Perforating Gun Spacer With Segmented Inner And Outer Tubes
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Solution Overview
Problem
Existing perforating gun connector designs fail to effectively manage fluid flow and pressure differentials during perforation, leading to potential housing deformation, gun sticking, and costly retrieval issues due to inadequate control over volume and pressure resistance.
Innovation Solution
The use of a small diameter inner tube for the detonating cord combined with a pressure-balanced, perforated outer tube configuration that maintains rigidity and strength, controlling fluid volume and minimizing deformation risks, while allowing for elastic or plastic deformation without distorting the outer tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If a traditional housing design with larger diameter is used, then the volume for formation fluid flow is increased, but the housing becomes susceptible to collapse and deformation under pressure differential
Solution Approach 1:
The housing is divided into an inner tube and an outer tube, creating a segmented structure. The inner tube contains the detonation cord and defines the chamber volume, while the outer tube provides structural support and pressure balance. This segmentation allows the volume to be controlled by the inner tube geometry while the outer tube maintains structural integrity under pressure differential.
Solution Approach 2:
Different parts of the housing have different functional properties. The inner tube is designed with specific diameter and wall thickness to control chamber volume and contain the detonation cord. The outer tube is designed with sufficient wall thickness and pressure-balancing features to resist collapse. Each tube is optimized for its specific function rather than using a uniform design throughout.
2Stress or pressure
If the inner tube diameter is reduced to control fluid volume, then pressure resistance is improved, but the detonation cord accommodation and assembly flexibility are constrained
Solution Approach 1:
The housing is segmented into inner and outer tubes with distinct functions. The inner tube diameter is optimized for pressure resistance and chamber volume control, while the outer tube provides structural support and maintains assembly flexibility. The detonation cord passes through the inner tube, which is itself positioned within the outer tube, allowing the system to accommodate standard cord diameters while maintaining a small effective chamber volume.
Solution Approach 2:
The inner tube is nested within the outer tube, creating a concentric configuration. The detonation cord is positioned within the inner tube, which is positioned within the outer tube. This nested arrangement allows multiple components to coexist in a compact space, maintaining pressure resistance while accommodating the detonation cord and preserving assembly flexibility.
3Strength
If the wall thickness of housing tubulars is increased to prevent deformation, then strength is improved, but the volume for formation fluid flow is reduced and material usage increases
Solution Approach 1:
The housing wall thickness requirement is segmented between the inner tube and outer tube. The inner tube has relatively thin walls since its primary function is to contain the detonation cord and define chamber volume, not to resist external pressure. The outer tube has sufficient wall thickness to provide structural support and resist collapse under pressure differential. This segmentation allows the total volume to be maintained while achieving the required strength.
Solution Approach 2:
Different wall thicknesses are applied to different parts of the housing based on their specific functional requirements. The inner tube wall thickness is optimized for containing the detonation cord and maintaining chamber geometry, while the outer tube wall thickness is optimized for pressure resistance. This localized optimization allows the system to achieve sufficient strength without unnecessarily reducing chamber volume or increasing material usage.
4Stability of the object's composition
If the housing is designed to be rigid to maintain shape, then structural integrity is improved, but the ability to tolerate pressure swings and shockwaves is reduced
Solution Approach 1:
The housing is segmented into an inner tube and an outer tube with a gap between them. The inner tube maintains the chamber shape and contains the detonation cord, providing shape stability. The outer tube provides structural support and can tolerate deformation without compromising the overall integrity. The gap between the tubes allows for pressure equalization and shockwave dissipation, enabling the system to tolerate pressure swings while maintaining structural integrity.
Solution Approach 2:
The gap between the inner and outer tubes acts as an intermediary space that mediates the interaction between the chamber pressure and the external environment. This gap allows pressure equalization and shockwave dissipation, protecting the rigid inner tube from excessive stress while maintaining the overall structural integrity of the housing assembly.
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 configuration enhances pressure resistance, reduces the likelihood of gun sticking, and maintains assembly integrity by managing fluid influx and pressure surges, especially in high-pressure environments with unconsolidated sandstones, thereby simplifying retrieval and maintaining perforation efficiency.
Implementation Method 1
differential pressures during firing of the guns and to further limit the potential volume in the gun for the formation fluid to fill after the guns are shot
Implementation Method 2
An outer tube that is in pressure balance can because it has a series of holes conforms to the shape of the remaining connector components so that even if the pressurized inner tube is distorted the guns will not be stuck at the connectors
Implementation Method 3
the detonation cord 12 is no longer there since it is consumed to shoot the guns
Implementation Method 4
A surrounding housing has machined recesses that are aligned with the shaped charges so that when the gun is set off the released energy exits through the housing recesses and creates perforation tunnels
Data Source
AI summary
Perforating gun connectors are provided with a small diameter inner tube to house the detonating cord and an outer load-bearing tube that is ported to be in pressure balance. The inner tube controls the volume in the gun for the well fluids to enter after the guns are fired and the initial pressure surge dissipates. The smaller diameter also increases pressure rating and diminishes the chance of plastic deformation. Since the inner tube is inset even some deformation is tolerated without distorting the outer tube due to the space between the tubes. A bored rod is used as a housing member or a layered single outer wall.