This effect would be especially advantageous when the seals are also pressed up against the stabilizer, in which case this holds them well in place. Thus, this allows for better force distribution and reduced deformation of both seals and bearing rings under different pressures and temperatures to increase protection of the plug and form a better seal. The combination of the seals and the stabilizer provide an improved effect for both as they can help hold each other in place.
When the various parts for the glass assembly are made, they will of course be made to specifications, but there will usually be some variation in their manufacturing tolerances. This can cause assembly to be difficult, and the final seal to be not optimal. For example, if the components of the glass assembly are made slightly larger than specified, the seal will be very tight and the assembly hard to get into place. Likewise, if too small, the seal achieved may not have quite enough pressure on it from the components and may leak. The height adjustor addresses these problems. By loosening it, insertion of the glass assembly into its place in the housing is easy. When the glass assembly is put in place, the height adjustor can be adjusted so it applies just the right amount of pressure on the glass assembly, not too much pressure which could ultimately crack the plug or damage other components, and not too little pressure so the seal would be too loose and could leak, but just right to form a proper seal
In some aspects, the techniques described herein relate to a glass assembly including: a plug with an edge surface, the edge surface including a top edge surface, middle edge surface, and a bottom edge surface; wherein the middle edge surface contains the widest portion of the plug; and wherein the middle edge surface is curved.
In some aspects, the techniques described herein relate to a glass assembly, wherein the top edge surface or the bottom edge surface is a straight surface.
In some aspects, the techniques described herein relate to a glass assembly, wherein both the top edge surface and the bottom edge surface is a straight surface.
In some aspects, the techniques described herein relate to a glass assembly including: a plug with an edge surface, the edge surface including a top edge surface, middle edge surface, and a bottom edge surface; wherein the middle edge surface contains the widest portion of the plug; and wherein a stabilizer is arranged in contact with the middle edge surface.
In some aspects, the techniques described herein relate to a glass assembly, further including a sealing element in contact with the plug surface.
In some aspects, the techniques described herein relate to a glass assembly, further including a bearing ring in contact with the plug surface.
In some aspects, the techniques described herein relate to a glass assembly, further including a bearing ring and a sealing element, both in contact with the plug surface, wherein the sealing element is arranged between the bearing ring and the stabilizer.
In some aspects, the techniques described herein relate to a glass assembly, further including a first bearing ring, a second bearing ring, a first sealing element, and a second sealing element, all in contact with the plug surface, wherein: the first sealing element is arranged between the first bearing ring and the stabilizer; and the second sealing element is arranged between the second bearing ring and the stabilizer.
In some aspects, the techniques described herein relate to a glass assembly, wherein the middle edge surface is curved.
In some aspects, the techniques described herein relate to a glass assembly wherein the middle edge surface is curved.
In some aspects, the techniques described herein relate to a plug assembly including: a glass assembly, arranged in a housing the glass assembly including a plug with an edge surface, the edge surface including a top edge surface, middle edge surface, and a bottom edge surface; a seat arranged to support the plug; a breaker object configured to break the plug and wherein the middle edge surface contains the widest portion of the plug; and wherein a stabilizer is arranged in contact with the middle edge surface.
In some aspects, the techniques described herein relate to a plug assembly, wherein the middle edge surface is curved.
In some aspects, the techniques described herein relate to a plug assembly, wherein the stabilizer is not fluid tight.
In some aspects, the techniques described herein relate to a plug assembly, wherein glass assembly further includes a first bearing ring, a second bearing ring, a first sealing element, and a second sealing element, all in contact with the plug surface, wherein: the first sealing element is arranged between the first bearing ring and the stabilizer; and the second sealing element is arranged between the second bearing ring and the stabilizer.
In some aspects, the techniques described herein relate to a plug assembly wherein the seat 20 is arranged to move in axial direction toward the breaker object 30 when a threshold absolute pressure or threshold differential pressure is reached.
In some aspects, the techniques described herein relate to a plug assembly, further including a shear ring, the shear ring including a shear ring lip wherein the seat is supported by the shear ring lip; the end of the seat opposite of the glass assembly extends past the top of shear ring lip on the side toward the glass assembly.
In some aspects, the techniques described herein relate to a plug assembly, further including a breaker holder, wherein the breaker holder is configured to hold the breaker object fixed in place, and there is a seat pocket between the seat and the breaker assembly, where in the at least a portion of the seat enters a seat pocket, wherein: seat is in contact with the breaker object.
In some aspects, the techniques described herein relate to a plug assembly, further including a shear ring, the shear ring including a shear ring lip, wherein the seat is supported by the shear ring lip.
In some aspects, the techniques described herein relate to a plug assembly, further including a sealing area, wherein the sealing area is the region of the housing and seat in contact with the first sealing element and the second sealing element; and wherein, the sealing area is non-parallel with the axial axis of the plug assembly.
In some aspects, the techniques described herein relate to a plug assembly, further including a shear ring, the shear ring including a shear ring lip wherein the seat is supported by the shear ring lip; the end of the seat opposite of the glass assembly extends past the top of shear ring lip on the side toward the glass assembly.
The above and further features of the invention are a set forth with particularity in the appended claims and advantages thereof will become clearer from consideration of the following detailed description. Embodiments of the present invention will now be described, by way of example only, with reference to the following diagrams wherein:
10
11
12
13
14
15
60
61
62
63
64
65
66
20
21
22
23
24
30
31
32
40
41
42
50
51
100
110
120
130
140
200
Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying figures. Alternative embodiments will also be presented. The figures are intended to be read in conjunction with both the summary, the detailed description, and any preferred and/or particular embodiments, specifically discussed or otherwise disclosed. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided by way of illustration only. Several further embodiments, or combinations of the presented embodiments, will be within the scope of one skilled in the art.
As described, there are various ways to open plugs. In the examples given below, the plugs are opened applying pressure, which brings a breaker object 30 into contact with the plug 10, causing it to break. The breaker object 30 does not have to be operated in this manner. Instead applied pressure or a different kind of signal such as that provided by a control line could cause the breaker object 30 to be brought into contact with the plug 10, or it could cause the breaker object 30 to explode, and this explosion could break the plug 10. In some cases the seat 20 will not necessarily move in an axial direction, or move at all. Alternatively, the plug 10 may be designed to be broken by milling it open. The plug 10 could then be arranged in a glass assembly 15, and said glass assembly 15 could be directly secured in the housing 140.
Plugs that can be opened using pressure, operate upon the principle of a plug 10 arranged in a housing 140 of a plug tubular 100. The plug 10 is part of a glass assembly 15 which prevents fluid connection between the upper tubular 110 on the upstream side of the plug and the lower tubular 120 on the downstream side of the plug. A glass assembly 15 comprises the plug 10 and is arranged on a seat 20 for support. Pressure is applied to one side of the plug (normally from the upstream side). At a predetermined absolute pressure, or a predetermined differential pressure, the seat 20 moves in an axial manner until the plug 10 makes contact with a breaker object 30. Upon contact, the plug will disintegrate, and flow through the tubular 100 is restored. The sealing area 13 is the area or areas where it is fluid tight between the plug 10 and the tubular body 130 and/or the plug 10 and the seat 20. Please note that although the examples below refer to a plug 10 opened by applying pressure from above, e.g. a so-called pump open type plug, it is also possible to open the plug 10 with by applying pressure from below, e.g. a so-called surge open type plug. Also note that the plug assembly 200 can be used in a casing, a liner, a tubing, or any other metal pipes used downhole, with any outer and inner diameters.
One important feature for this invention is the curved outermost edge of the plug 10 and details of the sloped or perpendicular sealing area 13.
The plug tubular 100 comprises a plug assembly 200 arranged in a housing 140 in a tubular body 130. The tubular body 130 comprises an upper tubular 110 on the upstream side of the plug 10 and a lower tubular 120 on the downstream side of the plug 10. The plug assembly 200 comprises a glass assembly 15, a seat 20, a breaker assembly 32, and a shear ring 50.
The glass assembly 15 comprises a plug 10, a sealing element 11, a stabilizer 12 and a bearing ring 14. The sealing element 11 prevents fluid from traveling around the plug 10. In the example shown, this is found between the plug 10 and the housing 140 on one side and the plug 10 and the seat 20 on the other side. A bearing ring 14 is arranged between the plug 10 and the housing 140 one side and the plug 10 and the seat 20 on the other side. A common example of a sealing element 11 is an O-ring. Note that while glass assembly 15 is called a “glass assembly” it refers to the plug 10 (regardless of material, including non-glass materials).
The sealing area 13 is the area on the housing 140 and seat 20 that is in contact with the sealing element 11. It is this area which accounts for the plug 10 being fluid tight. The sealing element 11 could be arranged on the outside of the plug 10, in a groove in the plug 10, or a groove in the housing 140 and/or seat 20. As will be disclosed below, it is also possible for other elements to be fluid tight as well. Those elements will further contribute to the sealing area 13, but the often the main seal is formed by the sealing element 11. The sealing area 13 does not include the areas in which a fluid tight seal is not provided.
The stabilizer 12 helps to hold the plug 10 in place during operation. Depending upon the exact configuration, it may be possible for the plug 10 to twist in the housing 140 without it. Also, similar to the bearing ring 14 (discussed shortly) it can keep the edge of the plug 10 from making contact with any hard metal surface. The stabilizer 12 shown in all of the figures is curved to match the curved shape of the middle surface of the plug 10. The stabilizer 12 could also be called a middle bearing ring due to its position in between the two “outer” bearing rings 14.
While it is possible for the bearing rings 14 and/or stabilizer 12 to seal somewhat against fluid, and thus be included in the sealing area 13, it is preferable that the stabilizer 12 is not fluid tight. For installation, by cutting slits or separations in the stabilizer 12, it will make it easier (or perhaps even possible depending on the exact geometries) to install. If the stabilizer 12 is such a cut ring, the two ends of the cut can be made to overlap to make the diameter of the stabilizer 12 smaller so that it can be easily inserted. Depending upon the material and/or geometries, this may be necessary. Slits will render the stabilizer 12 non-fluid tight and completely ineffective as a sealing component. Additionally, another reason for not requiring that it be fluid tight is that a wider choice of materials is then available.
The main purpose of the bearing ring 14 is to help reduce the possibility of contact between the plug 10 and hard metal surfaces (e.g. the housing 140 and the seat 20). At higher pressures, a contact between a hard metal surface and the plug 10 could result in a premature breaking. Common materials for bearing rings 14 are soft enough to provide cushioning between the plug 10 and adjacent hard components, such as the seat 20 or housing 140, thus preventing premature breaking of the plug. An example of such materials are soft metals, rubber or plastics, preferably PEEK.
Materials for a stabilizer 12 also include the same soft materials as are used for bearing rings 14, but hard materials such as those used for the other plug assembly components may be used, such as steel or glass.
If needed, the sealing element 11 can be held in place by a stabilizer 12 and/or a bearing ring 14. A stabilizer 12 prevents the sealing element 11 from being pressed toward the outside of the plug 10, and a bearing ring 14 can help hold the sealing element 11 from being pressed toward the inside of the plug when under operation.
A breaker assembly 32 is an element that contains and supports the breaker object 30. A breaker object 30 is arranged to break the plug 10 when they make contact. In the example shown, the breaker object 30 is held in a breaker holder 31. It is also possible for the breaker object 30 to be directly affixed to the housing 140.
The glass assembly 15 is supported by the seat 20. The plug 10 will be directly or indirectly supported by the topmost portion of the seat 20, the seat surface 21. When the seat 20 moves in an axial direction, the plug 10 will move with it. In the example shown, the seat 20 has a breaker pocket 22 that is arranged such that the breaker object 30 pass through the seat 20. The seat 20 has a seat lip 23. This is a protrusion that extends past the shear ring lip 51 of the shear ring 50. Because the seat 20 extends at least a portion past the edge of the shear ring lip 51, the shear ring lip 51 is held in place when plug assembly 200 has completed its operation.
Beneath the seat 20 is the seat pocket 24. The seat pocket 24 is a space that can receive the seat 20 when it moves in an axial direction under operation.
A shear ring 50 is arranged such that it supports the seat 20 on its shear ring lip 51. When the proper threshold pressure (absolute or differential) is reached, the shear ring will break into two different pieces. One portion will remain stationary, and the shear ring lip 51 will travel axially. Note that instead of a shear ring, shear pins, or other such elements could be used. Note that the shear ring 50 can have different shapes. That of
Depending upon operating conditions and material composition concerns, it may be possible for the glass assembly 15 to include a plug 10 and a single sealing element 11, or a plug 10 and a stabilizer 12.
It is possible that the stabilizer 12 is made up of more than one separate piece. For example, this could be due to the physical dimensions of the system or the shape of the plug 10 or housing 140 or seat 20. It could also make installation simpler. As shown in the previous figures, the bearing ring 14 and the stabilizer 12 help to hold each of the sealing elements 11 in place.
Also shown is the arrangement where the seat lip 23 is held in place by the shear ring lip 51 to prevent the shear ring lip 51 from entering the wellbore.
The preferred angle of the chamfers is between 1 and 45 degrees, preferably 25 to 45 degrees, measured from the centerline. 90 degrees (perpendicular to the centerline) is also a good alternative. The radius of curvature of the rounded outer edge is preferably between 1 mm and 10 mm. The angle on the overside and underside of the plug does not need to be the same.
While the tubular body 130 in the figures is shown as comprising an upper tubular 110 and a lower tubular 120, it could also be made of a single continuous piece.
In
The plugs 10 shown in
Under higher pressures, these areas can become susceptible to premature breakage. However, the plug 10 in
The degree of fluid tightness is largely determined by the number and placement of sealing elements 11. For example, there could be the same number of stabilizers 12 as plugs 10, to avoid twisting, and two sealing elements 11 for each plug 10. For another example, if there are multiple plugs, rather than have one or two sealing elements 11 and one stabilizer 12 per plug, it is possible that there is only a sealing element 11 in contact with the uppermost plug 10 (as refenced to uphole) and another sealing element 11 in contact with the downhole most plug 10. The bearing ring could be in contact with the edges of all of the plugs 10, or only in contact with less than all of the plugs 10. This can be accomplished using a single stabilizer 12 or several stabilizers 12.
The sealing area 13 in the case of multiple plugs 10 or multiple layers of material in the plug 10, is determined in the same way as for a single plug of a single layer (i.e. the regions of the plug 10 that are fluid tight as determined by the sealing element 11 and other possible contributors).
Thus, a plug assembly 200 has at least three different positions, depending upon the status of the plug’s integrity and its position. In the first position, the seat 20 is stationary with respect to the tubular body 130 and the plug is intact. After the pressure threshold requirements are met, the plug assembly 200 transitions from the first position to the second position. In the second position, the seat 20 has moved axially until the plug 10 is in contact with the breaker object 30. The third position is when the plug 10 is destroyed and fluid connection is reestablished through the tubular 100. Note that the tubular 100 is in the same position as the plug assembly 200 that it houses. The plug 10 is arranged in the glass assembly 15. The sealing area 13 (not shown) would be where each sealing element 11 makes contact with the housing 140 (not shown) and/or the seat 20 (not shown).
In the disclosed example, the height adjuster 40 comprises an adjustment seat 41 and a mechanical adjuster 42. By adjusting the mechanical adjuster 42 (e.g. a nut or spring), the distance of the height adjuster 40 from the plug 10 is changed. In this example, the adjustment of the mechanical adjuster 42 moves the adjustment seat 41.
An example of a glass assembly 15 is disclosed comprising a plug 10 (the example shown is the same as in
In an example, the height adjuster 40 can have threads on the outside which match threads in the housing 140 or tubular body 130. By turning the height adjuster 40, the gap between the adjustment seat 41 and the plug 10 would be adjusted. The threads do not need to run along the entire body of the height adjuster 40. They can for example run only on the upper portion (towards uphole) of the height adjustor, while the lower portion (towards the plug) has no threads against the housing but rather a seal against the housing. In this way the height adjuster 40 is a single piece, there is no separate mechanical adjuster 42. This is a preferred example of the height adjuster 40, as only one component is needed.
Thus, the height adjuster 40 is not limited to the example shown in
The top edge surface 63 and bottom edge surface 65 are in reference to the middle edge surface 64. The middle edge surface 64 will be the edge surface 66 that contains the widest portion of the plug 10. In
However, in examples of the plug 10 in
In the examples of
While the examples of
Please note that “step of” is not to be interpreted as “step for”. By “comprised of”, “comprising”, “comprises” etc. we are referring to an open set and by “consisting of” we are referring to a closed set.
Modifications to the embodiments previously described are possible without departing from the scope of the invention as defined by the accompanying claims. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit the subject matter claimed. Reference to the singular is also to be construed as relating to the plural unless expressly stated otherwise. Any reference numbers in the claims are provided as a courtesy and are not to be interpreted as limiting the claim in any way.
