1. A method for assessing connectivity between two or more objects in a hydrocarbon reservoir in order to manage development of the reservoir, comprising: (a) specifying a data volume of data elements on a discrete two or three-dimensional grid, said data representing a selected characteristic of the hydrocarbon reservoir at each cell in the grid; (b) specifying location of at least two objects in the data volume; (c) determining all Voronoi curves (2-D) or surfaces (3-D) in the data volume for the at least two objects as propagation seeds, said Voronoi curves or surfaces defining where fronts started simultaneously from each object meet, wherein front propagation speed at each cell location is a function of the data element at that cell; (d) locating all saddle points on the Voronoi curves/surfaces; (e) for each saddle point, finding a locally optimal path between two objects nearest to the saddle point by finding optimal paths between the saddle point and the two objects; and (f) assessing connectivity of the at least two objects based on the locally optimal paths connecting them.