Beyond Boundaries: Achieving Safe and Efficient Delivery of Deep Play Exploration Wells

Abstract This paper provides a comprehensive analysis of frontier exploration in deep HTHP play wells, specifically those exceeding 6 km depth in Northern Sultanate of Oman and targeting deep and sour formations. The study focuses on advancements in well design optimization, drilling dynamics, and operational efficiencies to achieve critical well objectives safely while reducing costs and minimizing health, safety, and environmental (HSE) impacts, despite the challenges posed by high subsurface uncertainties such as a wide range of pore pressure- fracture gradients (PPFG), highly sour environments with H2S, and hard rock formations. To address these challenges, a multifaceted approach was employed, integrating advanced well design, hybrid completion techniques, and optimized material selection. This includes comprehensive drilling dynamics, geomechanical strategies, and rigorous planning and execution efforts. Innovative material usage, such as hybrid completions for increased fracturing pressure, played a pivotal role in overcoming the unique conditions of Northern Sultanate of Oman's deep geological formations. The application of these methodologies resulted in significant achievements: cost savings exceeding $2.6 million, operational efficiencies with less than 0.4% non-productive time, and substantial mitigation of HSE impacts. Notably, well-1 utilized an optimized hybrid casing string, saving over $600,000 and reducing equipment runs. Wells 2 and 3 demonstrated the effectiveness of new hybrid completion approaches, enhancing fracturing capabilities under high-pressure conditions. The project has proven its expectations in terms of hydrocarbons, illustrating the potential of deep play wells to yield substantial returns and valuable geological data for ongoing exploration efforts. These results underscore the success of the optimized approaches in handling harsh reservoir conditions and exceptionally hard rock formations, setting new benchmarks for safe and efficient deep play exploration. Additionally, the paper introduces groundbreaking techniques like hybrid completions and surface-applied pressure in B-Annulus optimization, offering robust solutions for deep play exploration challenges. The successful replication of these techniques across critical sour wells in Petroleum Development Oman (PDO) showcases their potential to revolutionize deep and deeper play gas exploration, promising substantial advancements in exploration capabilities and industry standards.