Contribution Rate of MWD Survey Error Sources on Well Trajectory Measurement Error

Since the number of error sources is too large and the standard deviations of the error sources are really difficult, it is of great practical significance to study the contribution rate of each error source on the wellbore trajectory measurement error. The error sources of well trajectory measurement using MWD (Measurement While Drilling) are introduced, and the contribution rate calculation model of each error source on well trajectory measurement error is established. The contribution rate of each error source on well trajectory measurement error is analyzed with an example. The research shows that the error sources contribute most to the well trajectory measurement error for each main semi-axes of the error ellipsoid are different; the error sources contribute most to the well trajectory measurement error are different in the vertical section, the inclined section and the horizontal section; the error source associated with the sensors contributes least to the well trajectory measurement error compared with other sources of error. In drilling engineering, it is necessary to give the standard deviation of the main error sources as accurately as possible to better evaluate the well trajectory measurement error.