Nested Tubing Head Wellhead Assembly Design
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Solution Overview
Problem
The installation and configuration of wellheads in oil and gas drilling are time-consuming, costly, and risky due to the cumbersome process of mounting and demounting blowout preventers (BOPs) when transitioning between drilling and production phases.
Innovation Solution
A wellhead assembly design featuring a nested tubing head that can be landed within a casing head through a BOP, eliminating the need to nipple-down and nipple-up the BOP during installation, and allowing direct access to the annulus between production tubing and casing through the walls of the wellhead assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional wellhead assembly with separate tubing head and casing head is used, then the BOP can be mounted on the tubing head for pressure control during drilling, but the process of mounting and demounting the BOP when transitioning between drilling and production phases is time-consuming and costly
Solution Approach 1:
The tubing head is nested within the casing head, allowing the tubing head to be landed inside the casing head through the BOP. This nested configuration eliminates the need to mount and demount the BOP when transitioning between drilling and production phases, as the tubing head can be installed while the BOP remains in place on the casing head.
2Productivity
If the tubing head is landed within the casing head through the BOP, then the installation process is simplified and accelerated, but the structural complexity of the wellhead assembly increases
Solution Approach 1:
The tubing head is designed to be landed within the casing head through the BOP, creating a nested structure where the tubing head resides inside the casing head. This nesting approach simplifies the installation process by eliminating separate mounting steps while the structural complexity is managed through standardized interfaces and landing mechanisms.
3Reliability
If the BOP remains mounted on the casing head during tubing head installation, then safety is maintained during pressure control operations, but the cumbersome process of nipple-down and nipple-up must be performed
Solution Approach 1:
The nested design allows the tubing head to be installed within the casing head while the BOP remains mounted on the casing head. This eliminates the need to nipple-down and nipple-up the BOP during configuration transitions, maintaining safety while simplifying operations.
4Adaptability or versatility
If access to the annulus between production tubing and casing is needed, then operational flexibility is improved, but additional access points and sealing mechanisms increase device complexity
Solution Approach 1:
The wellhead assembly is designed with multi-functional capabilities, including the ability to access the annulus between production tubing and casing through the nested structure. The casing head and tubing head are designed with integrated sealing mechanisms and access points that serve multiple functions: pressure control, annulus access, and structural support, reducing the need for separate dedicated components.
Data Source
AI summary
A wellhead assembly includes a casing head and a tubing head that is landed within the casing head when the tubing head is landed. The casing head has top and bottom ends, and its bottom end is coupled to surface casing. The tubing head also has top and bottom ends, and its bottom end is coupled to an additional casing string, such as production casing. The tubing head can be landed on the casing head through a blowout preventer.