Shaped Charge Liner Geometry for Consistent Perforation Holes
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Solution Overview
Problem
Current perforation systems in the oil and gas industry face challenges in creating consistent and predictable entrance hole diameters and perforation tunnel dimensions, leading to unpredictable fracturing results and increased costs due to variations in design and environmental factors.
Innovation Solution
The use of shaped charges with a liner having a subtended angle of 100° to 120°, which creates a constant diameter jet that forms consistent entrance holes and perforation tunnels, unaffected by factors such as casing diameter, gun diameter, and water gap, ensuring a variation of less than 7.5% in entrance hole diameters and perforation tunnel dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional shaped charges are used with varying design and environmental factors, then the perforation system can adapt to different casing and gun configurations, but the entrance hole diameter and perforation tunnel dimensions vary significantly (greater than 7.5% variation)
Solution Approach 1:
The patent applies parameter changes by optimizing the liner geometry parameters (subtended angle of 100° to 120°, aspect ratio, and radius) to create a shaped charge that produces consistent entrance hole diameters regardless of variations in casing diameter, gun diameter, or water gap. This geometric parameter optimization resolves the contradiction by making the perforation outcome insensitive to design and environmental variations.
Solution Approach 2:
The patent applies local quality by designing the liner with a specific subtended angle range (100° to 120°) and conical exterior surface proximate the apex, creating a localized geometric feature that controls the jet formation. This localized geometric optimization ensures consistent entrance hole dimensions while maintaining adaptability to different overall system configurations.
2Device complexity
If conventional shaped charges are used, then the system can be simplified with fewer design constraints, but the fracturing results become unpredictable due to large variations in entrance hole diameter
Solution Approach 1:
The patent establishes specific parameter ranges for the liner (subtended angle of 100° to 120°, aspect ratio, radius) that must be maintained to achieve reliable and predictable fracturing results. These parameter constraints resolve the contradiction by providing clear design guidelines that ensure consistent performance while maintaining relatively simple charge construction.
3Reliability
If the entrance hole diameter is over-designed to account for variation, then consistent fracturing results can be achieved, but the costs increase significantly
Solution Approach 1:
The patent optimizes the liner parameters to achieve entrance hole diameter consistency without requiring over-design. By controlling the subtended angle (100° to 120°) and other geometric parameters, the system achieves reliable fracturing results with precise rather than excessive design, thereby reducing material costs while maintaining treatment consistency.
4Ease of manufacture
If the liner subtended angle is outside the 100° to 120° range, then the charge design can be simplified or adapted to different applications, but the entrance hole diameter variation exceeds 7.5%
Solution Approach 1:
The patent identifies the optimal parameter range (subtended angle of 100° to 120°) that balances manufacturing feasibility with precise entrance hole diameter control. This parameter specification resolves the contradiction by providing a manufacturable design range that achieves the required 7.5% diameter consistency while remaining practical to produce.
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 approach enables more effective and predictable fracturing treatments by maintaining consistent entrance hole diameters and perforation tunnel dimensions, reducing pressure variations and energy loss, and allowing for targeted pump rates without the limitations of conventional systems.
Implementation Method 1
The charges are loaded in a perforation gun and are typically shaped charges that produce an explosive formed penetrating jet in a chosen direction
Implementation Method 2
the liner shaped with a subtended angle about an apex of the liner such that a jet formed with the explosive creates an entrance hole in the inner well casing and the outer well casing
Implementation Method 3
the liner having an exterior surface, the exterior surface substantially conical proximate the apex; the subtended angle of the liner ranges from 100° to 120°
Data Source
AI summary
A re-fracturing method using a perforating gun system in a multistring wellbore casing with an inner well casing installed in an outer well casing. The charges in the perforating system include a case, a liner positioned within the case, and an explosive filled within the liner. The liner shaped with a subtended angle about an apex of the liner such that a jet formed with the explosive creates an entrance hole in the inner well casing and the outer well casing; the liner having an exterior surface, the exterior surface substantially conical proximate the apex; the subtended angle of the liner ranges from 100° to 120°. The method includes covering the existing openings with the inner casing, perforating with the perforating system and creating constant diameter entrance holes in the outer casing and fracturing through the inner casing and outer casing.