Sedimentary Basins Formation and evolution of sedimentary basins

& their geo-energy potential

Hanneke VERWEIJ Email: jmverweij@gmail.com

7-11 January 2013

Politecnico di Torino

Formation of sedimentary basins

Sedimentary Basins Formation and evolution of sedimentary basins

& their geo-energy potential

Formation of sedimentary basins Mechanisms of basin formation Classification of sedimentary basins Characterization sedimentary basins

Evolution of sedimentary basins Evolution plate-tectonic setting Fluids, porosity, permeability Compaction Burial history Temperature and heat flow

Geo-energy potential of sedimentary basins Introduction Geothermal energy potential Introduction to petroleum systems

Evolution of petroleum systems

Geo-energy potential

Subsurface Natural Energy Resources

Non-renewable Conventional

Non renewable Unconventional Renewable

Coal Oil Gas

Geothermal

Unconventional gas Tight gas Shale gas Basin gas

Coalbed methane

Unconventional oil Oil shales Heavy oil Tar sands

Renewability

The energy extracted from a renewable energy source is replaced in a natural way by an additional amount of energy and the replacement takes place on a similar timescale as that of the extraction (Axelsson et al. 2001)

Course focus

Subsurface Natural Energy Resources

Non-renewable Conventional

Non renewable Unconventional Renewable

Coal Oil Gas

Geothermal

Unconventional gas Tight gas Shale gas Basin gas

Coalbed methane (Gas hydrates)

Unconventional oil Oil shales Heavy oil Tar sands

Why Sedimentary Basins?

The major petroleum basins of the world (Halbouty 1986 in: Gluyas and Swarbrick 2006)

Almost all of the world's petroleum occurs in sedimentary basins

Sedimentary Basins

All those areas in which sediments can accumulate to considerable thickness and be preserved for long geological time periods (Einsele 2000)

Sediment source Transport of sediments Sediment sink (Sedimentary Basin)

Sediments and sedimentary rocks

Sediments and sedimentary rocks

Plate tectonics create relief to provide both the source and the sink

Schematic example of relation source-sink and coupled mountain building and basin evolution related to collision of continental plates (Cloetingh et al. 2007)

Sedimentary Basins

All those areas in which sediments can accumulate to considerable thickness and be preserved for long geological time periods (Einsele 2000)

Genetic classification based on mechanisms of

basin formation

Mechanisms of Basin Formation

Sedimentary basins are related to prolonged subsidence

Mechanisms for subsidence are related to

processes in lithosphere Lithosphere is composed of plates that are in

relative motion to each other Basin formation is related to plate tectonics

Plate tectonics and basin formation Deformation

Lithospheric plates are constantly moving. The motion of plates set up

plate boundary forces. These forces induce deformation of rocks concentrated along the plate boundaries, where the plates are colliding and moving away from each other.

(Allen and Allen 2005)

Plate tectonics and basin formation Deformation

Example of local plate movement

(Cloetingh et al. 2007)

Deformation Different types of deformation

Three materials of different mechanical properties: a rubber band, chewing gum and a

piece of paper (from top to bottom). What will happen to the different materials when they are stretched out?

(Kre Kullerud 2003)

Deformation Different types of deformation

The rubber band and the chewing gum are stretched The piece of paper is ripped in two pieces

What happens if the materials are no longer stretched?

(Kre Kullerud 2003)

Deformation Different types of deformation

The materials are no longer stretched: Rubber band: retains its original form; it was only temporarily

deformed by the stretching: elastic deformation Chewing gum: permanently deformed: ductile deformation Paper: permanently deformed: brittle deformation

(Kre Kullerud 2003)

Deformation Three stages of deformation

Stress: when external forces are acting on a body, the body is subjected to

stress (stress: force per unit area) Strain: the deformation of the body (change in shape) Rocks (like the green rectangle) may undergo deformation through 3 stages:

initially elastic, then plastic and finally brittle (Kre Kullerud 2003)

Deformation Elastic deformation

First part of deformation is elastic If the stress is released, the body retains its original shape and size

(Kre Kullerud 2003)

Deformation Plastic deformation

More stress is applied, the elastic limit is exceeded

If the stress is released, the body will not return to its original shape and size: it has undergone permanent deformation

In geology: ductile deformation = permanent change of shape without loss of continuity (bending)

(Kre Kullerud 2003)

Deformation Brittle deformation

By further increasing the stress, the body will eventually fracture: it has undergone brittle deformation

(Kre Kullerud 2003)

Deformation Forces related to motion of plates

Compressive forces (push on planes): squeezing and shortening Tensional forces (pull on planes): stretching Shearing forces (acting parallel on planes): pushing two parts in

opposite directions

(Kre Kullerud 2003)

Deformation

Type of deformation (ductile or brittle) depends upon temperature, pressure, strain rate and composition material

(Kre Kullerud 2003)

Brittle deformation in response to tensional forces

Normal Fault

Brittle deformation in response to compressive forces

Thrust fault (Sognefjorden, Norway)

Reverse Fault

Brittle deformation

Footwall and hanging wall of a fault

Brittle deformation in response to shearing forces

Strike-slip faults (= transform faults)

Ductile deformation in response to compressive forces

Ductile deformation in reponse to compressive forces

Folds

After erosion

Lithosphere and Asthenosphere Deformation

Lithosphere is rigid and mechanically strong outer part of earth

Upper part mantle has same mechanical strength as crustal rocks.

Asthenosphere is mechanically much weaker than lithosphere

Lithosphere consists of a number of large plates that move relative to each other (plate tectonics)

Lithosphere and Asthenosphere

Lithosphere: Rigid; behaves as coherent plate = Crust and Upper Mantle: Crust

Oceanic: 3-15 km thick and is composed of basalt (igneous); density ~ 2,800 kg/m3;Young age (3.8 billion years old).

Upper Mantle Density ~ 3,300 kg/m3 Asthenosphere

Ductile Weaker than lithosphere

Where is Moho deepest and why?

Depth (km) to the Mohorovicic discontinuity obtained from geophysical data (After Dezes et al. 2004; in:Cloetingh et al 2007)

(Moho = Mohorovicic discontinuity = seismic discontinuity between the base of the Earth's crust and the top of the mantle. P waves passing through the Moho change their velocity by approximately one kilometer per second, with the higher velocity occurring in the mantle and the lower in the crust.)

Mechanisms of Basin formation Vertical balancing of forces: Isostasy

Simple isostasy model: the lithosphere exerts stress on the weaker asthenosphere which, over geologic time flows laterally such that the load (change in load) of the lithosphere is accommodated.

Airys iceberg model of isostasy

Mechanisms of Basin formation Vertical balancing of forces: Isostasy

Vertical balancing of forces to a depth of compensation

(pressures at B and D are equal)

Pressures at B and D are equal:

(gz)seawater + (gz)sediment + (gz)oceanic crust + (gz)mantle =

(gz)continent crust + (gz)mantle

Local vertical balancing of forces Isostasy

Gravitational equilibrium between the lithosphere and asthenosphere

Seawater (= 1.02 g/cc; z = 1 km)

Thickness?

Mechanisms of Basin formation Isostasy & vertical loading

Sedimentary BasinsFormation and evolution of sedimentary basins & their geo-energy potentialSedimentary BasinsFormation and evolution of sedimentary basins & their geo-energy potentialGeo-energy potentialRenewabilityCourse focus Why Sedimentary Basins?Sedimentary BasinsSediments and sedimentary rocksSediments and sedimentary rocksSedimentary BasinsMechanisms of Basin FormationPlate tectonics and basin formationDeformationPlate tectonics and basin formationDeformationDeformationDifferent types of deformationDeformationDifferent types of deformationDeformationDifferent types of deformationDeformationThree stages of deformationDeformationElastic deformationDeformationPlastic deformationDeformationBrittle deformationDeformationForces related to motion of plates DeformationBrittle deformation in response to tensional forcesBrittle deformation in response to compressive forcesBrittle deformationBrittle deformation in response to shearing forcesDuctile deformation in response to compressive forcesDuctile deformation in reponse to compressive forcesLithosphere and AsthenosphereDeformationLithosphere and AsthenosphereDiapositiva numero 31Mechanisms of Basin formation Vertical balancing of forces: IsostasyMechanisms of Basin formation Vertical balancing of forces: Isostasy Local vertical balancing of forcesIsostasyMechanisms of Basin formationIsostasy & vertical loading