Innovative Well Pad Design to Address Field Congestion Challenges and Cost Optimization

Abstract Mature field congestion is introducing challenges for future developments on surface and subsurface aspects. The objective of this paper is to share ADNOC Onshore and TotalEnergies’ s combined effort and experience in mitigating the surface and subsurface congestion issues thanks to an innovative and cost-effective revision of the well pad concept. The different types of existing Mature Field well pads were screened and the typical large Well Pad, providing full flexibility at the project level, was selected for analysis and further optimization to ease its implementation in surface congestion context. The initial step was to assess the key drivers for the current well pad layout. Collected data were used as a basis to design a new pad concept considering rig fleet capabilities and best engineering practices for similar facilities. Considerations were made regarding the possibility to drill with any rig from the existing AON fleet and the requirement to minimize production shortfalls during well intervention. Downhole congestion was also looked at, relying on specific simulations performed in various configurations. In the pad utility area, it was found possible to achieve a significant footprint reduction by applying different design principles. Large volume of piping, valves & instrumentation were removed from the Wellbay area (moved to manifold area) and a culvert concept was implemented to accommodate well flowlines. Well pad shape was optimized by relocating the utilities area close to the well bay area. Minimal WH spacing was assessed considering 2 types of rigs (one skidding and one non-skidding). The optimum WH distance was found to be 15m considering optimization of drilling operations, ability to cap the well and possibility to perform Work Overs with a drilling rig. It was demonstrated that distance could be reduced to 10m if smaller WO units were made available. Considering downhole congestion only, simulations showed that WH spacing could be reduced to less than 5m and still be able to drill any well with no significant impact on cost and duration. Specific drillability issue on new wells were also studied and resolved. Advantages of such a novel well pad design are: Overall footprint reduction by 60% (divided by 3) without major compromise on initial well pad designing criteria'sSignificant Capex savingsMassive reduction of piping length and hydrocarbon inventory (at least 30% reduction)Minimized time for preparation of WO & equipment re-installation after WOFaster drilling operations when skidding rig can be used (batch drilling)