Systems And Methods For Modeling Drillstring Trajectories
First Claim
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1. A method for modeling a drillstring trajectory, comprising:
- calculating an initial value of force and an initial value of moment for each joint along a drillstring model using a conventional torque-drag model, a tangent vector, a normal vector and a bi-normal vector for each respective joint;
calculating a block tri-diagonal matrix for each connector on each joint; and
modeling a drillstring trajectory by solving the block tri-diagonal matrix for two unknown rotations at each connector.
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Abstract
Systems and methods for modeling drillstring trajectories by calculating forces in the drillstring using a traditional torque-drag model and comparing the results with the results of the same forces calculated in the drillstring using a block tri-diagonal matrix, which determines whether the new drillstring trajectory is acceptable and represents mechanical equilibrium of drillstring forces and moments.
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Citations
20 Claims
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1. A method for modeling a drillstring trajectory, comprising:
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calculating an initial value of force and an initial value of moment for each joint along a drillstring model using a conventional torque-drag model, a tangent vector, a normal vector and a bi-normal vector for each respective joint; calculating a block tri-diagonal matrix for each connector on each joint; and modeling a drillstring trajectory by solving the block tri-diagonal matrix for two unknown rotations at each connector. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A program carrier device for carrying computer executable instructions for modeling a drillstring trajectory, the instructions being executable to implement:
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calculating an initial value of force and an initial value of moment for each joint along a drillstring model using a conventional torque-drag model, a tangent vector, a normal vector and a bi-normal vector for each respective joint; calculating a block tri-diagonal matrix for each connector on each joint; and modeling a drillstring trajectory by solving the block tri-diagonal matrix for two unknown rotations at each connector. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification