# 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.

![](/files/-MhYbtBn3Ny2iF8EAI8N)

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

![](/files/-MhYbg7p6j_UTxAvDuvu)

![](/files/-MhYc9UkPdU8XwIoRCju)

![](/files/-MhYcND_v46sGMhMW6M9)

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.


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