Case Histories

Case histories from a range of locations demonstrate the variety of projects recently undertaken by CERSA

 Turbidite reservoir model analogues: Chloridorme basin, Québec, Canada (Marathon Oil)

Deep-marine clastic basins can be host to major hydrocarbon deposits and assessing their economic potential and undertaking reservoir engineering modelling requires a firm understanding of the geometric arrangement of turbidite sandstone bodies on all scales.  Classic examples of deep-marine sedimentation styles preserved in the Cloridorme Formation, Gaspé Peninsula, were the subject for this study.  The Cloridorme rocks record deposition in submarine fan and fan-fringing complexes, including channelised canyon features and sedimentary dykes. Their overall vertical and lateral facies associations were documented in detail and used as analogues by which to visualise changing net:gross ratios on bed to basinal scales.  They also afforded study of the physical conditions by which sediment can be transported and distributed by sediment-gravity-flow processes; the findings of which have broad applicability to any such setting worldwide.

 

 Sequence stratigraphic framework of the Carboniferous of Fife: a North Sea reservoir analogue (Amerada Hess, Marathon, BP)

Onshore Carboniferous successions that fringe the coastline of SE Scotland are the best representative examples of the largely non-marine sedimentary systems that form hydrocarbon targets in the subsurface of the central and northern North Sea. CERSA has provided numerous field excursions for the petroleum industry to highlight the depositional character of these mixed siliciclastic-carbonate rocks that represent ancient fluvial-deltaic through marginal-marine settings. These trips enable first-hand experience in examining the nature of sequence stratigraphic surfaces, their attributes relative to 3-D seismic imaging, and evaluating the effect of syn-sedimentary volcanic and tectonic activity in influencing reservoir heterogeneity and character.

 

 Geological framework of Otavi Group base metal deposits, Namibia (Ongopolo Mining, Mount Isa Mines Namibia)

The Tsumeb district, Namibia, is one of the world’s finest base metal mining regions. The Otavi Group rocks, in which the ore bodies are housed, are known to contain additional zones of mineralisation that are, in some instances, hundreds of kilometres from the Tsumeb area. CERSA staff have expertise in the Otavi Group and correlative successions across Namibia and have provided the mining industry with insights into the stratigraphic framework in which the ores occur.  Novel applications of detailed sequence stratigraphic mapping, combined with chemostratigraphy (C-O isotopic profiles), has refined understanding of the geological framework of the Otavi Group and enabled development of predictive models of the locations and stratigraphic intervals that hold the most promise in targeting for exploration.

 

 Natural hazard assessment: rock fall, University House, St Andrews

This Case Study involved examination and evaluation of a rock fall that occurred along the coastline of the St Andrews seafront as a result of natural sea-cliff retreat.  The rock fall involved some ca. 209 tons of material that collapsed catastrophically onto the underlying tidal terrace.  A geological investigation of the adjacent areas of sea cliff was undertaken, the hazardousness of the fall was evaluated and a reconnassaince evaluation made of the stability of the cliff in the area of the fall.  The Study also outlined a specified set of recommended actions that were provided to the local authorities to guide their decision making and clean-up procedures.