Charge tube end plate

Abstract

An end plate for securing and orienting a charge tube within a downhole-perforating gun. The end plate includes apertures for receiving locating tabs on the end of the charge tube to ensure the end plate is affixed to the charge tube in a specific orientation. The end plate includes an alignment tab that mates with a corresponding alignment groove in the perforating gun barrel for ensuring insertion of the charge tube into the perforating gun barrel in correct orientation to ensure the perforating charges exit through pre-designed scallops in the perforating gun barrel. A series of apertures may be present within the end plate to allow usage with one of a variety of sizes of charge tube. The end plate may include manipulation spaces along the circumference of the end plate to allow the end plate to be properly positioned or retrieved. The end plate may include an attachment system for attachment of an initiating device.

Description

FIELD OF THE INVENTION [0001] The present invention relates generally to well perforation tools. More particularly, the present invention relates to an end plate for securing a charge tube within the barrel of a perforating gun. More particularly, the present invention relates to an end plate for securing a charge tube within the barrel of a perforating gun having an attachment system for an initiating device. BACKGROUND OF THE INVENTION [0002] During the production life of an oil or gas well, it often becomes necessary to perforate the well casing and cement liner of the well in order to obtain access to further deposits within the formation. Several technologies have been developed for this purpose, including the use of downhole explosives, which are generally shaped charges placed and targeted to perforate the casing at a specific well depth and in a specific pattern. Generally, a “gun” containing a series of tailored shaped explosive charges, and a firing head are either run on ...

AI Technical Summary

Benefits of technology

[0010] It is an object of the present invention to obviate or mitigate at least one disadvantage of previous perforating gun assembly systems.

[0013] In another aspect, the present invention provides a process for assembling a perforating gun including the steps of obtaining a charge tube with open ends, the charge tube loaded with charges and having an arrangement of locating tabs on at least one of the open ends; providing an end plate slideable within a perforating gun barrel and having a corresponding arrangement of alignment apertures for mating with the locating tabs, the end plate also having an alignment system for mating in specific orientation with the inner surface of a perforating gun barrel, affixing the end plate against the end of the charge tube such that the locating tabs mate with the alignment apertures; and inserting the charge tube and end plate into the perforating gun barrel such that the alignment system properly orients the end plate and the charge tube within the perforating gun barrel to align the charges with weakened or scalloped portions of the perforating gun barrel.

Problems solved by technology

Due to the large size and weight of each component to be assembled (charge tube, perforating charges, and gun barrel), proper alignment of components during assembly is critical, however misalignment can often go undetected due to shearing of the aluminum alignment mechanism during accidental misassembly.

Misalignment of a charge tube within the gun barrel may cause gun failure, resulting in a poorly fractured formation which may or may not be detected, or damage to the tubing or casing.

Moreover, if the formation is poorly fractured, and reperforation is an option, it may be difficult, if not impossible, to retrieve the now misshapen gun components from their downhole location (in a worst case scenario).

Due to the minimal threading depth, the depth of the alignment slot is limited, which in turn limits the size and effectiveness of the mating alignment tab on the aluminum end collar of the prior art.

An additional disadvantage to current end collars is cost.

As the end collars are manufactured by casting or machining, the cost of current end collars is relatively high, including the cost of dies and molding equipment and special machinery.

This mechanical engagement, while having the advantage of simple assembly, introduces disadvantages to the system by providing movable and deformable parts, reducing the integrity of the system.

In addition, it does not sufficiently address the issue of misalignment.

It is susceptible to insecure assembly by reliance on deformed tabs, and provides little room for manipulation during the assembly process, which often takes place in the field.

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