The Present is the Key to the Plio-Pleistocene: Seafloor Analogues at Shell’s GB 516 Serrano Discovery
Published:December 01, 2000
Michael C. Dean, Kevin M. King, James R. Booth, 2000. "The Present is the Key to the Plio-Pleistocene: Seafloor Analogues at Shell’s GB 516 Serrano Discovery", Deep-Water Reservoirs of the World, Paul Weimer
Download citation file:
Prospect Serrano is located approximately 220 miles southwest of New Orleans and 6 miles southeast of the Auger TLP in Garden Banks Block 516. The Shell GB 516 #1 well, drilled in 1996, has encountered 86 net feet of Pleistocene age (P. lacunosa) gas pay at the main objective horizon. The objective horizon occurs in the largely channelized bypass seismic facies assemblage (e.g., Prather et al., 1998), and is mapped regionally as a highly continuous draping seismic event. In offset penetrations the objective horizon is sand lean and generally associated with pyroclastic sediments. Mapping of 3D seismic data and comparisons to the present day seafloor, however, suggest a sand-prone depositional setting at the Serrano prospect. Loop level attributes and interval isochores indicate that several depositional systems were active at Serrano. In addition, present day seafloor bathymetry reveals the presence of a backstop setting within low-relief ponded accommodation space (e.g., Prather et al., 1998). Furthermore, images of the present day seafloor support the interpretation of multiple sediment entry points and offer clues to depositional and erosional relationships preserved in the subsurface. The seafloor analogue is instrumental to understanding the distribution of sheet sands, depositional and erosional bypass channel systems, debris flows, and large-scale erosional gorge systems at the Serrano prospect. The seafloor is a present-day analogue of Pleistocene depositional processes in the Gulf of Mexico and is a valuable tool in reservoir prediction.
Some of the terminology used in this paper is common within Shell, but less well known in the oil industry in general. The following table defines some of this terminology.