udFacies and Depositional Environment Analysis of Alternate Channel Bodies in the Flank of a Sag Structureud

摘要

The down-dip (40o) portion turbidite Cenozoic deposits of the western sag structure in the Bohai bay ud been characterized for stratigraphy. Laterally tracking continuity in temporal data becomes challenging with increase in offset. In achieving this and ground-truthing results from core data, spatialuddata is indispensable. A good subsurface resolution on seismic data is key to understanding both theuddistribution and extent of lithological units earlier identified as hydrocarbon prolific. Rock physics andudpetrophysical properties when understood and appropriately utilized does well in showing vital correlations inherent in subsurface lithological units. Deterministic approach to linking pattern on logs proved slightly useful in this study. Each have its’ distinct depositional cycle ranging from 3 cycles for wells 13-2, 35-4 and 46-2 to 4 cycles for 24-5. It has been discovered that well 13-2 has less complex structure while well 46-2 is most distal occurring at the toe of the sag structure, has the most complex geometry. However, hidden vital information became obvious when methods of seismic interpretation and post-inversion multi-attribute analyses were used within the same cross section to discover subtle alternating channel sand lobes that is explorable within an unfaulted and slightly com-pacted synsedimentary sequence. These were presented in log panels, cross-sections and maps.ud