A general model for borehole positioning analysis
The model is based on the error described in terms of the covariance matrix. Propegation of error from measurement to position uncertainty is then found by linear transformations of the covariance matrix. Main advantages of the outlined methodology are:
- Systematic and random errors are treated in a unified framework.
- The error model is flexible, i.e, not operational, sensor, or tool specific. New positioning tools can easily be incorporated.
- Several error sources are handled by the simultaneous use of the respective covariance matrices.
- The model handles errors that are systematic on some scale and random on other scales, both within a single well, for single or multiple surveys, and for multi-well surveys.
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