A new type of grid used in the dynamic simulation model of the giant Troll Field is presented. The grid consists of a stratigraphic and a horizontal layered part. Hence, it is named hybrid grid. The horizontal part encompasses the thin oil zone and a small distance into the gas cap and water zone, the rest of the grid follows the stratigraphy. The reason for choosing such a grid for the Troll Field is the dipping stratigraphic layering, a thin oil column, and the large area that the field covers.Another factor is the long horizontal wells that drain the oil. The horizontal grid has a high vertical resolution of 2 m to accurately capture the thin oil column, and for satisfactorily representing horizontal wells close to the fluid contacts. Above and below the horizontal grid the layers follow the stratigraphy to represent the geology with a minimum number of grid blocks. The paper shows why the hybrid grid is superior compared to other grid types for a gas field with a thin oil column, and covering a large area. The paper also describes how to build a hybrid grid, and the work processes for up-scaling and history matching the model. The new Troll model has currently replaced the 15 simulation models that previously were used to represent dynamically the Troll Field.