Emergency Wellhead Seal Assembly for Stuck Casing Strings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing wellhead assemblies face challenges in sealing the annular space between a wellhead housing and a casing string that has become stuck during the casing string's installation, necessitating a reliable and effective emergency seal solution.
Innovation Solution
An emergency seal assembly with an elongate body featuring inner and outer metal or elastomer seals, set using a hydraulic setting tool and locked in place by a rotational mechanism, to create a secure seal between the wellhead housing and the casing string.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional wellhead assembly is used without an emergency seal assembly, then the structure is simpler, but the casing string cannot be suspended when stuck and fluid leakage occurs
Solution Approach 1:
The emergency seal assembly is divided into separate functional components: an inner seal for sealing against the casing string, an outer seal for sealing against the wellhead housing, a setting mechanism for activating the seals, and a locking mechanism for maintaining the sealed state. This segmentation allows each component to perform its specific function independently while working together to provide reliable sealing.
Solution Approach 2:
The emergency seal assembly is pre-installed and positioned within the wellhead assembly before the casing string is run into the well. The seal elements are prepared in advance within their respective grooves and flutes, ready to be activated by the setting mechanism if the casing string becomes stuck, eliminating the need for complex field repairs or replacements.
2Reliability
If the inner seal is set using a hydraulic setting tool and locked with a rotational mechanism, then the seal is secure and reliable, but the operation becomes more complex
Solution Approach 1:
The hydraulic setting tool utilizes hydraulic pressure to actuate the inner seal against the casing string. The hydraulic fluid is directed through a lumen in the setting tool to a piston or diaphragm that pushes the seal element into sealing contact, providing a reliable and controlled sealing action without requiring excessive manual force.
Solution Approach 2:
The rotational locking mechanism replaces a complex multi-step manual locking procedure with a simpler rotational action. By rotating the locking tool, a cam or cam-like surface engages with a corresponding feature in the seal assembly, automatically securing the seal in place through mechanical interlocking rather than requiring multiple fastening operations.
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 emergency seal assembly effectively seals the annular space, allowing for the suspension of the casing string and maintaining a barrier against fluid contamination, even when the casing string is stuck, thereby ensuring the integrity of the wellhead assembly.
Implementation Method 1
set using a hydraulic setting tool
Implementation Method 2
locked in place by a rotational mechanism
Data Source
AI summary
A seal assembly for sealing between a casing string and a wellhead housing is provided. In one embodiment, a system includes a seal assembly (80) received within a bore (48) of a wellhead housing (20). The seal assembly can include an elongate body (82), an inner seal (86) positioned within the elongate body to seal between the elongate body and a well casing (46), and a setting ring (88) positioned within the elongate body to apply a setting load to the inner seal to energize the inner seal between the elongate body and the well casing. The system can also include a running tool (100) having an end received within the elongate body of the seal assembly, and a piston setting assembly (110) including a piston (112) and a push sleeve (114) for setting the inner seal via the setting ring. Additional systems, devices, and methods are also disclosed.