Abstract:

Reservoir architectures of meandering river are complex and the lithologic surfaces cross the isochronic ones. Traditional seismic facies analytical method can not satisfy seismic interpretation of reservoir architectures on reservoir development scale. Outcrop detection with ground penetrating radar (GPR), 3D seismic forward modeling and real seismic data are employed in this study. The influences of seismic frequency and strata thickness on seismic reflection of meandering rivers are analyzed. Principle and method of meandering fluvial interpretation with stratal slices are studied. Seismic sedimentology interpretation workflow for meandering rivers is created. It is found that (1) seismic events in high frequency seismic data are reflection of isochronic surfaces formed by point bar complexes, while those in low frequency data are reflection of lithologic surfaces; (2) seismic reflection characters of bars vary with thickness, this causes the ambiguity in its seismic interpretation. Three key points of this method were proposed: (1) making full use of geologic information from vertical and horizontal dimensions of 3D seismic data; (2) taking fluvial sandbody as an integrated genetic body in 3D space; (3) using hierarchic interpretation method and interpreting sandbodies of different hierarchy with particular technologies. This method and workflow are used in seismic sedimentologic interpretation in the Gulf of Mexico, and architecture of point bar complexes are characterized in 3D space.

Key words:  meandering river, reservoir architecture, seismic sedimentology, reservoir development scale, hierarchical, stratal slice