High Density Cluster Perforating Gun with Standoff Carrier
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Solution Overview
Problem
Small diameter perforating guns face challenges in achieving high shot density due to charge interference and the need for reduced charge size, which affects perforation depth and production, and existing systems lack sufficient standoff for effective jet penetration in smaller guns.
Innovation Solution
The design incorporates a gun carrier with internal features such as scallops or hyperdomes that create a standoff between shaped charges and the internal wall, allowing for increased spacing and effective detonation without reducing charge caliber, enabling high density perforations in smaller guns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If shaped charges are spaced at intervals along the length of the perforating gun to achieve high shot density, then the number of perforations per unit length increases, but the charge caliber must be reduced which significantly reduces the amount of explosives and deteriorates perforation depth
Solution Approach 1:
The patent transitions from linear spacing of charges along the gun length to a three-dimensional cluster arrangement where charges are positioned in multiple planes (first plane with 3 charges, second plane with 4 charges). This spatial reconfiguration allows high shot density without reducing charge caliber, as charges utilize volumetric space rather than merely linear spacing.
Solution Approach 2:
The patent employs nested charge cases where smaller charge cases are positioned within or adjacent to larger ones in a compact three-dimensional arrangement. The first charge case contains 3 shaped charges in a first plane, while the second charge case contains 4 shaped charges in a second plane, creating a nested cluster configuration that maximizes charge density without compromising individual charge size.
2Reliability
If the detonator cord sets off charges in sequence to avoid charge interference, then charge interference is prevented, but the detonation timing and spacing become critical constraints on charge placement and gun design
Solution Approach 1:
The patent extracts the detonation sequencing function from the charge placement geometry by using a longitudinal detonator cord that passes through all charge cases in sequential order. This separates the spatial arrangement (which achieves high density through 3D clustering) from the temporal detonation sequence (handled by the linear cord progression), reducing design constraints on charge placement.
Solution Approach 2:
The detonator cord acts as an intermediary element that mediates the detonation sequence between the power source and individual charges. By routing the cord longitudinally through both charge cases in a defined sequence (first through charges in the first plane, then through charges in the second plane), it provides a simple mechanical means of sequential detonation without requiring complex electronic timing or simultaneous detonation mechanisms.
3Length of stationary object
If smaller diameter guns are used to reduce wellbore invasion, then wellbore invasion is reduced, but the gun length and internal volume are reduced making it difficult to achieve high shot density without reducing charge size
Solution Approach 1:
The patent resolves the space constraint of small-diameter guns by transitioning from two-dimensional linear charge arrays to three-dimensional charge clusters. By arranging charges in multiple planes (first plane with 3 charges, second plane with 4 charges) and utilizing vertical spacing between planes, the design achieves high shot density within the limited internal volume of a compact gun body with outer diameter of 3-4 inches.
Solution Approach 2:
The patent employs curved or scalloped internal features in the gun carrier walls to create standoff distances between charges and the gun body. These curved geometries (scallops extending into the gun carrier wall) allow optimal charge positioning within the constrained space, maintaining required standoff for effective jet penetration while maximizing the number of charges that can be accommodated in the limited volume.
4Ease of operation
If relief ports are drilled through the gun body to provide charge exit points, then charge ejection is enabled, but burr formation around exit holes causes damage and requires additional clearance space
Solution Approach 1:
The patent extracts the charge ejection function from traditional through-wall relief ports by using end plates with radial slots that allow charges to be ejected radially outward from the charge cases. This eliminates the need for burr-prone through-wall holes in the gun body, as charges exit through controlled slots in the end plates where burr formation is minimized and does not compromise gun structural integrity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution allows for effective high-density perforations with increased standoff, preventing charge interference and maintaining charge caliber, resulting in improved perforation depth and production efficiency in smaller diameter guns.
Implementation Method 1
These are shaped charges that produce an explosive-formed penetrating jet in the chosen direction in which the charge is directed
Implementation Method 2
The firing of the perforating gun detonates charges that are loaded in the perforation gun
Data Source
AI summary
A perforating gun for use in a well casing, the gun having a gun carrier extending along a longitudinal axis; plural shaped charges located inside the gun carrier, in groups of three, a first group of three shaped charges being positioned in a first single plane, transverse to the longitudinal axis, and a second group of three shaped charges being positioned in a second single plane, transverse to the longitudinal axis; and a charge holder configured to carry the plural shaped charges, the charge holder configured to be inserted into the gun carrier. The first and second groups of three charges are spaced along the longitudinal axis so that a third single plane, transverse to the longitudinal axis, intersects each of the six shaped charges of the first and second groups of three charges, to achieve an ultra-short, high-density, perforating gun.