Combining accurate and less accurate survey data to determine borehole trajectory

摘要

A well survey process for combining highly accurate well survey data with lower quality survey data in such manner that survey determination of overall borehole trajectory is improved. The inclination and/or azimuth of the wellbore path at each of the wellbore survey stations is acquired with a Measuring-While-Drilling (MWD) tool or other survey instrument maintained stationary within the wellbore. Continuous survey measurements, for inclination and/or azimuth are taken during the drilling process and therefore less accurate due to significant drilling noise. Stationary survey measurement is more accurate but infrequently sampled, while continuous inclination and/or azimuth measurement is less accurate but more frequently sampled. The objective is to augment a conventional minimum radius of curvature approximation of the wellbore trajectory between the survey stations with whatever reliable information can be extracted from the continuous inclination and/or azimuth measurements. The continuous position augmentation of the conventional minimum radius of curvature approximation minimizes wellbore trajectory errors between survey stations and thus enhances the accuracy of the calculated spatial position or trajectory of the wellbore being drilled.