Rotating Shaped Charge Holder for Sealed, High-Pressure Guns
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Solution Overview
Problem
Existing perforating gun assemblies require tandem seal adapters for sealed connections, leading to increased length and cost, and the use of rotating charge tubes can cause tool failure due to friction and wear, while step-down contours in gun housings may result in collapse under high pressure.
Innovation Solution
A rotating shaped charge positioning device with a shaped charge holder and initiator holder coupled via a rotation coupling, allowing for a sealed connection without tandem seal adapters, and a gun housing with a continuous banded scallop geometry to withstand elevated pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tandem seal adapters are used to provide sealed connections between adjacent perforating guns, then sealing reliability is improved, but the overall length of the perforating gun assembly increases and manufacturing cost increases
Solution Approach 1:
The patent integrates the sealing function directly into the perforating gun housing structure by forming a sealing surface on the housing itself, rather than using separate tandem seal adapters. This merging of functions eliminates the need for additional sealing components and reduces overall assembly length while maintaining sealing reliability.
Solution Approach 2:
The perforating gun housing is designed to perform multiple functions: it provides structural containment, enables rotation of the charge holder, and creates sealed connections with adjacent guns. The housing incorporates a sealing surface that allows it to function as both a structural component and a sealing element, eliminating the need for dedicated seal adapters.
2Reliability
If tandem seal adapters are used to provide sealed connections, then sealing reliability is improved, but manufacturing cost increases
Solution Approach 1:
The sealing function is merged into the housing structure, eliminating the need for separate seal adapter components. This reduces the total number of parts that need to be manufactured, assembled, and inventoried, thereby reducing manufacturing cost while maintaining sealing reliability.
Solution Approach 2:
The housing is designed as a multi-functional component that provides both structural support and sealing capability. By making the housing itself capable of creating sealed connections, the design reduces the number of specialized components needed, simplifying manufacturing and reducing costs.
3Ease of operation
If a rotating charge tube is used to orient shaped charges, then firing orientation control is improved, but friction and wear increase leading to tool failure
Solution Approach 1:
The patent replaces the traditional rotating charge tube mechanism with a rotating shaped charge holder that operates on a different mechanical principle. The new design uses a rotation coupling mechanism that reduces friction and wear by improving the bearing surface contact and distributing loads more effectively, thereby maintaining orientation control while reducing tool failure.
Solution Approach 2:
The invention changes the mechanical parameters of the rotation system by modifying the bearing surfaces and contact points. The rotation coupling mechanism uses optimized surface geometry and material properties to reduce friction coefficients and wear rates, allowing for reliable repeated rotations without tool failure.
4Ease of manufacture
If step-down contours are machined on the gun housing wall, then manufacturing cost is reduced, but the housing may collapse under high pressure
Solution Approach 1:
The patent applies local quality by providing reinforcement specifically at the banded scallop regions where the housing wall is thinned. Instead of making the entire housing uniformly thick (which would increase manufacturing complexity), the design locally strengthens only the areas where pressure resistance is critical, maintaining overall structural integrity while preserving manufacturing efficiency.
Solution Approach 2:
The housing incorporates composite construction with regions of varying wall thickness and material properties. The banded scallop areas feature reinforced construction that combines the thinned-wall design for weight reduction with localized strengthening features that maintain pressure resistance, creating a composite structure that balances manufacturing ease with structural strength.
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
The solution provides a reliable, sealed connection and prevents gun housing collapse under high pressure, reducing assembly complexity and tool failure.
Implementation Method 1
Typical known rotating charge carrying devices can gravitationally orient an opening of a shaped charge to a desired firing angle
Implementation Method 2
a surface signal actuates an ignition of a fuse or detonator, which in turn initiates a detonating cord, which detonates the explosive charges to penetrate/perforate the casing
Implementation Method 3
The perforating gun includes explosive charges, typically shaped, hollow or projectile charges, which are initiated to perforate holes in the casing and to blast through the formation
Data Source
AI summary
A shaped charge positioning device may include a shaped charge holder, an initiator holder coupled to the shaped charge holder via a first rotation coupling, and a shaped charge receptacle provided on the shaped charge holder. The shaped charge receptacle may be rotatable around a central longitudinal axis of rotation of the shaped charge positioning device relative to the initiator holder. A perforating gun assembly may include a shaped charge holder provided in a gun housing chamber and rotatable relative to the gun housing. A wellbore tool string may include a first gun housing including a first shaped charge holder rotatably coupled to a second gun housing including a second shaped charge holder. An initiator provided in the first gun housing may be electrically coupled to an initiator provided in the second gun housing.