Streamline Simulation With an API Tracking Option

Abstract

Abstract There are several offshore oil fields where vertical and horizontal density variations can be found. In order to study this type of reservoir, conventional Black-Oil simulators with an option called API Tracking have been used. This option allows one to define a three-dimensional oil density distribution at the beginning of the simulation and track its variations due movement of oil in the reservoir. Streamline-based simulators can be much faster than conventional finite difference simulators when applied to large and heterogeneous models, which are exactly the most likely to have initial oil property variations. However, current streamline simulators don't have the API Tracking option and can only consider oil with uniform gravity throughout the reservoir. In this work, a 3D incompressible streamline simulator has been modified in order to model oil composition variations, like conventional simulators with API Tracking, keeping the advantages of the streamline method. Mathematically, this option is similar to considering miscible gas injection; this method could also be used to study injection and geological storage of CO2, for instance. To validate this work, comparisons were made between streamline and grid-based simulators. We analyzed saturation distributions and simulation run time using a fine-grid reservoir description, based on the SPE 10 model that represents a North Sea field. The results showed that API tracking can be used with streamline simulators with all the advantages of the method, including reduced run time in relation to conventional simulation, while giving similar results.