Project: Sedimentology and allostratigraphy of a shale-dominated, high-accommodation foredeep: the Shaftesbury Formation (Late Albian), NE British Columbia
The PhD project is concerned with the Late Albian (early Cretaceous) Shaftesbury Formation, which was deposited in the proximal part of the Western Canada foreland basin, in British Columbia. The abundance of mudstone in the Shaftesbury Formation makes it an ideal natural laboratory in which to study patterns and mechanisms of mud dispersal on an ancient marine shelf – a topic of intense current interest and debate. An abrupt lateral change to nearshore sandstones, conglomerates, and alluvial deposits in the extreme west provides exposure to coarser-grained sediments that are more traditionally considered to be of high reservoir quality. The excellent three-dimensional stratigraphic control available from both outcrop and subsurface provides the basis for relatively precise paleogeographic reconstruction of facies belts, and hence of sediment dispersal pathways. Analysis can proceed from the scale of a hand sample (millimetres) to the entire basin (hundreds of kilometres). Few studies provide data over this range of scales. Two specific, and contrasting economic aspects are relevant to this project: First, the study encompasses the ‘Fish Scales sandstone’ which is a very organic-rich unit with the potential to source hydrocarbons and host shale gas; Secondly, the nearshore sandstone facies (Goodrich Formation) are presently being exploited (e.g. by Talisman) as shallow subsurface sources of water for injection into deeper hydrocarbon-producing horizons. Not all sandstones produce water equally well, and hence an understanding of facies character may improve our ability to choose successful horizons to perforate.