Optimizing production from a multilateral well requires understanding and characterization of the well and completion performance in the flow path from the reservoir to the separator. Situations when crucial information may be gathered includes transient flow phases such as cleanup and restart after shut-ins. Understanding the inflow from the near-wellbore into each lateral and monitoring the functionality of completion components are important tools in establishing completion effectivness and wellbore performance. This paper describes new applications of chemical tracers in multilateral horizontal wells and utilizes flowbacks in understanding cleanup efficiency, confirming inflow from the toe-section of long horizontal wells and monitoring the functionality of ICV components based on a case study on four multilateral wells in the Alvheim field, Norway.

A new generation of chemical tracers were embedded in a polymer matrix and installed in ICD screens on four long horizontal multilateral wells. In total, 27 unique oil tracers were used for 12 months of oil marking period designed for monitoring early production. The oil tracers were released when the tracers were in contact with oil and mobilized to topside sampling point with the produced fluids when the wells were opened for cleanup. The samples were analyzed in a laboratory and the tracer responses were used to study cleanup efficiency and to monitor ICV during sequential cleanup of laterals. The tracers were also used to understand the inflow contribution from the toe section of each lateral. The case study showed that intelligent well tracers provide a direct proof of contribution from the toe-sections of the multilateral wells and enabled monitoring of ICV functionality and synchronization.

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