Tandem Locking Connector Assembly for Hand-Tool Wellhead Rigidization
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Solution Overview
Problem
Existing connector assemblies for securing hydrocarbon production system components to wellheads require powered torque tools to achieve sufficient torque for sealing and rigidization, which are often unavailable in the field, leading to time losses in tool procurement.
Innovation Solution
A connector assembly using tandem-acting outer and inner lock screws that generate connecting force through axial translation, allowing for full energization of the primary sealing member and rigidization of the connection without the need for power tools, utilizing a smaller diameter inner lock screw to achieve greater force with less torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a single lock screw is used to secure the connector assembly to the wellhead, then the device complexity is reduced, but the connecting force is insufficient to both energize the sealing member and rigidize the connection
Solution Approach 1:
The locking assembly is segmented into two functional components: an outer lock screw that draws the connector body against the wellhead to energize the sealing member, and an inner lock screw that drives the locking segment into the locking groove to rigidize the connection. This segmentation allows each screw to be optimized for its specific function while collectively providing the full range of required connecting forces.
Solution Approach 2:
The inner lock screw is nested within the outer lock screw, with the inner lock screw positioned inside the hollow interior of the outer lock screw. Both screws share a common longitudinal axis and work in tandem, with the inner lock screw providing additional axial force through the retainer member to drive the locking segment further into engagement, thereby multiplying the overall connecting force without proportionally increasing device complexity.
2Force
If high torque is applied to the lock screw to rigidize the connection, then the connecting force is sufficient, but powered torque tools are required which are often unavailable in the field
Solution Approach 1:
The nested dual-screw configuration allows the inner lock screw to multiply the axial force generated by the outer lock screw. The mechanical advantage provided by the nested arrangement enables sufficient preload force to be achieved with hand-applied torque using simple hand tools, eliminating the need for powered torque drivers or impact wrenches that are often unavailable in field conditions.
Solution Approach 2:
The retainer member acts as an intermediary that transmits and amplifies the axial force from the inner lock screw to the locking segment. This mechanical intermediary enables the system to generate high connecting forces through a two-stage process that can be manually operated without requiring powered tools.
3Reliability
If the lock screw is torqued to energize the sealing member, then the sealing function is achieved, but additional force is needed to rigidize the connection against bending forces
Solution Approach 1:
The locking assembly is divided into two functional stages: the outer lock screw performs the first stage of drawing the connector body against the wellhead to energize the sealing member and establish the seal, while the inner lock screw performs the second stage of driving the locking segment into the locking groove to rigidize the connection and provide additional preload force to resist bending forces from equipment weight and movement.
Solution Approach 2:
The nested dual-screw arrangement enables a sequential two-stage locking process where the outer lock screw first establishes the sealing function, then the inner lock screw is torqued to provide additional axial force that drives the locking segment further into engagement, thereby rigidizing the connection without compromising the previously established seal.
4Reliability
If powered torque tools are used to secure the connector assembly, then the connection is properly made up, but significant time is lost in procuring the tools
Solution Approach 1:
The connector assembly is designed to be self-sufficient for making up the connection without requiring external powered tools. The nested dual-screw locking mechanism is specifically engineered to generate sufficient connecting force through manual operation, allowing field personnel to properly secure the connector assembly using only simple hand tools that are always available, thereby eliminating time losses associated with procuring powered torque drivers or impact wrenches.
Solution Approach 2:
The nested lock screw configuration provides a mechanical advantage that enables hand tools to achieve the same connection integrity that would otherwise require powered tools. The inner lock screw multiplies the force from the outer lock screw, allowing proper engagement of the locking segment and energization of the sealing member to be achieved manually, thus eliminating the need to wait for powered tool availability.
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 connector assembly enables secure sealing and rigidization of hydrocarbon production system components to wellheads using hand tools, reducing the need for power tools and minimizing setup time.
Implementation Method 1
an outer lock screw which is threadedly received in a corresponding through hole in the connector body such that rotation of the outer lock screw in the through hole results in axial translation of the outer lock screw relative to the connector body
Implementation Method 2
an inner lock screw which is threadedly received in a corresponding through bore in the outer lock screw such that rotation of the inner lock screw relative to the through bore results in axial translation of the inner lock screw relative to the outer lock screw
Implementation Method 3
the locking assembly is able to generate sufficient connecting force to both energize the primary sealing member and rigidize the connection without the need for powered torque tools
Data Source
AI summary
A connector assembly for securing a first hydrocarbon production system component to a second hydrocarbon production system component which in turn is connected to a wellbore includes a tubular connector body having a first end which is connectable to the first component, an opposite second end, a connector bore which extends axially between the first and second ends, and a cylindrical recess which extends through the second end coaxially with the connector bore and is configured to receive an upper end portion of the second component. The connector assembly further includes a plurality of locking assemblies for securing the connector body to the second component. Each locking assembly includes a locking segment which is configured to engage a locking profile on the second component to thereby secure the connector body to the second component, an outer lock screw which is threadedly received in a corresponding through hole in the connector body, and an inner lock screw which is threadedly received in a through bore in the outer lock screw. In operation, rotation of the outer lock screw operates to move the locking segment a first distance into the locking groove, and rotation of the inner lock screw relative to the through bore in the outer lock screw operates to move the locking segment an additional second distance into engagement with the locking groove.