South Platte: A Case Study for New Deepwater Drilling Fluids

Abstract

Deepwater operators are now exploring new fields that require products and services to be at the forefront of technology. This is especially true in the Gulf of Mexico, where fields with pressure gradients higher than previous developments are particularly demanding. In the coming decade, the Gulf of Mexico will see the first development using equipment rated at 20,000 psi. In such fields, density requirements for drilling fluids regularly exceed 15 lbm/gal, and can surpass 16 lbm/gal. Despite being green fields, narrow drilling windows can be expected, which can prove challenging when optimizing rheology at such mud weights. The South Platte field operated by TotalEnergies faced this challenge after a long absence in the Gulf of Mexico. This paper presents the design, planning, and field execution for drilling fluids of the South Platte deepwater exploratory well in the Gulf of Mexico. The operator drilling team was anticipating several challenges for what would be its deepest well ever drilled, such as, the need of high-density mud (above 16 lbm/gal), with potential side effects such as fluids stability over long static periods, and potential drilling window limitation equivalent circulating density (ECD margin). The selected high-performance invert emulsion fluid (HPIEF) was designed to address these challenges. Facing one of the most active hurricane seasons on record, with 30 named storms, multiple well suspensions were necessary (6 well suspensions, 4 BOP disconnections). This eventually led to static periods greater than the 15-days stability at downhole conditions. Those periods were targeted at the design stage.