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The Valle Morado structure, located in northwest Argentina, is an approximately 7-km-long and 4-km-wide north-northeast–south-southwest–trending anticline cut by faults that involve Paleozoic basement and Mesozoic–Cenozoic sedimentary cover. Geological interpretation of a three-dimensional seismic survey that covers the structure, plus a well and two-dimensional regional-scale seismic lines, indicates that the Valle Morado is an Andean pop-up structure formed by foreland-directed faults, resulting from reverse reactivation of Cretaceous extensional faults dipping westward, and newly formed hinterland-directed reverse faults dipping eastward. The orientation of the preexisting extensional faults is nearly perpendicular to the Andean tectonic transport direction in the northern part of the structure and oblique toward the south, resulting in almost pure contraction in the north and transpression southward.
Curvature analysis performed on two interpreted reservoir seismic horizons suggests that the maximum density of open fractures is likely to occur along the anticline axis in the northern portion of the fold and along the northeast-southwest–striking foreland-directed, reactivated faults to the south. The direction of the open fractures interpreted from ultrasonic borehole image data along the well coincide with that of the open fractures predicted from the curvature analysis.
José Luis Masaferro has been a geologist/seismic interpreter since 1998 at Shell Technology Applications and Research Center (Carbonate Development Team) in the Netherlands. He received his Ph.D. from University of Miami in 1997 and the topic of his dissertation was on the interplay of tectonics and carbonate sedimentation in the Bahamas/Cuban foreland. He was a Fulbright fellow while pursuing his studies in Miami. He also worked for Texaco Petrolera Argentina as a geologist (1989–1991). While at Shell, he has been involved in different projects, including 3-D seismic visualization and interpretation, high-resolution sequence stratigraphy, and kinematic modeling. José's research interest is to integrate 3-D seismic data with borehole data to interpret carbonate depositional systems and translate them into reservoir subsurface models.Mayte Bulnes earned her geology degree (1987) and her Ms.C. degree and Ph.D. on the geology of the Cantabrian Mountains (1995) from the University of Oviedo (Spain). Prior to joining the University of Oviedo as a lecturer in structural geology in 1998, Mayte had postdoctoral fellowships at the Royal Holloway University of London and at the University of Oviedo. Mayte's present research interests include 2-D and 3-D structural analysis and restoration field and seismic examples of fault-related folds in different tectonic settings (contraction, inversion, and extension).
Josep Poblet earned a geology degree from the University of Barcelona (1986), where he also completed an M.Sc. degree and his Ph.D. on the geology of the Pyrenees. From 1992 to 1996, he undertook postdoctoral fellowships at the Royal Holloway University of London and at the University of Barcelona. Currently, Josep is a lecturer at the University of Oviedo. His present research includes geometric and kinematic modeling of fault-related folds (subsurface geometry, fracture/deformation patterns, and growth geometries) and its application to hydrocarbon exploration.
Neil Casson joined the Shell Group in 1983 with an M.Sc. degree in petroleum exploration seismology from the University of Oxford and a B.Sc. degree in geology and geophysics from the University of Durham, United Kingdom. He has worked in Shell España, Nederlandse Aardolie Maatschappij B. V., Shell Yemen, and the last four years with Sarawak Shell Berhad on the West Sabah Asset Team. Currently, he is working as a production geologist for Shell CAPSA, Argentina.