PEFORATING GUN CLUSTER SYSTEM FOR WELLBORE OPERATIONS

Description

TECHNICAL FIELD

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

BACKGROUND

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.

SUMMARY OF THE INVENTION

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.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a perforating gun cluster system in accordance with one embodiment of the present invention where the perforating gun cluster system comprises four perforating guns.

FIG. 2 is a perspective view of a perforating gun cluster system in accordance with one embodiment of the present invention where the perforating gun cluster system comprises sixteen perforating guns.

FIG. 3 is an exploded view of a perforating gun cluster system in accordance with one embodiment of the presenting invention where the perforating gun cluster system comprises sixteen perforating guns, but only one perforating gun is depicted for ease of reference.

DETAILED DESCRIPTION

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 FIG. 1, a perforating gun cluster system in accordance with one embodiment is illustrated and generally designated 10. The perforating gun cluster system 10 (“the system”) includes a central core 12 and a plurality of perforating guns 14 attached to the central core 12. Each perforating gun 14 includes an outer gun barrel 16, a shaped charge positioning tube (not shown), and a contact housing 18.

As shown in FIG. 1, the central core 12 includes a plurality of upper retaining arms 20 and a plurality of lower retaining arms 22. Each upper retaining arm 20 is paired with and connected to an upper end 24 of the respective perforating gun 14. Likewise, each lower retaining arm 22 is paired with and connected to a lower end 26 of the respective perforating gun 14, thereby retaining each perforating gun 14 to the central core 12 to give the perforating gun cluster system 10. The perforating gun cluster system 10 may include between two and thirty-two perforating guns 14, alternatively between two and sixteen perforating guns 14. Each upper retaining arm 20 and each lower retaining arm 22 defines a perforating gun aperture 38, 40 so that each perforating gun 14 is retained within the respective aperture of the upper retaining arm 20 and the respective aperture of the lower retaining arm 22.

As depicted in FIG. 1, the system includes four perforating guns 14. The plurality of perforating guns 14 are equally spaced about the central core 12. Each perforating gun 14 defines 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 barrel 16 of each perforating gun 14 defines a charge outlet 28 as seen in FIG. 1. The shaped charge positioning tube (not shown) of each perforating gun 14 defines a shaped charge opening (not shown). The shaped charge opening is configured to receive a shaped charge. The charge outlet 28 is radially aligned with the shaped charge opening. Both the charge outlet 28 and the shaped charge opening face radially outward from the central core 12. As shown in FIG. 1, the outer gun barrel 16 of each perforating gun 14 defines two charge outlets 28. Likewise, the shaped charge positioning tube of each perforating gun 14 defines two shaped charge openings. The system 10 according 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 28. The two charge outlets 28 and the two shaped charge openings are axially aligned with each other; however, this need not be the case, and the charge outlets 28 and shaped charge openings may be axially offset, so long as the charge outlets 28 are radially aligned with the respective shaped charge openings and the charge outlets 28 and shaped charge openings face substantially radially outward from the central core 12.

In some embodiments, each perforating gun 14 independently defines between 1 to 160 charge outlets 28 and the shaped charge positioning tube of each perforating gun 14 independently defines 1 to 160 shaped charge openings. It will be appreciated that the number of charge outlets 28 and shaped charge openings will be the same on the same perforating gun 14. The perforating gun cluster system 10 further comprises an at least one shaped charge. Generally, the perforating gun cluster system 10 will comprise a shaped charge for each shaped charge opening defined by the shaped charge positioning tube of each perforating gun 14. In these embodiments, the shaped charges are disposed within the respective shaped charge openings.

Referring now to FIG. 2, a perforating gun cluster system in accordance with one embodiment is illustrated and generally designated 10. The system 10 includes sixteen perforating guns 14. The central core 12 of the system 10 comprises an upper plate 30 connected to a lower plate 32 by a connecting rod 33. The upper plate 30 includes a plurality of upper retaining arms 34 and the lower plate 32 includes a plurality of lower retaining arms 36. Each upper retaining arm 34 is paired with and connected to an upper end of a respective perforating gun 14. Each lower retaining arm 36 is paired with and connected to a lower end 26 of the respective perforating gun 14. The connection of each perforating gun 14 with a pair of upper and lower retaining arms 34, 36 retains each perforating gun 14 within the perforating gun cluster system 10.

The upper plate 30 and the lower plate 32 each define a plurality of perforating gun apertures 38, 40. Each perforating gun 14 corresponds to a respective perforating gun aperture 38 in the upper plate 30 and a respective perforating gun aperture 40 in the lower plate 32. Each perforating gun 14 is retained within the respective gun aperture 38 of the upper plate 30 and the respective gun aperture 40 of the lower plate 32. As depicted in FIG. 2, the plurality of perforating gun apertures 38, 40 is defined by the plurality of upper retaining arms 34 and the plurality of lower retaining arms 36. Each perforating gun aperture 38 in the upper plate 30 is smaller than the corresponding perforating gun aperture 40 in the lower plate 32. The perforating gun apertures in the upper plate 30 are sized to receive the contact housing 18.

As shown in FIG. 2, the outer gun barrel 16 of each perforating gun defines two charge outlets 28. Likewise, the shaped charge positioning tube of each perforating gun 14 defines two shaped charge openings. These shaped charge openings are radially aligned with the respective charge outlets 28. The two charge outlets 28 are 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 FIG. 3, a perforating gun cluster system in accordance with one embodiment is illustrated and generally designated 10. The system 10 includes sixteen perforating guns 14. The central core 12 of the system 10 comprises an upper plate 30 connected to a lower plate 32 by a connecting rod 33. The upper plate 30 and the lower plate 32 each define a plurality of perforating gun apertures 38, 40. Each perforating gun 14 corresponds to a respective perforating gun aperture 38 in the upper plate 30 and a respective perforating gun aperture 40 in the lower plate 32. Each perforating gun 14 is retained within the respective gun aperture 38 of the upper plate 30 and the respective gun aperture 40 of the lower plate 32. Each perforating gun aperture 38 in the upper plate 30 is smaller than the corresponding perforating gun aperture 40 in the lower plate 32. The perforating gun apertures 38 in the upper plate 30 are sized to receive the contact housing 18. Notably, the embodiment depicted in FIG. 3 does not include retaining arms.

As shown in FIG. 3, the upper plate 30 is retained to the connecting rod 33 by two washers 42, two lock washers 44, and two nuts 46, with one of each washer 42, lock washer 44, and nut 46 on either side of the upper plate 30. Likewise, the lower plate 32 is retained to the connecting rod 33 by two washers 42, two lock washers 44, and two nuts 46, with one of each washer 42, lock washer 44, and nut 46 on either side of the lower plate 32. The contact housing 18 is received within a respective perforating gun aperture 38 in the upper plate 30. Each contact housing 18 is configured to establish an electrical connection with a firing head 49. Each contact housing 18 is connected to the outer gun barrel 16 of the perforating gun 14 by an upper threaded sub 48. The outer gun barrel 16 is further connected to a bull nose 50 by a lower threaded sub 52. The lower threaded sub 52 is positioned within a respective perforating gun aperture 40 in the lower plate 32.

In some embodiments, the number of perforating guns 14 is selected in view of the diameter of the perforating guns 14. For example, each perforating gun 14 has a diameter of 7″ and the system 10 comprises twelve perforating guns 14 or each perforating gun 14 has a diameter of 1.69″ and the system 10 comprises sixty perforating guns 14. The system 10 also 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 system 10 is a function of the diameter of the individual perforating guns 14 and the size of the central core 12.

Each perforating gun 14 defines 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 gun 14 is 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 gun 14 includes an outer gun barrel 16. The outer gun barrel 16 includes opposing ends and a cylindrical sidewall having an inner surface. The outer gun barrel 16 is cylindrical and includes a length that is greater than a length of the shaped charge positioning tube, such that the outer gun barrel 16 extends beyond the charge positioning tube. In addition, the outer gun barrel 16 includes 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 barrel 16 and the shaped charge positioning tube along its length. The outer gun barrel 16 further defines a charge outlet 28 facing radially outward from the central core 12.

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 12. 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 barrel 16 and the shaped charge positioning tube are generally formed from an electrically conductive material (e.g., stainless steel). As depicted in FIGS. 1-3, the outer gun barrel 16 of each perforating gun 14 defines two charge outlets 28 and the shaped charge positioning tube of each perforating gun 14 defines two shaped charge openings. The two charge outlets 28 and two shaped charge openings are radially aligned.

As shown in FIGS. 1-3, each perforating gun 14 also includes a contact housing 18. In some embodiments, the perforating gun 14 includes 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 housing 18 is partially received within opposing ends of the shaped charge positioning tube. Each contact housing 18 also 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.