Wedge-Shaped Casing Hanger Packing Element with BPI Pins
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Solution Overview
Problem
Casing hangers in oil and gas well completions face significant stress due to the heavy weight of casing strings and wellbore pressure, which can compromise their performance and longevity.
Innovation Solution
The casing hanger apparatus incorporates a wedge-shaped packing element and bi-directional pressure intensification (BPI) pins arranged in an angularly spaced configuration around the casing hanger. The BPI pins extend axially through the packing element and rings, providing pressure intensification in both directions to enhance sealing and support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional packing elements are used in casing hangers, then the structure is simpler, but the sealing performance deteriorates under high stress and pressure conditions
Solution Approach 1:
The packing element is divided into multiple segments or layers, each capable of deforming independently to seal against the casing and wellbore. This segmentation allows the packing element to better conform to irregular surfaces and maintain sealing under high stress, while the modular structure enables replacement of only damaged segments.
Solution Approach 2:
The packing element utilizes composite materials combining elastomeric compounds with reinforcement fibers or layered structures. This composite construction provides both the flexibility needed for sealing and the structural integrity to withstand hundreds of thousands of pounds of casing weight and wellbore pressure, resolving the contradiction between sealing performance and structural requirements.
2Reliability
If high compressive force is applied to compress the packing element for sealing, then the sealing performance improves, but the load on the casing hanger components increases
Solution Approach 1:
The packing element is designed to self-compress under the axial load of the casing string, converting the downward force directly into radial sealing pressure against the wellbore and casing. This self-service mechanism eliminates the need for additional compression devices or mechanisms, allowing the system to use its own operating load (casing weight) to achieve sealing without increasing overall compressive force requirements.
Solution Approach 2:
The packing element's material properties are engineered to change under load, with the elastomeric compound becoming more rigid and generating higher sealing pressure as compressive force increases. This non-linear stress-strain behavior allows the packing element to provide adequate sealing at lower loads while maintaining seal integrity under the high loads present during casing installation and production.
3Force
If the casing hanger is designed to support heavy casing weights, then the load-bearing capacity improves, but the stress on hanger components increases
Solution Approach 1:
The load-bearing function is distributed from a single-point suspension to a distributed annular contact between the packing element and the wellbore/casing. This dimensional change from point to surface contact spreads the hundreds of thousands of pounds of casing weight across a larger area, reducing stress concentration on any single component while maintaining overall load-bearing capacity.
Solution Approach 2:
The casing hanger components utilize composite material structures, including high-strength steel alloys and engineered elastomeric compounds, that provide both the strength to support heavy loads and the toughness to resist stress-induced failure. These composite materials offer superior strength-to-weight ratios and stress distribution characteristics compared to conventional materials.
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 allows for improved sealing and reduced load requirements for compressing the packing element, thereby enhancing the performance and longevity of the casing hanger under high stress conditions.
Implementation Method 1
a packing element having a wedge-shaped cross-sectional geometry and extending annularly between the upper ring and the lower ring
Implementation Method 2
The BPI pins extend axially from the upper ring through holes in the packing element to the lower ring
Implementation Method 3
bi-directional pressure intensification (BPI) pins arranged around the casing hanger in an angularly spaced apart configuration
Implementation Method 4
The BPI pins extend axially from the upper ring through holes in the packing element to the lower ring
Data Source
AI summary
A casing hanger apparatus includes an upper ring, a lower ring, and a packing element positioned between the upper ring and the lower ring. The packing element has an annular body with a wedge-shaped cross-sectional geometry. Bi-directional pressure intensification (BPI) pins are arranged around the casing hanger in an angularly spaced apart configuration, where the BPI pins extend axially from the upper ring through holes in the packing element to the lower ring. In some casing hanger apparatuses, a bushing member is positioned axially between the upper ring and the lower ring, where the BPI pins also extend axially through the bushing member.