DETERMINATION OF INITIAL TOOL ORIENTATION

摘要

A method of determining the initial orientation of a tool to be moved from a drilling site along a wellbore in the earth, comprises: defining a drilling site coordinate system which is fixed relative to said drilling site; defining a tool coordinate system which is fixed relative to said tool; providing at least one marker on said drilling site, defining at least one drilling site reference point which is fixed relative to said drilling site coordinate system; providing at least one marker on said tool, defining at least one tool reference point which is fixed relative to said tool coordinate system; determining the positions of said drilling site and tool reference points; and using said determined positions to perform a coordinate transformation between said drilling site and tool coordinate systems in order to determine the orientation of said tool.