Wellhead Tie-Back Rig Structure for Snubbing Load Resistance
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Solution Overview
Problem
Conventional mobile well rigs face challenges in securely anchoring to wellheads during high-pressure operations, posing safety risks for personnel and inability to resist snubbing loads effectively.
Innovation Solution
A wellhead mount and anchoring system is integrated into the rig structure, using structural tie-back points, beams, struts, and tensile members to provide a rigid anchor connection between the rig and wellhead, capable of resisting snubbing loads, and includes a two-section jointed mast with high-torque electrical servo motors and a lubricator system for safe tubular operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional mobile well rigs are used without integrated anchoring systems, then device complexity is reduced, but the rig cannot securely resist snubbing loads and may displace during high-pressure operations
Solution Approach 1:
The patent merges the anchoring system with the rig structure by integrating tie-back points directly into the rig framework. The anchorages are combined with the mast and outrigger system, creating a unified structure that provides both support and anchoring functions without requiring separate independent anchoring equipment.
Solution Approach 2:
The anchoring system is segmented into multiple independent tie-back points distributed throughout the rig structure. These discrete anchoring points can be individually connected to the wellhead, allowing the system to resist snubbing loads through distributed mechanical connections rather than requiring a single complex anchoring mechanism.
2Reliability
If the rig is not securely anchored to the wellhead, then ease of operation is improved, but safety is compromised during high-pressure well operations
Solution Approach 1:
The rig is pre-configured with integrated tie-back points and anchoring capabilities before operations begin. The mast and outrigger system are designed with built-in attachment points that can be quickly connected to the wellhead, eliminating the need for complex on-site anchoring operations while ensuring safety is built into the structure from the start.
3Force
If rig weight alone is used to resist snubbing loads, then device complexity is minimized, but the rig cannot reliably resist high snubbing forces
Solution Approach 1:
The patent employs counterbalancing mechanical linkages and tension members that create opposing forces to counteract snubbing loads. The outrigger system with its tension members and counterweights creates a mechanical balance that offsets the forces generated during tubular insertion and retrieval operations.
Data Source
AI summary
A mobile well rig can include a mast, an anchor that connects to a flange of a wellhead assembly, and a tensile member that transfers tensile loads between the wellhead assembly and the mast. A method of securing a mobile well rig to a wellhead assembly can include connecting an anchor to the wellhead assembly, connecting a tensile member to the anchor, and connecting the tensile member to a mast of the mobile well rig. A securement system can include an anchor secured to a wellhead assembly, a tensile member that transfers a tensile load between the wellhead assembly and a mast of a mobile well rig, and a strut that transfers a compressive load between the wellhead assembly and the mast.