Print this pageAAPG ANNUAL CONFERENCE AND EXHIBITION
Making the Next Giant Leap in Geosciences
April 10-13, 2011, Houston, Texas, USA
Gross Depositional Environment Offshore Nova Scotia
(1) RPS Energy, London, United Kingdom.
The Play Fairway Analysis (PFA) programme initiated by OETR (Offshore Energy Technical Research Association of Nova Scotia) is fundamentally based on the creation of Gross Depositional Environment (GDE) maps for key intervals. These maps are created through a thorough integration of paleo-environment data from wells with seismic facies analysis.
The methodology is essentially based on a rigorous sequence stratigraphic approach. The major innovation in this PFA study was the creation of a systematic sequence stratigraphic framework offshore Nova Scotia. This analysis was based on 20 key wells of which 6 had new biostratigraphic analyses.
The information from these key wells was extrapolated using seismic stratigraphy. Accurate well to seismic ties were established through careful calibration of sonic and density data together with well established well/seismic correlations methods. In order to ensure the highest possible resolution for calibration to the wells, key seismic lines were reprocessed to improve bandwidth and imaging. These well data were extrapolated using a large seismic database (~70,000 km of 2D and ~30,000 sq km of 3D).
The PFA workflow imposes a rigorous and disciplined integration process. This is designed to ensure that the various input elements of the study are internally consistent. The integration process is continual throughout the programme and is tested fully during the creation of the GDE maps. These maps necessarily have to honour all the data and interpretation that feeds into the process (from the most basic tectonic history, through biostratigraphy, depositional processes as evidenced by sedimentological studies, seismic stratigraphy and, in this instance, salt kinematics).
The PFA project included some 14 horizons that were mapped seismically for structural and stratigraphic control. Of these, 9 surfaces have significance for understanding the most prospective Cretaceous and Jurassic plays. The GDE maps for the most important intervals are interrogated for predictions of distribution of reservoirs, sources and seals.
This paper presents the overall methodology and illustrates the workflow with an example of source rock distribution.