METHOD FOR ESTIMATING A POSITION IN A WELLBORE

摘要

A method is disclosed which utilizes multiple overlapping surveys to estimat e a position in a wellbore and related position uncertainty. Multiple surveys ar e often taken over the same portion of a wellbore either concurrently or sequentially and/ or using various instruments. Each survey generates an estimated survey position and related uncertainty for a given location in the wellbore. By combining the estimated survey positions and uncertainties for these overlapping surveys, a resultant position and related ellipsoid of uncertainty is estimated. This resultant position estimates a position in the wellbore by incorporating the estimated survey positions and uncertainties of multiple overlapping surveys.