Middle Miocene Stratigraphic Traps, Southeast Manila Village Field, Louisiana

Abstract

ABSTRACT Southeast Manila Village Field, Louisiana, produces from two middle Fleming Group sandstones at depths ranging from 11,400 to 12,000 ft. Hydrocarbon production occurs mainly by a pressure deplion mechanism; a waterflood has been initiated to stabilize reservoir pressure. Fourteen wells have been drilled to date, and ultimate recovery from the field is estimated to be 4,609 MBO and 3,267 MMCFG. Thin sand bodies, designated as the 28 and 29 Sands, occur in a shale interval, which ranges in thickness from 500 to 600 ft. The reservoir rocks are thinly laminated, moderately to well-sorted, and very fine-grained sands. Thin sand laminations have sharp lower contacts with the interbedded shales, indicating episodic deposition. Foraminiferal assemblages indicate that the sands have been deposited in 100 to 400+ ft of water. The sands are probably the result of turbidity flow deposition in a distal-delta environment. Diagenetic reactions are, in part, responsible for the hydrocarbon accumulation in the sands. Dissolution of primary calcite cement and detrital K-feldspar grains has generated secondary porosity in the sands. Precipitation of authigenic minerals, such as chlorite, pyrite, siderite, kaolinite, illite, and mixed-layer clays has, however, influenced primary and secondary oil recovery. Migration and accumulation of hydrocarbons apparently halted secondary cementation by inhibiting the precipitation of authigenic clays.