Petrographic characterization and diagenetic evaluation of reservoir sandstones from Smørbukk and Heidrun fields, offshore Norway

Abstract

A detail qualitative and quantitative analysis based on thin section petrographic analyses of sandstone samples from the reservoir horizons of Smørbukk and Heidrun fields have been carried out to characterize the textural and mineralogical properties, and to evaluate the post depositional diagenetic changes. Smørbukk samples are medium-coarse grained, moderately sorted, tightly packed, submature–mature subarkosic and quartz arenites. Heidrun samples, on the other hand, are fine-medium grained, moderate-well sorted, moderate-loosely packed, mature-submature subarkosic and quartz arenites. Despite the detrital components (quartz, feldspar, lithic grains, mica, etc.) of both the fields are similar, silica cementation is more common in Smørbukk samples whereas early carbonate is the predominant cement in Heidrun samples. Smørbukk sediments are comparatively more compacted than those of the Heidrun fields. Overall reservoir quality in Heidrun field (8%–18%) is slightly better than that of Smørbukk field (5%–15%). The findings of this study will be helpful in the development phase of these fields and/or fields from similar geological setting. Keywords: Petrography, Diagenesis, Quartz arenite, Mineralogy, Porosity