1. An oil and gas prospecting method for predicting connectedness between parts of a potential hydrocarbon reservoir identified in a geophysical data volume corresponding to a subsurface region, comprising: obtaining a plurality of data elements, respectively corresponding to three-dimensional locations in the subsurface region, and generating a data volume consisting of discrete cells from the plurality of data elements; identifying an initial geobody corresponding to a potential hydrocarbon reservoir within the data volume by grouping cells in the data volume according to a selected connectivity criterion; selecting a rule that characterizes stratigraphically reasonable geobodies; in response to a determination that the initial geobody does not conform to the rule, segmenting the initial geobody into a plurality of fundamental geobodies via processing the data elements with an automated segmentation routine, wherein the fundamental geobodies each conform to the rule; and using the fundamental geobodies to predict connectedness between parts of the potential hydrocarbon reservoir.