See more from this Division: Topical Sessions
See more from this Session: Recent Advances in Deepwater Sedimentology: Science Driven by the Search for Natural Resources
Abstract:
Basin margin strata at Ballybunnion are coeval to sandy turbidite channels and lobes deposited on the basin floor. A cross section through the Ross Sandstone reveals a wedge of low net:gross, poor reservoir quality strata that physically separates sandy, basin-floor strata from the basin margin. The wedge of strata is referred to as the transition zone. The transition zone is composed of co-genetic debrite-turbidite beds, structureless siltstone, slumps, locally contorted shale, and laminated shale. Using data from the Ross Sandstone, two equations are defined that predict the size and shape of the transition zone. The equations use three variables to solve for width (w) and trajectory of the basinward side of the low net-to-gross wedge (beta).
Seismic examples from Gulf of Mexico minibasins reveal a wedge of transition zone sediments, similar to that in the Ross Sandstone. The variables w and beta can be used in subsurface basins to define two important drilling parameters. W corresponds to the minimum distance a well bore should be positioned from the basin margin to intersect sandy strata, and beta corresponds to the deviation the well bore needs in order to continue to intersect sandy strata.
See more from this Division: Topical Sessions
See more from this Session: Recent Advances in Deepwater Sedimentology: Science Driven by the Search for Natural Resources