Casing While Drilling Successfully Implemented for the First Time in High Risk Area of the Bahrain Field

Abstract

One known risk of the Awali field is hole collapsing in the surface section due to the presence of floating bloulders and cavities in areas of the field; resulting in wells being abandoned as conventional drilling was not enough to solve this issue. In 2019, Schlumberger and Tatweer Petroleum combined forces to improve production of Ostracod/Magwa shallow reservoirs by drilling wells in new areas of the field which included drilling in locations with offset wells that were abandoned due to hole collapse issues in the first 500’ interval. Drilling campaign started in june 2019 and drilled succesfully two wells, but two others were abandonned due to hole collapse issues. These abandonned wells were in very promising production areas as per the reservoir model and due to the shallowenest of the reservoir, it was not possible to move the surface location. Therefore, the issues in the surface section needed to be solved in order to maximize profits in the country. Following a rigerous study for determining which is the optimal solution for drilling the surface section in this area of the field, Casing While Drilling (CwD) technology was selected and implemented in August 2019 in well A-1530D, next to the previous abandoned wells. CwD operation was performed with excellent results by drilling from 101ft to 520ft with no issues. CwD successfully isolated the higly problematic zones in the surface section and more importantly, allowed to reach areas of the reservoir that had high potential for production.