Geochemistry, Diagenesis and Secondary Porosity Development of Late Jurassic-strata, Offshore Newfoundland, Canada
Date
2021-12-15
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Hydrocarbon prospectively in siliciclastic reservoirs is dependant on many attributes. Two key factors are: (i) a complete understanding of the geochemical character of source rock organic matter (OM) and (ii) assessing reservoir quality of the reservoir rocks. These two key factors are the primary focus of the research completed in this thesis. In this thesis OM types and distribution, the hydrocarbon potential, thermal maturity of source rock intervals, and the diagenetic mechanisms that control anomalously high secondary porosity in sandstone reservoir intervals from Jurassic-aged, Late-Tithonian strata of the Central Ridge and Flemish Pass Basin, offshore Newfoundland, Canada are studied. This thesis comprises an integration of petrographic analysis, geochemical programmed pyrolysis, organic petrology, and machine learning algorithms from samples taken from cores, side wall cores (SWC), and drill cuttings that intersect the Kimmeridgian-aged to Tithonian-aged sandstones, siltstones, and mudstones of the Central Ridge and Flemish Pass Basin. The sandstone intervals in this area have well preserved anomalously high secondary porosity (>25%) in relative deeply buried (2-3 km) reservoirs. The deltaic sediments that envelop the sandstone bodies have OM-rich and/or OM-lean zones that are largely controlled by depositional environment. Applying a novel machine learning algorithm (Random Forest Analysis) highlights the high hydrocarbon potential zones with a high level of accuracy using wireline log data. A paragenetic sequence was constructed to understand the diagenetic events that control porosity development in the sandstone reservoirs and the relationship to the source rock intervals. Here the model was tested that the high secondary porosity development is caused by dissolution of carbonate cement by short-chained carboxylic acid (SCCA) generation during thermal maturation of OM in the bounding deltaic sediments and the interlaminated OM in the sandstone reservoirs.
Description
Keywords
Petrography, Geochemistry, Organic Petrology
Citation
Gordon, J. B. (2021). Geochemistry, Diagenesis and Secondary Porosity Development of Late Jurassic-strata, Offshore Newfoundland, Canada (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca.