Surface Wellhead Housing Assembly for Annulus Leak Prevention
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Solution Overview
Problem
Conventional surface wellheads lack the tailored design and installation capabilities of subsea wellheads, leading to wellhead movement, damage to welds, and recurring leaks in the conductor-conductor and conductor-casing annuli, especially in complex subterranean conditions, resulting in costly repairs and production shut-ins.
Innovation Solution
A low-pressure surface wellhead housing system with an extension joint and extended casing head housing, pre-assembled offsite, that allows direct coupling to the conductor and surface casing, incorporating annulus valves for monitoring and reducing relative movement, and offsite welding for improved integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional surface wellhead designs are used, then installation is simpler, but wellhead movement and relative movement between components occur, causing weld damage and recurring leaks
Solution Approach 1:
The wellhead housing is divided into multiple modular sections (casing head housing, conductor head housing, extension joint) that can be assembled in different configurations. This segmentation allows each component to be optimized for its specific function while reducing relative movement between parts through precise mating interfaces and connection mechanisms.
Solution Approach 2:
The conductor head housing is nested within the casing head housing, creating a multi-layered structure that accommodates multiple conductors and provides stable support. This nested configuration reduces relative movement by providing multiple contact surfaces and distribution of mechanical loads across different components.
2Reliability
If offsite pre-assembly is implemented, then connection quality and leak prevention improve, but installation time and logistics complexity increase
Solution Approach 1:
Critical connections and welding operations are performed offsite during manufacturing, before the wellhead system is deployed to the well location. This preliminary action ensures high-quality connections with proper inspection and testing, eliminating the need for complex field welding operations and reducing installation time despite increased pre-assembly requirements.
Solution Approach 2:
Multiple components (casing head housing, conductor head housing, extension joint) are pre-assembled and welded together as an integrated unit at the manufacturing facility. This merging of components into a pre-assembled module improves connection integrity while simplifying field installation to a single unit deployment.
3Ease of operation
If surface wellheads are used instead of subsea wellheads, then operational complexity is reduced, but tailored design capabilities and installation flexibility are limited
Solution Approach 1:
The wellhead housing system is designed with universal features that can accommodate different conductor sizes, configurations, and well types. The modular architecture allows the same basic housing design to be adapted for various applications, providing subsea-level customization without the operational complexity of subsea systems.
Solution Approach 2:
Different sections of the wellhead housing are designed with specific local characteristics optimized for their functions. The conductor head housing has specialized features for conductor support and sealing, while the casing head housing is optimized for surface casing connection. This local quality optimization provides tailored design capabilities while maintaining overall operational simplicity.
Data Source
AI summary
A well system includes a wellbore, a conductor extended within the wellbore, and a wellhead installation arranged at an opening to the wellbore. The wellhead installation includes a low-pressure surface wellhead housing (LPWH) having opposing upper and lower ends, an extension joint secured to the lower end at an offsite location prior to delivery to the wellbore, an extended casing head housing (ECHH) providing a body having opposing first and second ends and sized to be received within the LPWH, the second end being secured to an uphole end of surface casing at an offsite location prior to delivery to the wellbore, and one or more annulus valves extending through a sidewall of the LPWH to provide fluid communication with a conductor-casing annulus defined between the conductor and the surface casing when the ECHH is received within the LPWH.