N393 Depositional Environments and Reservoir Development in Marginal Marine Settings: Reservoir Analogues from the Lusitanian Basin (Portugal)

Course Facts

Course Code:
N393
Duration:
3 days
Type:
Field
Physical Demand:
CEU:
2.4 Continuing Education Units
PDH:
24 Professional Development Hours
Certificate:
Certificate Issued Upon Completion

Summary

A field course analysing the distribution, architecture, internal characteristics, and reservoir quality of sandstone bodies from a wide range of predominantly Jurassic-Cretaceous age clastic depositional systems including fluvial, shoreface, estuarine and deep marine. Emphasis is on the spatial distribution of different depositional settings as controlled by the basinal framework associated with an active rift setting 

Duration and Training Method

This is a three-day field course to the central and southern part of the Lusitanian Basin comprising field examination of depositional systems at both seismic and, more commonly, sub-seismic, sandstone body scale. The proportion of field time to classroom time is approximately 90:10 and participants will learn via lectures, field-observations, exercises and group discussion.

Participants will learn to:

1. Interpret the sedimentology, stratigraphic architecture and reservoir potential of fluvial systems and wave/tide-dominated shorelines/shelves.
2. Analyse fluvial channel belts in terms of changing channel styles, net to gross variation and associated floodplain/overbank deposits.
3. Assess controls on the scale and distribution of sand bodies at outcrop and the nature of intrareservoir seals, permeability baffles and reservoir flow units in the bodies.
4. Assess interactions between rifting and sedimentation in an extensional passive margin setting.
5. Evaluate the response of the rift fill to structural inversion and its effect on sealing and trapping geometries.
6. Evaluate the use of geological data at different scales in building a robust depositional model for a clastic shoreline succession.

Developed over the western part of the country and extending offshore, the Lusitanian Basin is the largest of Portugal’s sedimentary basins. It comprises an area of some 22,000 km2 with a maximum sediment thickness of some 6 km. The bulk of the sedimentary fill comprises Late Triassic to Cretaceous strata. The Lusitanian Basin formed during the opening of the North Atlantic Ocean and records two main episodes of extension and rifting, with two further rifting phases also present.

A series of transtentional basins opened along the Atlantic Margin during the Mesozoic, and those in Portugal (including the Lusitanian Basin) were subjeced to compressional inversion during the Neogene. These sections illustrate the contrasting effects of strike-slip deformation, inversion tectonics and halokinetic diapirism, providing an opportunity to analyse the role of each in the preserved geology.

A thick continental succession seen in the north of the region at Baleal records the rapidly in-filled axial part of these rift basins during the late Jurassic. These sucessions include spectactular exposures of coastal plain systems raning from braid-plains to meander belts, tide-influenced distributary channels and marginal marine mouth bars.

To the south at Santa Cruz is exposed the shallow marine syn-rift fill within a rift sub-basin. Exposures allow the group to explore how the evolution of the sub-basin and how salt movements may have influenced deposition and later deformation. The latter includes spectacular examples of tranpressional folding and the formation of cataclastic fracture systems.

Jurassic shallow marine deposits extend further along the coast at Praia Azul and display good examples of marginal marine to lagoonal facies, characterised by specific fauanal communities.

Itinerary:

Day 0: Arrival and Introduction

  • Arrival into Lisbon, Portugal
  • Transfer to hotel followed by course introduction and field course safety briefing

Overnight: Peniche

 

Day 1: Source rock and Jurassic fluvial deposystems

  • Regional field introduction
  • Baleal area: Jurassic fluvial channel belts; variable net to gross fluvial channels
  • Peniche area: Regional source rocks, fan delta and carbonate basin margin

Overnight: Peniche

Day 2: Alluvial and tide-influenced deposystems

  • Pai Mogo: Low net to gross fluvial succession with lacustrine muds
  • Areia Branca: tidally-influenced river systems and mouthbar sandstones
  • Praia Azul area: Transgressive coastal lagoon and fringing sands

Overnight: Peniche

Day 3: Shelfal and shoreface clastics

  • Santa Cruz area: shelfal and shoreface clastics
  • Course wrap up and transfer to Lisbon for  flights home

Who should attend

This course is designed for geoscientists who wish to gain an insight into the nature of a wide range of reservoir analogue sandbodies deposited in a variety of marginal marine/paralic settings.

Prerequisites and linking courses

There are no specific prerequisite courses, but participants are expected to have an understanding of the basics of clastic sedimentology; this can be gained from attending N155: Introduction to Clastic Depositional Systems: a Petroleum Perspective,