Successful Deployment of New Generation Specialty Lost Circulation Material in Highly Fractured Formation, Offshore Abu Dhabi - Case Study

Abstract Drilling through faults and fractured formations has always been a challenge. In most cases wells have either been re-drilled as sidetracks or trajectories modified to avoid faults and fractures altogether. New technology products have been engineered and tested to overcome this challenge specifically to achieve a Techno-economic, safe operation. In this case deployment of a new generation Mult-Modular lost circulation material (LCM) was customized to effectively cure losses in these fractured formations, thus enabling drilling the well to the target reservoir zone. The loss mitigation plan for the subject well was prepared well in advance. Rigorous lab testing was performed on regular as well as larger slots to ascertain the plugging efficiency of the LCM. Formulations for both conventional LCM and Multi-Modal Composite LCM pills were optimized for this well based on lab tests. A clear decision tree was prepared with initial preference being to utilize conventional LCM pills first. LCM mixing and pumping procedures were detailed and discussed during the planning stage. Sufficient LCM inventory was made available for multiple pills to counter losses. The results of the careful planning were evident. A total of six LCM pills were pumped in different loss zones encountered in the 20 inch section at various depths. Compared to the conventional LCM pills, the Multi-Modal pills containing composite particles combined with the reticulated foam showed superior performance in curing the losses from 150-230 bbl/hr down to 10 bbl/hr in all the loss zones encountered. All combinations of conventional Lost Circulation Material (LCM) with high concentrations proved to be ineffective once severe or total losses were encountered in these formations (Saragi et Al, 2021). Each pill pumped cured losses ranging from total losses reducing to full return. The 12 ¼ inch section also saw similar loss behavior where a total of ten specialty Multi-Modal LCM pills were pumped at various depths which were successful in completely curing the losses. As a result both the 20 inch and 12 ¼ inch hole sections were successfully drilled to target depths. Multi-Modular LCM material including new technology foam material were implemented and successful in both lab and field trials in curing total losses. These pills were produced stable plugs able to withstand the pressure required for a successful solution. Proper design of the LCM can help avoid or at least minimize the impact of losses when drilling thief zones and improve wellbore integrity during the well's life cycle.