Structural and kinematic analysis of the Slyne and Erris Basins: understanding the link between structural evolution and traps

 

PhD Candidate: Conor O’Sullivan

Supervisor: Dr. Conrad Childs, Dr. Muhammad Mudasar Saqab & Prof. John Walsh

Funded by: This research is supported in part by a research grant from Science Foundation Ireland (SFI) under Grant Number 13/RC/2092 and is co-funded under the European Regional Development Fund and by PIPCO RSG and its members companies.

 

Abstract:

The Slyne and Erris basins are narrow, elongate, approximately co-linear NNE trending basins that lie on the continental shelf 50 to 100 km offshore NW Ireland. The basins formed during the Permo-Triassic to Cretaceous in response to WNW-ESE directed extension during the continental rifting process that ultimately led to Late Cretaceous Atlantic opening. They are part of a system of basins that stretches from the West of Shetland basins to the Porcupine basin and they preserve Permo-Triassic and Jurassic successions, with variable amounts of Cretaceous and Cenozoic strata. A pronounced angular unconformity placing Cretaceous to Cenozoic sequences (containing evidence of several phases of uplift/erosion) on Jurassic and older rocks indicates significant uplift and erosion which has removed much of the Jurassic section from these basins. These basins are underexplored but discoveries like the Corrib gas field and the Bandon oil discovery demonstrate the presence of a working petroleum system. This project aims to develop a robust structural framework for the Slyne and Erris basins, including a detailed timeline of the formation and development of these basins. Through detailed seismic mapping and integration of existing borehole data this project aims to understand the location and nature of transfer zones between sub-basins, the origin and nature of structures occurring in the hanging walls adjacent to major basin-bounding faults, shown to be effective hydrocarbon traps, and the influence of salt layers on the development of these basins. This knowledge will be used to understand the timing of trap formation and fault reactivation relative to periods of hydrocarbon generation, and to consider the impact of fault reactivation on the integrity of the various trap structures found in the Slyne and Erris basins. 

 

References:

Chapman, T.J., Broks, T.M., Corcoran, D.V., Duncan, L.A. and Dancer, P.N., 1999, January. The structural evolution of the Erris Trough, offshore northwest Ireland, and implications for hydrocarbon generation. In Geological Society, London, Petroleum Geology Conference series (Vol. 5, pp. 455-469). Geological Society of London.

Cunningham, G.A. and Shannon, P.M. 1997. The Erris Ridge: a major geological feature in the NW Irish Offshore Basins. J. Geol. Soc. Lond., 154, pp. 503-508.

Cunningham G.A. 2000. Rregional controls and mechanism of development of the Irish offshore Mesaozoic and Cenozoic Basins with emphasis on the Slyne and Erris Troughs. Unpublished PhD, University College Dublin.

Dancer, P.N., Algar, S.T., Wilson, I.R., 1999. Structural evolution of the Slyne Trough. In: Fleet, A.J., Boldy, S.A.R. (Eds.), Petroleum Geology of Northwest Europe: Proceedings of the 5th Conference. The Geological Society, London, pp. 445-453.

Dancer, P.N., Kenyon-Roberts, S.M., Downey, J.W., Baillie, J.M., Meadows, N.S., .Maguire, K., 2005. The Corrib gas field, offshore west of Ireland. In: Doré, A.G., Vining, B.A. (Eds), Petroleum Geology: North-West Europe and Global Perspectives - Proceedings of the 6th Petroleum Geology conference. The Geological Society, London, pp. 1035-1046.

Naylor, D., Shannon P.W., 2005. The structural framework of the Irish Atlantic Margin. In: Doré, A.G., and Vining, B. (Eds.) Petroleum Geology: North-West Europe and Global Perspectives – Proceedings of the 6th Petroleum Geology Conference. The Geological Society, London, pp. 1009-1022

Scotchman, I.S., Thomas, J.R.W., 1995. Maturity and hydrocarbon generation in the Slyne Trough, northwest Ireland. In: Croker, P.F., Shannon, P.M. (Eds.), The Petroleum Geology of Ireland's Offshore Basins. Geol. Soc. Spec. Publ., vol. 93, pp. 385–411.

Shannon P.M., Jacob, A.W.B., Makris, J., O'Reilly, B., Hauser, F., Vogt, U., 1994. Basin evolution in the Rockall region, North Atlantic. First Break 12, 515-522.

Trueblood, S. 1992. Petroleum geology of the Slyne Trough and adjacent basins. In: PARNELL, J. (ed.) Basins on the Atlantic Seaboard." Petroleum Geology, Sedimentology and Basin Evolution. Geological Society, London, Special Publication, 62, 315-326.

Trueblood S. & Morton, N. 1991. Comparative sequence stratigraphy and structural styles of the Slyne Trough and Hebrides Basin. Journal of the Geological Society, London 148, 197–201.