DIAGENET IC PECUL IAR IT IES OF POTENTIAL LOWER JURASSIC RESERVOIR SANDSTONES, TROMS 1 AREA, OFF NORTHERN NORWAY, AND

• Main Authors: Their Tectonic, S Ignif Icance, P. R Iches, I. Traub-sobott, W. Z Immerle, U. Zinkernagelt
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 1985
• Subjects: Norway; Northern Norway; Troms
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.616.9218; http://www.minersoc.org/pages/Archive-CM/Volume_21/21-4-565.pdf

ABSTRACT: In the Troms 1 area, sediments of Early to Middle Jurassic age, ranging from alluvial plain deposits at the base, passing through coastal plain/tidal f at sediments up into high-energy nearshore shallow marine sands, mark a transgression. The sandstones, classified as mineralogically and texturally mature quartz-arenites, are potential reservoir ocks in the eastern part of the area. The apparent supermaturity, however, is of secondary origin because unstable detrital components were dissolved during diagenesis. The succession of complex diagenetic processes was: (i) mechanical compaction and simultaneous pressure solution, (ii) partial dissolution with corrosion of detrital quartz and dissolution of unstable fragments, (iii) silica cementation, (iv) calcite cementation, (v) partial carbonate dissolution, (vi) kaolinite/Fe carbonate cementation i the remaining pore space. Porosity and permeability of the sandstones are controlled by the degree of silicification and by dissolution processes. Two dissolution stages led to partial 'skeletonization ' f the detrital framework and to elimination of unstable detrital grains. The first stage was a basic process leading to corrosion of detrital quartz and creating transitory secondary porosity; the second stage was acidic leading to the present preserved secondary porosity. Diagenetic dissolution channels formed. The degree of diagenetic alteration