This paper describes the interventionless approach that was successfully executed during the Pyrenees early production phase to identify the timing and location of water breakthrough. Chemical inflow tracers were installed in key production wells within the lower completion along the horizontal production sections. Results from this work have supported the reservoir simulation history matching process and confirmed the performance of the inflow control devices (ICDs). These data in conjunction with the real time rate information from subsea multiphase meters has allowed proactive reservoir and production management that has contributed to the early identification of additional infill opportunities.

The initial development of inflow tracers was initially designed to provide qualitative information about identifying the location of water breakthrough in production wells. The proof of concept and application for water detection, initiated the development of oil tracers for oil inflow monitoring. Different approaches to install them permanently within a completion component were used, to provide risk free, reliable production monitoring without the need for intervention. Installing unique chemical tracers that are embedded in polymer materials in sand screens or pup joints, along select locations in the lower completion was to correlate where the oil and water is flowing along the production interval and how much. Innovation in the chemistry and materials designed to release to a target fluid (oil or water), enabled non electric wireless monitoring capabilities for many years of longevity in harsh well conditions, such as high temperature and highly acidic stimulation fluids. The evolution of inflow tracer signal interpretation, qualitative and quantitative interpretation workflows using models have also provided valuable insight to inflow characterisation. The latter can provide zonal rate information like wireline conveyed production logging tools, by inducing transients through shut in's or rate changes to create tracer signals that are transported by flow to surface and captured in sample bottles for laboratory analysis. A model based approach to match the measured signals with proprietary models through history matching workflow has also been developed. There are hundreds of well installations utilising inflow tracing monitoring technology today, where the majority have been in open hole completions in both sandstone and naturally fractured carbonate reservoirs on land, offshore environments in both platform and deep water sub-sea environments producing through long tie backs to FPSO's. The monitoring sensors are adaptable to most completion types in conventional and unconventional reservoirs. In most cases, inflow tracers can monitor clean-up efficiency, any subsequent restart and steady state production. Practical case studies will discuss the development of robust and reliable inflow tracer and technology and how operators have applied it over the past decade in a chronological order.

Tracers are applied as embedded in polymers that are placed in the downhole completion. The Tracer Systems are designed to change behaviour as a function of the surrounding medium. Such behavior can be the release of tracer into one medium while keeping tight in another. Released tracers will migrate to surface where topside fluid samples are analyzed and the tracer concentrations in those are the basis for extracting Well Inflow Information. The Tyrihans well, B-IAH T2, was cleaned-up in two sections and the 1100m long toe section was equipped with 3 unique oil soluble tracers that were placed along the production zone. The objective was to evaluate the quality of clean-up and (if necessary) also during a production restart 6 months later. The well had a downhole temperature of 137 o C, higher than the operating temperatures for available Permanent Tracer Systems. So a new Tracer System had to be developed and qualified for the case. RESMAN's tracer systems indicate that the toe is contributing as expected to the fluid production and that additional production occurs along the well bore. All completion fluids in the lower completion seem to be fully cleaned-up. All 3 tracers adds value to the interpretation. Extra information on the fluid dynamics of the clean-up process could be indicated.