Application of Dynamic Gridding Techniques to IOR/EOR Processes

摘要

This paper describes applications of a robust nested dynamic grid method that dynamically determines grid modifications in an implicit simulation mode. The implicit nature allows for the use changes of properties in space and time to define refinement/coarsening criteria. The method is illustrated with examples for different IOR/EOR –processes. IOR/EOR processes have moving fronts and require an accurate description at a scale much smaller than typical grid block sizes used in black-oil simulations. Furthermore, they require extra components and phases and/or thermal properties, and sometimes chemical reactions between components. Consequently, simulation of these processes on a high resolution grid throughout a reservoir is still not practical with today’s computing power. A solution is to start on a course grid that is dynamically adjusted to provide sufficient resolution where needed. The challenges are in identifying where and when to adjust the grid. An implicit scheme guarantees that refinements occur where the actual fronts go. No assumptions on where fronts move have to be made before hand. This makes application robust and allows strict control on the number of blocks by minimizing the refined zone(s). This is of particular importance for nested refinements as the number of blocks rapidly grows with extra refinement levels. The combined use of changes in properties in space and in time allows for criteria that sharply define fronts. Application of dynamic gridding in water-flooding, chemical-flooding, gas injection, SAGD, and in-situ combustion demonstrate that optimal criteria are different for different processes.