Patent Application
20050247450
The present invention relates generally to fire resistant well tools and components, and more particularly to a perforating gun assembly protected by a heat resistant and/or flame retardant coating.
Well operations typically involve the use of tools and tool components that are heat or flame-sensitive or even explosive when exposed to high temperature stresses or fire. For example, one operation that is performed in completing a well using an explosive tool is the creation of perforations in a formation. This is typically done by lowering a perforating gun string containing explosive shaped charges to a desired depth in a wellbore and activating the gun string to fire the shaped charges. The shaped charges when fired create perforating jets that form holes in surrounding casing as well as extend perforations into the surrounding formation.
The handling of perforating tools (e.g., charge carriers, loading tubes, detonators) or explosive components (e.g., shaped charges, propellants, actuators) during transportation, assembly, and operation necessarily involves the risk of exposure to heat or flame. Such exposure may damage the tools resulting in faulty operation, or worse ignite the explosive components causing bodily injury and/or severe damage to property.
A need thus exists for a method and apparatus to protect heat and/or flame-sensitive well tools, and explosive tool components and elements.
In general, according to an embodiment, the present invention provides heat resistant and/or flame retardant oil and gas well tools and explosive tool components.
For example, embodiments of the present invention include well tools and explosive tool components protected by a heat resistant and/or flame retardant coating.
In general, according to another embodiment, the present invention provides heat resistant and/or flame retardant containers and packing material for shipping, transporting, packaging, and/or storing oil and gas well tools, explosive tool components, and explosives.
For example, embodiments of the present invention include containers and packing material protected by a heat resistant and/or flame retardant coating for storing, shipping, and packaging well tools, explosive tool components, and explosive.
Other or alternative features will be apparent from the following description, from the drawings, and from the claims.
The manner in which these objectives and other desirable characteristics can be obtained is explained in the following description and attached drawings in which:
It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.
In the specification and appended claims: the terms “connect”, “connection”, “connected”, “in connection with”, and “connecting”are used to mean “in direct connection with”or “in connection with via another element” the term “set”is used to mean “one element”or “more than one element” and the term “downhole tool”is used to mean “an explosive well tool”, “an explosive well tool component” and/or “an explosive for use in well operations”. As used herein, the terms “up”and “down”, “upper”and “lower”, “upwardly”and downwardly“, “upstream”and “downstream” “above”and “below” and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly described some embodiments of the invention. However, when applied to equipment and methods for use in wells that are deviated or horizontal, such terms may refer to a left to right, right to left, or other relationship as appropriate.
Generally, a protection system is provided for shielding explosive tools and/or explosive tool components from exposure to high temperature stresses or fire. More particularly, embodiments of the present invention include oil and gas well tools having explosive components—such as perforating tools—having a heat resistant and/or flame retardant coating to prevent detonation during a fire or exposure to heat and flame.
In embodiments of the present invention, any heat resistant and/or flame retardant coating (also referred to herein as “thermal coating”) may be used to protect a well tool or tool component. For example, FX-100® coating by Flame Seal Products, Inc. is a Class A, super-intumescent coating which may be applied to a variety of materials including, but not limited to, metal, plastic, wood, paper, and other porous or non-porous materials. FX-100® coating forms a thick, insulating barrier when exposed to fire. Another example is Albi Clad 800™coating by Albi Manufacturing. Albi Clad 800™ coating is a solvent-based, intumescent mastic fire protective coating capable of resisting weathering and severe environmental stresses and is applicable to many materials including, but not limited to, steel, concrete, and other construction materials. Albi Clad 800™expands from a thin coating into a foam-like substance when exposed to fire. Yet another example is Corr-Paint™ CP40XX coating by Aremco Products, Inc. Corr-Paint™CP40XX coating is a series of silicone-based, heat resistant coatings formed using a water-dispersable silicone resin. Corr-Paint™ CP40XX coatings adhere to various materials including, but not limited to, metals, ceramics, refractories, and quartz, and are resistant to outdoor weathering, UV light, salt spray, chemical corrosion, thermal cycling. While embodiments of heat resistant and/or flame retardant well tools and tool components in accordance with the present invention may be manufactured and used with any one or a combination of these particular coatings, it is intended that other embodiments may use any one or combination of any other heat resistant and/or flame retardant coatings.
In producing heat resistant and/or flame retardant well tools, a thermal coating may be applied to the surface of the well tools or tool components by brush, roller, spray or other application method.
An embodiment of the present invention includes heat resistant and/or flame retardant perforating tools.
Once assembled, the gun string 50 is positioned in a wellbore 60 that is lined with casing 62. A tubing or pipe 64 extends inside the casing 62 to provide a conduit for well fluids to wellhead equipment (not shown). A portion of the wellbore 60 is isolated by packers 66 set between the exterior of the tubing 64 and the interior of the casing 62. The perforating gun string 50 may be lowered through the tubing or pipe 64 on a carrier line 70 (e.g., wireline, slickline, or coiled tubing). Once positioned at a desired wellbore interval where the gun string 50 is fired to create perforations in the surrounding casing and formation. In the event that a propellant material is used, the firing of the perforating gun 50 ignites the propellant material thereby generating a pressurized gas from the burning of the propellant material. The gas penetrates the formation via the perforations and cleans the perforation tunnels by pushing out debris. The pressurized propellant gas may also stimulate the surrounding formation to facilitate production by fracturing the formation.
Alternatively, an embodiment of the present invention may also include a capsule charge having a thermal coating for protection from heat and/or flame. For example, as shown in
In embodiments of the present invention, the loading tube 40 may be fabricated from conventional metal materials (e.g., tubular steel, pipe, sheet metal, or equivalent materials) or non-metal materials (e.g., stamped and/or molded paper pulp, plastic, high-density polystyrene, or other equivalent materials). In these embodiments, the coating 44 is applied onto the metal or non-metal material.
In other embodiments, the heat resistant and/or flame retardant perforating assembly may include propellant material positioned outside the gun 50 or casing 62 (
While some embodiments of the present invention have been described with respect to a heat resistant and/or flame retardant perforating gun, it is intended that other embodiments include other explosive well tools having a thermal coating including, but not limited to, an explosive tubing cutter. An example of an explosive tubing cutter is described in U.S. patent application Ser. No. 10/017,116, published as US 2003/011120 A1, which is incorporated herein by reference. As with embodiments of the perforating gun described above, embodiments of the explosive tubing cutter may include a carrier or housing coated with a thermal coating, at least one shaped charge coated with a thermal coating, or both.
Another embodiment of the present invention includes heat resistant and/or flame retardant explosive components. For example, detonators, detonating cords, firing heads, initiators, charges, switches, processor units, power supplies, and other explosive components may be coated with a thermal coating to protect from damage or inadvertent ignition during manufacturing, shipping, packaging, assembly, and/or operation.
While the embodiment shown in
Another embodiment of the present invention includes heat resistant and/or flame retardant explosive actuators for actuating downhole tools and/or systems by igniting an explosive. For example, U.S. Pat. No. 6,651,747, which is incorporated herein by reference, includes an anchoring device for use in a perforating operation to prevent movement of a perforating gun downhole. To actuate and set the anchor device, an electrical signal detonates a detonator release mechanism, which causes engagement mechanisms to engage the inner wall of the casing or tubing. In accordance with the present invention, the anchoring device and/or the detonator release mechanism may be coated with a heat resistant and/or flame resistant coating to prevent accidental detonation when exposed to heat or flame. Also, for example, U.S. Pat. No. 6,102,120, which is incorporated herein by reference, includes a downhole zonal isolation tool having an epoxy sleeve for sealing against a casing. An embodiment of the isolation tool includes a local heat source (e.g., thermite or some other exothermic pyrotechnic energy source) contained in a housing, which when actuated cures the epoxy sleeve. In accordance with the present invention, the zonal isolation tool and/or the local heat source may be coated with a thermal coating to prevent accidental ignition when exposed to heat or flame.
Yet another embodiment of the present invention includes heat resistant and/or flame retardant packaging, and shipping materials for safely transporting and storing heat and/or flame-sensitive well tools, explosives, and/or explosive components.
Still with respect to
While this embodiment includes a container 300 and packing materials 400 for holding one or more shaped charges 10, it is intended that other embodiments of the present invention include containers and/or packing materials coated with a thermal coating for carrying any heat and/or flame-sensitive well tools, explosives, and/or explosive components including, but not limited to, perforating guns, carriers, loading tubes, gun adapters, tubing cutters, detonators, detonating cords, firing heads, initiators, charges, propellants, explosive actuators, switches, processor units, power supplies, RDX, HMX, HNS, and/or TATB explosives, and so forth.
Although only a few exemplary embodiments of this invention have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention.
