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 V enezuela 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 seis mic data set over a large part of the field. The seismic data were tie d by synthetic to well-log data by several wells having sonic and dens ity information and then integrated with the high-resolution genetic s tratigraphic framework established from well-log correlations. Two key surfaces identified on the seismic data correlated directly to two st ratigraphically defined sequence boundaries, maximum flooding surfaces (MFS) 80 and 100. A third seismic surface correlated approximately wi th the stratigraphically defined MFS 62. Collectively, these surfaces form fundamental control surfaces from which seismic attribute analysi s and imaging from inverse modeling were undertaken. Four depositional trends detected by the seismic imaging and attribute analysis have im portant implications for reserve growth potential, guiding future fiel d 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 we re identified where the sandstones intersect structurally high positio ns. The distribution of thick distributary-mouth-bar facies, and moreo ver, the boundary with adjacent thin-bedded strandplain facies, were s imilarly detected by mapping average seismic amplitudes in a 35-ms tim e 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-ampl itude anomalies coinciding with thick fluvial sandstones overlying MFS 62 display faulted boundaries and are interpreted as direct hydrocarb on indicators, providing obvious infill drilling locations, and finall y, a marine ravinement surface separating the key oil-producing reserv oirs below MFS 80 was identified by seismic inversion.