Permeability Porosity Packing
Transcript of Permeability Porosity Packing
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Prof. Christoph HeubeckInstitut für Geologische WissenschaftenFreie Universität BerlinMalteserstr. 74-10012249 BerlinGERMANY
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Packing, Porosity, and Permeability
Today‘s LectureWhy is this important ?
Links und Literatur
Porosity and scale
Porosity Development with depth as a function of …
PermeabilityDefinitionRelationship to porosity
PorosityDefinitionTypesSandstones and Carbonates
Packing
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Why do we need a porous system ?
Fundamentals of civilisation• water• Heat, convection and conduction• Mineralizing solutions
Permits storage (porosity) and transmission (permeability) of liquids and gases
Packing in loose sand
(Simplification: spheres, loose)
• Porosity is independent of grain size• Porosity is dependent of packing• Packing is dependent on depositional and diagenetic
history
Cubic packingCoordination number = 6; φ = 0.42)
Rhombic packing(coordination number = 8: φ = 0.26)
Differences in packing in recent dunes(fine-grained quartz sand)
Saltation
Avalanches Grain fall
39 %
47 %
43 %Schenk (1981)
Packing in loose sand
Φ =
Packing: Approximating Reality
grain sizes due to to sorting (eolian vs. alluvial fan)
grain shapes and orientations
Lithologies / solubility
Degree of cementation
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Packing (and Porosity) in sandstones is therefore dependent on
• Lithology (resistance against compaction)•Grain size•Grain orientation•Grain sorting•Degree of cementation
Fundamental Reservoir Properties
Porosity (φ; to store) Permeability (k; to flow)
high φ; high k
low φ; high k
low φ; low k
high φ; low k
The plumbing of a reservoir ?
http://www.micromeritics.com/pore_cor.htmlWhy is this important ?
Links und Literatur
Porosity and scale
Porosity Development with depth as a function of …
PermeabilityDefinitionRelationship to porosity
PorosityDefinitionTypesSandstones and Carbonates
Packing
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What is pore space ?
Cement: Chemically precipitated minerals connecting grains
Matrix: Mechanically or chemically instable particles (mostly of clay minerals, fine-grained quartz, and calcite).
Pores: A network, mostly filled with gas or liquid, of open space
Framework:mechanically stable; Sedimentedparticles
How is pore space quantified ?
Fundamental: Concentration of solids, C
C = VSolids / VTotal(%)
Porosity is therefore the ratio of pore volume to total volume.
Porosity φ is that part of the sedimentary rock notoccupied by solids.
φ = 1 - C (%)
thereforeφ = 1 - (VSolids / VTotal)
or
φ = (VTotal - VSolids ) / VTotal
Porosity Ranges
Sand and gravel 20-50 % Till 10-20 % Silt 35-50 % Clay 33-60 % Clastic sediments typically 3-30 % Limestone <1 to 30 %
Basalt 1-12 % Tuff 14-40 % Pumice - 87 %
Fractured crystalline rock 1-5 % Unfractured crystalline rock ~0.1 %
http://geodynamics.wustl.edu/classes/hydrology/lectures/ch_02/ch_02.html
What porosity types exist ?
1. DescriptiveIn sandstones: Intergranular, Intragranular, Fracture, Dissolution, .In carbonates: Many
3. Geneticprimary / secondary
2. Engineering / Technicaleffective / ineffective
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Descriptive porosity (in a sandstone)
Intragranular
Dissolution porosity
Intergranular
Fracture porosity
Engineering Porosity
Total Porosityφt = φeff + φineff
Effective Porosity φeff
• contributes to fluid flow• connected porosity• intergranular or fracture
Ineffective Porosity φineff
• is in sandstones mostly intragranular porosity
Primary porosity:
Pore space remaining after deposition
Secondary porosity:
Results of • Dissolution of existing
minerals (grains / cement) • Sediment shrinkage• Fracturing
Genetische Porosität Genetic Porosity: Primary
Primary porosity in sandstones is mostly intergranular
Rotliegend Sandstone, Northern Germany
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Genetic Porosity: Secondary
• Secondary “oversized pores”: Dissolution of instable volcanic or metamorphic grains
Carboniferous Escarpment Fm., fluvio-eolian, Bolivia
Secondary porosity
Dissolved VRF, Feldspar
Secondary, intergranular, probably ineffective porosity
Rotliegend Sandstone, Northern Germany
Secondary porosity
http://www.creationresearch.org/vacrc/sem04.html
Etched Feldspar
Secondary, intragranular, probably ineffective porosity
Carbonates
Mineralogy: Calcite / Aragonite / Dolomite
Particle size
Sequence stratigraphy:Upbuilding, outbuilding, onlap, offlap …
Facies: Platform, Reef, Ramp, Slope
…
http://mgg.rsmas.miami.edu/groups/csl/trips/bahamas.htm
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Why the distinction ?
varied or independentconsistentφ-k correlation
commonly inadequaterepresentativeCore plugs
feasible to impossiblefeasible or easyVisual estimate
majorminor – moderateImportance of fracturing
major!minor – moderateInfluence of diagenesis
greatly varied„negative“ of particlesPore shape
f (diagenetic and biologic processes)f (particle size, sorting)Pores sizes
Interparticle and intraparticleinterparticleTypes of primaryporosity
40-70%25-40%Amount of primaryporosity
CarbonatesSandstones
Choquette and Pray, 1970
Types of porosity in carbonates
Fabric-Selective Not Fabric-SelectiveFractureChannelVugCavern
Fabric-Selective or Not
Breccia Boring Burrows Shrinkage
Choquette and Pray, 1970
InterparticleIntraparticleFenestralShelterGrowth-Framework
Prim
ary
IntercrystalMoldic
Sec
onda
ry
Why is this important ?
Links und Literatur
Porosity and scale
Porosity Development with depth as a function of …
PermeabilityDefinitionRelationship to porosity
PorosityDefinitionTypesSandstones and Carbonates
Packing
Permeability: Definition
… is a measure of the ability of a fluid or a gas to cross a network of pores
• measured in Darcy (D, oder mD)• a measure of the degree of interconnectedness of pores• Critical neumber and size of pore throats
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How is permeability measured ?
What influences the throughput of a fluid (Q) through a porous solid ?
Length l
Fluid viscosity µ
Cross-sectional area A
Pressure difference ∆p
l
µ
∆p
A
Q ~ A
µ∆p
l
therefore
(-)
(+)
(+)
(-)
Permeability - Darcy’s Law
Q ~ A
µ∆p
l
l
µ
∆p
A
kProportionality constant
Q = k Aµ∆p
l
What influences the throughput of a fluid (Q) through a porous solid ?
Permeability - Darcy’s Law
How is permeability measured ?Q = k A
µ∆p
l
Fluid reservoir, known volume, graded scale
Standardized geometry (A, l)Rate Q = V / t
keep ∆pund T constant
Permeability - Porosity
How are permeability and porosity related ? (in a sandstone)
0.01
0.10
1.00
10.00
100.00
1000.00
10000.00
0.00 0.05 0.10 0.15 0.20 0.25 0.30porosity (v/v)
perm
(mD
)
RT 1 > 3500 k/phiRT 2 450 - 3500RT 3 150 - 450RT 4 6.32 - 150RT 5 > 6.32
0.1µ
0.25µ
0.5µ
5 µ
2 µ
1 µ
20 µ
10 µ
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Permeability - Porosity
How are permeability and porosity related ?
Porosity (%)
Per
mea
bilit
y(m
D)
How are phi and k related ?
0.01
0.10
1.00
10.00
100.00
1000.00
10000.00
0.00 0.05 0.10 0.15 0.20 0.25 0.30porosity (v/v)
perm
(mD
)
RT 1 > 3500 k/phiRT 2 450 - 3500RT 3 150 - 450RT 4 6.32 - 150RT 5 > 6.32
0.1µ
0.25µ
0.5µ
5 µ
2 µ
1 µ
20 µ
10 µ
• Important for permeability prediction
• Empirical equations based on calibrated samples
• z.B. Carman-Kozeny equationK ~
Pe
Sv
• Pe = effective Porosity• Sv = surface (specific per unit volume of solid) ( in turn dependent on
grain size)
K = Pe
3
5 Sv (1-Pe)2
Permeability - Porosity
Why is this important ?
Links und Literatur
Porosity and scale
Porosity Development with depth as a function of …
PermeabilityDefinitionRelationship to porosity
PorosityDefinitionTypesSandstones and Carbonates
Packing 1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Factors of porosity with depth:• Maximum depth• Mean grain size • Composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
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1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Factors of porosity with depth:• Maximum depth• Mean grain size • Composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
mechanicalshaking, -1000m
grain fracturingand bending,
-1000mchemical compaction: CaCO3, SiO2-cement,
>500m
cement and mineral dissolution: carbonate, anhydrite, feldspars
through CO2 ^
dehydration of smectite to illite (2000-3000m): -15% Vol. !
completely cemented
Mechanical compaction
Rotliegender Sandstein, Norddeutschland
Grain bending
Pressure effects
Mechanical breakage of plagioclase
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Leaching and Dissolution
Leached tuffaceous(fine-grained volcanic) fragment
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Coase-grained
Fine-grained
Factors of porosity with depth:• Maximum depth• Mean grain size• Composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Quartzarenite
LithareniteRFs clay minerals
Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
1
3
2
4
5
6
7
8
9
10
0 10 20 30 40
Lithic ss (>>5% / km)
Arkosic
ss(~5
% / km)
Quartz
ose ss
(< 5%
/ km)
Dickinson and Suczek (1979)
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1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence and mineralogical composition
Quarzarenite
LithareniteRFs clay minerals
0 10 20 30 40 50 60 70 80 90 100
Qm
0
10
20
30
40
50
60
70
80
90
100
F
0
10
20
30
40
50
60
70
80
90
100
Dissected Arc
R e c y c l e d
Transitional Arc
Undissected Arc
Basement Uplift
Transitional Continental
CratonInterior
quartzose rec.
transitional rec.
lithic rec.
L0 10 20 30 40 50 60 70 80 90 100
Q
0
10
20
30
40
50
60
70
80
90
100
F
0
10
20
30
40
50
60
70
80
90
100
Dissected Arc
Recycled Orogen
Transitional Arc Undissected
Arc
Basement Uplift
Transitional Continental
CratonInterior
Composition and provenance
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence and mineralogical composition
LithareniteRFs clay minerals
Folk; 1951, nach Blatt, 1980
0 Low Moderate High Extreme
Removal of Clay
MatureSubmature SupermatureImmature
Much Clay Little or no clay
Grains not well sorted Grains well sorted
Grains not rounded Grains rounded
Sorting of nonclayfraction Rounding of grains
Total input of modifying kinetic energy
Quarzarenite
Mechanical compaction and porosity
Devonian greywacke, Taunus, Germany
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
High: 4°C / 100m
Low: 1.3°C / 100 m
Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
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1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Carboniferous
Jurassic-CretaceousPermo-
Triassic
Paleocene
Selley, 1978
Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Overpressurecompartments due to high
pore pressure
Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
1
3
2
4
5
6
7
8
0 5 10 15 20 25 30 35 40
Depth dependence
Oil fill preventscementation
Factors of porosity with depth:• Maximum depth• Mean grain size • Mineralogical composition• Temperature gradient• Age• Pressure• Hydrocarbon fill
Why is this important ?
Links und Literatur
Porosity and scale
Porosity Development with depth as a function of …
PermeabilityDefinitionRelationship to porosity
PorosityDefinitionTypesSandstones and Carbonates
Packing
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How is permeability (k) and porosity (φ) related ?
• (sub-) microscopic pore scale (µm - mm)• hand sample (mm - dm)• outcrop (m - 100 m)• reservoir (100 m - x km)• basinal scale (xx km - xxxx km)
How is permeability (k) and porosity (φ) related ?
Grain and Pore Scale
Coarse Medium Fine Very Fine Silt
Very Poor
Poor
Moderate
Well
Very Well
Extremely well
0.125 0.0625 0.251.0 0.5 0.044
Grain Size
Sorti
ng
26
28
30
34
38
40
42
32
36
400
200
100
50 25 10 5
2.5
1.0
0.5
0.2
After Beard and Weyl, 1973
1-100µ
0.1-10 mm
1-10 cm
0.1-1m
φmin
φmax
Kmin ?Kmax ?
Levels of Reservoir Heterogeneity
0.1-10 km
1- 100 m
How is permeability (k) and porosity (φ) related ?
Grain and Pore Scale
Kaolinite
Hairy IlliteRotliegendes-Problem
http://www.creationresearch.org/vacrc/sem02.html
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How is permeability (k) and porosity (φ) related ?
Reservoir or outcrop scale
Simple Tank
Layered Tank
NaturalReservoir
Permeability - Porosity
Literature
• Moore, Clyde H., 2001, Carbonate Reservoirs: Developmetns in Sedimentology, 55; Elsevier.
• Füchtbauer, Sedimente und Sedimentgesteine, p. 150-161.
• Blatt, H., 1990, Sedimentary Petrology (for diagenesis)
• Hutcheon, I., 1990, Aspects of diagenesis in coarse-grained silicilcastic rocks: in McIlreath, I., and D.W. Morrow, eds., Diagenesis: Geoscince Canada Reprint Series 4, p. 165-176.
• Allen, J.R.L., 1985, Principles of Physical Sedimentology (Chapter on Packing, p. 21-38)
• Barwis, McPherson, J.G., and Studlick, J.R.J., eds., Sandstone Petroleum Reservoirs: Springer (New York), 583 p.
• Wilson, M.D., 1994, Reservoir Quality Assessment and Prediction in Clastic Rocks: SEPM Short Course Notes 30, 432 p.
Permeabilität - Porosität
Links
• Eine virtuelle Tour durch die Porenräume eines Ölreservoirs (Pilotstudie des US DOE) http://greenwood.cr.usgs.gov/pub/dds/dds-033/USGS_3D/ssx_txt/all.htm
• Porosität und Permeabilität, angewandt auf die Erdölgeologie eines ganzen sedimentärenBeckens: http://www.ags.gov.ab.ca/AGS_PUB/ATLAS_WWW/ATLAS.HTM
• AAPG webseite: http://www.aapg.org
• Handout for the Geol 463 class at the University of Saskatoon (where is that ? Ask your Instructor); a few pages of good text; some figures : http://www.usask.ca/geology/classes/geol463/46306b.pdf
• Debra K. Higley, Michael P. Pantea, and Roger M. Slatt, 1997, 3-D Reservoir Characterization of the House Creek Oil Field, Powder River Basin, Wyoming: U.S. GEOLOGICAL SURVEY DIGITAL DATA SERIES DDS-33; Website, http://pubs.usgs.gov/dds/1997/dds-033/USGS_3D/ssx_txt/all.htm, V1.00 (access Dec. 11, 2002)