PRACTICAL CONSIDERATION FOR APPLICATION OF FAST MARCHING METHOD INTO HETEROGENEOUS DUAL POROSITY RESERVOIR MODELS

Abstract

The shale oil/gas is one of the most prospective natural resources due to its huge amount of reserves, and, thus, its development plays a role in making a great contribution to resolve the problem of energy deficiency all over the world. However, because of the uniqueness of shale reservoirs, it is by no means easy to expect reservoir performance from current commercial reservoir simulators. Hence, the improvement of practical shale reservoir simulators is significant to make progress on the development of shale reservoirs. As for this, Fast Marching Method has shown its strength of fast prediction of reservoir performance. This research employs two approaches to improve the applicability of Fast Marching Method: the use of Multistencil Fast Marching and the application of Fast Marching Method into heterogeneous dual porosity models.

In this study, Multistencil Fast Marching Method is employed to improve the accuracy of Diffusive Time of Flight (DTOF) calculation. Originally, Fast Marching Method has taken into account only directly adjacent cells to derive DTOF, which ends up with smaller transmissibility than that of commercial softwares. In case of Multistencil Fast Marching Method, the derivation of more accurate DTOF is achieved by considering the diagonal cells in addition to the directly adjacent cells. In the following study, Fast Marching Method is applied into heterogeneous dual porosity reservoir models (DPSP). In this model, Fast Marching grids are generated based on DTOF of fracture. Matrix grids are supposed to belong to their fracture grids. Thus, appropriate averaging methods for matrix properties need to be investigated so that it selects most representative parameters among heterogeneous matrices. Subsequently, Fast Marching Method is extended to multiple phase reservoir models, and then some case studies not only with heterogeneous matrix properties but also with heterogeneous fracture properties are conducted in order to show the robustness of this method. Lastly, the field application was conducted to show the wide applicability of FMM.