Abstract: Oil Recovery Strategies in Tide-Dominated Estuarine-Fill Sequences in the Lower Misoa Formation (Lower Eocene), Maraven Bloque I Area, Lake Maracaibo, Venezuela

AMBROSE, W. A., S. K. RAEUCHLE, M. SALEEM AKHTER, F. P. WANG, E. H. GUEVARA, NELIDA AGOSTINI, PEDRO MUNOZ, MILEIDA MEDINA, ALFREDO LEON, and NESTOR PARRA

An integrated reservoir-characterization study by the Bureau of Economic Geology and Maraven, S.A., targets more than 29 metric tons (greaterthan 180 million stock-tank barrels) of unproduced oil in lower Eocene estuarine reservoirs in a 15.5-km² (6-mi²) area in the northeastern part of Maraven's Bloque I Area. Uncontacted oil occurs in fault-bounded compartments, and bypassed oil remains in poorly swept areas adjacent to elongate pathways of water encroachment along sandy estuarine-channel depositional axes. More than 25 new strategic infill wells, recompletions, and water-injection wells are projected to enhance recovery of the remaining oil resource.

The lower Eocene in Bloque I consists of multiple estuarine-fill sequences, 30.5 to 91.5 m (100 to 300 ft) thick, bounded below by tidal-ravinement surfaces and capped by flooding surfaces. Limited accommodation space resulted in tidal ravinement and erosion of lowstand fluvial and estuarine-delta plain deposits associated with early stages of paleovalley fill.

Unrecovered hydrocarbon resources in Bloque I are mainly delineated by 3-D seismic RMS amplitude maps. These maps suggest areas of high hydrocarbon saturation on the downthrown side of normal faults and in a major fault-bounded compartment east of the left-lateral strike-slip Icotea Fault. Deeper, untested reservoirs in the eastern part of Bloque I, highlighted by 3-D seismic amplitude anomalies, are projected to greatly extend the productive life of Bloque I.

AAPG Search and Discovery Article #90942©1997 AAPG International Conference and Exhibition, Vienna, Austria