Atlantic Canada Offshore R&D: Nova Scotia Play Fairway Analysis
Authors: Luheshi Matt , Roberts David , Wilson Hamish , Weston Janice , Nunn Keith 
Published: May 2011

In April 2009 a comprehensive review of the prospectivity of the offshore Nova Scotia Basin was commissioned by the Offshore Energy Technical Research Association of Nova Scotia (OETR). This was fundamentally based on a complete reevaluation of the exploration history of the Scotian margin.

This paper describes the overall approach used in this study and presents the main results and key conclusions.

The play fairway program addressed three key issues:Plate Tectonic Reconstruction: a better understanding of the rift history of the Nova Scotia/Morocco conjugate margin pair was needed. Understanding the relationship between rifting and salt deposition is critical in developing models for potential syn-rift and early post rift depositional environment and the development of source rocks.Sequence Stratigraphic Framework: lack of a published modern sequence stratigraphic framework for the margin has impeded the development of robust regional exploration models. Hence the program included a re-evaluation of the biostratigraphy of several key wells, which were integrated with the seismic interpretation, and tectonic models, to build a comprehensive sequence framework.Forensic Geochemistry: although much geochemical data exists on the margin through the many hydrocarbon shows and discoveries, the source rock story was not well understood. The program has undertaken a systematic evaluation of the geochemistry of source rocks and hydrocarbon fluids. An important component of this work was analysis of hydrocarbon bearing fluid inclusion found in the salt. A key goal of this project was to demonstrate evidence for lacustrine or restricted marine early Jurassic source rocks, which would considerably enhance the hydrocarbon potential of the area.

The program integrated a number of specialist sub-projects to help develop a robust regional exploration model for the Scotian margin. These included extensive work on biostratigraphy, plate tectonics, seismic interpretation, geochemistry, petroleum systems analysis as well as acquisition of new geophysical data (refraction seismic) and reprocessing of multichannel and existing refraction seismic. The whole integrates to deliver a set of Gross Depositional Environment (GDE) maps built on internally consistent sequence and seismic stratigraphic interpretations. A key component of this was development of a thorough understanding of the salt kinematics offshore Nova Scotia. The complex salt dynamics have had a very significant influence on sediment dispersal pathways and present a significant challenge to oil and gas exploration.

The paper shows the underlying geological models that underpin the prospectivity of the Scotian margin. A number of plays can be been defined, including Jurassic carbonates, delta and deep marine reservoir systems, sourced locally or from deeper syn/post rift lacustrine/restricted marine sediments. Extensive large-scale salt related structures show the potential of a high value petroleum province in the under-explored shelf/deep water areas offshore Nova Scotia.