First Deployment of a Novel Advanced Tracers System for Improved Waterflood Recovery Optimization

Abstract We are developing an integrated, real-time system for deploying Advanced Tracers cost-effectively in a ubiquitous and potentially long-term way. This campaign is for the sake of increasing the oil recovery factor in large waterflooded reservoirs through improved optimization of the water injection for oil production. This paper explains key features of this novel system and reports main results from the ongoing field test of our second-generation tracer material and detection methodology. Existing inter-well tracers require elaborate laboratory processing for analysis and are not compatible with ubiquitous or real-time deployment. Additionally, conventional tracer material and service costs are not economically viable for widespread and long-term deployment; also, available material barcodes compatible with carbonate reservoirs may be inadequate to monitor dozens of wells simultaneously. Our system addresses all of these inadequacies using novel materials and detection methods, with detailed modeling studies providing strong justification of the financial benefit of this tracer deployment through quantification of increased oil recovery from waterflooded reservoirs. Key elements of this new inter-well Advanced Tracers system include: An optically-detectable tracer material that can in principle be detected in real-time or near real-time at low limits of detection (LODs), even in the presence of background oil in producing water by means of an intrinsic oil background-subtraction method. The material also has high mobility in high-salinity carbonate reservoirs.A rich palette of tracer barcodes (potentially 50 - 100 or more) to enable simultaneous injection and sampling in dozens of nearby wells.Modeling feasibility studies, performed on an ensemble of different reservoir geometries and with sensitivity analyses, showing that including routine inter-well tracer data along with injection and production rates improves the history match quality and therefore, the optimization of the water injection and oil extraction rates so as to achieve a few percent increase in net present values (NPV). Recent field tests of the detectability and discrimination of injected prototype tracer materials will be described. This work adapts novel technology development at the state of the art of modern nanotechnology and bioanalysis to the long-term reservoir stewardship objectives. The integrated, real-time tracer-detection system promises financial benefits through increased NPV and/or ultimate recovery factor via better optimization of water injection.