Analysis of Palaeoenvironment, Palaeoclimate and Palaeooceanographic Models to Predict Distribution of Source Rocks Offshore Nova Scotia (part of the PAGEO research program)

The objective of this work is to predict the distribution of Tithonian and early Jurassic (Toarcian, Pliensbachian, Sinemurian, Hettangian) source rocks based on biogeographic principles derived from modern environments, and palaeoenvironmental interpretations derived from palaeogeographic mapping and general circulation modelling.

If we can validate the results of the prediction against the relatively well-constrained risk maps of the Tithonian source, we can dramatically improve the confidence of risk mapping for the aggregate early Jurassic, and even discriminate risk for various intervals within the early Jurassic. The early Jurassic source rock has been assigned by default to the Pliensbachian for modelling purposes, by analogy to known source rock occurrences on conjugate margins. If the Scotian early Jurassic source rock plausibly could be attributed to another one of the early Jurassic stages, there might be meaningful changes in expectations about maturation and charge timing. Even if the Tithonian predictions differ from the current Tithonian risk assignment, there will be room for substantive comparison between the two methods of evaluation away from well control, where concepts drive the interpretation in both cases. This work will focus on the offshore of Nova Scotia but will incorporate Getech’s Globe data from a much wider area (North and Central Atlantic) to provide regional context and constraint.

This project will analyse palaeoenvironment, palaeoclimate and palaeooceanographic models to predict the distribution of source rocks offshore Nova Scotia, validating the results of the prediction against the relatively well-constrained risk maps of the Tithonian source with the objective to improve the confidence of risk mapping for the early Jurassic source intervals. This work will focus on offshore Nova Scotia but will incorporate Getech’s Globe data from a much wider area (North and Central Atlantic) to provide regional context and constraint.

Outcomes

  1. Broad scale palaeogeographic reconstructions for the North and Central Atlantic for the Jurassic timeslices including structural framework, depositional environments, palaeo-Digital Elevation Models (DEMs) and palaeodrainage networks.
  2. Getech’s palaeoceanographic and palaeoatmospheric circulation maps modified to reflect any updates in coastline and/or bathymetry, along with maps of predicted upwelling and water-column oxygen parameters.
  3. Higher resolution palaeoenvironmental maps highlighting areas of potentially mud-rich depositional environments, combining existing coastline, bathymetric, and gross depositional environment interpretations with Nova Scotia well data and additional new literature. These will be fully attributed and show locations of all input data used in their construction.
  4. Organic Facies Prediction (OFP) models of initial (pre-maturation) Total Organic Carbon (TOC) content and Hydrogen Index (HI) of sediments deposited within the AOI undertaken in Component 5.
  5. Esri ArcGIS mxd. Database containing:

Project Data

  • Cultural Data
  • Input data location points (Getech/OERA data e.g. wells, outcrop samples etc.)
  • Input data location lines (Getech/OERA data e.g. seismic lines, cross sections, reconstruction lines etc.)

Structural and Tectonic Data Layers

  • Present Day Structural elements: 1:1M scale, including activation histories.
  • Sedimentary basin architecture polygons: including main basins, sub-basins, intra-basinal highs, intra-basinal troughs.

Regional Palaeogeographic Maps

  • Paleogeographic reconstructions of the Northern and Central Atlantic for the five Jurassic time intervals including: structural framework, depositional environments and lithologies, tectonophysiographic terranes, Digital Elevation Models (DEMs) and palaeodrainage networks.

Earth System Modelling (ESM) and Organic Facies Prediction Layers

  • The outcomes from the Upwelling modelling and Organic Facies Prediction modelling will be included, as well as the ESM input layers.

Paleoenvironmental Source Rock Risk Maps

  • These will be presented for the five Jurassic time intervals.
Team

Principal Investigators: Gemma Scougal, Andy Quallingham, William Heins, Abi Redmile, Kerri Wilson, Laura Wilson, Antoni Alcaraz, Getech Group plc, Leeds, UK

Date
November 2020 – June 2021