Peforating Gun Cluster System for Wellbore Operations

The present invention relates to a perforating gun cluster system to generate perforations through a wellbore casing.

In oil and gas operations, perforating guns are used to create perforations in a wellbore casing and surrounding rock formations. A gun string containing multiple perforating guns can be lowered into the wellbore on a wireline, slickline, or coiled tubing. Each perforating gun includes shaped charges that, when fired, are formed into high-velocity jets that penetrate the wellbore casing and create perforations in the surrounding rock.

The design and configuration of perforating guns are pivotal factors influencing the efficiency and success of well completion operations. Perforating guns are sized and configured based on a multitude of considerations, including the geological characteristics of the formation, wellbore dimensions, reservoir depth, pressure conditions, and anticipated production rates. These guns are tailored to meet the unique requirements of each wellbore, ensuring optimal penetration and perforation density while minimizing risks associated with formation damage and loss of wellbore integrity. Consequently, the development of perforating guns that can be accurately sized and configured for specific wellbore conditions remains a significant challenge in the industry, necessitating innovations aimed at enhancing precision, reliability, and overall performance in hydrocarbon recovery operations.

Accordingly, there remains a continued need for an improved perforating gun for wellbore operations, particularly bespoke applications to particular wellbores.

An improved perforating gun system is provided. The perforating gun system, referred to herein as a perforating gun cluster system, includes a central core and a plurality of perforating guns attached to the central core and spaced radially outwardly therefrom. Each perforating gun includes an outer gun barrel including a plurality of charge outlets and a contact housing on one end of the shaped charge positioning tube including an electrical connector plug protruding axially therefrom. The central core further includes a plurality of upper retaining arms, a plurality of lower retaining arms, and a connecting rod therebetween. Each upper retaining arm is paired with and connected to an upper end of the respective perforating gun. Each lower retaining arm is paired with and connected to a lower end of the respective perforating gun such that each perforating gun is retained in the perforating gun system.

Another improved perforating gun is provided. The perforating gun system includes an upper plate and a lower plate. The upper plate includes a first plurality of axial openings. The lower plate includes a second plurality of axial openings. The lower plate is axially spaced apart from the upper plate, such that the first plurality of axial openings are aligned with the second plurality of axial openings. A connecting rod rigidly couples the upper plate to the lower plate. The perforating gun system further includes a plurality of perforating guns disposed between the upper plate and the lower plate. Each one of the plurality of perforating guns is aligned with a respective axial opening in the upper plate and a respective axial opening in the lower plate.

The upper plate and lower plate are circular plates. The upper plate and the lower plate each comprise a plurality of retaining arms. The connecting rod is centrally disposed between the plurality of perforating guns. The plurality of perforating guns are equally spaced about the connecting rod.

According to one embodiment, the system comprises four perforating guns. In other embodiments, the system may comprise between two and sixteen perforating guns. The four perforating guns are equally spaced about the central core. The central core comprises a plurality of upper retaining arms and a plurality of lower retaining arms, wherein each upper retaining arm is paired with and connected to an upper end of the respective perforating gun and each lower retaining arm is paired with and connected to a lower end of the respective perforating gun such that each perforating gun is retained in the perforating gun cluster system. A connecting rod rigidly couples the plurality of upper retaining arms to the plurality of lower retaining arms.

The outer gun barrel of each perforating gun defines a charge outlet, a shaped charge positioning tube of each perforating gun defines a shaped charge opening, and both the charge outlet and the shaped charge opening face radially outward from the central core. The outer barrel of each perforating gun defines two charge outlets. Each perforating gun further comprises at least one shaped charge. Each of the perforating guns may define an independently selected diameter of between 1″ to 7″. The outer gun barrel of each perforating gun may independently define between 1 to 160 charge outlets.

According to another embodiment, the system comprises sixteen perforating guns. The sixteen perforating guns are equally spaced about the central core. The outer gun barrel of each perforating gun defines at least two charge outlets, and the charge outlets face radially outward, away from the connecting rod. The plurality of upper retaining arms comprise an upper plate and the plurality of lower retaining arms comprise a lower plate. The upper plate and the lower plate are rigidly coupled to the connecting rod. Each perforating gun is clamped between the upper plate and the lower plate. The upper plate and the lower plate each define a plurality of perforating gun apertures, with each perforating gun corresponding to a respective perforating gun aperture in the upper plate and a respective gun aperture in the lower plate. Each upper retaining arm is paired with and connected to an upper end of the respective perforating gun and each lower retaining arm is paired with and connected to a lower end of the respective perforating gun such that each perforating gun is retained in the perforating gun cluster system.

These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawing and appended claims.

Before embodiments of the invention are explained in detail, it is to be understood that the invention is not limited to the details of operation or to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention may be implemented in various other embodiments and may be practiced or carried out in alternative ways not expressly disclosed herein. In addition, it is to be understood that the phraseology and terminology used herein are for the purpose of description and should not be regarded as limiting. The use of “including” and “comprising” and variations thereof is meant to encompass the items listed thereafter and equivalents thereof as well as additional items and equivalents thereof. Further, enumeration may be used in the description of various embodiments. Unless otherwise expressly stated, the use of enumeration should not be construed as limiting the invention to any specific order or number of components. Nor should the use of enumeration be construed as excluding from the scope of the invention any additional steps or components that might be combined with or into the enumerated steps or components.

The following detailed description is merely exemplary in nature and is not intended to limit the oilfield perforating gun cluster system as described herein. Furthermore, there is no intention to be bound by any theory presented in the preceding background or the following detailed description. The description is not in any way meant to limit the scope of any present or subsequent related claims.

As used here, the terms “above” and “below”; “up” and “down”; “upper” and “lower”; “upwardly” and “downwardly”; and other like terms indicating relative positions above or below a given point or element are used in this description to more clearly describe some embodiments. 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 diagonal relationship as appropriate.

Referring now to, a perforating gun cluster system in accordance with one embodiment is illustrated and generally designated. The perforating gun cluster system(“the system”) includes a central coreand a plurality of perforating gunsattached to the central core. Each perforating gunincludes an outer gun barrel, a shaped charge positioning tube (not shown), and a contact housing.

As shown in, the central coreincludes a plurality of upper retaining armsand a plurality of lower retaining arms. Each upper retaining armis paired with and connected to an upper endof the respective perforating gun. Likewise, each lower retaining armis paired with and connected to a lower endof the respective perforating gun, thereby retaining each perforating gunto the central coreto give the perforating gun cluster system. The perforating gun cluster systemmay include between two and thirty-two perforating guns, alternatively between two and sixteen perforating guns. Each upper retaining armand each lower retaining armdefines a perforating gun aperture,so that each perforating gunis retained within the respective aperture of the upper retaining armand the respective aperture of the lower retaining arm.

As depicted in, the system includes four perforating guns. The plurality of perforating gunsare equally spaced about the central core. Each perforating gundefines an independently selected diameter of between 1″ and 38″, alternatively between 1″ and 21″, alternatively between 1″ and 10″, or alternatively between 1″ and 7″.

The outer gun barrelof each perforating gundefines a charge outletas seen in. The shaped charge positioning tube (not shown) of each perforating gundefines a shaped charge opening (not shown). The shaped charge opening is configured to receive a shaped charge. The charge outletis radially aligned with the shaped charge opening. Both the charge outletand the shaped charge opening face radially outward from the central core. As shown in, the outer gun barrelof each perforating gundefines two charge outlets. Likewise, the shaped charge positioning tube of each perforating gundefines two shaped charge openings. The systemaccording to this embodiment therefore comprises eight shaped charge openings and is configured to include eight shaped charges. These shaped charge openings are radially aligned with the respective charge outlets. The two charge outletsand the two shaped charge openings are axially aligned with each other; however, this need not be the case, and the charge outletsand shaped charge openings may be axially offset, so long as the charge outletsare radially aligned with the respective shaped charge openings and the charge outletsand shaped charge openings face substantially radially outward from the central core.

In some embodiments, each perforating gunindependently defines between 1 to 160 charge outletsand the shaped charge positioning tube of each perforating gunindependently defines 1 to 160 shaped charge openings. It will be appreciated that the number of charge outletsand shaped charge openings will be the same on the same perforating gun. The perforating gun cluster systemfurther comprises an at least one shaped charge. Generally, the perforating gun cluster systemwill comprise a shaped charge for each shaped charge opening defined by the shaped charge positioning tube of each perforating gun. In these embodiments, the shaped charges are disposed within the respective shaped charge openings.

Referring now to, a perforating gun cluster system in accordance with one embodiment is illustrated and generally designated. The systemincludes sixteen perforating guns. The central coreof the systemcomprises an upper plateconnected to a lower plateby a connecting rod. The upper plateincludes a plurality of upper retaining armsand the lower plateincludes a plurality of lower retaining arms. Each upper retaining armis paired with and connected to an upper end of a respective perforating gun. Each lower retaining armis paired with and connected to a lower endof the respective perforating gun. The connection of each perforating gunwith a pair of upper and lower retaining arms,retains each perforating gunwithin the perforating gun cluster system.

The upper plateand the lower plateeach define a plurality of perforating gun apertures,. Each perforating guncorresponds to a respective perforating gun aperturein the upper plateand a respective perforating gun aperturein the lower plate. Each perforating gunis retained within the respective gun apertureof the upper plateand the respective gun apertureof the lower plate. As depicted in, the plurality of perforating gun apertures,is defined by the plurality of upper retaining armsand the plurality of lower retaining arms. Each perforating gun aperturein the upper plateis smaller than the corresponding perforating gun aperturein the lower plate. The perforating gun apertures in the upper plateare sized to receive the contact housing.

As shown in, the outer gun barrelof each perforating gun defines two charge outlets. Likewise, the shaped charge positioning tube of each perforating gundefines two shaped charge openings. These shaped charge openings are radially aligned with the respective charge outlets. The two charge outletsare axially aligned with each other. Likewise, the two shaped charge openings are axially aligned with each other. It will be appreciated that this embodiment comprises a total of 32 shaped charge openings and is configured to include 32 shaped charges.

Referring now to, a perforating gun cluster system in accordance with one embodiment is illustrated and generally designated. The systemincludes sixteen perforating guns. The central coreof the systemcomprises an upper plateconnected to a lower plateby a connecting rod. The upper plateand the lower plateeach define a plurality of perforating gun apertures,. Each perforating guncorresponds to a respective perforating gun aperturein the upper plateand a respective perforating gun aperturein the lower plate. Each perforating gunis retained within the respective gun apertureof the upper plateand the respective gun apertureof the lower plate. Each perforating gun aperturein the upper plateis smaller than the corresponding perforating gun aperturein the lower plate. The perforating gun aperturesin the upper plateare sized to receive the contact housing. Notably, the embodiment depicted indoes not include retaining arms.

As shown in, the upper plateis retained to the connecting rodby two washers, two lock washers, and two nuts, with one of each washer, lock washer, and nuton either side of the upper plate. Likewise, the lower plateis retained to the connecting rodby two washers, two lock washers, and two nuts, with one of each washer, lock washer, and nuton either side of the lower plate. The contact housingis received within a respective perforating gun aperturein the upper plate. Each contact housingis configured to establish an electrical connection with a firing head. Each contact housingis connected to the outer gun barrelof the perforating gunby an upper threaded sub. The outer gun barrelis further connected to a bull noseby a lower threaded sub. The lower threaded subis positioned within a respective perforating gun aperturein the lower plate.

In some embodiments, the number of perforating gunsis selected in view of the diameter of the perforating guns. For example, each perforating gunhas a diameter of 7″ and the systemcomprises twelve perforating gunsor each perforating gunhas a diameter of 1.69″ and the systemcomprises sixty perforating guns. The systemalso defines a diameter of between 2″ and 42″, alternatively between 4″ and 24″, alternatively between 6″ and 18″. It will be appreciated that the diameter of the systemis a function of the diameter of the individual perforating gunsand the size of the central core.

Each perforating gundefines an independently selected length of between 0.5 feet and 40 feet, alternatively 1 foot to 20 feet, alternatively 2 feet to 10 feet, or alternatively 1 foot to 5 feet. Each perforating gunis configured to contain a certain number of shaped charges per foot. The number of shots per foot is between 1 shot/foot to 6 shots/foot, alternatively 2 shots/foot, alternatively 1 shot/foot.

Each perforating gunincludes an outer gun barrel. The outer gun barrelincludes opposing ends and a cylindrical sidewall having an inner surface. The outer gun barrelis cylindrical and includes a length that is greater than a length of the shaped charge positioning tube, such that the outer gun barrelextends beyond the charge positioning tube. In addition, the outer gun barrelincludes an inner diameter that is greater than an outer diameter of the shaped charge positioning tube, such that an annular gap is present between the outer gun barreland the shaped charge positioning tube along its length. The outer gun barrelfurther defines a charge outletfacing radially outward from the central core.

The shaped charge positioning tube includes a cylindrical body having multiple shaped charge openings that receive a corresponding number of shaped charges. The shaped charge openings are axially aligned with each other in the illustrated embodiments but may be angularly offset from each other in other embodiments. The shaped charge openings face radially outward from the central core. The shaped charge positioning tube includes two shaped charge openings per perforating gun in the illustrated embodiment, while in other embodiments the shaped charge positioning tube can include greater or fewer openings. The shaped charge positioning tube is received with the outer gun barrel.

The outer gun barreland the shaped charge positioning tube are generally formed from an electrically conductive material (e.g., stainless steel). As depicted in, the outer gun barrelof each perforating gundefines two charge outletsand the shaped charge positioning tube of each perforating gundefines two shaped charge openings. The two charge outletsand two shaped charge openings are radially aligned.

As shown in, each perforating gunalso includes a contact housing. In some embodiments, the perforating gunincludes a second contact housing. Each contact housing is formed from an electrically insulating material (e.g., molded plastic). In addition, in embodiments where there are two contact housings, each contact housingis partially received within opposing ends of the shaped charge positioning tube. Each contact housingalso includes an electrical connector plug protruding axially from the contact housing. The electrical connector plug may be a banana pin connector plug. The electrical connector plug may include a spring plunger.

The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.