Abstract: Pre-Platform Exploration of High Island Blocks A-560 and A-561

Jeffrey W. Lund, John S. King, Richard Berlitz, J. A. Gilreath

Winning bids of $15,179,748 and $2,041,709 for High Island Blocks A-561 and A-560 were submitted by the Clark Group at the May 29, 1974, OCS lease sale. These bids were based on interpretation of geophysical data which indicated hydrocarbon accumulations in an anticlinal structure downthrown to a major fault.

Eight exploratory wells were drilled on these blocks between June 1975 and October 1976. The exploratory drilling program confirmed the presence of hydrocarbons and revealed an unexpectedly complex stratigraphy and variety of trapping mechanisms.

Information from several sources clarified the stratigraphic picture prior to the selection of a platform location. Computed logs were used for water-level identification in shaly sandstones and for correlation. Dipmeter results and petrographic analysis of sidewall cores were used for identification of sand types, transport directions, and depositional environments. Geochemical analysis provided clues to the source of the oil.

Integration of the improved geologic model of submarine fans and seismic data permitted the location for the initial platform to be selected. An 8-pile platform will be set in the summer of 1978.

AAPG Search and Discovery Article #90965©1978 GCAGS and GC Section SEPM, New Orleans, Louisiana