Recently, during the third-section drilling operation of Well N1-1-1, ZPEC Oil Services drilling fluid team successfully applied a special oil layer protection fluid, providing a solid technical safeguard for the efficient development of the Coastal Oilfield. The Coastal Oilfield reservoir is characterized by shallow burial depth and fine pore throats, with strong water sensitivity and velocity sensitivity. Using conventional drilling fluids could easily cause irreversible damage, such as pore throat blockage and clay swelling, directly affecting well productivity. To overcome this challenge, the drilling fluid team performed multiple rounds of material screening, formula tuning, and performance testing based on the geological characteristics of the block. By integrating the company’s self-developed polyamine inhibitor and high-efficiency plugging agent, they successfully developed a special oil layer protection fluid featuring low density, low solids, strong plugging capability, and low formation damage. Meanwhile, materials, such as storage tanks, were prepared in advance to ensure smooth field operations.

During the operation, the drilling fluid team stuck to the principle of using dedicated fluid for dedicated purposes and implemented meticulous casing tubing management and maintenance. They established a closed-loop management model, encompassing “laboratory formulation, on-site regulation, and whole-process monitoring.” Technical personnel remained on site throughout the whole process, conducting real time fluid performance monitoring and adjusting operational parameters to effectively prevent impurities from invading the reservoir and inhibit clay swelling and dispersion. After drilling through the oil layer, the protection fluid was precisely displaced by brine to preserve the original permeability of the formation to the greatest extent, thereby avoiding reservoir contamination at the source.

The successful completion of the third-section operation of Well N1-1-1 not only validated the safety and reliability of the new process but also achieved the goal of zero reservoir damage. Moving forward, the drilling fluid team will continue to optimize reservoir protection technology, leveraging technical innovation and refined management to support the high-quality and sustainable development of overseas oilfields.

(ZPEC Oil Services/Text by Chen Fei and Wang Wei, Photo by Wang Wei)