Eocene tectonic controls on reservoir distribution in VLE 196, Block V, Lamar Field, Maracaibo Basin, Venezuela

摘要

Integrated interpretation of three-dimensional seismic and well-loggingdata reveals a prominent ??????pop-up?????? structure associated with the VLE 400 fault onthe regional unconformity between the Eocene and Miocene in the VLE 196field, Maracaibo basin, Venezuela. The VLE 400 fault family, an eastern splayof the left-lateral Icotea fault in the basin, played an important role inhydrocarbon migration and accumulation in the field. Hydrocarbons accumulatedto the east of the fault but not to the west. The ??????pop-up?????? structure on the Eoceneunconformity has a four -way dip closure, straddling the fault and extending tothe west of the fault. Structures of the Misoa Formation, which is the mainreservoir developed below the unconformity in the basin, differ from the structureof the unconformity. The structure of the Misoa Formation shows a tilted uplift ofthe eastern block of the fault dipping toward the east caused by thrust tectonicmovements. Thrust movement and following strike-slip movements provided additional accommodation space to the west of the fault and generatedexpanded thickness of Eocene sediments compared to the area east of the fault.The thickness of the Misoa Formation east and west of the fault shows nosignificant changes. Expanded sediments overlie the Misoa Formation in thewestern block in lateral contact with Misoa sediments eastern block act as alateral seal.Ductile movement of the Guasare Formation shale contributed to thelateral sealing of the fault against the reservoir rocks in the eastern block.Mobilization of the Guasare Formation modified the structure of overlyingformations including the anticline of the Eocene unconformity.The growth strata provide useful information of reactivation of e xistingfaults, especially subtle movements which are not recognized by conventionalseismic interpretation. Growth strata isochrons shows subtle reactivation of theVLE 400 fault family during Miocene time.