Wellbore Positional Uncertainty and Correction of Directional Drilling

Abstract

Wellbore surveying is the interactive process used to obtain wellbore positions according to well trajectory which connects surface coordinates to subsurface coordinates. The measured values such as the measured depth, inclination, and azimuth are used to calculate well paths with a specified reference system. However, errors exist between the true wellbore position and surveyed wellbore position, including depth measurement errors of the drillstring and wireline, misalignment errors, geomagnetic model, and magnetic interference errors. Therefore understanding and evaluating wellbore positional errors is critical for hitting reservoir targets, collision avoidance, and drilling relief wells. In this paper, wellbore positional uncertainty has been reviewed and the application of survey corrections in single and multiple wells has been investigated.