Integrating 3-D seismic imaging and seismic attribute analysis with genetic stratigraphy: Implications for infield reserve growth and field extension, Budare Field, Venezuela
Despite being a mature oil producer, the Budare Field in the Eastern Venezuela Basin offers considerable reserve growth potential because of stratigraphic and structural complexity. Our ability to resolve these complexities was enhanced following acquisition in 1995 of a 3-D seismic data set over a large part of the field. The seismic data were tied by synthetic to well‐log data by several wells having sonic and density information and then integrated with the high‐resolution genetic stratigraphic framework established from well‐log correlations. Two key surfaces identified on the seismic data correlated directly to two stratigraphically defined sequence boundaries, maximum flooding surfaces (MFS) 80 and 100. A third seismic surface correlated approximately with the stratigraphically defined MFS 62. Collectively, these surfaces form fundamental control surfaces from which seismic attribute analysis and imaging from inverse modeling were undertaken. Four depositional trends detected by the seismic imaging and attribute analysis have important implications for reserve growth potential, guiding future field development. An incised valley, filled primarily with thick fluvial sandstones, was detected by mapping average seismic amplitudes between the MFS 62 and 80 markers, and several step‐out drilling locations were identified where the sandstones intersect structurally high positions. The distribution of thick distributary‐mouth‐bar facies, and moreover, the boundary with adjacent thin‐bedded strandplain facies, were similarly detected by mapping average seismic amplitudes in a 35-ms time window below MFS 80. The mouth‐bar facies coincide with the crestal position of a potentially large, structurally defined field extension supporting multiple potential infill wells. Several high‐negative‐amplitude anomalies coinciding with thick fluvial sandstones overlying MFS 62 display faulted boundaries and are interpreted as direct hydrocarbon indicators, providing obvious infill drilling locations, and finally, a marine ravinement surface separating the key oil‐producing reservoirs below MFS 80 was identified by seismic inversion.