Seismic and Geologic Evidence of Complex "Positive Flower" Structures Along Confining Bends in Strike Slip Faults, Lake Maracaibo, Venezuela

Abstract

Abstract Since 1996, International Reservoir Technologies (IRT) and Petroleos de Venezuela, SA (PDVSA) have completed four (4) integrated studies within Block V Lamar, Block VI Lamar, Block V Centro, and Centro Sur Lago Areas of Lake Maracaibo, Venezuela. These studies have identified four major and numerous minor "positive flower" structures along confining bends of three major strike slip faults. These flower features provide the structural trap that has accounted for some 623 MMstb of oil production from the Eocene Misoa B and C sands. Positive flower structures are often dismissed as non-existent and are often interpreted as reactivated normal faults with reverse movement. Although the normal displacement is true on the examples shown in this paper, we will show several examples of bounding arcuate reverse faults that coalesce into a single fault at depth commonly referred to as "Positive Flower" structures. 3D seismic, in conjunction with dipmeters, logs, fluid contacts, engineering tests and production data provided the necessary information to build a detailed, comprehensive and consistent 3D geologic model of these structures. The integration and use of all possible data sources was key to accurately mapping the associated reservoirs. The studies have led to improved knowledge of the timing and development of flower structures with respect to hydrocarbon migration and trapping. Production continues in these structures and development drilling continues both within the flower structures and to drain oil that has been trapped on the underside of bounding reverse faults. The integrated study approach has lead to optimized development of these complex "Positive Flower" structures, but is also applicable to other structural and stratigraphic regimes.