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Eocene tectonic controls on reservoir distribution in VLE 196, Block V, Lamar Field, Maracaibo Basin, VenezuelaChoi, Byeonggoo 30 October 2006 (has links)
Integrated interpretation of three-dimensional seismic and well-logging
data reveals a prominent âÂÂpop-upâ structure associated with the VLE 400 fault on
the regional unconformity between the Eocene and Miocene in the VLE 196
field, Maracaibo basin, Venezuela. The VLE 400 fault family, an eastern splay
of the left-lateral Icotea fault in the basin, played an important role in
hydrocarbon migration and accumulation in the field. Hydrocarbons accumulated
to the east of the fault but not to the west. The âÂÂpop-upâ structure on the Eocene
unconformity has a four -way dip closure, straddling the fault and extending to
the west of the fault. Structures of the Misoa Formation, which is the main
reservoir developed below the unconformity in the basin, differ from the structure
of the unconformity. The structure of the Misoa Formation shows a tilted uplift of
the eastern block of the fault dipping toward the east caused by thrust tectonic
movements. Thrust movement and following strike-slip movements provided additional accommodation space to the west of the fault and generated
expanded 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 no
significant changes. Expanded sediments overlie the Misoa Formation in the
western block in lateral contact with Misoa sediments eastern block act as a
lateral seal.
Ductile movement of the Guasare Formation shale contributed to the
lateral sealing of the fault against the reservoir rocks in the eastern block.
Mobilization of the Guasare Formation modified the structure of overlying
formations including the anticline of the Eocene unconformity.
The growth strata provide useful information of reactivation of e xisting
faults, especially subtle movements which are not recognized by conventional
seismic interpretation. Growth strata isochrons shows subtle reactivation of the
VLE 400 fault family during Miocene time.
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Application of Growth Strata and Detrital-Zircon Geochronology to Stratigraphic Architecture and Kinematic HistoryBarbeau, David Longfellow Jr. January 2003 (has links)
Growth strata analysis and detrital-zircon geochronology are useful applications of stratigraphy to tectonic problems. Whereas both tools can contribute to kinematic analyses of supracrustal rock bodies, growth strata are also useful for analyzing the influence of tectonics on stratigraphic architecture. This study reports: 1) a conceptual model for growth strata development; 2) stratigraphic and kinematic analyses of growth strata architectures from growth structures in southeastern Utah, the Gulf of Mexico, and northeastern Spain; and 3) the detrital-zircon geochronology of the Salinian block of central coastal California. Kinematic sequence stratigraphy subdivides growth strata into kinematic sequences that are separated by kinematic sequence boundaries. Kinematic sequences can be further partitioned into kinematic domains based on the termination patterns of strata within a kinematic sequence. Salt- related fluvial growth strata from the Gulf of Mexico and southeastern Utah contain stratigraphic architectures that are unique to different kinematic domains. Offlap kinematic domains contain fluvial strata indicative of high slopes, low accommodation rates, and strong structural influence on paleocurrent direction. Onlap kinematic domains contain fluvial strata indicative of moderate slopes, high accommodation rates, and decreased structural influence on paleocurrent direction. The stratigraphic architecture of alluvial -fan thrust -belt growth strata in northeastern Spain does not display a marked correlation with kinematic domain, and is most easily interpreted using existing models for autocyclic alluvial -fan evolution. Detrital- zircon (U -Pb) geochronologic data from basement and cover rocks of Salinia suggest that Salinia originated along the southwestern margin of North America, likely in the vicinity of the Mojave Desert. The presence of Neoproterozoic and Late Archean detrital zircons in Salinian basement rocks also suggest that Salinian sediments were recycled from miogeoclinal sediments of the western margin of North America.
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