Oil and Gas
Oil and Gas | Clastics
Source to Sink: Provenance, Sediment Routing and Reservoir Characterisation (Southern Pyrenees, Spain)
The Cenozoic history of the Southern Pyrenees preserves whole depositional systems in multiple stages of development; the nature of the erosional realm can be reconstructed from provenance data, structural elements have demonstrable controls on sediment routing, and sedimentation packages can be traced from fluvial through paralic and shelf deposits to slope and deeper water facies. Excellent exposures allow the characteristics of different elements of the systems to be evaluated in terms of reservoir properties, sediment architecture, and reservoir connectivity.
Duration and Training Method
This is a field course, supported by short classroom sessions.
- Apply structural studies in both source and depositional areas to determine the pathways of sediment.
- Understand the interplay between tectonics, bedrock character, base level, and climatic controls on sediment supply into basins.
- Use petrographic and geochemical tools in provenance analysis and correlation through depositional systems.
- Appreciate the differences between endorheic (internally drained) and exorheic (externally drained) basin systems and the effects on stratigraphy and sediment distributions.
- Characterise reservoir facies in alluvial, fluvial, lacustrine, coastal, shelf, slope and deeper water settings.
- Appreciate the key controls on fluid flow and recovery in different depositional systems.
- Select appropriate field analogues for reservoirs, in the context of depositional system, basin structure and scale.
At each outcrop, the depositional setting will be reviewed in terms of a potential reservoir. The depositional architecture and its influence on reservoir connectivity and heterogeneity will be discussed and producing analogues studied.
Key topics to be covered are:
- Tectonic controls on sediment routing systems into the Eocene Tremp-Graus Basin and the Miocene Ebro Basin: the reactivation of extensional faults into thrusts, their development through time evidenced from facies distributions and the effect of rotation of thrust sheets on apparent sediment transport pathways.
- Provenance analysis is an under-utilised tool in understanding the controls on sediment character and as a means of correlating within a basin: a record of the unroofing history of a sediment source area can be constructed from the Miocene Ebro basin deposits, where distinct depositional systems can be established using field-based petrography.
- Contrasting fluvial tracts formed in a valley-confined setting in the Eocene with distributive fluvial systems in the Miocene: river deposits in the Tremp-Graus basin can be traced through palaeovalleys to the interface with coastal deposits in the west, exhibiting a conventional base-level control; in the Ebro Basin fluvial systems were distributive, showing a down-system decrease in sediment body dimensions through to an interface with lacustrine facies
- Sediment-body geometries will be compared in fluvial, tidally-influenced coastal and shelf deposits and in slope and basinal settings: reservoir-scale, and in some cases, seismic resolution scale outcrops provide a broad suite of analogues for clastic units in the subsurface
- Reservoir characterisation of clastic depositional facies in each of the different settings, considering the scales of heterogeneities within and between reservoir units.
- The importance of analogues in building geological models of a subsurface reservoir, pitfalls and key considerations when choosing appropriate analogues for any system.
The following itinerary is intended as a guide, and may be modified according to weather and/or the participants' interests and focus.
Day 0: Arrive Barcelona and travel to Tremp
Day 1: Field
- Mas de Faro – fluvial system, supply and routing
- Calvera Pass – endorheic basin proximal facies
- La Roca – fluvial facies near shoreline
- Overnight in Graus
Day 2: Field
- Pano – coastal, barrier and lagoonal facies
- Roda de Isabena – shelf tidal sandstones
- Overnight in Ainsa
Day 3: Field
- Ainsa – slope and submarine fan channel
- Core Store – slope and submarine fan channel
- Broto – submarine fan lobe facies
- Overnight in Ainsa
Day 4: Field
- Piraces – fluvial system architecture (endorheic system)
- Albero Bajo – channel body stacking patterns
- Roldan – basin margin facies and provenance signatures
- Overnight in Huesca
Day 5: Field and departure
- Monzon – fluvial reservoir characterisation
- Transfer to Barcelona for departure
Who Should Attend and Prerequisites
The course is aimed at geoscientists, petrophysicists, and reservoir engineers who wish to better understand clastic depositional systems from basin-scale to reservoir scale. Multi-disciplinary asset teams would benefit from attendance as a group.