Discovery ofpeperites on Marambio Island, Antarctica, with considerations of their emplacement

The finding of peperite breccias on Marambio Island allows to confirm the existence of at least two different pulses in the instrusion of basaltic dykes within the James Ross Island Volcanic Group. Two important bodies of peperites were recognized at Filo Negro and Geoantar hill. They were formed by the intrusion of basaltic dykes in the unconsolidated Paleogene sediments of Sobral Formation. The breccias are composed of vesicular glassy fragments, and volcanic and sedimentary lithic constituents in a sand matrix. The intrusions were probably emplaced at very shallow depth and are possibly related to a younger volcanic pulse, dated at 1.3 Ma. © 1997 Asociaciôn Geolôgica Argentina.Fil:Caselli, A.T. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.Fil:Massaferro, G.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina

Obtaining Permeability From Seismic Data - A New Breakthrough in Carbonate Reservoir Modelling

This reference is for an abstract only. A full paper was not submitted for this conference. Abstract Shell's Carbonate Team has been developing a method in which post-stackseismic can be used to estimate average interval matrix permeability incarbonates. The foundation of the technique is a new model, which describes quantitative relationships between sonic velocity, porosity and permeability. This model relates a pore shape factor from the poro-elasticity theory with permeability from lab measurements. This pore shape factor describes the 3Dpore structure and can be extracted from inverted post-stack seismic data. Additionally, this factor relates to pore connectivity and, therefore, to permeability. After the concept was tested and successfully proven on plug scale, the first implementation focused on a large carbonate field in the Middle East. This accumulation had all the ingredients to perform a full field test of the concept - good thickness for multiple seismic reflections, matrix-dominated permeability, single mineralogy (calcite), superb seismic data and enough wells with good compressional and shear sonic logs. Introducing pore structures in the characterisation of carbonate reservoirs from acoustic data helps resolve the ambiguity in porosity/permeability prediction. In the test case, we have demonstrated that: the new rock property prediction is much more accurate than properties predicted by commercial inversion packages,pore structure can be extracted from 3- Dpost-stack seismic,a permeability indicator can be estimated from inverted seismic anda permeability indicator volume proved to produce a superior history match against a permeability model constructed from extensive welldata </jats:sec