A computer-implemented method of identifying compartments of a reservoir structure, the method comprising: obtaining structural data corresponding to a geological structure of a reservoir, CHARACTERIZED IN THAT the method further comprises: generating a topological net (504; 710; 802; 1208) based on the structural data, the topological net comprising critical points (404; 422; 520; 616; 712, 714, 724, 718; 804; 1210, 1212) and poly segments (508; 806; 1214) connecting the critical points, whereby the topological relationship of the reservoir is extracted from the reservoir geometry, using a depth function as a real value function that maps the reservoir data structure as the domain of the function to the depth range of the reservoir; wherein the generation of the topological net comprises: (i) defining a real value function that maps the reservoir structure to depth values; (ii) computing one or more local minima, one or more local maxima, or any combination thereof based on the real value function; (iii) identifying one of the one or more local minima, one or more local maxima, and any combination thereof as the critical points; and (iv) representing the critical points in the topological net; identifying potential compartments (406, 408; 424, 426; 522, 524; 618, 620, 622, 624; 720, 722; 1216, 1218) of the reservoir structure based on the topological net; identifying spill or break-over (404; 520; 616; 718; 1220) relationships among the potential compartments based on the critical points of the topological net; and using a resulting geologic model provided by the topological net to guide future production decisions, such as whether and where to drill new well bores. generating a topological net (504; 710; 802; 1208) based on the structural data, the topological net comprising critical points (404; 422; 520; 616; 712, 714, 724, 718; 804; 1210, 1212) and poly segments (508; 806; 1214) connecting the critical points, whereby the topological relationship of the reservoir is extracted from the reservoir geometry, using a depth function as a real value function that maps the reservoir data structure as the domain of the function to the depth range of the reservoir; wherein the generation of the topological net comprises: (i) defining a real value function that maps the reservoir structure to depth values; (ii) computing one or more local minima, one or more local maxima, or any combination thereof based on the real value function; (iii) identifying one of the one or more local minima, one or more local maxima, and any combination thereof as the critical points; and (iv) representing the critical points in the topological net; (i) defining a real value function that maps the reservoir structure to depth values; (ii) computing one or more local minima, one or more local maxima, or any combination thereof based on the real value function; (iii) identifying one of the one or more local minima, one or more local maxima, and any combination thereof as the critical points; and (iv) representing the critical points in the topological net; identifying potential compartments (406, 408; 424, 426; 522, 524; 618, 620, 622, 624; 720, 722; 1216, 1218) of the reservoir structure based on the topological net; identifying spill or break-over (404; 520; 616; 718; 1220) relationships among the potential compartments based on the critical points of the topological net; and using a resulting geologic model provided by the topological net to guide future production decisions, such as whether and where to drill new well bores. <EOS>