Drilling Time Optimization by De-Risking a Re-Engineered Well Architecture Implemented in Offshore Shallow-Water Tertiary Wells in Gulf of Mexico

Abstract

Abstract The Gulf of Mexico area is well known for the high complexity of its wells. Whether on deepwater or shallow-water fields, wells on each field require specific customization on wellbore architecture and drilling practices to drill faster without compromising well integrity standards, safety, and oil production. Wellbore architecture is essential for the success of drilling operations and ensure the lifetime of the well throughout production and interventions. In the early stages of field development, a conservative approach increases the chances of success and obtains all the relevant information for well production and drilling optimization. This project describes the successful implementation of an optimized 3 casing-strings wellbore geometry in two shallow-water fields, de-risking engineering and drilling practices applied to accelerate well delivery. Different challenges are present across the area, related to mechanical stuck pipe while crossing geological faults, unstable formations due to mechanical disturbance, differential stuck pipe due to heterogenous formation pressure with depleted sands, lost circulation on weak zones and collision with other wells departing from the same location. Additionally, many of the quality events occurred in these fields were associated to incorrect operational strategies implemented, mainly during BHA or casing tripping. In close coordination between G&G (Geological and Geophysical department) and drilling engineering, the new casing points were carefully selected Based on offset wells and logging data, the strategy was to maintain high parameters when conditions allowed it and adjust them while crossing weaker zones. The strategy to minimize the risk of pack-off while drilling required ensuring that the hole is cleaned properly while drilling at highest ROP, sweeping pills schedule, bridging material and reaming procedures before connection, minimizing pack-off risk while drilling and saving time with clean trips. A further step to enhance performance and prevent high impact events was to exploit opportunities for real-time monitoring to ensure procedural adherence and follow the measures in the detailed multi-disciplinary risk analyses for critical activities. Additionally, leveraging the improved architecture, an integral multi-bowl wellhead was designed and implemented, giving practical advantages for casing running, and operational time reduction.