Using a tracer as a monitoring technique to measure the migration of the injected fluid in the reservoir is relatively inexpensive method, and it applied in numerous fields throughout the world. The application of tracer can assess the volumetric sweep to quantify the amount of fluid flowing from injectors to producers. It gives an indication of offending injectors. Tracer helps in addressing the communication between different reservoir units. Another objective is delineation of flow barriers to identify the geological features that dominate the flow directionality (i.e. high permeability streaks, faults, fractures, etc) to determine directional permeability trends. The information obtained from tracer can reduce the model uncertainty and provide better tuning for future prediction.
The tracer data is used to generate not only qualitative information but also a substantial amount of quantitative data. Primarily, chemical tracers should be tested against a number of reservoir formation rocks and found not to adsorb or retard. Tracers are injected in the injectors and the samples are collected from nearby producers. Analysis of tracer concentration versus time curves from individual producing wells enables interwell flow characteristics to be determined so that improvements can be made to optimize sweep effectiveness of the hydrocarbon reserve. A record of base line sampling and analyses from all producers should be conducted. A frequent sampling and analysis are performed to understand the reservoir characteristics and performance.
After the application of tracer technique, the following results were observed: The first breakthrough was detected after about one year; due to the short distance between the injector and the producer. The second breakthrough was detected after about three years; due to the reservoir characteristic in the producers. An identical patterns of tracer response was seen, indicates almost homogenous reservoir in the tracer injected. This points out towards a similar depositional pattern across the reservoir. Most of tracers are observed downward towards the flank area. Tracer direction was to the least pressure area (flank) due to high offtake. No breakthrough was observed in the attic wells due to high pressure area.
Tracer technology is inexpensive method used to provide inflow directional information, and it has no impact on the completion design and effectively prove the reservoir characterizations and well performance.