Biopolymer Free Reservoir Drill-In Fluid Breaking Boundaries and Exceeding Expectations: The United States Gulf of America Development Journey

Abstract In the US Gulf of America, a field spanning four blocks in the Mississippi Canyon was drilled and is being produced. The wells here reach depths of 31,000 feet, with an estimated peak production of 100,000 barrels of oil equivalent per day. The elevated reservoir pressure and temperature required innovative reservoir drilling fluids. A high-density, biopolymer- free, water-based Reservoir Drill-In Fluid was developed to meet these demanding criteria, ensuring productivity and minimal formation damage. This success resulted from extensive collaboration between the client and service provider. This campaign had three phases, two of which employed open hole gravel packs (OHGP). Phase 1 utilized high-density divalent brine-based systems with unique chemistries, including Reservoir Drill-in Fluid, Screen Running Fluid, Gravel Pack Carrier Fluids, and a filter-cake breaker. In Phase 3, the formulations were optimized for highly depleted conditions, with an expected overbalance of up to 9400 psi, an industry first. The fluid adjustments in coordination with techniques like controlled mud line (CML) drilling and acid soluble wellbore strengthening were crucial to the successful drilling and completions of the highly depleted formations in Phase 3. Phase 1 campaign successfully drilled and completed 8 producer wells, generally surpassing operational expectations and achieving production rates with low skin factors, and despite the necessary tweaks to the formulation, Phase 3 maintained this performance with 2 additional reservoirs drilled through depleted zones. This paper presents extensive data on fluid design, testing, and field execution, highlighting challenges from a water-based completion fluids perspective. This case history may serve as a global template for OHGP completions using water-based technologies, with significant focus to the preservation of formation integrity while maintaining high overbalance pressure performance and wellbore strengthening.