Well Logs and 3D Seismic Data Integration Using Geostatistical Methods, Lomas del Cuy Field–Golfo San Jorge Basin–Argentina

Abstract The Estancia San Justo Norte Area in the Lomas del Cuy Field was characterized using geostatistical methods. The distributions and thickness of sand bodies were determined within an area of over 20 square km, with 42 drilled wells, and 3D seismic interpreted by REPSOL-YPF. The intervals of interest were determined from well logs, correlated throughout the field and related with the 3D seismic data. The appropriate reflectors were identified in the seismic, and time windows were established so that these would match the selected intervals. A total of seven windows was used and within each of them 25 seismic attributes was extracted. On the other side, petrophysical evaluations were made from well logs obtaining results for gross, net and net pay thickness and average petrophysical properties within the intervals. Good correlations were found between petrophysical properties and certain seismic attributes in 6 of the 7 windows. In these cases, cokriging was used to map the petrophysical properties integrating the seismic data. As a result, petrophysical maps guided by seismic attributes were obtained for net thickness, net/gross, net porosity thickness and average net porosity. These maps proved very useful for determining new well locations. The results clearly indicate that the application of this technique is very effective for describing the fluvial type reservoirs with small lateral continuity, typical of the Golfo San Jorge Basin. Geostatistical methods were good predictors of sand body distributions in each of the analyzed intervals. This data is extremely valuable in the development of fields when it is integrated with the rest of the available information in the area.