Running Tool Locking System for Torque Isolation
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Solution Overview
Problem
Existing systems for rotating casing strings in the oil and gas industry face challenges with threaded connections that can become over-tightened, making disengagement difficult, and may result in dropped or broken seals due to improper torque application.
Innovation Solution
A system and method for locking a running tool with a tubular member using a locking assembly that allows concentric longitudinal movement and synchronous rotation, featuring retractable pins or an outer locking tubular to securely engage and disengage the connection based on landing on a load shoulder, ensuring torque is applied effectively without relying on reverse rotation for disengagement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If torque is applied through threaded connection between running tool and mandrel casing hanger, then rotation of casing string is achieved, but the threaded connection becomes over-tightened making disengagement difficult
Solution Approach 1:
The connection system is segmented into two independent functional components: a threaded connection for longitudinal engagement and a separate locking assembly with locking pins for torque transmission. This segmentation allows the threaded connection to remain loose for easy disengagement while the locking pins handle torque application independently.
Solution Approach 2:
The locking pins act as an intermediary mechanism between the running tool and mandrel casing hanger for torque transmission. Instead of relying on the threaded connection to transmit torque, the locking pins serve as the intermediary that transfers rotational force, preserving the threaded connection for only its intended longitudinal function.
2Power
If torque is applied through threaded connection, then rotation is achieved, but the seal between tubular connections may break due to over-tightening
Solution Approach 1:
The force transmission path is segmented so that axial loads are carried by the threaded connection while radial and torsional loads are carried by the locking pins. This segmentation prevents the seal from being subjected to excessive tightening forces that would compromise its integrity.
Solution Approach 2:
The locking pins serve as an intermediary that absorbs and transmits torque and lateral forces, protecting the sealed threaded connection from these stresses. The pins mediate the force transmission in a way that preserves seal integrity by preventing over-tightening.
3Reliability
If locking pins are used to lock running tool and mandrel hanger, then torque can be applied without over-tightening threads, but the locking assembly adds structural complexity
Solution Approach 1:
The locking pins are designed to be self-actuating through spring biasing and alignment features. The pins automatically engage and lock when the running tool is lowered onto the mandrel hanger, eliminating the need for complex manual locking procedures or additional actuating mechanisms.
Solution Approach 2:
Guide pins serve as intermediaries that facilitate the alignment and engagement of the locking pins with the port openings. This intermediary mechanism simplifies the overall locking assembly by providing a straightforward alignment path rather than requiring complex adjustment mechanisms.
4Device complexity
If conventional threaded connection is used for rotation, then simple structure is maintained, but reverse rotation is required for disengagement which complicates the operation
Solution Approach 1:
The connection system is segmented into longitudinal engagement (threaded connection) and rotational locking (locking pins) functions. This segmentation allows the threaded connection to be simple in structure while the locking pins handle the rotational aspect, enabling easy disengagement by simply lifting the running tool without requiring reverse rotation.
Solution Approach 2:
The locking pins are designed with spring biasing that allows them to dynamically engage during lowering and automatically disengage during lifting. This dynamic design eliminates the need for reverse rotation to disengage, as the pins simply ride out of engagement when the running tool is lifted away from the mandrel hanger.
Data Source
AI summary
A system and method for locking together a running tool and a tubular member to rotate the tubular member. The system includes a tubular member and a running tool adapted to engage in a mechanical connection such that the running tool and the tubular member are arranged concentrically and moveable longitudinally together. The system includes a locking assembly adapted to lock the tubular member and the running tool together once the tubular member and the running tool are engaged in the mechanical connection, so that torque applied to the running tool is applied to the tubular member through the locking assembly to rotate the running tool and the tubular member synchronously. The locking assembly is adapted to unlock the tubular member and the running tool when the tubular member is landed on a shoulder of an outer tubular member so that the mechanical connection can then be disengaged.