Multi-Zone Completion Design Optimization in Offshore Prolific Carbonate Reservoirs: A Systematic Approach

Abstract

Completion design is a key factor in maximizing well inflow performance and deliverability throughout the life of a well. During the early stages of development of a green oil field located offshore Abu Dhabi, improved subsurface understanding from data gathering led to the modification of the initial completion design. This paper presents a systematic approach utilizing an integrated workflow to successfully optimize multi-zone horizontal well completions to lower development costs, reduce risks and increased field recovery. The final well architecture was implemented in the Early Production Scheme (EPS) and Full Field Development (FFD) phases of the development. The main achievements of the integrated completions design are: ○Increased well productivity and deliverability.○Optimized completion strategy for low efficient gas lift wells.○Reduced risks in well construction and completion phases.○Improved completion flexibility for life-of-well intervention operations.○Optimized slot allocation to increase recovery with more wells.○Utilized full benefits of conductor sharing technology.○Added flexibility to successfully appraise an undeveloped carbonate reservoir and to incorporate it into the development plan.○Adopted new methodology for lower completion design in multilayer reservoirs.○Considered simultaneous dual system injection and production (SIP) wells. The comprehensive approach presented is valuable in establishing a total life-cycle workflow during the early stage of field development, which can be embedded in any completion design strategy. The completion solutions highlight significant benefits from overcoming well-known challenges in offshore environment such as space limitations, slot availability, and cost optimization. The end product is a life-cycle design identified for each specific reservoir with reduced operational constraints and well intervention complexity.