Reservoir modeling has changed from use of 2D maps to a 3D workflow involving detailed shared earth models that are scaled up for reservoir simulation. The quality of simulation models has improved through incorporation of additional geological features of the reservoirs. This process can be slow. The complex models cannot be updated frequently enough or they carry uncertainty. Decision-driven reservoir modeling (DDRM) creates and uses reservoir models that are only as complex as needed and bring uncertainty into predictions more thoroughly than before. This advanced reservoir-modeling technology uses a scale-independent nongrid-based design, generates detail realization on the ny, merges static and dynamic elements, and uses uncertainty prediction from uncertainty models.