Hierarchical Sedimentary Characterization and Modeling of Submarine Channels

 

PhD Candidate: Kishan Soni

Supervisor: Dr Tom Manzocchi, Professor Peter Haughton

Funded by: Petroleum Infrastructure Programme, supported by Irish Centre for Research in Applied Geosciences (iCRAG)

Abstract:

Submarine channels are major conduits of sediment transport from the shelf to the basin floor, they preferentially erode more and deposit less along the slope and vice versa along the basin floor. Over the last two decades, numerous oil and gas discoveries have been made in deepwater basins (e.g., Campos Basin, Brazil, Offshore West Africa, Nile, Mahakam Delta, northern Gulf of Mexico, West of Shetland Islands, Offshore West Ireland (Laux S. 2013 and Weimer P. et al. 2007) and mid-Norway) in either channels or fans. And being one of the geometries of interest for many more discoveries to come in future, they have received considerable attention in the oil and gas industry.

Submarine channel system evolution in geological time scale can very well be understood as a process of multiple events which occur in response to changes in relative sea level, sediment supply, topography, planar movement (lateral migration), vertical stacking (aggradation), sinuosity, rate of erosion/deposition etc. This evolution pattern results in a hierarchy among the channel geobodies where smaller channels (level 2) are integral parts of bigger channels (level 1), and they of an even bigger channel (channel belt, level 0). Separating each hierarchical level channel body (primary objects) from the bigger hierarchy channel are levees/lobes modeled as sheets (secondary objects). The overall aim of this research is to examine the suitability of different numerical modelling approaches for reproducing such hierarchical sedimentary systems. A geomodeling workflow to capture bed scale hierarchy observed in faulted and unfaulted turbidites systems was recently documented in Manzocchi T. et al. 2007; using an in house compression based modeling package where Net to Gross (NTG) and Amalgamation Ratio (AR, measure of connectivity between objects of same hierarchy) are distinctly input for modelling relevant objects (fans/channel). NTG and AR estimates can be recorded from geological studies of outcrops analogue to the field in consideration or can be inferred from petrophysical logs and/or seismic data (3D/2D).

Such an approach in geomodelling allows for creation of reservoir scale but bed-resolution 3D models which can be used for flow simulation to analyse the role of multiple scales of geological heterogeneitiy and object connectivity on oil production, reservoir pressure, sweep of reservoir fluid by the injected fluid and other production characteristics, in a similar fashion to that described in Zhang L. et al. 2015 for deepwater fan complexes.

 

References:

Laux S., 2013, Cairn Energy PLC’s Ireland Entry as Part of aNorth Atlantic Conjugate Margin Exploration Strategy, presentation, Atlantic Ireland 2013 Conference, Dublin

Manzocchi T., Walsh J.J., Tomasso M., Strand J., Childs C. & Haughton P.D.W., 2007, Static and dynamic connectivity in bed-scale models of faulted and unfaulted turbidites, P:309–336, Structurally Complex Reservoirs, Special Publications, The Geological Society of London 2007

Weimer Paul and Slatt Roger M., with contributions by Renaud Bouroullec, Richard Filon, Henry Pettingill, Matthew Pranter, and Gabor Tari; 2007, AAPG Studies in Geology 57, Chapter 6, Deepwater-Reservoir Elements: Channels and Their Sedimentary Fill, P 171-275. 

Zhang L., Manzocchi T., and Ponten A., 7-11 September 2015, Hierarchical Parameterisation and Modelling of Deep-water Lobes, Petroleum Geostatistics 2015, Biarritz, France