Perforating Gun Self-Positioning Protrusions for Consistent Stand-off
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Solution Overview
Problem
Conventional oilfield perforating guns in deviated or horizontal wells experience varying water stand-off distances, leading to inconsistent perforation hole sizes, which reduces the efficiency of hydraulic fracturing operations due to higher pressure drops and uneven fluid distribution through perforations.
Innovation Solution
A self-positioning system for perforating guns featuring protrusions that provide a finite number of rotational positions and desired water clearances, ensuring consistent perforation hole sizes by maintaining fixed gun-to-casing orientations, thereby reducing the standard deviation of hole diameters and eliminating the need for costly scallops on the gun carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional perforating guns are used in deviated or horizontal wells without positioning features, then the gun can be conveyed into the well easily, but the water stand-off distance varies leading to inconsistent perforation hole sizes
Solution Approach 1:
The positioning system segments the gun carrier surface into multiple discrete protrusion locations arranged at specific angular intervals (e.g., 0°, 120°, 240°). Each protrusion acts as an independent positioning element that contacts the casing at a predetermined location, dividing the continuous rotation problem into discrete angular positions.
Solution Approach 2:
The protrusions are pre-positioned on the gun carrier at specific locations before the gun is conveyed into the well. This preliminary positioning ensures that when the gun reaches the target depth, the shaped charges are already oriented at the correct angular positions relative to the casing, eliminating the need for complex active positioning mechanisms during operation.
2Productivity
If multiple perforating guns are conveyed together in a single tool string, then operational efficiency is improved for multi-stage fracturing, but the positioning complexity increases to maintain consistent orientations
Solution Approach 1:
The protrusion-based positioning system serves multiple functions: it positions individual guns within the string, maintains angular orientation of multiple guns relative to each other, and ensures consistent positioning of the entire string within the casing. This universal positioning mechanism eliminates the need for separate positioning systems for each gun.
Solution Approach 2:
Multiple perforating guns are combined into a single tool string with shared positioning features. The protrusions on each gun carrier work together with the casing to maintain consistent angular orientations of all guns in the string, allowing simultaneous or sequential operation of multiple guns without requiring independent positioning mechanisms for each.
3Manufacturing precision
If scallops are added to the gun carrier to maintain contact with the casing, then positioning is improved, but the cost and manufacturing complexity increase
Solution Approach 1:
Instead of modifying the gun carrier with complex scallop features that require precise machining and welding, the invention inverts the approach by adding simple protrusions to the outer surface of the gun carrier. These protrusions are easier to manufacture and position, and they achieve the same positioning function by contacting the casing at discrete points rather than requiring continuous surface contact.
Data Source
AI summary
A self-positioning system for a perforating gun or gun string is provided. The self-positioning system includes a plurality of protrusions extending outwardly from the perforating gun or the gun string for providing a finite number of rotational positions and/or for providing a desired water clearance. The protrusions include one or more groupings of at least three protrusions, the protrusions being angularly offset from each other about the outer circumference of the perforating gun or gun string.