A review of deformation bands in reservoir sandstones: geometries, mechanisms and distribution HAAKON FOSSEN1,2,3*, ROGER SOLIVA4, GREGORY BALLAS5, BARBARA TRZASKOS2, CAROLINA CAVALCANTE2 & RICHARD A. SCHULTZ6 1Department of Earth Science and Museum of Natural History, University of Bergen, Postboks 7803, 5007 Bergen, Norway 2Departamento de Geologia, Universidade Federal do Parana´ – Setor de Cieˆncias da Terra, Caixa Postal 19.001, Centro Polite´cnico - Jardim das Ame´ricas, 81531-980 Curitiba, PR, Brazil 3Instituto de Geocieˆncias, Universidade de Sa˜o Paulo, 05508-900, SP, Brazil 4Geosciences Montpellier, Universite´ de Montpellier, Campus Triolet, CC060, Place Euge`ne, Bataillon, 34095 Montpellier Cedex 05, France 5Institut Franc¸ais de Recherche pour l’Exploitation de la Mer, Pointe du Diable, 29280 Plouzane´, France 6Petroleum and Geosystems Engineering, The University of Texas at Austin, Austin Texas 78712 USA *Correspondence:
[email protected] Abstract: Deformation bands are common subseismic structures in porous sandstones that vary with respect to deformation mechanisms, geometries and distribution. The amount of cataclasis involved largely determines how they impact fluid flow, and cataclasis is generally promoted by coarse grain size, good sorting, high porosity and overburden (usually .500–1000 m). Most bands involve a combination of shear and compaction, and a distinction can be made between those where shear displacement greatly exceeds compaction (compactional shear bands or CSB), where the two are of similar magnitude (shear-enhanced compaction bands or SECB), and pure compaction bands (PCB). The latter two only occur in the contractional regime, are char- acterized by high (70–1008) dihedral angles (SECB) or perpendicularity (PCB) to s1 (the maxi- mum principal stress) and are restricted to layers with very high porosity.