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Graham McElhinney: Downhole referencing techniques in borehole surveying. PathFinder Energy Services, April 19, 2005: US06882937 (30 worldwide citation)

A method for determining rotational offset between first and second gravity measurement devices deployed on a downhole tool is disclosed. The method includes positioning the tool in a previously surveyed section of a borehole that provides a historical survey including at least three previously surv ...


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