Diagenetic effects of compaction on reservoir properties: The case ofearly callovian “Dalle Nacrée” formation (Paris basin, France)

• Published in: Journal of geodynamics Vol. 101; pp. 5 - 29
• Main Authors: Nader, Fadi H., Champenois, France, Barbier, Mickaël, Adelinet, Mathilde, Rosenberg, Elisabeth, Houel, Pascal, Delmas, Jocelyne, Swennen, Rudy
• Format: Journal Article
• Language: English
• Published: Elsevier 2016
• Subjects: Applied geology; Earth Sciences; Fluid mechanics; Geophysics; Mechanics; Physics; Sciences of the Universe; Jurassic; Stylolites; Oolitic reservoirs; Fluid flow; Burial diagenesis; Porosity plugging; Oxygen isotopes; Petrophysical properties
• ISSN: 0264-3707
• DOI: 10.1016/j.jog.2016.05.010

The impact of compaction diagenesis on reservoir properties is addressed by means of observations madeon five boreholes with different burial histories of the Early Callovian “Dalle Nacrée” Formation in theParis Basin. Petrographic analyses were carried out in order to investigate the rock-texture, pore spacetype and volume, micro-fabrics, and cement phases. Based on the acquired data, a chronologically orderedsequence of diagenetic events (paragenesis) for each borehole was reconstructed taking the burial historyinto account. Point counting and a segmentation algorithm (Matlab) were used to quantify porosity, aswell as the amounts of grain constituents and cement phases on scanned images of studied thin sections.In addition, four key samples were analyzed by 3D imaging using microfocus X-ray computer tomography.Basin margin grainstones display a different burial diagenesis when compared to basin centre grain-stones and wackestones. The former have been affected by considerable cementation (especially byblocky calcite) prior to effective burial, in contrast to the basin centre lithologies where burial and com-paction prevailed with relatively less cementation. Fracturing and bed-parallel stylolitization, observedespecially in basinal wackestone facies also invoke higher levels of mechanical and chemical compactionthan observed in basin marginal equivalents. Compaction fluids may have migrated at the time of burialfrom the basin centre towards its margins, affecting hence the reservoir properties of similar rock texturesand facies and resulting in cross-basin spatial diagenetic heterogeneities.