An integrated approach combining tracer injection/monitoring and other surveillance application for reservoir management in Rang Dong basement reservoir

Abstract

Rang Dong basement reservoir is a granitic naturally fractured reservoir. Unlike carbonate fractured system, basement matrix porosity is negligible. The storage and production are dominated by the fracture system. After primary depletion, water injection was commenced to further improve the oil recovery and production of the reservoir. Water injection in fractured reservoir is particularly challenging as it is very much dependant on the fracture connectivity, geometry and orientation. To manage the water injection strategy of the basement reservoir, a thorough understanding of the fluid flow is crucial. Therefore, radioactive tracer injection/monitoring were employed in different part of the field to obtain information on fluid path.Tracer injection/monitoring have been established as a proven and efficient technology to obtain information on well-to-well communication, heterogeneities and fluid dynamics. However, interpretation may in some cases not straight forward, therefore integration with other types of reservoir and production data are important to get a consistent and accurate interpretation.This paper demonstrates an integrated approach where it combined tracer injection/monitoring with other surveillance application for well planning and reservoir management. One of the surveillance is the monitoring of the water chemical composition through regular sampling and analysis of produced water. This method serves as the tracking of movement of formation/aquifer water and injected seawater. Another analysis involves the monitoring of produced water isotopes. Oil finger printing is also used as another source of information to be combined into the overall interpretation. Oil finger printing is used to identify any reservoir compartmentalization, reservoir extent and connectivity. Other reservoir data and applications used are well production performance, well pressure transient analyses, material balance analyses and etc.This paper documents some actual examples where the tracer injection/monitoring analyses integrated with all available information were used to derive at actual well planning or reservoir management strategy that was eventually applied in the field.