Correlation of Wellbore Geometry with Geo-Mechanics and Drilling Practices in a Giant Offshore Field in Abu Dhabi

Abstract

Over the course of drilling wells in one of ADNOC Offshore fields, there have been numerous endeavors in the Crestal region of the field with each well presenting its unique array of issues and challenges related to well construction, stability and delivery. Even while drilling two identical wells with extremely similar well designs and architecture, the wells encountered different and at times opposite responses from the formations being drilled. This resulted in the well construction becoming more problematic than expected in some cases while in others the situation was completely opposite, thus drilling and well construction went extremely smooth delivering the well ahead of time as opposed to the nearby sister well. While the denominators may be segregated based on commonality and differences, there is one particular aspect of the drilling process and planning that has been significantly overlooked, the Azimuth of the well particularly in the crestal region of the field. Over the years, investigation into the well trajectory, the well fluids and intrinsic properties have been dissected to arrive at a result but has not produced the expected success. The Azimuthal impact on the resultant seems to have been ignored to the extent of not understanding the Azimuth impact on a well trajectory. It is of paramount importance to investigate and identify the imp act since the related stresses and their directions directly define and drive the stability and the optimal mud weight needed to drill successful wells.