Destruction mechanism for a dissolvable sealing device

A sealing device relates to a plug that includes a crusher mechanism, where the sealing device includes one or more glass layers positionable in a wellbore. The glass in a barrier phase bears against at least one seat or support sleeve arranged axially displaceably in the wellbore, where the at least one seat or support sleeve bears against the glass by means of a supporting hydraulic fluid in a pressure support chamber, the seat or support sleeve being configured to be released, be displaced axially, and to crush the glass when the supporting hydraulic fluid is released from the pressure support chamber.

The present disclosure relates to a crusher mechanism for a sealing device. The present disclosure incorporates the entire disclosure of PCT Application Publication No. WO 2016/195508 A1 for all purposes, including specifically the entire disclosure relating to the disclosed embodiments of the destruction mechanism and sealing device.

BACKGROUND

Such sealing devices may be dissolvable and may be used, for example, for pressure testing, where they also will function as barriers to the reservoir, in zone isolation or in borehole workover.

It is known to use plugs of a dissolvable material, such as glass, ceramic, salt, etc., where the plug may be removed or crushed after use in such a way as to leave behind very few remnants or fragments. Such plugs of a dissolvable material, if correctly configured, are removable with or without explosives in a predictable and safe manner.

Plugs comprising one or more glass layers stacked upon or above one another maybe removed without the use of explosives by utilizing techniques that include percussion tools, spikes that are thrust into the dissolvable material, balls or other articles that serve to create tensions in the dissolvable material, or puncturing of the layer disposed between the two or more glass layers (if plugs comprise more than one glass layer), where the volume contains a film or a sheet of a material other than glass.

This layer between the two or more glass layers, comprising a firm and/or a sheet of a material other than glass, may comprise a fluid, a plastic material, a rubber material, a felt material, a paper material, glue, grease, etc. The layer may be substantially solid or entirely or partially deformable/liquid. The volume between the glass layers, which may be provided with at least one of the aforementioned materials, will enable the plug to attain the desired strength and toughness during use by providing for the uptake of loads exerted on the plug in the form of a differential pressure between the under- and upper side of the plug. This may involve accommodation of loads in the form of load transfer, load distribution, or limitation of bulging as a result of frictional forces between two or more layers of glass or other suitable dissolvable or crushable materials.

If there is one glass layer, the plug during use must attain the desired strength and toughness through provision for the uptake of loads exerted on the plug in the form of a differential pressure between the under- and upper side of the one glass layer. This means that the one glass layer must be capable of receiving the entire load, both from above and below if required, on full load accommodation.

NO321976, filed on 21 Nov. 2003, describes a glass plug comprising a plurality of layers or stratiform glass discs between which are provided layers of a material other than glass. NO321976 is the very first patent publication that describes a layered glass plug. NO321976 explains why there should be provided strata or layers, as disclosed above, between the glass discs of a material other than glass, and is included in its entirely in this document.

NO325431, filed on 23 Mar. 2006, relates to an apparatus and method for crushing a dissolvable sealing device of the aforementioned type. NO325431 employs a relief chamber and an adjustable connecting means forming a fluid communication channel between the layer, the liquid film or the volume between the glass discs and relief chamber when the adjustable connecting means is set in an open position. When the adjustable connecting means is set in an open position, the content between the glass discs is «punctured» and evacuated, and the load on (one or more of) the glass layers exceeds what they are designed to tolerate, which causes them to rupture. In addition, the apparatus according to NO325431 comprises a plurality of pin devices which are arranged to apply point load stresses on the glass layers when the connecting means is readjusted, with the pin bodies additionally serving to ensure that the glass layers rupture in a safe manner when the connecting means is reset. Thus, the intended function of NO325431 is to provide for rupture of the plug through resetting of the connecting means to an open position so that the space between the glass layers is punctured and the pressure drops drastically and quickly. The pressure support function will thereby disappear, and the glass the glass layers will be bent until they rupture and disintegrate, one by one. In addition, NO325431 discloses the possibility of arranging pins around the glass layers, where the pins are designed to produce point load stresses in the glass to weaken the strength of the glass layers. The way the pins' function is disclosed in NO325431, the pins have either a «passive» function, i.e., they are stationary and come into contact with the glass layers when these are bent or after the adjustable connecting means has been activated, or the pins are «actively» activated by means of the adjustable connecting means when it is activated, i.e., the pins are pushed against the glass layers and thereby produce point load stresses. In both cases, the point load stresses by the pins are produced as a causal effect of activation of the adjustable connecting means, since it is a precondition for the disclosed function of the plug that the space between the glass layers is punctured and the pressure falls drastically and quickly, with the glass layers thereby being bent and thus point loaded or, alternatively, that the sum of the tensions produced in the glass layers when the space between the glass layers is punctured/evacuated and the pins are pressed into the glass layers exceeds the level of tolerance of the glass layers so that they rupture. Thus, the pins do not function alone; they are dependent on the condition that the content between the glass layers is evacuated.

NO331150 discloses a crushable plug, for example of glass, which comprises a plurality of pin devices (spikes, claws, tips, points, compression ring) which are actuated to press radially into a glass layer so that it ruptures, said glass layer comprising pre-formed weakened points/areas that facilitate the crushing when the pin devices are pressed in against the plug. It is further disclosed in NO331150 that the weakened areas are formed by virtue of microfractures in the glass, such as those caused by honing. If one examines FIG. 3 in NO331150, one sees disclosed fractures that spread inwardly in the glass from the points of the pin devices. This type of fracture formation is what is assumed to have occurred when glass plugs of this kind are crushed. Since the glass layers are pulverized by crushing, it has thus not been evident how these glass layers were crushed. NO331150 shows a plug comprising one single glass layer. Although the description does not rule this out, NO331150 shows no embodiment comprising several glass layers. NO331150 therefore provides no teaching as to how the disclosed solution could potentially be adapted to a plug comprising more than one glass layer.

The present disclosure relates to a crushable or dissolvable plug comprising one or more glass layers, optionally other suitable materials, where the plug is removed without the use of explosives, with the disclosure providing a crusher mechanism that is predictable, safe and easier to utilize.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

FIG. 1shows an embodiment of a sealing device1, for example a plug, having a crusher mechanism comprising several glass layers2, where one or more spikes3either bear, entirely or partially, against one or more sides of glasses2, or are mounted at a distance from glass2. The sealing device1may be dissolvable in that the glass is a dissolvable material. The embodiment inFIG. 1shows that the spike or spikes are mounted at a distance from glass2.

According to the embodiment shown inFIG. 1, the glasses2are supported by a support sleeve4. Support sleeve4is arranged to be displaceable in an axial direction if there is a pressure support fluid6in a pressure support chamber12. Pressure support chamber12is in communication with a relief chamber9for pressure support fluid6. In the barrier phase for plug1, pressure support fluid6will prevent the displacement of sleeve member4in an axial direction (toward the right inFIG. 1) as long as a valve8is closed. When valve8is opened, i.e., in a crushing phase, pressure support fluid6is released into relief chamber9, and support sleeve4will be displaced in an axial direction (toward the right inFIG. 1) in such a way that the glasses are moved together with support sleeve4until the spike or spikes3strike and crush the glasses2.

The spike or spikes3may be mounted in a separate sleeve member5, which optionally may also be axially displaceable (toward the left inFIG. 1), but does not have to be. A potential advantage of having both support sleeve4and sleeve member5be displaceably mounted can be that the net acceleration between glasses2and spike or spikes3increases (i.e, they strike each other faster and harder), so that glasses2are crushed more predictably. Such an embodiment can thereby also enable the system to be constructed smaller, which conserves space.

It is understood that a further alternative embodiment may be that support sleeve4stays in fixed position and that only sleeve member5, with spikes3mounted thereon, is axially displaced toward the left when pressure support fluid6is released from pressure support chamber12.

Valve8may be mounted such that it is in communication with the upper side of the well tubing11(in contrast to the reservoir side21). The valve is arranged such that when the pressure from the upper side11exceeds a certain level, then valve8opens for communication between pressure support chamber12and relief chamber9through channels7and13. Valve8may also be controlled by other means, e.g., by pressure cycles, telemetry, or a signal of some kind.

FIG. 2shows another embodiment of a sealing device where the sealing device has only one glass.

The sealing device includes plug2and various parts of the crusher mechanism comprise the sealing means in the form of O-rings and other relevant packings that are necessary in order for plug2to retain its seal during the barrier phase, at the same time as the crusher mechanism shall function as intended both during the barrier and the crusher phases (e.g., pressure support fluid6must under no circumstances be allowed to escape or leak out during the barrier phase).

FIG. 3shows an alternative embodiment of the sealing device, that includes a plug. Here the spike or spikes3are diagonally mounted loosely at the glass (or glasses)2, while a ball14functions as a power transmission means around a turn so that when an axial pin15is displaced (toward the right inFIG. 3), then spike3will move diagonally into glass2.

This embodiment does not include a pressure support chamber, but instead comprises a chamber18having essentially a low or atmospheric pressure. Chamber18may contain air or another suitable gas.

An axially displaceable sleeve member16(displaceable toward the right inFIG. 3) is mounted in such a way that it, firstly, closes off a plurality of perforations18opening radially in toward the wellbore and, secondly, is in communication with a valve or release organ22. In the barrier phase, valve or release organ22can serve to close off either a pressure chamber (not shown) containing a fluid under high pressure (substantially higher than the pressure in chamber18), or a channel opening in toward the wellbore. In the crushing phase, valve17is opened so that sleeve16is displaced sufficiently far to uncover the perforations20opening radially in toward the wellbore, as the pressure in the wellbore is then let in at the upper side of sleeve16, and exerts a pressure against the annulus19. Sleeve member16will thereby be displaced with great force against pin(s)15, which via balls14causes spikes3to be driven into glass2, which is thereby crushed.

FIG. 4corresponds to the embodiment shown inFIG. 3after the glass has been crushed.

Alternatively, valve or release organ22may comprise a spring member (not shown) which is held in restraint, whereby, upon being released, it shoves sleeve member16sufficiently far to uncover the perforations18opening radially in toward the wellbore.

Valve or release organ22may be controlled by, e.g., pressure cycles, telemetry, or a signal of some kind. A so-called ticker device may be an example of an organ which is triggered by means of pressure cycles.

Various aspects pertaining to the present disclosure, where some have already been mentioned above, are disclosed in the following:

According to one embodiment of the present disclosure, glass2in a barrier phase bears against at least one seat or support sleeve4arranged axially displaceably in the wellbore, where the at least one seat or support sleeve4bears against glass2by means of a supporting hydraulic fluid6found in a pressure support chamber12, the seat or support sleeve4being arranged to be released, displaced axially, and to crush the glass2when the supporting hydraulic fluid6is released from its pressure support chamber12.

The supporting hydraulic fluid may be locked in chamber12by means of a valve, bursting disc, shear pin, interchangeable part or a similar releasable mechanism8. Other releasable mechanisms might also be contemplated.

Releasable mechanism8may also be triggered by means of a desired number of well pressure cycles from the well or by means of another signal. The releasable mechanism8maybe, for example, a ticker device.

In the crushing phase, releasable mechanism8permits supporting hydraulic fluid to flow out into one or more relief chambers9. The pressure in the one or more relief chambers should, in that event, be lower than the pressure in the pressure support chamber, in which case the pressure in the one or more relief chambers9may be approximately atmospheric, but does not have to be. Releasable mechanism8, e.g., a valve, may be mounted in such a way that after releasing the supporting pressure fluid, if this results in displacement of sleeve member5toward the left past channel7, it opens through channel10and toward the well pressure in wellbore11. In that event, sleeve member5will be subjected to strong pressure against annulus19, whereupon the movement of the sleeve member is accelerated substantially and will strike the spike or spikes3with a powerful (more powerful) force.

According to another embodiment of the crusher mechanism, where glass2in a barrier phase also bears against at least one seat or support sleeve4, the glass is crushed by the second sleeve member (16) being displaced when it is released.

It shall be understood that the phrase “the glass” is intended to denote one or more glass elements.

Between the at least one seat or support sleeve4and the second sleeve member16, there may be arranged a fluid-filled chamber18having a lower pressure than the well pressure.

Alternatively, between the at least one seat or support sleeve4and the second sleeve member16, there may be arranged a fluid-filled chamber18having a higher pressure than the well pressure.

The at least one seat or support sleeve4may be fixedly mounted in relation to the wellbore, but does not have to be. If there is a supporting hydraulic fluid6in chamber18, then the seat or support sleeve4will remain stationary against the glass in the barrier phase. The fluid-filled chamber18may have a substantially lower pressure than the well pressure. Chamber18may contain air or another suitable gas.

Sleeve member5;16may be arranged such that, in the barrier phase, it covers over a plurality of perforations20opening radially in toward the wellbore. In this case, sleeve member5;16in the crushing phase may be arranged such that it uncovers a plurality of perforations20opening radially in toward the wellbore when sleeve member5;16is displaced, thereby producing an additional powerful push against the annulus19of the sleeve, which causes the crusher device to strike more forcefully against the glass.

Also, in this and other embodiments the releasable mechanism may be triggered by means of a desired number of well pressure cycles from the well or another signal. The releasable mechanism8may be a so-called ticker device.

The releasable mechanism8can, in the crushing phase, cause the supporting hydraulic fluid to flow out into one or more relief chambers9. This embodiment is not shown per se, but it shares features that are shown inFIGS. 1-2 and 3-4, respectively. In this case the pressure in the one or more relief chambers9may be lower than in the fluid-filled chamber18, for example but not necessarily—approximately atmospheric.

Also, in this or other embodiments the crusher device may comprises spike means3which may include one or more of the group: spikes, pins, pegs, knives and annular casings.

It shall be understood that the various spike means may be tangentially, radially, diagonally and/or longitudinally mounted, or combinations of these. The annular casings may be formed with sharp edges or the like, but they do not have to be, since a hard blow against the glass can in itself be sufficient to crush the glass securely.

FIGS. 3 and 4show that the releasable mechanism17may be positioned behind the second sleeve member16, such that releasable mechanism17serves to push against an annulus19on second sleeve member16in the crushing phase.

Alternatively, the releasable mechanism17may be arranged in communication with the fluid-filled chamber18such that sleeve member5;16in the crushing phase is displaced by being drawn by a negative pressure when releasable mechanism17permits fluid6to flow out from chamber18into the one or more relief chambers9. Such an embodiment is basically shown inFIGS. 1and2, but it requires that the seat or support sleeve4remains stationary or is displaced substantially more slowly than sleeve member5and that the spike or spikes have a sufficient stroke length to strike the glass with sufficient force and security.