Reservoir Simulation with High Volume of Tracers whilst Retaining Performance

Tracking fluid movement in a reservoir using single-well tracer and inter-well tracer tests is an important mechanism for optimizing recovery. In full-field simulations with a high number of tracers, the solution to tracer systems can be computationally expensive because each tracer requires the solution of a linear system with dimension equal to the grid size. Hence, for an increasing number of hydrocarbon components, grid size, and number of tracers, the performance of the simulator degrades. Relying on the nature of the material balance equations governing the tracer flow, we propose to utilize a convenient feature of the underlying partial differential equations (PDEs) in that the matrix-form equations of all tracers carried by a given fluid phase or component are the same, and only the right-hand sides of the corresponding linear systems change. We provide an overview of the optimal linear solver for solving tracer linear systems in different scenarios (e.g. high volume of tracers). Moreover, we show that by overlapping computation on the central processing unit (CPU) and the graphic processing unit (GPU), we can significantly reduce the impact of solving the tracer equations on the overall simulator performance, which enables running a simulation with a high volume of tracers.