Abstract This paper presents a case on the innovative development of an ultra-thin, tight carbonate reservoir through the drilling of extended 2000-meter horizontal wells in an oil field located in Block-5, Oman. This approach resulted in lower wells density compared to the conventional 1000-meter length with minimal operational consequences which effectively reduced carbon emissions and minimized the environmental footprint while unlocking tight reservoirs and improving Net Present Value. The carbonate reservoir in this field is characterized by a thickness of less than two meters and low permeability (less than one millidarcy), leading to substantial production decline due to the restricted flow of formation fluids, which adversely affects overall reservoir productivity. The adopted strategy not only improved productivity but also reduced well density, thereby mitigating the environmental and safety challenges typically associated with high well-density areas. Between 2021 and 2024, six new long wells were successfully drilled, marking a significant advancement in the field's development. The production results of these long wells were evaluated and compared to the performance of the 1000-meter wells. The extended 2000-meter wells exhibited enhanced productivity, ranging between 10 – 30%. Such successful outcomes, combined with the projected reduction in overall development costs, prompted a comprehensive reassessment of the field development, leading to updates in both the static and dynamic models. Based on the forecasts derived from the updated model, the decision was made to expand the development plan, proposing 11 additional wells in the field. This strategic decision would maximize the recovery of this field while minimizing the well density, compared to the development with 1000-meter wells. A detailed study was undertaken to establish a clear development strategy for the field. The analysis revealed that extending the horizontal wells to 2000-meter could significantly improve NPV and profitability, driven by the increased productivity of longer wells and the reduction in overall operational costs. Furthermore, the lower number of wells contributes to a reduced environmental footprint, enhancing the sustainability of this field development. The results observed in this field highlight the potential for implementing the extended lateral wells approach in two other nearby fields with similar geological properties, specifically low permeability and ultra-thin reservoirs. Overall, this innovative strategy would unlock previously untapped reserves, demonstrating the importance of innovation and adaptive strategies in the oil and gas industry. By challenging conventional methods and embracing new approaches, companies can achieve sustainable growth and maximize the value of their assets more efficiently while minimizing their operational and environmental footprint.
Ajmi et al. (Mon,) studied this question.