Increasing BHA and wellbore complexity create a need for case specific engineering modeling software. Hence, mathematical modeling of the mechanical and dynamical behaviour of BHAs under various downhole conditions such as different wellbore curvatures has become routine. This paper discusses an advanced engineering model and the verification of its predictions with downhole measurements.

First the mathematical model and the downhole dynamics measurement sub are introduced. Next, three examples comparing measured and predicted steady state bending loads are presented. While the predicted and measured results match well, detail and accuracy of input parameters such as wellbore curvature are proven essential.

Lateral natural frequencies of the model are compared to the peaks in the measured frequency spectrum. In conclusion, the general validity of the model regarding bending loads and vibrations is evaluated.

Backward whirl dynamics is evaluated by comparing downhole measurements with time domain model simulations. The predictions meet the downhole measurements both in frequency and magnitude.

Keywords:
vibration, bha, spe 93864, backward whirl, modeling & simulation, upstream oil & gas, measurement sub, downhole measurement, analysis model, heisig
Subjects:
Well Planning, Drillstring Design, Drilling Operations, Drilling Equipment, Trajectory design, Drillstring dynamics, Directional drilling
Copyright 2005, Society of Petroleum Engineers
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