ROBERTS, DWIGHT E. "SKIP," Consultant, Southlake, TX
Old oil and gas field often lack the integration of modern seismic and paleontology. As the result, additional reserves can be overlooked. The 1985 discovery on the southeast flank of Lake Washington field by Rosewood Resources, Inc., et al., is such an example. Located 40 mi south-southeast of New Orleans is Lake Washington field, Plaquemines Parish, Louisiana. The field was discovered in 1931 and has produced in excess of 350 MMBOE from over 400 wells completed
in numerous upper and middle Miocene deltaic sands. The tectonic setting is that typically associated with a piercement salt/shale diapir. With the complexity of normal listric and radial faulting, sand/shale pinch-outs, and unconformities, the development of the discovery had to incorporate all information from the geoscientists and engineers. In assembling the subsurface maps, the reservoir model had to honor the seismic, paleontology, and individual well production performances. Six fold seismic data shot in 1968 on the southeast flank of the field identified two main bounding down-to-the-coast normal listric faults forming the fault trap. This untested fault block was originally drilled in 1982. Due to mechanical problems, the well was abandoned. Before abandonment, a TDTK log was run. Because of poor gamma-ray and sigma response and no mud-log shows, the company elected to plug the well. The poor gamma-ray and sigma response was due to masking caused by the thick casing dollars. The lack of shows in the Textularia "L" section was due to an overbalanced mud system, as the well drilled through the highly permeable, unconsolidated, and subnormally pressured sands. In 1984, new 24 fold seismic data were shot. The updated interpretation of the seismic and subsurface data, along with a detail bathymetric ecological study, was incorporated into the geological model. This synergism of the disciplines resulted in the discovery of an additional 8 MMBO.
AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)