Porosity and permeability in volcanic rocks: A case study on the Serie Tobífera, South Patagonia, Argentina

The Middle to Late Jurassic Serie Tobífera belongs to the Chon-Aike Province and extends all over Patagonia and the Antarctic Peninsula. It consists largely of ignimbrites, epiclastics and rhyolitic lavas and was considered only a minor reservoir rock for oil with fracture permeability. Petrographic...

Full description

Bibliographic Details
Language:unknown
Published: 2004
Subjects:
Online Access:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03770273_v132_n1_p31_Sruoga
https://hdl.handle.net/20.500.12110/paper_03770273_v132_n1_p31_Sruoga
Description
Summary:The Middle to Late Jurassic Serie Tobífera belongs to the Chon-Aike Province and extends all over Patagonia and the Antarctic Peninsula. It consists largely of ignimbrites, epiclastics and rhyolitic lavas and was considered only a minor reservoir rock for oil with fracture permeability. Petrographic and petrophysical data in selected core samples from the Austral Basin were collected to determine the processes controlling the porosity and permeability of these volcanic rocks. The sequence of processes occurring during cooling and in the post-cooling stages can modify, sometimes substantially, their original petrophysic characteristics. The results show that the highest porosity and permeability occur in rocks with quench fractured glasses and in non-welded ignimbrites with gas-pipe structures, followed by autobrecciated rhyolites. Welded ignimbrites, massive glasses and fresh rhyolites have the lowest permeabilities. The new data indicate that tectonic fracturing is not as significant as was considered before and application of these concepts are relevant in the assesment of volcanic reservoir quality. © 2003 Elsevier B.V. All rights reserved.