Lockhart Crossing Field: New Wilcox Trend in Southeastern Louisiana

Abstract

In 1982, a significant onshore oil discovery in the lower Eocene Wilcox was made at Lockhart Crossing field, illuminating a new oil trend in southeast Louisiana. Twenty-eight producers and nine dry holes were drilled, resulting in development of 3,400 productive acres with estimated recoverable reserves of 21 million bbl of oil after secondary recovery. The main field reservoir is a 40 to 80-ft (12 to 24-m) marine sandstone. The dominant facies is an upward-coarsening sequence of very fine to fine-grained glauconitic sandstone deposited as a nearshore marine bar. The associated facies is a younger, upward-fining, channelized sequence of medium to very fine-grained sandstone. Faulting initiated channeling and erosion into the existing nearshore bar facies with subsequent deposition of channel fill. Together these two facies constitute one reservoir. The primary trapping mechanism is structural, in the form of a rollover anticline. This solution gas drive reservoir is normally pressured and displays a concave-downward producing water level that initially masked the true productive limits of the field.