Plug

Abstract

An improved plug for sealing a tubular as described. The improved plug comprises a plug body, the plug body comprising a propellant and an initiator adapted to initiate the propellant upon a signal. Upon initiation the propellant deflagrates causing the plug body to at least partially disintegrate.

Claims

1. An improved plug for sealing a tubular; the improved plug comprising: a plug body, the plug body comprising a propellant and at least one other material; and an initiator adapted to initiate the propellant upon a signal; wherein upon initiation the propellant deflagrates causing only the propellant to at least partially disintegrate, disintegration of the propellant causing the plug body to at least partially collapse.

2. The plug of claim 1, wherein the plug body fully comprises the propellant.

3. The plug of claim 1, wherein the plug further comprises a housing, the housing adapted to receive the plug body.

4. The plug of claim 3, wherein the housing is adapted to engage, in use, a tubular wall.

5. The plug of claim 1, wherein the plug further comprises one or more sensors.

6. The plug of claim 5, wherein the plug further comprises a transmitter adapted to transmit information from location to the surface.

7. An improved plug for sealing a tubular; the improved plug comprising: a plug body, the plug body comprising a consumable and at least one other material; and an initiator adapted upon a signal to expose the consumable to a condition in which the consumable will be consumed causing only the consumable to disintegrate, disintegration of the consumable causing the plug body to at least partially collapse.

8. An improved tool for sealing a tubular; the improved tool comprising: a tool body, the tool body comprising a consumable and at least one other material; and an initiator adapted upon a signal to expose the consumable to a condition in which only the consumable will be consumed, causing the consumable to at least partially disintegrate, disintegration of the consumable causing the plug body to at least partially collapse.

9. An improved tool for use downhole; the improved tool comprising: a tool body, the tool body comprising a propellant, and at least one other material; and an initiator adapted to initiate the propellant upon a signal; wherein upon initiation the propellant deflagrates causing only the propellant to at least partially disintegrate disintegration of the propellant causing the tool body to at least partially collapse.

10. The tool of claim 9, wherein the tool further comprises one or more sensors.

11. The tool of claim 10, wherein the tool further comprises a transmitter, transmitter being adapted to transmit information from the sensors to a remote location such as surface.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Embodiments of the present invention will now be described with reference to the accompanying drawings in which:

(2) FIG. 1 is a schematic of a plug shown fitted in an oil well tubular prior to ignition according to a first embodiment of the present invention;

(3) FIG. 2 is a schematic showing the plug of FIG. 1 after ignition;

(4) FIG. 3 is schematic of the plug of FIG. 1;

(5) FIG. 4 is a schematic of a plug according to a second embodiment of the present invention;

(6) FIG. 5 a schematic of a plug according to a third embodiment of the present invention;

(7) FIG. 6 is a schematic of a plug according to a fourth embodiment of the present invention shown fitted in an open hole prior to ignition;

(8) FIG. 7 is a schematic showing the plug of FIG. 6 after ignition;

(9) FIG. 8 is a schematic of a tool according to a fifth embodiment of the present invention shown fitted in oil well;

(10) FIG. 9 is a schematic showing the plug of FIG. 8 after ignition.

(11) FIG. 10 is a schematic perspective view showing a plug according to a sixth embodiment of the present invention;

(12) FIG. 11 is a schematic perspective view showing a plug according to a seventh embodiment of the present invention;

(13) FIG. 12 is a schematic perspective view showing a plug according to a eighth embodiment of the present invention; and

(14) FIG. 13 is a schematic perspective view showing a plug according to a ninth embodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

(15) Reference is first made to FIG. 1, a schematic of a plug, generally indicated by reference numeral 10, shown fitted in a well tubular 12 according to a first embodiment of the present invention.

(16) The tubular 12 is located within a cased portion 14 of wellbore 16. The annulus 18 between the well tubular 12 and the wellbore cased portion 14 is sealed by a packer 20.

(17) The plug 10 seals the well tubular 12 from downhole pressure.

(18) The plug 10 can be seen in more detail on FIG. 3, a schematic of the plug 10 of FIG. 1. The plug 10 comprises a plug body 22 made of a block of propellant 28, particularly potassium perchlorate, an initiator 24 and a plug housing 26.

(19) Activation of the initiator 24 by a signal from surface results in the propellant block 28 burning away leaving only the housing 26 in the well tubular 12, as shown in FIG. 2.

(20) In alternative embodiments the plug body 22 could be made of a foam matrix permitting the plug 10 to be lowered in to the wellbore cased portion 14 passed a restriction (not shown). Once in position, a propellant could activate the foam such that the plug housing 26 is pushed outwards into engagement with the wellbore cased portion 14.

(21) An alternative plug 110, according to a second embodiment of the present invention is shown in FIG. 4. This plug 110 has a body 122 comprising a propellant block 128 surrounded by composite 130 of compressed gravel or glass in a propellant matrix. In this case the propellant block 128 supports the composite 130 and ignition of the propellant block 128 causes the propellant block 128 and the propellant matrix to burn away resulting in collapse of the composite 130.

(22) An alternative plug 210 according to a third embodiment of the present invention is shown in FIG. 5. Again this plug 210 comprises an initiator 224 a propellant block 228 and a collapsible matrix 230. Referring to FIG. 5B, an end view of the plug 210 it can be seen that the collapsible matrix 230 is a series of metallic segments 232 contained within a rubber sleeve 234. The segments 232 are keyed together by the propellant block 228. Once the initiator 224 triggers the propellant block 228, the block 228 will burn away and the metal segments 232 and the remainder of the plug 210 can fall apart.

(23) FIG. 6 shows a schematic of a plug 310 according to a fourth embodiment of the present invention. The primary difference of this plug 310 is that it is intended for setting in a cased wellbore 314 rather than a wellbore tubular. The plug 310 incorporates rubber sealing pads 336 adapted to form a sealing engagement with the cased wellbore 314.

(24) Again, the plug body 322 comprises a block of propellant 328 which burns away as shown in FIG. 7 upon initiation.

(25) A fifth embodiment shown in FIGS. 8 and 9. In this embodiment, the propellant body portion 428 is the ball and ball housing in a ball valve 440. Again when the initiation happens the ball and ball housing 428 burn up leaving a clear through bore 442, as shown in FIG. 9.

(26) A sixth embodiment of the present invention is shown in FIG. 10. In this embodiment the plug 510 comprises three concentric layers of material 512, 514, 516. The inner layer 512 comprises a first propellant material 518, the second layer 514 comprises a second propellant material 520 and the third layer 516 comprises three rings of propellant material 522, 524, 526.

(27) The use of different propellant materials creates different rates of deflagration as the plug 510 collapses. Each layer is separated by an isolating sheath (not shown) and has its own initiator (not shown). This arrangement allows each layer to be triggered without igniting an adjacent layer.

(28) A seventh embodiment of the present invention is shown in FIG. 11. In this embodiment, a plug 610 is an annular plug fitted in an annulus 611 between a tube 612 and a casing 614 (shown in broken outline for context). The plug 610 further comprises a first transceiver sensor 616 and a second transceiver sensor 618, the first sensor 616 being located on an upper surface 620 of the plug 610 and the second sensor 618 being located on a lower surface 622 of the plug 610.

(29) These sensors 616, 618 are in communication with surface and relay information relating to the pressure in the annulus 611 above and below the plug. This information may be used to decide when to collapse the plug 610, for example, when the pressure is equalised across the plug 610.

(30) An eighth embodiment of the present invention is shown in FIG. 12. In this embodiment, a plug 710 has an outer annular block of propellant 712 with an internal block of propellant 714. The internal block of propellant tapers from both ends towards the middle of the plug 710. Located in the middle of the plug 710 is a flow turbine 716. The flow turbine 716 is embedded in the internal block of propellant 714. In use, the plug 710 would be set in a wellbore and at an appropriate moment, the internal block of propellant 714 would be initiated and would burn away leaving the flow turbine 716 in a conduit 718 through the outer annular block of propellant 712.

(31) The flow turbine 716 would then be able to measure flow rates or generate an electric current from the flow through the plug conduit 718.

(32) In alternative embodiments, the internal block of propellant could be burnt away leaving just the annular block of propellant 712, the annular block of propellant 712 then being used as a hanger or a tool support to suspend an object into the well below the annular block of propellant 712.

(33) A ninth embodiment of the present invention is shown in FIG. 13. In this embodiment, a plug 810 is made of a propellant outer body 812, and two cylindrical inner bodies 814, 816 of propellant. The thinner body 816 is lined with a steel sheath (not shown) to isolate it from the propellant outer body 812.

(34) In use when plugging a conduit, the thinner body 816 can be initiated and consumed to open up a flow path through the plug 810 to equalise pressure. This allows the rest of the plug 810 or just the larger inner body to 814 be initiated and consumed, thereby opening the conduit up again.

(35) Various modifications and improvements may be made to the above-described embodiment without departing from the scope of the invention. For example, although propellant is shown in some of the embodiments, any suitable consumable may be used. A rubber or chemical composition that when exposed to wellbore fluid or a non-wellbore fluid is consumed and may be the consumable. A solid that dissolves in water is another example, another might a solid that melts when exposed to heat and another may be that it breaks up when exposed to pressure.

(36) In other embodiments the plug may include chemical tracers to mark fluids flowing through the plug.