Methods for analyzing the connected quality of a hydrocarbon reservoir are disclosed. A model of a portion of the reservoir is divided into cells, each cell having a volume and some attributes, and wherein a speed function is assigned to a portion of the cells. A reference cell is chosen. A connectivity between cells in the reservoir is determined by solving an Eikonal equation that describes the travel time propagation, said propagating front progressing outward from a reference cell until an ending condition is met, said Eikonal equation being solved by a fast marching method with propagation velocity as a function of spatial position being provided by the speed function. Regions of the reservoir are characterized by their connective quality to the reference cell using the connectivity.