Linerless Shaped Charge Assembly for Tubular Annulus Sealing
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Solution Overview
Problem
Cement used in wellbores is porous and can develop micro annulus leaks, open channels, and other defects, allowing gas and fluids to seep into the wellbore, which can cause cracks, decay, and contamination.
Innovation Solution
A shaped charge assembly without a liner is used to selectively expand the wall of tubulars, creating a protrusion that compresses the cemented areas, reducing the porosity of the cement by reducing the number of micro annulus pores and collapsing open channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tubular wall is expanded to compress the cement annulus, then porosity is reduced and micro annulus leaks are sealed, but the tubular wall structure is altered
Solution Approach 1:
The patent applies local quality by creating localized protrusions or bumps on the tubular wall surface that contact the cement annulus. Only specific localized regions of the tubular wall are expanded rather than the entire wall, concentrating the compressive effect on the cement annulus while minimizing overall geometric alteration of the tubular
Solution Approach 2:
The patent resolves the geometric conflict by transitioning from a smooth cylindrical tubular wall to one with radial protrusions. This dimensional change adds radial complexity to the wall geometry, enabling localized cement compression without compromising the overall cylindrical integrity and functionality of the tubular
2Shape
If explosive charges are used to expand the tubular wall, then the protrusions are formed to compress cement, but the explosive material and liner add device complexity
Solution Approach 1:
The patent applies the taking out principle by removing the liner component from the traditional shaped charge assembly. This extraction simplifies the device structure while maintaining the essential function of forming tubular wall protrusions through controlled explosive expansion, reducing device complexity without compromising the shaping capability
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 effectively reduces micro annulus leaks and seals off unintended fluid flow, enhancing the integrity of the wellbore by compressing the cement and strengthening the tubular wall.
Implementation Method 1
igniting the explosive material causes a shock wave that travels radially outward
Implementation Method 2
expand the wall of the tubular radially outward to form a protrusion
Implementation Method 3
compressing the cemented areas, reducing the porosity of the cement by reducing the number of micro annulus pores and collapsing open channels
Data Source
Figure 1~4
Figure 2A~2B
Figure 2C~2D
AI summary
A shaped charge assembly for selectively expanding a wall of a tubular includes a housing comprising an outer surface facing away from the housing and an opposing inner surface facing an interior of the housing. First and second explosive units are each symmetrical about an axis of revolution. Each explosive unit includes an explosive material formed adjacent to a backing plate and includes an exterior surface facing and being exposed to the inner surface of the housing. An aperture extends along the axis from one backing plate to the other backing plate. An explosive detonator is positioned along the axis adjacent to, and externally of, the one backing plate. The first and second explosive units comprise a predetermined amount of explosive sufficient to expand, without puncturing, at least a portion of the wall of the tubular into a protrusion extending outward into an annulus adjacent the wall of the tubular.