Casing Hanger Locking Device Integrated with Bit Sub
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Solution Overview
Problem
Conventional casing hanger locking devices require multiple trips for installation and retrieval, making them expensive and inefficient, especially in subsea drilling operations, where they interfere with other components and necessitate dedicated tooling.
Innovation Solution
An apparatus comprising a bit sub with a tong neck, stabilizing fins, a casing hanger locking device with an expandable ring, and a selective retrieval collar that allows for the installation and selective retrieval of the locking device during bit run and retrieval operations, reducing the need for multiple trips by integrating the locking device with the drill string components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional locking device is installed in the wellhead, then upward loads are controlled and casing hanger stability is improved, but device complexity increases and multiple trips are required for installation and retrieval
Solution Approach 1:
The locking device is merged with the drill string by attaching it to the bit sub, allowing the locking function to be integrated with the drilling operation rather than requiring a separate wellhead installation. This combines the drilling tool assembly with the locking functionality.
Solution Approach 2:
The drill string assembly is given multiple functions: it performs drilling operations and simultaneously carries the locking device for controlling upward loads. The bit sub serves both as a drilling component and as the mounting platform for the locking mechanism.
2Reliability
If a locking device is installed in the wellhead, then upward load control is improved, but loss of time increases due to multiple trips required for installation and retrieval
Solution Approach 1:
The locking device installation is merged with the bit run operation, allowing both functions to be accomplished in a single trip. The locking device travels down with the drill string and is deployed during the same operation used for drilling.
Solution Approach 2:
The locking device is pre-positioned on the bit sub before entering the wellbore, so that when the bit sub reaches the casing hanger, the locking device is already in place and can be immediately activated without requiring additional trips for installation.
3Reliability
If a locking device is installed in the wellhead, then casing hanger position control is improved, but ease of operation worsens due to dedicated tooling and retrieval requirements
Solution Approach 1:
The locking device is self-contained on the drill string assembly and can be deployed and retrieved using the existing drilling equipment. The drill string itself serves as the deployment mechanism, eliminating the need for dedicated retrieval tooling.
Solution Approach 2:
The drilling equipment performs multiple functions: it drills the wellbore, positions the locking device, and can retrieve the locking device. The same drill string and wellhead equipment used for drilling operations are also used for locking device management.
4Reliability
If a locking device is installed in the wellhead, then pressure control is improved, but mechanical interference increases with subsequent casing runs
Solution Approach 1:
The locking device is extracted from the wellhead location and relocated to the drill string assembly. This removes the interference problem at the wellhead while maintaining the pressure control function during drilling operations.
Solution Approach 2:
The locking device position is made dynamic rather than fixed - it travels with the drill string and can be deployed or retrieved as needed. This allows subsequent casing runs to proceed without permanent obstruction at the wellhead.
Data Source
AI summary
An apparatus and methods for installing and selectively retrieving a casing hanger locking device within a wellhead system during the bit run and retrieval operations are provided. An embodiment is an apparatus comprising: a bit sub comprising a tong neck, a cylindrical portion below the tong neck, and at least one stabilizing fin below the cylindrical section, wherein the at least one stabilizing fin comprises a keyway; a casing hanger locking device comprising an annular structure and an expandable ring disposed around an upper portion of the annular structure, the casing hanger locking device disposed around the bit sub; an actuation sleeve that engages with the casing hanger locking device; and a selective retrieval collar comprising a segmented retrieval ring, wherein the selective retrieval collar is attached to the bit sub, the actuation sleeve, and the casing hanger locking device.