title: Diagenetic Evolution and Reservoir Quality of Sandstones in the North Alpine Foreland Basin: A Microscale Approach.
abstract: Siliciclastic reservoir rocks of the North Alpine Foreland Basin were studied focusing on investigations of pore fillings. Conventional oil and gas production requires certain thresholds of porosity and permeability. These parameters are controlled by the size and shape of grains and diagenetic processes like compaction, dissolution, and precipitation of mineral phases. In an attempt to estimate the impact of these factors, conventional microscopy, high resolution scanning electron microscopy, and wavelength dispersive element mapping were applied. Rock types were established accordingly, considering Poro/Perm data. Reservoir properties in shallow marine Cenomanian sandstones are mainly controlled by the degree of diagenetic calcite precipitation, Turonian rocks are characterized by reduced permeability, even for weakly cemented layers, due to higher matrix content as a result of lower depositional energy. Eocene subarkoses tend to be coarse-grained with minor matrix content as a result of their fluvio-deltaic and coastal deposition. Reservoir quality is therefore controlled by diagenetic clay and minor calcite cementation.Although Eocene rocks are often matrix free, occasionally a clay mineral matrix may be present and influence cementation of pores during early diagenesis. Oligo-/Miocene deep marine rocks exhibit excellent quality in cases when early cement is dissolved and not replaced by secondary calcite, mainly bound to the gas-water contact within hydrocarbon reservoirs.
authors.affiliation: 1Department of Applied Geosciences and Geophysics,Montanuniversitaet Leoben,A-8700 Leoben,Austria.
authors.forename: Doris
authors.initials: D
authors.lastname: Gross
authors.affiliation: 1Department of Applied Geosciences and Geophysics,Montanuniversitaet Leoben,A-8700 Leoben,Austria.
authors.forename: Marie-Louise
authors.initials: ML
authors.lastname: Grundtner
authors.affiliation: 1Department of Applied Geosciences and Geophysics,Montanuniversitaet Leoben,A-8700 Leoben,Austria.
authors.forename: David
authors.initials: D
authors.lastname: Misch
authors.affiliation: 1Department of Applied Geosciences and Geophysics,Montanuniversitaet Leoben,A-8700 Leoben,Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Riedl
authors.affiliation: 1Department of Applied Geosciences and Geophysics,Montanuniversitaet Leoben,A-8700 Leoben,Austria.
authors.forename: Reinhard F
authors.initials: RF
authors.lastname: Sachsenhofer
authors.affiliation: 2Rohoel-Aufsuchungs AG,Schwarzenbergplatz 16,A-1015 Wien,Austria.
authors.forename: Lorenz
authors.initials: L
authors.lastname: Scheucher
keywords: Cenozoic reservoir sandstones; Mesozoic reservoir sandstones; North Alpine Foreland Basin; Upper Austria; carbonate cement; clay mineral cement; reservoir quality