Production data from several Shuaiba fields in the Sultanate of Oman demonstrate the oil recovery from capillary transition zones. This is underpinned by extensive detailed experimental and theoretical modeling studies describing favored oil mobility and residual oil saturation in transition zones in the Shuaiba formation reservoir. Nonetheless the economical development of capillary transition zone reservoirs, especially those with thin oil columns, remains an ongoing challenge and necessitates addressing uncertainties related to characterizing the lateral variations in initial oil saturation distribution, water flooding displacement, sweep efficiencies and accurate prediction of oil production.
This paper discusses good practices for ongoing developments of transition zone fields and predicting their performance. The key enablers are: (1) properly characterized initial saturation height functions for long horizontal well planning, (2) implementation of consistent set of hysteresis saturation functions in the reservoir simulation models and (3) geosteering tools for accurate well placement and spacing. Examples of predicted well performances for a field compared to the actual production data will be shown. The results highlight the generic trends in transition zone oil production and the recommended procedures for static and dynamic modeling during field development planning.