Abstract

Optimizing resources and pushing the drilling limits to tap into deeper reservoirs at minimal cost has always been the primary objective of many operators worldwide. Moreover, the prolonged current market conditions are pressurizing every stakeholder involved within the well-delivery process to reduce time and the associated costs like never before. This paper deals with an Offshore Artificial Island project where the drilling limits were constantly challenged by adopting new technologies and practices in an extended-reach drilling (ERD) campaign.

The complexity of these extended-reach wells was managed effectively with excellent planning and execution. Implementation of new and existing technologies and the adoption of revamped operational practices has managed the challenges of equipment capabilities, torque and drag, ECD, wellbore stability, hole cleaning and stuck pipe avoidance to name a few. The project drilled longer wells at less costs. This approach has resulted in drilling and completion of wells comfortably within the equipment-rating envelope. Additional technological means such as newly developed lubricant and mechanical drill pipe torque reducer subs helped reduce the friction factor and eliminate drill string buckling. Existing technology in the bottom-hole assembly (BHA) minimized the tortuosity in the wellbore, along with transmitted real-time downhole drilling data (Torque, Weight on Bit, Mechanical Specific Energy, and Equivalent Circulating Density) which helped in active drilling parameters optimization for efficient drilling. Similar technologies and practices were used in landing the completion string.

The geo-mechanical studies undertaken at the concept stage and later revised against the offset well information helped in drilling the troublesome shale formations with no associated events. Specific importance was given to maximizing the hole cleaning by having the right tools in the BHA that could accommodate higher flow rates while using a tandem drill string for lower hydraulics. In addition, the newly formulated field / formation specific drilling and reaming practices minimized the stuck pipe, saving approximately 10% in overall well costs.

This paper discusses the successful drilling of a number of offshore ERD wells with various complexities and tailored solutions with minimal downhole problems and within continuously revising planned times and budgets. The lessons learned and techniques associated with drilling of extended-reach wells at lower costs will be detailed in this paper. This information would give insights and considerations to all stakeholders who intend to drill extended reach wells or challenge their current limiters. This proven successful methodology and its results are considered a benchmark for the nearby fields in the region.

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