Appendix D – Error Model Description

The error model implemented in Well Seeker is the ISCWSA MWD error model as described in SPE paper 67616 by H. Williamson. This paper contains a full explanation of the ISCWSA work. The error model used within this program uses the error terms and one sigma magnitudes described below.

The model does not use any bias terms and it implements the latest misalignment and tool face independent terms as listed below.

Misalignment terms taken from SPE90408 by Torkildsen, Ekseth, Weston, Havardstein and TF independent terms from “Borehole survey error model documentation” – CDR-SM-03 – by Copsegrove Developments.