Geochemical Review and Hydrocarbon Type Prediction for the Porcupine Trough
This study was conducted by IGI Ltd. in association with Collinson Jones Consulting Ltd. and OceanGrove Geoscience Ltd. Although completed in 1996, the report was updated in 2015 with the conversion of the database to p:IGI-3 format with calculation of new ratios, improved georeferencing of wells and internally consistent stratigraphy. 1-D models for the key drilled wells for calibration are also now provided in Zetaware’s Genesis format to compliment the original models in BasinMod format. Very few wells have been drilled since the original report, but interest in the Porcupine Basin has been recently renewed, culminating in the 2011 and 2015 Atlantic Margin Oil & Gas Exploration Licensing Rounds and the award of licenses in late 2011 and early 2016.
The aim of the project was to reduce hydrocarbon exploration risk by investigating the geological and geochemical controls on oil and gas charges to traps within the Porcupine Basin. The report contains over 600 pages, in pdf format, and includes an evaluation of the Lower Cretaceous source potential as well as the Jurassic (Middle and Upper), and also includes oil-oil and oil-source correlation.
Existing released (in 1996) geochemical data supplemented by results from extensive new geochemical analyses of 13 wells are interpreted in the context of the regional geology. Samples for the new analytical programme were chosen to fill in data gaps and to eliminate paradoxical interpretations in the released data. The data were compiled into a single integrated geochemical database, based on all 25 wells drilled in the basin at the time of the study, with the focus of the interpretations mainly being on data from 12 wells in the main basin.
A coarse regional seismic grid was used to create regional maps of 7 key horizons. These seismic maps are used as the stratigraphic basis for regional geothermal and maturity modelling using Platte River’s BasinMod 1-D software. Modelling was performed on 15 drilled wells for calibration purposes, followed by construction of a grid of 48 pseudowell 1-D models. Maturity maps were constructed for base Tertiary, base Cretaceous, base Late Jurassic and base Middle Jurassic horizons at 4 key times during basin development. Source rock facies and maturation maps have been co-joined to produce a generation/migration model and the predicted results compared with the chemical and physical properties of the migrated hydrocarbons recovered from tests and shows in the basin. The objective has been to produce a model predicting the hydrocarbon types (phase and composition) and volumes for different parts of the basin. Estimates of the timing of generation in the various depocentres are also provided. Errors and risks are discussed in the context of volumetric modelling of ultimate hydrocarbon charges for defined drainage polygons.
The report deliverables comprise:
- The extensive report in pdf format (main text and Appendices, including data reports)
- The geochemical database in p:IGI and Excel formats
- All 1-D basin modelling files in BasinMod format & key wells in Genesis format