Low Pressure Wellhead System for Sealing Integrity and Thermal Expansion
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Solution Overview
Problem
Existing wellhead systems struggle to ensure sealing integrity in the annuli of large diameter casings and to withstand thermal expansion cycles, which can lead to fluid leaks and operational issues.
Innovation Solution
A low pressure wellhead system that includes a conductor casing secured to the wellhead, a casing hanger with a hanger shoulder that engages a load shoulder on the wellhead, and a contingency landing joint with a centralizer ring that supports the casing within the wellhead, ensuring sealing integrity and accommodating thermal expansion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional wellhead system is used with large diameter casings, then the wellbore structure is established, but sealing integrity in the annuli cannot be ensured and thermal expansion cannot be accommodated
Solution Approach 1:
The wellhead system is segmented into multiple functional components: a wellhead housing, a casing hanger with sealing elements, and a contingency landing joint with a centralizer ring. This segmentation allows each component to independently address specific functions - the casing hanger provides sealing in the annulus between the conductor casing and production casing, while the centralizer ring accommodates thermal expansion by allowing axial movement. This resolves the contradiction by dividing the system into specialized segments that collectively achieve both sealing integrity and thermal expansion accommodation.
Solution Approach 2:
The centralizer ring is designed as a dynamic component that can move axially along the contingency landing joint to accommodate thermal expansion of the conductor casing. The casing hanger similarly allows for axial movement while maintaining sealing integrity through its sealing elements. This dynamic design enables the system to adapt to thermal expansion cycles without compromising sealing, resolving the contradiction between reliability and adaptability.
2Strength
If the large diameter casing is set to prevent wellbore collapse, then structural support is provided, but fluid communication with the annulus is blocked and sealing integrity cannot be verified
Solution Approach 1:
The contingency landing joint with the centralizer ring serves as an intermediary component that bridges the gap between the conductor casing and the production casing. It provides a controlled interface that allows fluid communication with the annulus for testing sealing integrity, while the conductor casing maintains its load support function. This intermediary component enables verification of sealing without compromising the structural role of the large diameter casing.
Solution Approach 2:
The system incorporates preliminary sealing and testing capabilities through the casing hanger and centralizer ring assembly before full production operations begin. This allows sealing integrity to be verified in advance through fluid communication tests, ensuring reliability before the system enters its primary load-bearing and production phase.
3Productivity
If shallow hazard formations are explored to increase production potential, then resource recovery is improved, but the risk of fluid influx from shallow hazards increases
Solution Approach 1:
The system converts the potential harm of shallow hazard formations into a benefit by implementing a controlled testing and sealing mechanism. The contingency landing joint and casing hanger assembly allow for deliberate fluid communication tests that can detect shallow hazards before they become problems. By actively testing and sealing the annulus, the system transforms the risk associated with shallow hazard exploration into a controlled process that ensures safety while maintaining productivity.
Solution Approach 2:
The casing hanger with its sealing elements provides beforehand cushioning against potential shallow hazard influx. The sealing mechanism is installed and tested before production begins, creating a protective barrier that prevents harmful fluids from shallow formations from entering the wellbore. This prior cushioning allows safe exploration of shallow hazard formations while maintaining production potential.
Data Source
AI summary
A well system includes a wellhead installation positioned above and extending over a wellbore, the wellhead installation including a low pressure wellhead (LPWH) providing a body having opposing upper and lower ends, and an internal through-bore defined within the body and extending between the upper and lower ends, two or more fluid outlets defined through a sidewall of the body to facilitate fluid communication with the internal through-bore, and a load shoulder defined within the internal through-bore axially uphole from the two or more fluid outlets. Conductor casing is secured to the lower end of the body of the LPWH, and a casing hanger is operatively coupled to an extension of casing and extends concentrically within the conductor and into the wellbore, the casing hanger defining a hanger shoulder engageable with the load shoulder when the casing hanger is lowered into the LPWH.