SabiriyahMauddud is a giant carbonate reservoir in North Kuwait, under active water flood using 18 inverted 9-spot patterns and 11 peripheral injectors. Water flooding operations require proper understanding of the connectivity between the injectors & producers so that the assurance on water flood sweep is properly diagnosed and corrective actions are initiated. The objective of the paper is to share the planning, sampling & integrated analysis of the tracer applications to enhance the water flood efficiency in a pattern(P- 1) in SabiriyahMauddud at the Crestal part surrounded by four nearby patterns (P-2; P-3; P-4 & P-5) & intersected with numerous faults.

Extensive data illustrating the reservoir connectivity was pre-analyzed in an integrated manner. The data covered permeability trends; openhole logs; RFT data; mapping of high perm streaks; pressure response as time-lapsed static Bottom hole pressure surveys; PVT data; oil rate & water cut trends since the start of water flood activities in 2000. Also, the salinity contrast was used to understand the water movement pathways, as low salinity sea water was injected in a purely depletion drive segment, with no mobile formation water. The diagnostics, however, could not be fully conclusive as the surrounding producers of P-1 were also receiving injection support from P-2; P-3; P-4 & P-5 (surrounding patterns). Distinctive Chemical tracers were injected into P-1 as well as surrounding P-2; P-3; P-4 & P-5, with a comprehensive sampling program at all associated producers. Continuing with sampling & tracking over a period of 2 years has helped to understand the high speed zones and inter-pattern connectivity.

Injectors of Pattern-1 were found to be in excellent connectivity with the surrounding producers, with partial support from the injectors for P-2; P-3; P-4 & P-5. The information helped to scale down the injection allowable for the injector of P-1, resulting in average reduction in water cut from 50-60% to 30-45%. Further optimization is planned in future by isolating the high perm layer from the surrounding producers during rig over jobs and even by horizontal sidetrack of producers for upper part and injectors for lower part (which is high perm zone).

Tracer information, thus, added value to the understanding of the water flood connectivity which has been duly integrated into reservoir models during history match. Also, as the way forward, the strategy has been expanded to all other patterns & even horizontal injectors and is under implementation.

Value was added to the water flood surveillance activities in North Kuwait by proving this way of diagnosing the connectivity in a challenging & heterogeneous reservoir under active water flood.

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