1. Field of Disclosure
The present disclosure relates to an apparatus and method for perforating a well casing and/or a subterranean formation.
2. Description of the Related Art
Hydrocarbon producing wells typically include a casing string positioned within a wellbore that intersects a subterranean oil or gas deposit. The casing string increases the integrity of the wellbore and provides a path for producing fluids to the surface. Conventionally, the casing is cemented to the wellbore face and is subsequently perforated by detonating shaped explosive charges. When detonated, the shaped charges generate a jet that penetrates through the casing and forms a tunnel of a short distance into the adjacent formation. Often, the region that is perforated, and in particular the walls of the tunnel, may become impermeable due to the stress applied to the formation by the perforating jet as well as stresses that may be caused during the firing of the perforating gun. The loss of permeability and other harmful effects, such as the introduction of debris into the perforation, may adversely affect the flow of hydrocarbons from an intersected hydrocarbon deposit.
In aspects, the present disclosure addresses the need for perforating devices and methods that provide cleaner and more effective well perforations.
The present disclosure provides devices and methods for efficiently perforating a formation. In aspects, an illustrative method for perforating a formation intersected by a wellbore may include positioning a shaped charge and a reactant composite material in a carrier; positioning the carrier in the wellbore; detonating the shaped charge; and disintegrating the reactant composite material using a shock generated by the detonated shaped charge. The method may also include initiating a first deflagration by using carbon and heat resulting from the detonation of the shaped charge and an oxygen component of the disintegrated reactant composite material. In embodiments, the method may also include initiating a second deflagration using heat from the first deflagration. Such initiating may include applying the heat to an oxygen component of the disintegrated reactant composite material and a fuel. The fuel may be supplied by a case of the shaped charge and/or a support member for the shaped charge. The support member may be a tube or strip. In embodiments, the reactant composite material may include an oxidizer and an inert binder. In one configuration, the reactant composite material may not include a fuel component. In other configurations, the reactant composite material may include an oxidizer, a fuel component and an inert binder. Also, the reactant composite material may be formulated to be oxygen overbalanced in any of these embodiments.
In aspects, the present disclosure provides a system for perforating a formation intersected by a wellbore. The system may include a carrier, a shaped charge positioned in the carrier; and a reactant composite material positioned in the carrier. The reactant composite material may be configured to disintegrate upon detonation of the shaped charge. In arrangements, the reactant composite material may be interposed between shaped charges. Also, the reactant composite material may include an oxygen component in an amount sufficient to consume substantially all of the carbon resulting from detonation of the shaped charge.
In aspects, the present disclosure further provides a method for perforating a formation intersected by a wellbore. The method may include positioning a plurality of shaped charges and a plurality of pellets formed at least partially of reactant composite material in a carrier; positioning the carrier in the wellbore; disintegrating the plurality of pellets by detonating the plurality of shaped charges; generating a first quantity of gas using carbon and heat resulting from the detonation of the shaped charge and an oxygen component of the disintegrated reactant composite material; and generating a second quantity of gas by applying heat resulting from the generation of the first quantity of gas to an oxygen component of the disintegrated reactant composite material and a fuel.
The above-recited examples of features of the disclosure have been summarized rather broadly in order that the detailed description thereof that follows may be better understood, and in order that the contributions to the art may be appreciated. There are, of course, additional features of the disclosure that will be described hereinafter and which will form the subject of the claims appended hereto.
For detailed understanding of the present disclosure, references should be made to the following detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings, in which like elements have been given like numerals and wherein:
As will become apparent below, the present disclosure provides a safe and efficient device for enhanced perforation of a subterranean formation. In aspects, the present disclosure uses a gas-generating material carried within a perforating gun that, when activated, produces a high-pressure gas that cleans the perforations resulting from the detonation of the shaped charges in the perforating gun.
Conventionally, the rapidity of the chemical reaction of an explosive may be used as a method of classification. Explosive materials, which react very violently, are often classified as high explosives. These materials are typically used for applications requiring extremely high pressures dissipated over a very short time (e.g., microseconds). For purposes of this disclosure, such reactions will be referred to as a high order reaction or high order detonation, or simply explosion. Some explosive materials may be formulated to react more slowly. These materials, which may be classified as low explosives, may release a large amount of energy over a relatively longer time period (e.g., milliseconds). This relatively slowly released energy may be more useful as a propellant where the expansion of the combustion gases is used to do work. For purposes of this disclosure, such reactions will be referred to as a low order reaction or low order detonation, or simply a deflagration. Embodiments according to the present disclosure may use both of these distinct chemical reactions. For example, in some embodiments, the high order reaction will be followed by a low order reaction. In other embodiments, two distinct low order reactions may occur. In still other embodiments, a high order reaction may be followed by two distinct low order reactions. Illustrative systems, methods and devices that enhance wellbore perforation activities utilizing such reactions are discussed in greater detail below.
The present disclosure is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments of the present disclosure with the understanding that the present disclosure is to be considered an exemplification of the principles of the disclosure, and is not intended to limit the disclosure to that illustrated and described herein. Further, while embodiments may be described as a system made up of several components or as a combination of two or more features, it should be understood that the individual components or individual features may themselves represent advancements over the prior art and may be utilized separate and apart from any give system or combination. Moreover, no feature or combination of features should be construed as essential unless expressly stated as essential.
Referring initially to
In one embodiment, the perforating gun 10 is configured to perforate and fracture a formation in a single trip, the perforations being enumerated with 22. As will be described more fully below, the material for producing a high-pressure gas for cleaning perforations in the formation is carried in a suitable location in the gun 10.
Referring now to
In still other embodiments, one or more elements making up the perforating gun 10 can be formed from the gas-generating material. For example, a casing 36 of the shaped charge 14 can be formed partially or wholly from a gas-generating material. In another arrangement, a volume of gas-generating material 38 can be positioned inside the casing 38. In still other arrangements, the carrier tube 20, charge tube 16 or other component of the perforating gun 10 can be formed at least partially of a gas-generating material.
Referring now to
In embodiments, the RCM may be formulated to increase the power, performance and/or usefulness of a shaped charged explosive by making available sufficient oxidizing compounds for reaction with the carbon residue that occurs from the detonation of the shaped charge. This oxygen can initiate a deflagration reaction that follows the detonation of the shaped charge. By way of illustration, the following balance equation shows the products of reaction resulting from the detonation of TNT:
C6H2(NO2)3CH3=6CO+2.5H2+1.5N2+C Eq. (1)
As can be seen, the carbon is not fully converted to Carbon Monoxide because of insufficient available oxygen. Explosives with free carbon remaining at the completion of the chemical reaction are considered to have a negative oxygen balance (OB %). For example, TNT may have an OB % of 74%.
In embodiments of the present disclosure, the RCM supplies sufficient oxidizing material to utilize the carbon residue in a secondary reaction:
C(S)+O2(g)+CO2(g)ΔH=−393.5 kJ Eq. (2)
By way of example, the RCM may combine an oxidizer, such as Potassium Perchlorate, with an explosive, such as TNT. The manner in which the two components are mixed will control the timing and rapidity of the secondary reaction.
As shown in the
In one variant of the
It should be understood that the oxidizer may be positioned elsewhere in the perforating gun. Illustrative examples of embodiments utilizing the oxidizer in a shaped charge 60 are discussed with reference to
Referring now to
Referring now to
Referring now to
The liner 86 employs multiple angles in order to form a projectile that cuts a relatively large hole in the carrier housing 16 (
It should be appreciated that the first and second angles 96 and 98 enable their associate portions of the liner 86 to respond or react differently to the shock wave applied from a detonation. For instance, the first angle 96 may be selected such that the shock wave folds the intermediate conical section 204 into the perforating jet. The second angle 98 may be selected such that the shock wave forms the terminating conical section 206 into a disk or platen-type object having a larger diameter than the perforating jet. In one aspect, the first and second angles 96 and 98 orient the walls making up intermediate conical section 204 and the terminating conical section 206 to have different impact angles with the shock wave traveling through the shaped charge. In another aspect, the first and second angles 96 and 98 orient the walls making up intermediate conical section 204 and the terminating conical section 206 to allow a functionally effective amount of explosive material behind the skirt portion 94. By functionally effective amount, it is meant that there is sufficient explosives in order to shape and propel a jet formed by the skirt portion 94 in a desired manner.
The liner 86 may be formed of powder metals or powder metals blended with ductile materials such as aluminum, zinc, copper, tungsten, lead, bismuth, tantalum, tin, brass, molybdenum, etc. Materials such as plasticizers or binder may also be included in a material matrix of the liner 86. The liner 86 may also be formed of malleable solid or sheet metals such as copper, zinc, and Pfinodal. Reactive or energetic materials may also be utilized in the liner 86. In some embodiments, the liner 86 is made of a single material or blend of materials. In other embodiments, the liner 86 utilizes two or more different materials. For example, the skirt portion 94 may be formed of a material different from the material used in the remainder of the liner 86.
In certain applications, an oxidizer may be used in conjunction with the gas-generating material. Suitable oxidizers include potassium sulfate and potassium benzoate. The oxygen released by the oxidizers can combine with a metal fuel such as zinc and/or with carbon or hydrogen (e.g., rubber). Also, materials such as calcium sulfate hemihydrate can function as both a hydrate and a high temperature oxidizer. Additionally, material can be used in conjunction with the gas-generating material to increase the available heat of reaction. Suitable materials include a metal such as finely divided aluminum.
From the above, it should be appreciated that what has been disclosed includes, in part, a method for perforating a formation intersected by a wellbore. The method may include positioning a shaped charge and a reactant composite material in a carrier; positioning the carrier in the wellbore; detonating the shaped charge; and disintegrating the reactant composite material using a shock generated by the detonated shaped charge. The method may also include initiating a first deflagration by using carbon and heat resulting from the detonation of the shaped charge and an oxygen component of the disintegrated reactant composite material. In embodiments, the method may also include initiating a second deflagration using heat from the first deflagration. Such initiating may include applying the heat to an oxygen component of the disintegrated reactant composite material and a fuel. The fuel may be supplied by a case of the shaped charge and/or a support member for the shaped charge. The support member may be a tube or strip. In embodiments, the reactant composite material may include an oxidizer and an inert binder. In one configuration, the reactant composite material may not include a fuel component. In other configurations, the reactant composite material may include an oxidizer, a fuel component and an inert binder. Also, the reactant composite material may be formulated to be oxygen overbalanced in any of these embodiments.
From the above, what has been disclosed also includes a system for perforating a formation intersected by a wellbore. The system may include a carrier, a shaped charge positioned in the carrier; and a reactant composite material positioned in the carrier. The reactant composite material may be configured to disintegrate upon detonation of the shaped charge. In arrangements, the reactant composite material may be interposed between shaped charges. Also, the reactant composite material may include an oxygen component in an amount sufficient to consume substantially all of the carbon resulting from detonation of the shaped charge.
From the above, what has been disclosed further includes a method for perforating a formation intersected by a wellbore. The method may include positioning a plurality of shaped charges and a plurality of pellets formed at least partially of reactant composite material in a carrier; positioning the carrier in the wellbore; disintegrating the plurality of pellets by detonating the plurality of shaped charges; generating a first quantity of gas using carbon and heat resulting from the detonation of the shaped charge and an oxygen component of the disintegrated reactant composite material; and generating a second quantity of gas by applying heat resulting from the generation of the first quantity of gas to an oxygen component of the disintegrated reactant composite material and a fuel.
The foregoing description is directed to particular embodiments of the present disclosure for the purpose of illustration and explanation. It will be apparent, however, to one skilled in the art that many modifications and changes to the embodiment set forth above are possible without departing from the scope of the disclosure. Thus, it is intended that the following claims be interpreted to embrace all such modifications and changes.
This application takes priority from U.S. Provisional Application Ser. No. 61/022,753, filed Jan. 22, 2008. This application is a continuation-in-part of U.S. patent application Ser. No. 11/252,958, filed Oct. 18, 2005 now U.S. Pat. No. 7,621,332, titled “System and Method for Performing Multiple Downhole Operations.”
Number | Name | Date | Kind |
---|---|---|---|
4491185 | McClure | Jan 1985 | A |
6354219 | Pratt et al. | Mar 2002 | B1 |
6991044 | Zhang et al. | Jan 2006 | B2 |
20070084604 | Haney et al. | Apr 2007 | A1 |
20070240880 | Olsen | Oct 2007 | A1 |
Number | Date | Country | |
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20090183916 A1 | Jul 2009 | US |
Number | Date | Country | |
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61022753 | Jan 2008 | US |
Number | Date | Country | |
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Parent | 11252958 | Oct 2005 | US |
Child | 12356362 | US |