Origin, distribution and paragenetic sequence of carbonate cements in the Ben Nevis Formation, White Rose Field, Jeanne d'Arc Basin, offshore Newfoundland, Canada

• Main Author: Normore, Leon Scott
• Format: Thesis
• Language: English
• Published: Memorial University of Newfoundland 2006
• Subjects: Ben Nevis; Canada; Nautilus; Newfoundland
• Online Access: https://research.library.mun.ca/6666/; https://research.library.mun.ca/6666/1/LeonSNormore.pdf; https://research.library.mun.ca/6666/3/LeonSNormore.pdf

The Aptian-Albian quartz arenite sandstones of the Ben Nevis Formation were deposited in a storm dominated shoreface setting during a marine transgression. Sediment grain size, and poikilotopic calcite cement are largely accountable for the reduction in porosity and permeability, resulting in mean permeabilities on the order of < 1 to 300 mD. The objective of this study is to develop a knowledge of the paragenetic sequence during early and late diagenesis, relating timing and source of cements to attempt to predict cement distribution, its effect on reservoir-scale fluid connectivity and its use as a development and exploration tool at White Rose Field and potential extensions nearby. The union of several analytical methods are required to decipher 120 million years of diagenesis. Diagenetic evolution of the authigenic cements is investigated using core description, and optical petrography, with corroboration from carbon and oxygen isotopic analyses. -- The paragenetic sequence identified in this study consisted of four phases of authigenic cement precipitation and four dissolution events, three of which acted on detrital components and the final dissolution phase acting on ferroan calcite cement. To understand the diagenetic sequence of any sedimentary rock unit, it is important to determine physical, geochemical and biological variations in depositional environment, as the compounded effect of all these will define the course of diagenesis. Transgressing a deep shelf environment over a shallow shoreface environment will decrease the rate of deposition, bioclastic content and sand/shale ratio, while increasing mud content, distance from shoreline and bioturbation. The transgressive nature of the Ben Nevis Formation compacts Ben Nevis sandstones beneath the Nautilus shales, building pore fluid pressure, transporting fluids vertically and obliquely towards the shoreline. -- While there is a significant volume of serpulid worm tubes, bivalves and gastropods, it may be thin, compacted and often discontinuous ...