Drill String Joint Loosening Using Torque Feedback
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Solution Overview
Problem
Existing methods for loosening drill string joints often result in excessive wear on components and require repeated attempts due to the inability to detect whether the joint has been properly loosened, leading to inefficiency and increased wear.
Innovation Solution
A method that uses a rotation unit to apply a torque in a joint loosening direction, monitors the torque representation, and employs a joint loosening mechanism to determine if the joint is loosened, generating a signal when successful, thereby reducing unnecessary attempts and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a joint loosening mechanism is used to apply high loosening torque to firmly tightened joints, then the joint can be loosened, but excessive wear is imposed on the drill string components
Solution Approach 1:
The system continuously monitors the torque applied by the rotation unit during the loosening process. When the monitored torque indicates that the joint has been successfully loosened (detected through torque variation or threshold crossing), the joint loosening mechanism automatically stops applying torque. This feedback control prevents excessive torque application and the associated wear that would occur with conventional continuous torque application methods.
2Reliability
If repeated attempts are made to loosen tightly fastened joints without detection capability, then the joint may eventually loosen, but time is wasted and wear is increased
Solution Approach 1:
The system provides real-time feedback by monitoring torque parameters during the loosening process. When the joint is successfully loosened, the torque signature changes in a detectable way (torque drop or variation). This immediate feedback allows the control system to confirm successful loosening and stop further attempts, eliminating the time waste associated with repeated unsuccessful attempts on already-loosened joints.
Solution Approach 2:
The patent replaces the conventional mechanical trial-and-error loosening approach with a monitoring-based control system. Instead of relying on mechanical indicators or operator judgment, the system uses torque sensing and electronic control to detect joint loosening status, enabling more efficient and wear-free operation.
3Reliability
If continuous torque application is used to ensure joint loosening, then the joint will eventually loosen, but unnecessary wear occurs after the joint is already loosened
Solution Approach 1:
The monitoring system detects when the joint has been successfully loosened through characteristic torque variations or threshold crossings. Upon detection, the control system immediately terminates torque application from the joint loosening mechanism. This feedback-driven termination prevents the continuous torque application that causes unnecessary wear after the joint is already loosened.
Data Source
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AI summary
The invention relates to a method for determining the state of a joint (134, 135, 136, 137) joining a first and a second drill string component (105, 106, 131, 132, 133). A drill rig (100) comprises a rotation unit (109) for rotating the drill string (107) and means for determining a representation of a torque applied by the rotation unit. A joint loosening mechanism (140, 300) distinct from the rotation unit (109) apply a joint loosening torque acting on the drill string (107) when loosening a joint (134, 135, 136, 137). The method comprises applying a torque in a joint loosening direction by means of the rotation unit (109), and applying a joint loosening torque acting on the drill string by means of the joint loosening mechanism (140, 300). The torque applied by the rotation unit is monitored during the applying of the joint loosening torque and it is determined whether the joint (134, 135, 136, 137) is loosened based on the monitored representation of the torque applied by the rotation unit (109).