Applying modern interpretation techniques to old hydrocarbon fields to find new reserves: A case study in the onshore Gulf of Mexico, USA

摘要

This study shows how the use of current geological investigative techniques, such as sequence stratigraphy and modern seismic interpretation methods, can potentially discover additional hydrocarbons in old fields that were previously considered depleted. Specifically, we examine the White Castle Field in South Louisiana, which has produced over 84.1 million barrels of oil and 63.1 billion cubic feet of gas but retains additional recoverable hydrocarbons. The field has pay sections ranging from late Oligocene to late Miocene. The upper Oligocene to early Mocene package, which was underexploited and understudied during the previous exploitation phase, contains three primary reservoirs (Cib Haz, MW, and MR). During most of the late Oligocene, the White Castle Salt Dome was located in a minibasin on the continental slope. The Cib Haz and MW reservoirs were deposited in this minibasin and offer great exploitation potential. The Cib Haz interval is an amalgamation of slumped shelfal limestones, sandstones, and shales interpreted to represent a lowstand systems tract (LST). The MW comprises a shelf-edge delta deposit that is also interpreted as part of a LST. The MR reservoir is interpreted as an incised valley fill located in the continental shelf that was deposited during a lowstand of sea level after the minibasin was filled. Finally, it appears that the minibasin acted as a self-contained hydrocarbon system during the late Oligocene, suggesting the possibility of a shale play. In this study, several new areas of interest are revealed that could contain economical amounts of hydrocarbons.