Method and system for detecting a state of a joint of a drill string
AssigneeEpiroc Rock Drills Aktiebolag
InventorsMattias Göthberg, Samuel Enblom
Life of this patent
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Abstract
The present invention relates to a method for determining state of at least one joint of a drill string of a drill rig, the drill rig including a percussion device for inducing shock waves into the drill string, and a sensor for sensing stress waves in the drill string caused by impacts of the percussive device, the method comprising, when a stress wave is induced into the drill string by the percussive device: determining a representation of the incident stress wave caused by the percussive device; determining a representation of a reflected wave representing a reflection of the incident stress; estimating a stiffness of the at least one joint by estimating a force exerted on the at least one joint by the incident wave.
Claims16
A method for determining state of at least one joint of a drill string of a drill rig, the drill rig comprising a percussion device that comprises a percussive element for inducing shock waves into the drill string, and a sensor for sensing stress waves in the drill string caused by impacts of the percussive element, the method comprising:
- when a stress wave is induced into the drill string by the percussive element:
- determining a representation of the stress wave caused by the percussive element;
- determining a representation of a reflected wave representing a reflection of the stress wave when reaching the at least one joint;
- estimating a stiffness of the at least one joint, the stiffness being estimated by estimating a force exerted on the at least one joint by the stress wave and a displacement caused by the force, and
- generating a signal representing the state of the at least one joint based on the estimated stiffness.
A system for determining state of at least one joint of a drill string of a drill rig, the drill rig comprising a percussion device that comprises a percussive element configured for inducing shock waves into the drill string, and a sensor configured for sensing stress waves in the drill string caused by impacts of the percussive element, the system is configured to:
- when a stress wave is induced into the drill string by the percussive element:
- determine a representation of the stress wave caused by the percussive element;
- determine a representation of a reflected wave representing a reflection of the stress wave when reaching the at least one joint;
- estimate a stiffness of the at least one joint, the stiffness being estimated by estimating a force exerted on the at least one joint by the stress wave and a displacement caused by the force, and
- generate a signal representing the state of the at least one joint based on the estimated stiffness.
A rock drill rig, comprising a system for determining state of at least one joint of a drill string of the drill rig, the drill rig comprising a percussion device that comprises a percussive element configured for inducing shock waves into the drill string, and a sensor configured for sensing stress waves in the drill string caused by impacts of the percussive element, the system is configured to:
- when a stress wave is induced into the drill string by the percussive element:
- determine a representation of the stress wave caused by the percussive element;
- determine a representation of a reflected wave representing a reflection of the stress wave when reaching the at least one joint;
- estimate a stiffness of the at least one joint, the stiffness being estimated by estimating a force exerted on the at least one joint by the stress wave and a displacement caused by the force, and
- generate a signal representing the state of the at least one joint based on the estimated stiffness.
Dependencies are inferred from the claim text.