It’s The Fluids

That Count

Fall 2010

M. BatzleSEG Honorary Lecture

The Great Wave off Kanagawa by the Japanese artist Hokusai

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•WATER and BRINE(BRINE = H2O + Salt)

•HYDROCARBONSOilGas

TYPES of PORE FLUIDS

GasMixtures

•DRILLING MUD

•PRODUCTION FLUIDSMiscible Injectants(CO2, Enriched Gas)

From Ivar Brevik, STATOIL

SANDSTONE VELOCITY

VE

LOC

ITY

(k

m/s

)4

3

VpV

ELO

CIT

Y

(km

/s)

2

DIFFERENTIAL PRESSURE (MPa)

0 25 50

Vs

from Han, 1986.

Vp = K + 4/3 G

ρρρρ( ) 1/2

Vs = Gρρρρ( )

1/2

One description of the influence of pore fluids on seismic velocity can be found in Gassmann’s Equations. The fluid effect is seen in the red ellipse.

GASSMANN’S EQUATION

Velocity & Modulus:

Ksat = Kdry +K0

-2(K0 – Kdry)2

K0-2(K0 – Kdry) + φ φ φ φ (1/Kf - 1/K0)

Kf = Fluid modulus Kdry = Dry bulk modulusKsat = Saturated bulk modulusKo = Mineral bulk modulusG = Shear modulus (sometimes ‘µµµµ’)Vp = Compressional velocityVs = Shear velocityφφφφ = Porosityρρρρ = Density

ρρρρsat = ρρρρ0 (1- φφφφ) + φρφρφρφρf

Density:

•WATER and BRINE(BRINE = H2O + Salt)

•HYDROCARBONSOilGas

TYPES of PORE FLUIDS

GasMixtures

•DRILLING MUD

•PRODUCTION FLUIDSMiscible Injectants(CO2, Enriched Gas)

Steam

BRINE COMPOSITION versus DEPTH

O

H H

WATER a.k.a. H 2O

2.7 A

Hinch, 1980

δ+

δ-

2.7 A

Water + Ions(usually NaCl)

ClNa

Dickerson et al., 1970

HeavyOil

Water Wet

silicaSilicaHeavyOil

Oil WetM. Schmutz et al., 2010

SP , Resistivity &Thermal Profile

Mt. PrincetonGeothermal AreaColorado

Revil et al., 2010

BRINE DENSITY versus PRESSRE, TEMPERATURE, & SALINI TY

Brine density as a function of temperature pressure and salinity (ppm = parts per million NaCl). Solid circles are from Zarembo and Fedorov (1975).

BULK MODULUS versus PRESSRE, TEMPERATURE, & SALINIT Y

PR

ES

SU

RE

CRITICALPOINT

LIQUID

GENERAL PHASE BEHAVIOR: Water

Tcp = 647 K, 374 CPcp = 22.067 MPa

TEMPERATURE

PR

ES

SU

RE

GASSOLID

T.P.

Schematic phase behavior for a simple pure substance

Ttp = 273 K, 0 C Ptp = 611.73 Pa

Density of water & steam

DE

NS

ITY

(g/

cm3 ) 0.1 MPa

10

40

70

Vapor Point

DE

NS

ITY

(g/

cm3 )

0.6

0.8

1.2

1.0

Sun et al., 2007

4000 600200 800

TEMPERATURE (C)

DE

NS

ITY

(g/

cm

0

0.2

0.4

CT SCANS SandpackCoarse Sand w/o THF-Hydrates Coarse Sand w/ THF-Hydrates

Guest Molecules

Gas Hydrate Crystal Structures

STRUCTURE I

Water Molecules STRUCTURE I

STRUCTURE II

STRUCTURE H

O = C = OC HH

H

H

C

H

H

C HH

H

H

Guest Molecules:

Methane Carbon DioxideEthane IMF - GEOMAR

•WATER and BRINE(BRINE = H2O + Salt)

•HYDROCARBONSOilGas

TYPES of PORE FLUIDS

GasMixtures

•DRILLING MUD

•PRODUCTION FLUIDSMiscible Injectants(CO2, Enriched Gas)

Steam

Gas

Hydrocarbons come in many flavors, each with specific properties. In addition, complex mixtures of thes components will change composition under differing conditions.

PR

ES

SU

RE

CRITICALPOINT

LIQUID

GENERAL PHASE BEHAVIOR: PURE COMPOUND

Water CO

TEMPERATURE

PR

ES

SU

RE

GASSOLID

T.P.

Water

Butane

CO2

Fluid – Density

800

1000

1200Fluid Density [kg/m

3] Brine

CO2

0 2 4 6 8 100

200

400

600

Fluid Pressure [MPa]

Fluid Density [kg/m

Butane

CO2

Fluid – Modulus

2000

2500

3000Fluid Modulus [MPa] Brine

0 2 4 6 8 100

500

1000

1500

Fluid Pressure [MPa]

Fluid Modulus [MPa]

Butane

CO2

GENERAL PHASE BEHAVIOR: MIXTURE

PR

ES

SU

RE

CRITICALPOINT

TEMPERATURE

PR

ES

SU

RE

PR

ES

SU

RE

Liquid-LikeBehavior CRITICAL POINT

BLACK OIL

VOLATILEOIL

RETROGRADECONDENSATE

DRY GAS

GENERAL PHASE BEHAVIOR

PR

ES

SU

RE

TEMPERATURE

Gas-LikeBehavior

Two PhaseRegion

VELOCITY of LIGHT OIL as a FUNCTION of DENSITY

VE

LOC

ITY

(m

/s)

141.5ρρρρ(SG)

- 131.5API =

50 40 30 20 10Oil API

DENSITY (g/cm 3) [of dead oil at STP]

VE

LOC

ITY

(m

/s)

PRESSURE

TEMPERATURE

HC Fluid Velocity vs. Pressure

1000

1500

Vel

ocity

(m

/s)

LIQUID

0

500

0 2 4 6 8 10

Pressure (Mpa)

Vel

ocity

(m

/s)

GAS

Calculation from FLAG program. Bubbles start to exsolve from this fluid when pressure drops below bubble point (about 3.8 MPa)

PR

ES

SU

RE

Liquid-LikeBehavior CRITICAL POINT

BLACK OIL

VOLATILEOIL

RETROGRADECONDENSATE

DRY GAS

GENERAL PHASE BEHAVIOR

PR

ES

SU

RE

TEMPERATURE

Gas-LikeBehavior

Two PhaseRegion

600

800

Vel

ocity

(m

/s)

28

35

41 MPa

HEAVY GAS COMPRESSIONAL VELOCITY

400

10 30 50 70 90 110

Temperature (c)

Vel

ocity

(m

/s)

15

20

Near the critical point, a heavy gas can act like either a liquid or a gas.

PROPERTIES and BEHAVIOR of

HEAVY OILS

SMITH, 1926

DESTRUCTION of SODOM and GOMORRAH

Heavy oils are an enormous resource. T. Appenzeller, (2004)

Biodegradation

Hunt, 1996

1 0

1 2

1 4

1 6

1 8

2 0

North Sea

California

0

2

4

6

8

0 5 1 0 1 5 2 0 2 5 3 0 3 5 4 0 4 5

TIME

Alaska Heavy

SARA fractionation

• S- Saturates: Straight or branched alkanes (paraffins)

• A- Aromatics: Contain at least one benzene ring

• R- Resins: propane-insoluble, pentane-soluble fraction

• A- Asphaltenes: soluble in carbon disulfide but soluble in carbon disulfide but

insoluble in petroleum ether or ninsoluble in petroleum ether or n--pentanepentane (Huh?)

Molecular Structure of Asphaltene Proposed for 510C Residue of Venezuelan

Crude by Carbognani [INTEVEP S.A. Tech. Rept., 1992]

3D Picture of Carbognani's Model of Venezuelan Crude Asphaltene Molecule

(Courtesy of Prof. J. Murgich)

Michael Jardine

Chemical Controls on Viscosity

Rel

ativ

e V

isco

sity

ASPHALTENES

Henaut 2001

Weight Fraction of Asphaltenes

Rel

ativ

e V

isco

sity

Viscosity versus temperature for oils from several sources

The heavy oil or ‘pitch’ drop experiment described by Edgeworth et al. (1984)

VE

LOC

ITY Liquid

Glass

Quasi-Solid

TEMPERATURE

VE

LOC

ITY Liquid

Glass P. Liquid P.

Han et al., 2008

Calculated “Fluid” shear velocity dependence on viscosity

HEAVY OIL

CARBONATEGRAIN

HEAVY OIL

Scanning electron microscope image of the Uvalde carbonate saturated with heavy oil.

3

4

Velocity [km/s]

25C

60C

40C

25C

VP

1

2

1 10 100 1000 10000 100000 1000000

Frequency [Hz]

25C

60C

40C

VS

Frequency dependence of the Uvalde heavy oil-saturated sample. As expected, velocity decreases with increasing temperature. Also, dispersion becomes significant within the seismic band as temperature increases.

A similar amount of dispersion was detected by Doug Schmitt (1999) when comparing a sonic log to a VSP.

DURI FIELD STEAM FLOOD, SEISMIC TIME LAPSE

Jenkins et al. (1997)

DURI FIELD STEAM FLOOD, SEISMIC TIME LAPSE

Jenkins et al. (1997)

PR

ES

SU

RE Liquid-Like

Behavior

CRITICAL POINT

BLACK OIL

VOLATILEOIL

RETROGRADECONDENSATE

DRY GAS

GENERAL PHASE BEHAVIOR

HEAVYOIL

PR

ES

SU

RE

TEMPERATURE

Gas-LikeBehavior

Two PhaseRegion

Calculated Fluid Modulus versus PressureOil API = 7, GOR = 2 L/L, T = 20 C

1500

2000

2500

3000

3500B

ulk

Mod

ulus

(M

pa)

.

Bulk modulus MPa

Mix Mod. Mpa

Gas Mod. Mpa 0MIXTURE

0

500

1000

1500

0 5 10 15 20

Pressure (Mpa)

Bul

k M

odul

us (

Mpa

) .

Gas Mod. Mpa 0

Calc. Fluid Modulus versus TemperatureOil API = 7, GOR = 2 L/L, P = 2 MPa

1500

2000

2500

3000

Mod

ulus

(M

pa)

.

Bulk modulus MPa

Mix Mod. Mpa

Gas Mod. Mpa

0

500

1000

0 50 100 150 200 250

Temperature (C)

Mod

ulus

(M

pa)

.

Gas Mod. Mpa1.827

MIXTURE

FLUIDS:

- Our main exploration and monitoring targets

HEAVY OIL:

-Properties complex but systematic:compositional & phase changes

- Can have a strong geophysical signature

- Properties strongly temperature dependent

- Seismic properties strongly frequency dependentUltrasonic = sonic Log = Seismic

- Can act like a solid: Propagates a shear wave (viscoelastic)

- Small GOR has large effect

- Enormous resourceHEAVY OIL:

Live

Oil

Vis

cosi

ty (

cp)

100

1000

10000

141.5ρ - 131.5API =

API Gravity

Live

Oil

Vis

cosi

ty (

cp)

0.1

1.0

10

(Al-Mamaari, et al., 2006)

SHEAR MODULUS and QUALITY FACTORin UVALDE HEAVY OIL & ROCK @ 12.6 Hz

SH

EA

R M

OD

ULU

S

Log

10(G

)

ROCK G

(From Jyoti Behura)

Log 1

0S

HE

AR

MO

DU

LUS

L

og

TEMPERATURE (oC)

CO2 Velocity – Near Critical Point

Davies and Wallace, 1992

Phase behavior for a condensate gas showing a possible P-T path during production. If the fluid crosses the dew point line in the formation, liquids will be left behind.