GB2544616A

GB2544616A - Downhole tool

Info

Publication number: GB2544616A
Application number: GB1616531.8A
Authority: GB
Inventors: Oag Jamie; Younger Rae; Dantuma Johnston Sidney
Original assignee: Spex Engineering UK Ltd
Current assignee: Spex Engineering UK Ltd
Priority date: 2014-11-18
Filing date: 2015-11-18
Publication date: 2017-05-24
Anticipated expiration: 2035-11-18
Also published as: GB2544616B; GB201616531D0

Abstract

A tool for manipulating material in a downhole environment, such as casing 12 or production tubing comprises a confined propellant source 26 and an ignition mechanism for igniting the propellant source. Upon ignition of the propellant source 26, the propellant deflagrates thereby creating at least one stream of combustion products 44. Confinement of the propellant source 26 is such that the stream(s) of combustion products 44 is/are directed towards the material to be manipulated. A modifying agent 28 may combine with the stream of combustion products 44 to manipulate the material.

Description

Downhole Tool Field

The present invention relates to a tool for manipulating a tubular, such as casing or production tubing, in a downhole environment. Particularly, embodiments of the present invention relate to a tool for stripping casing and cement in a well abandonment operation.

Background

There are situations in which it is desirable to remove a portion of casing or tubing from an oil or gas well. A typical situation may be to remove a length of casing to allow a permanent cement plug to be installed, prior to well abandonment. Current Oil and Gas UK Guidelines for the Abandonment of Wells (July 2015, Issue 5) dictate that a permanent barrier, typically a cement plug, must be formed between the reservoir and the seabed to act as one of a number of permanent barriers when a well is abandoned or plugged. This measure is intended to isolate the well and reduce the possibility of pressure migration in order to prevent hydrocarbons and other well fluids from underground reservoirs leaking past the barrier(s) and coming to surface and spilling into the sea.

In some situations, prior to installing the cement plug to abandon or plug the well, it is necessary to remove the production tubing, casing and other downhole tubulars, and the cement or other downhole fixings that secure the well to the bedrock.

Casing may also be removed to undertake a casing repair, or to expose the cement behind the casing to allow cement repair. In some cases, where cemented casing is used, for example, there may be a leak path in the cement behind the casing or between casing layers. Rectifying such a breach may also require the removal of a casing section and associated cement before forming new cement and repairing the casing.

Conventional removal of cemented casing uses, for example, milling tools or hydro-abrasive cutters which remove the casing and associated cement by gradually cutting or milling away small portions of metal and cement. These are slow processes and therefore make such an operation very expensive and time consuming.

Perforating charges have also historically been used to penetrate a casing wall, to allow fluid communication through the casing wall and to allow cementing behind. Perforations only produce small holes through the target, whereas large holes are often desirable.

Summary

According to a first aspect of the present invention there is provided a tool for manipulating material in a downhole environment, the tool comprising: a confined propellant source; an ignition mechanism for igniting the propellant source; wherein upon ignition of the propellant source, the propellant deflagrates, creating at least one stream of combustion products, the propellant source being confined such that the/each stream of combustion products are directed towards the material to be manipulated.

In at least one embodiment of the invention a tool is provided which uses a stream of combustion products created by combustion of a propellant source to manipulate a tubular by, for example, ablation, cutting, displacement, removal, heating, abrasion, or erosion. This method is much faster than conventional processes leading to time and resource savings, and associated reduced costs. A propellant is an explosive material which has a low rate of combustion and once ignited burns or otherwise decomposes to produce propellant gas. This gas is highly pressurised, the pressure driving the gas and other combustion products away from the propellant, forming a stream of combustion products. A propellant can burn smoothly and at a uniform rate after ignition without depending on interaction with the atmosphere, and produces propellant gas and/or heat on combustion and may also produce additional combustion products.

The tool may comprise a housing.

The propellant source may be confined in a housing.

In other embodiments the tool housing may comprise the propellant source.

The housing may define a chamber, the chamber having at least one outlet.

The propellant source may be directed towards the material to be manipulated through the chamber outlets.

The propellant source may be located within the chamber.

The tool may further comprise at least one modifying agent, the modifying agent combining with the/each stream of combustion products to manipulate the material.

The material may be a tubular.

The/each stream of combustion products may be directed towards an internal or external surface of the tubular.

According to a further aspect of the present invention there is provided a tool for manipulating a material, the tool comprising: a body defining a chamber for housing at least one propellant source; at least one nozzle, the/each nozzle having an inlet and an outlet, the the/each inlet being in fluid communication with the chamber; and at least one mechanism for igniting the/each propellant sources; wherein, upon ignition, at least one of the propellant sources combusts to release a combustion jet which, in use, flows out of the tool through the/each nozzle outlet towards a material to be manipulated.

The combustion jet may be at least one stream of combustion products. The body may be a housing. A method of penetrating a section of tubular, comprises: providing a tool, the tool comprising a body defining a chamber for housing a propellant, at least one nozzle, the/each nozzle having an inlet and an outlet, the/each inlet being in fluid communication with the chamber and at least one mechanism for igniting the propellant; wherein, upon ignition, the propellant releases a gas which flows out of the tool through the/each nozzle outlet in the form of at least one gas jet towards, in use, a tubular surface to be penetrated; running the tool into the tubular at a desired location; and penetrating the internal surface of the tubular with the/each gas jet. A method to remove a section of casing or tubing from a downhole location, comprises: providing a tool, the tool comprising a body defining a chamber for housing a propellant, at least one nozzle, the/each nozzle having an inlet and an outlet, the/each inlet being in fluid communication with the chamber and at least one mechanism for igniting the propellant; wherein, upon ignition, the propellant releases a gas which flows out of the tool through the/each nozzle outlet in the form of at least one gas jet towards, in use, a tubular surface to be penetrated; running the tool into the casing at a desired location; penetrating the internal surface of the casing with the/each gas jet; and removing fragments of casing from their original location. A method of plugging an oil or gas well to be abandoned or decommissioned, comprises: providing a tool, the tool comprising a body defining a chamber for housing a propellant, at least one nozzle, the/each nozzle having an inlet and an outlet, the/each inlet being in fluid communication with the chamber and at least one mechanism for igniting the propellant; wherein, upon ignition, the propellant releases a gas which flows out of the tool through the/each nozzle outlet in the form of at least one gas jet towards, in use, a tubular surface to be penetrated; the body of the tool may itself be a propellant cast; running the tool into the casing at a desired location; penetrating the internal surface of the casing with the/each gas jet; removing fragments of casing and cement from their original location; and providing cement to form a plug.

It will be understood that features listed as preferable non-essential in respect of one aspect may be equally applicable to another aspect and are not repeated for brevity.

Brief Description of the Drawings

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

Figure 1 is a side view of a tool for manipulating casing shown positioned in a section of a well according to a first embodiment of the present invention;

Figure 2 is a section of the tool Figure 1;

Figure 3 is a section of the tool of Figure 1 during deflagration of the propellant source;

Figure 4 is a section of the tool of Figure 1 during deflagration of the propellant source;

Figure 5 is a section of the tool of Figure 1 during deflagration of the propellant source;

Figure 6 is a section of the well of Figure 1 after the tool has been removed and a cement plug fitted;

Figure 7 is a side view of a tool for manipulating casing shown positioned in a section of a well according to a second embodiment of the present invention;

Figure 8 is a section of the tool Figure 7;

Figure 9 is a section of the tool of Figure 7 during deflagration of the propellant source;

Figure 10 is a section of the tool of Figure 7 during deflagration of the propellant source;

Figure 11 is a section of the well of Figure 7 after the tool has been removed;

Figure 12 is a section of the well of Figure 7 following installation of a cement plug; and

Figure 13 is a section of a tool for manipulating casing shown positioned in a well during deflagration of the tool’s propellant source according to a third embodiment of the present invention.

Detailed Description of the Drawings

Reference is first made to Figure 1, a side view of a tool, generally indicated by reference numeral 10, for manipulating casing 12 in a well 14 according to a first embodiment of the present invention. The casing 12 is shown attached to bedrock 16 by cement 18. Particularly, the tool 10 is for removing a section of the casing 12 and the cement 18 attaching the casing to the bedrock 16, to permit a cement plug to be installed in this section in advance of the well 14 being abandoned.

The tool 10 is lowered in to the well on a wireline 19 and anchored in position by three circumferentially displaced anchors 46 (of which one is visible on Figure 1) to prevent axial movement of the tool 10, as will be explained in due course.

Additionally referring to Figure 2, a section through the tool 10 of Figure 1, it can be seen that the tool 10 comprises a housing 20 defining a chamber 22, the chamber 22 having a series of outlets 24 in the form of nozzles.

Inside the chamber 22 is a propellant source 26 containing a propellant 27 and particles of a modifying agent 28, in this case aluminium oxide. The propellant source 26 has a coating 30 which defines an opening 32 at an end of the coating 30, the opening 32 exposing a section 36 of the propellant 27 to the interior of the chamber 22. Adjacent the exposed propellant section 36 is an ignition mechanism 38 adapted to ignite the propellant section 36.

Directly below the propellant 27 is a deflector plate 39 defining a profiled deflection surface 40, the deflection surface 40 being profiled to direct a flow towards the outlets 24.

Operation of the tool 10 will now be described with reference to Figures 3 and 4, sections of the tool 10 of Figure 1 showing the tool 10 in use. Referring firstly to Figure 3, with the anchors (not shown in this Figure) in place, the ignition mechanism 38 has ignited the exposed propellant section 36 creating a combustion zone 42 on the propellant source 26. As the propellant 27 deflagrates, a stream of highly pressurised combustion products 44 is released. The stream of combustion products 44 is driven downwards away from the propellant 27 due to the pressure within the stream 44 and, in particular, generated at the combustion zone 42. Within the stream of combustion products 44 are the particles 28 of aluminium oxide which have been released from the propellant source 26. The thrust created by the stream of combustion products 44 is prevented from driving the tool 10 upwards by the anchors 46, therefore the thrust drives the stream 44 and the particles 28 towards the deflector plate 39.

The stream of combustion products 44 containing the particles 28 impacts on the deflector plate 39 and are deflected along the deflection surface 40 towards the outlets 24. The combustion products 44 and the particles 28 are funnelled through these nozzles 24 and impact on the casing 12.

The four nozzles 24 are spaced equidistant around the circumference of the housing 20, the nozzles 24 being arranged in opposed pairs. This arrangement keeps the tool 10 centralised in the well 14 as the thrust generated at each nozzle 24 is countered by the thrust generated by the nozzle 24 on the opposite side of the housing 20. However, the nozzles 24 are angled to the radius of the tool 10 such that the thrust generated by the nozzles 24 cause the tool 10 to rotate, such that the stream of combustion products 44 and the associated particles 28 cut a circumferential ring through the casing 12.

The stream of combustion products 44 has burned the aluminium oxide particles 28 such that they have sapphire-like properties. The stream of combustion products 44 has also accelerated the particles 28 and this combination of speed and heat induced change of properties results in the particles 28 carving into the casing 12 by displacing the casing material. In addition the stream of combustion products 44 heats the casing 12, facilitating the removal of material by the particles 28.

Referring to Figure 4, the removal of the casing 12 strips back the casing 12 leaving exposed regions 60 of cement 18.

Referring to Figure 5, as propellant source 26 deflagrates, the coating 30 burns with it, exposing new propellant 27 to the combustion zone 42. With the deflagration of the propellant source 26 under control, the anchors 46 can be partially released to permit the tool 10 to rise slowly of the well 14 and create an extended section of exposed cement 18.

Once the propellant source 26 is exhausted, the exposed cement 18 can be removed. This cement 18 is weakened by the heat and the tool 10 is run in again (not shown) and the anchors 46 are applied to the weakened cement, causing the cement 18 to crumble and fall away leaving an exposed section 62 of bedrock 16 (Figure 6).

This exposed section 62 can then be plugged with a cement plug 64 permitting the well 14 to be abandoned.

Reference is now made to Figure 7, a tool 110 for manipulating casing 112 in a well 114 according to a second embodiment present invention.

The arrangement of the tool 110 and the surrounding well 114 is similar to that of the first embodiment and similar reference numerals have been used, incremented by 100. The tool 110 is for a similar purpose; that is to strip a section of casing 112 and associated cement 118 from bedrock 116.

The tool housing 120 includes an elongate lattice outlet arrangement 124. The outlet arrangement 124 extends the entire length of the housing 120.

Referring to Figure 8, a section through the tool 110 of Figure 7, this Figure shows the propellant source 126 as being much wider than the propellant source 26 of the first embodiment, the propellant source 126 filling the entire width of the housing 120.

Beneath the propellant source 126 is a void 154, the purpose of which will be discussed in due course.

As can be seen most clearly from Figures 7 and 8, the outlet 124 contains a frangible seal 150 which extends up the outlet 124 to above the top of the void 154. From the top of the seal 150 upwards, the outlet 124 is sealed by the propellant source covering 130. It will be noted there is no deflector plate on this embodiment.

The tool 110 of this embodiment further includes upper and lower packer seals 156,158 for sealing a wellbore section 160.

Operation of the tool 110 will now be discussed. The tool 110 is lowered into position and the upper and lower packers 156, 158 are set to seal the wellbore section 160. It is in the section 162 that the casing 112 is to be manipulated.

Referring to Figure 9, the ignition mechanism 138 (shown on Figure 8) is activated and this ignites the exposed propellant section 136 creating a stream of combustion products 144 which fill the void 154. Pressure builds up inside the void 154 until a threshold pressure is reached which overcomes the strength of the frangible seal 150 breaking the seal and allowing the stream of combustion products to flow through the outlet 124.

As the outlet 124 is a slot rather than a circular nozzle, the flow of combustion products 144 comes out as a blade 180 rather than as a jet.

The housing 120 is made of a sacrificial material. As the flow of combustion products 144 passes through the outlet, the flow 144 skims off the housing edges 182 which define the outlets 124. A sacrificial material comes off in particulate form and becomes entrained in the flow 144, the particles 128 acting as the modifying agent 128 which is propelled onto the surface of the casing 112 to strip back the casing 112, leaving exposed regions of cement 160.

Referring to Figure 10, a section view of the tool 110 of Figure 7, as the propellant source 126 deflagrates, the coating 130 burns with it revealing more of the outlet 124.

Referring to Figure 11, a section through the well 114 after the casing 112 has been stripped back to the cement 118 by the tool 110 of Figure 7, once the propellant source 126 has fully deflagrated, a lattice arrangement of grooves 184 carved into the casing 112 showing the exposed cement 118.

Application of mechanical force, for example, on the well section 162 will remove the remaining casing fragments 186 and the exposed cement 118. Then, as per the first embodiment, a cement plug 164 can be installed in the well section 162, permitting the well 114 to be abandoned.

Reference is now made to Figure 13, a tool 210 for manipulating casing 212 in a well 214 according to a third embodiment present invention.

The arrangement of the tool 210 and the surrounding well 214 is similar to that of the first embodiment and similar reference numerals have been used, incremented by 200. The tool 210 is for punching holes in a section of casing 212 and associated cement 218 through to the bedrock 216.

The primary differences between the tool 210 of this embodiment and the tool 10 of the first embodiment resides in, first, the outlets of the tool 210 being in the form of nozzles 224 which extend around the circumference of the tool 210. These nozzles 224 are directed downwardly to maximise the effect of moving casing material by impacting the casing at an acute angle.

The second difference resides in the deflector plate 239 which is a sacrificial plate from which the stream of combustion products 244 scours off the modifying agent 228. The stream of combustion products 244 with the entrained modifying agent 228 punch a ring of holes 290 through the casing 212 and cement 218.

Various modifications may be made to the above-described embodiments without departing from the scope of the invention. For example the nozzles may change the characteristics of the stream of combustion products by, for example, being cooled or being impregnated with material or being sonically resonated or by having a surface which is textured or grooved.

In other embodiments, the stream of combustion products may impart additional energy to the tubular. This energy may be in the form of heat. Additionally, the stream of combustion products may exert a pressure on the tubular. Alternatively or additionally the combustion products may exert a force on the tubular. For example, particulate within the combustion products and carried within the stream may impact the surface of the tubular and exert a force. This additional energy can be used to dislodge the manipulated casing and the associated cement securing it to the bedrock. There may be more than one mode of interaction with the tubular. For example, the tubular may be heated to melting point while at the same time subjected to pressure.

In further embodiments, the combustion products may enhance thermal conductivity by forming a flux or thermally conductive layer at the tubing or the combustion products may react at the tubular or in transit to the tubular. For example, particles may chemically react or combust at the tubing.

Clause 1. A tool for manipulating a tubular in a downhole environment, the tool comprising: a housing defining a chamber, the chamber having at least one outlet; a propellant source located within the chamber; an ignition mechanism for igniting the propellant source; and at least one modifying agent provided in or adjacent the tool or generated by the tool; wherein upon ignition of the propellant source, the propellant source is adapted to deflagrate, creating at least one stream of combustion products, the chamber directing the stream of combustion products through the/each outlet, towards the tubular to be manipulated, the/each stream of combustion products combining with at least one modifying agent to manipulate the tubular.

Clause 2. The tool of clause 1, wherein in use, the at least one modifying agent cracks, displaces, erodes, ablates, abrades or removes at least a portion of the tubular to be manipulated.

Clause 3. The tool of either of clauses 1 or 2, wherein in use, the/each stream of combustion products heat the tubular to be manipulated.

Clause 4. The tool of any preceding clause, wherein the tool is configured to be anchored to the tubular

Clause 5. The tool of any preceding clause, wherein the propellant source comprises a plurality of propellants.

Clause 6. The tool of clause 5, wherein each propellant is adapted to combust separately.

Clause 7. The tool of either of clauses 5 or 6, wherein the ignition mechanism is configured to ignite at least some of the propellants in a sequence.

Clause 8. The tool of either of clauses 5 or 6, wherein the ignition mechanism is configured to ignite at least some of the propellants substantially simultaneously.

Clause 9. The tool of any of clauses 5 to 7, wherein at least one propellant has a different function to at least one of the other propellants. Clause 10. The tool of any preceding clause, wherein the/each stream of combustion products is generated without generating heat or with minimal heat generation.

Clause 11. The tool of any preceding clause, wherein the propellant source is formed of the combination of two or more materials within the tool. Clause 12. The tool of any preceding clause, wherein the propellant source is arranged to create an intermittent stream of combustion products. Clause 13. The tool of any preceding clause, wherein once ignited, the propellant source defines a combustion zone.

Clause 14. The tool of clause 13, wherein as the propellant source deflagrates, the combustion zone moves relative to the tubular to be manipulated.

Clause 15. The tool of any preceding clause, wherein the tool further comprises at least one deflector for deflecting the/each stream of combustion products.

Clause 16. The tool of clause 15, wherein the/each deflector defines a deflection surface.

Clause 17. The tool of either of clauses 15 or 16, wherein the/each deflector is movable.

Clause 18. The tool of any of clauses 15 to 17, wherein the/each deflector is positioned in the path of the/each stream of combustion products. Clause 19. The tool of any of clauses 15 to 17, wherein the/each deflector is adapted to move into the path of the/each stream of combustion products.

Clause 20. The tool of any of clauses 15 to 19, wherein the/each deflector is arranged to split the/each stream of combustion products.

Clause 21. The tool of any of clauses 15 to 20, wherein the/each deflector is adapted to maintain a substantially constant distance from the combustion zone.

Clause 22. The tool of any of clauses 15 to 21, wherein the/each deflector comprises a sacrificial material.

Clause 23. The tool of clause 22, wherein the sacrificial material contains the at least one modifying agent.

Clause 24. The tool of any of clauses 15 to 23, wherein the/each deflector has a coating which is adapted to be gradually eroded, ablated, abraded or removed by the/each stream of combustion products.

Clause 25. The tool of any preceding clause, wherein there are a plurality of said outlets.

Clause 26. The tool of clause 25, wherein the outlets extend circumferentially around the housing.

Clause 27. The tool of either of clauses 25 or 26, wherein the outlets extend axially along the housing.

Clause 28. The tool of clause 27, wherein, where the outlets extend axially along the housing, the outlets open over a period of time.

Clause 29. The tool of any preceding clause, wherein the/each outlet opens sequentially along the length of the tool.

Clause 30. The tool of any preceding clause, wherein the/or each outlets is sealed.

Clause 31. The tool of any preceding clause, wherein the/or each outlets is sealed by an opening mechanism.

Clause 32. The tool of clause 31, wherein the opening mechanism is adapted to open the/or each outlets in response to an environmental condition being reached.

Clause 33. The tool of clause 32, wherein the opening mechanism comprises a frangible portion.

Clause 34. The tool of clause 33, wherein the frangible portion is a shear pin.

Clause 35. The tool of any preceding clause, wherein at least a portion of at least one outlet points obliquely outwards from the housing.

Clause 36. The tool of any preceding clause, wherein at least a portion of at least one outlet points perpendicularly outwards from the housing. Clause 37. The tool of any preceding clause when dependent on clause 25, wherein at least a portion of each of a plurality of outlets points in convergent directions.

Clause 38. The tool of clause 37, wherein at least some of the/each outlet points in convergent directions and their respective stream of combustion products converge at or beyond the target surface.

Clause 39. The tool of any preceding clause, wherein at least one outlet is a nozzle having a nozzle inlet and a nozzle outlet, the nozzle being in fluid communication with chamber.

Clause 40. The tool of clause 39, wherein at least one of the/each nozzle is moveable with respect to the housing.

Clause 41. The tool of clause 40, wherein at least one of the/each moveable nozzle moves defining a pattern on the tubular to be manipulated. Clause 42. The tool of any preceding clause, wherein at least one outlet is adapted to enable a thrust force from an outlet to be used to move the tool in a well.

Clause 43. The tool of any preceding clause, wherein at least one outlet is adapted to enable a thrust force from an outlet to be used to bring the tool into closer proximity to the target.

Clause 44. The tool of any preceding clause, wherein at least one outlet is adapted to enable a thrust force from an outlet to be used to move components within the tool.

Clause 45. The tool of any preceding clause, wherein at least one outlet is adapted to enable a thrust from the outlet to move the outlet in a predefined path to cut predefined sections from the tubular.

Clause 46. The tool of any preceding clause, wherein at least one of the at least one modifying agent is formed by the combustion of the propellant source.

Clause 47. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is formed separately from the combustion of the propellant source.

Clause 48. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is present prior to ignition of the propellant source.

Clause 49. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is present within the propellant source. Clause 50. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is aluminium oxide.

Clause 51. The tool of any preceding clause, wherein at least one of the at least one modifying agent reacts with the environment and/or the tubular to be modified.

Clause 52. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is introduced into the stream of combustion products.

Clause 53. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is drawn into the stream of combustion products by a venturi or similar geometric profile.

Clause 54. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is mechanically or forcibly introduced into the propellant gas and/or stream of combustion products.

Clause 55. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is applied to the surface of the tubular to be manipulated.

Clause 56. The tool of any one of clauses 1 to 45, wherein at least one of the at least one modifying agent is a flux.

Clause 57. The tool of any preceding clause, wherein the tool includes a sacrificial portion.

Clause 58. The tool of clause 57, wherein the/each stream of combustion products releases at least one of the at least one modifying agent from the sacrificial tool portion

Clause 59. The tool of any preceding clause, wherein the tool is pressure and/or heat containing

Clause 60. The tool of any preceding clause, wherein the tool further includes a sealing mechanism.

Clause 61. The tool of clause 60, wherein the sealing mechanism is adapted to form a seal to isolate a section of tubular to be manipulated. Clause 62. The tool of any preceding clause, wherein the tool comprises an enhancing mechanism for enhancing the/each stream of combustion products.

Clause 63. The tool of clause 62, wherein the enhancing mechanism changes the flow characteristics of the/each stream of combustion products. Clause 64. The tool of clause 63, wherein the enhancing mechanism is the application of an eddy current to the/each stream of combustion products. Clause 65. The tool of clause 64, wherein the eddy current is pulsed.

Clause 66. The tool of any of clauses 62 to 65, wherein the enhancing mechanism imparts additional energy to the/each stream of combustion products or changes the shape and/or direction of the/each stream of combustion products.

Clause 67. The tool of any of clauses 62 to 66, wherein the enhancing mechanism is oxygen to enhance the burning of the propellant or the tubular to be manipulated.

Clause 68. The tool of any of clauses 62 to 67, wherein the enhancing mechanism could be the production of a gas, in some embodiments through propellant combustion, which displaces the fluid in the vicinity of the tool. Clause 69. A method of manipulating a tubular in a downhole environment, the method comprising: positioning a tool having a housing defining a chamber, the chamber having at least one outlet; a propellant source located within the chamber; and an ignition mechanism for igniting the propellant source adjacent a tubular to be manipulated, igniting the propellant source such that at least one stream of combustion products is generated, the chamber directing the/each stream of combustion products through the/each outlet, the outlet directing the/each stream of combustion products towards the tubular to be manipulated, the/each stream of combustion products including a modifying agent to modify the tubular to be manipulated.

Clause 70. The method of clause 69 further comprising increasing thrust of the/each stream of combustion products.

Clause 71. The method of clause either of clauses 69 or 70 further comprising increasing the energy of the/each stream of combustion products. Clause 72. The method of any of clauses 69 to 71 further comprising changing the direction of the/each stream of combustion products.

Clause 73. The method of any of clauses 69 to 72 further comprising applying a shockwave to the tubular to be manipulated.

Clause 74. The method of any of clauses 69 to 73 further comprising changing the physical properties of the tubular to be manipulated.

Clause 75. The method of any of clauses 69 to 74 further comprising cooling the tubular to be manipulated.

Clause 76. The method of any of clauses 69 to 75 further comprising applying mechanical force to the tubular to be manipulated.

Claims

1. A tool for manipulating material in a downhole environment, the tool comprising: a confined propellant source; an ignition mechanism for igniting the propellant source; wherein upon ignition of the propellant source, the propellant deflagrates, creating at least one stream of combustion products, the propellant source being confined such that the/each stream of combustion products are directed towards the material to be manipulated.

2. The tool of claim 1, wherein the tool comprises a housing.

3. The tool of claim 2, wherein the propellant source is confined in the housing.

4. The tool of claim 3, wherein the housing comprises the propellant source.

5. The tool of any of claims 1 to 3, wherein the housing defines a chamber, the chamber having at least one outlet.

6. The tool of claim 5, wherein the propellant source is directed towards the material to be manipulated through the/each chamber outlet.

7. The tool of either of claims 5 or 6, wherein the propellant source is located within the chamber.

8. The tool of any of claims 1 to 7, wherein the tool further comprises at least one modifying agent, the modifying agent combining with the/each stream of combustion products to manipulate the material.

9. The tool of any of claims 1 to 8, wherein the material is a tubular.

10. The tool of claim 9, wherein the /each stream of combustion products is directed towards an internal or external surface of the tubular.

11. A tool for manipulating a material, the tool comprising: a body defining a chamber for housing at least one propellant source; at least one nozzle, the/each nozzle having an inlet and an outlet, the/each inlet being in fluid communication with the chamber; and at least one mechanism for igniting the/each propellant sources; wherein, upon ignition, at least one of the propellant sources combusts to release a combustion jet which, in use, flows out of the tool through the/each nozzle outlet towards a material to be manipulated.

12. The tool of claim 11, wherein the combustion jet is at least one stream of combustion products.

13. The tool of either of claims 11 or 12, wherein the body is a housing.