Losses? No Problem. Unconventional Solutions to Cure Unconventional Losses and Improve Wellbore Instability Problems in Saudi Arabia

摘要

Saudi Aramco faces a wide array of challenges in maintaining wellbore stability during drilling and primary cementing operations. As a result, it has revised its strategies and methods for remediating losses during well construction operations. Implementation of these strategies, with some adopted from deep-water operations, has led to improved zonal isolation and operational efficiencies. The conventional methods used to cure losses during drilling, i.e., with cement plugs, can be inefficient, usually requiring multiple attempts with mixed success. To improve the plug success rate, a revised method focuses on the hydrostatics of the cementing fluids as well as on advanced placement methods based upon the loss circulation boundary conditions. During primary cementing across multiple zones, challenges include ultra-high permeability, low bottom-hole pressures (BHPs), and carbonates with a high number of natural fractures. The risk of losses during cement placement is high, and such losses have led to inconsistent zonal isolation. A revised strategy for designing the cementing fluids used during primary cementing, based upon the revision of methods used for cement plugs, which face these same risks, has shown improved zonal isolation success. The article details the methods, strategies, and case histories involved to improve wellbore instability problems.