--> ABSTRACT: A Re-Evaluation of Play Risks and Volumes Offshore Nova Scotia, by Wilson, Hamish; Luheshi, Matt; Roberts, David; Colletta, Bernard; #90135 (2011)

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A Re-Evaluation of Play Risks and Volumes Offshore Nova Scotia

Wilson, Hamish 1; Luheshi, Matt 1; Roberts, David 1; Colletta, Bernard 2
(1)RPS Energy, London, United Kingdom. (2) BEICIP FRALAP, Paris, France.

A systematic play fairway analysis (PFA) is used to evaluate the hydrocarbon potential of offshore Nova Scotia. This structured approach builds a detailed play assessment on the foundation of understanding the structural evolution of the basin.

Four main plays, as defined by reservoir, have been identified:

1. Upper Jurassic delta system

2. Mid/Upper Jurassic Carbonate bank

3. Hauterivian delta system

4. Albian delta system

The main hydrocarbon production and exploration to date has focused on the Albian delta system and Jurassic carbonate bank. Recent exploration has failed due to a lack of understanding of the sediment dispersal pathways from the shelf to slope. Therefore reservoir prediction is a critical element of the PFA project. A detailed well and seismic sequence stratigraphic analysis has been done, that establishes the evolution of the shelf slope break through time. This is used to predict sand channel systems from shelf to slope. Further amplitude modeling work supports reservoir prediction into the deep water.

These plays are charged from two source models:

1) Terrigenous source horizons corresponding to maximum flooding surfaces in the Tithonian, Hauterivian and Albian. These source horizons are mature to over mature today and are likely to have sourced the hydrocarbons in the gas producing fields on the margin.

2) A regional Lower Jurassic syn to early post rift restricted marine source rock is postulated. This is supported by an evaluation of the rift mechanism, combined with oil typing from both Nova Scotia and Morocco. Oil seeps and traces in piston cores provide evidence for this regional source, outside the extent of the Jurassic and Cretaceous delta systems.

Petroleum systems modeling has confirmed hydrocarbon generation and timing for each of these source horizons and used to create charge risk maps. These maps have been combined with common risk segment (CRS) maps for reservoir and seal to produce composite common risk segment maps. Areas of high potential have been identified. The presentation will finish with YTF, risks and prospect size assessment for each play.

 

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.