No Slide Title · ¾ Development of sub sea centrifugal separator system (Framo Purification) ......

FLUCHA II Fluid Characterisation at Elevated Pressures and Temperatures

Prof. Johan Sjöblom, Ugelstad Laboratory

Department of Chemical Engineering

NTNU, Trondheim, Norway

FLUCHA

IIU g e l s t a d L a b o r a t o r y

FLUCHA II - Ambitions

Characterization of true crude oil systems and emulsions at elevated pressures and temperatures

Establish reference systems which will explain the component –wise behaviour together with their interactions.

Thermodynamic simulations of heavy surface active components (at different P and T).

Experimental characterisation of crude oil/reference systems and corresponding emulsions at elevated pressures.

Performance of chemicals (demulsifiers and inhibitors) at high pressures.

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FLUCHA II - AmbitionsTechnical (industrial) applications (outside the programme)

Transport and stabilization of gas hydrate slurries in oil/gas/water mixtures

High pressure/temperature separation (sub sea / down hole conditions)

Development of sub sea centrifugal separator system (Framo Purification)

Development of chemicals with high pressure performance

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FLUCHA II - OrganisationReference Group (of Sponsors):

NFR Aud Alming

ABB John Dan FriedemannPål Jahre Nilsen

Norsk Hydro Per GrammeLiv Thorsen

Statoil Einar Eng JohnsenArild Westvik

TotalFinaElf Ingvild Andersen Jean-Luc Volle

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FLUCHA II - Employees

Post docsHarald KallevikØystein SætherGisle Øye

PhD Candidates:Inge Harald AuflemNarve AskeTrond Erik HavreLinn Bergflødt / University of Bergen

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Approach: Physico-chemical characterisation

Emulsion stability

Paper III

Crude oil properties

Paper II

Fluid behaviour and control

Crude oil composition

Paper I

Crude oil structure

Papers IV and V

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AsphaltenesHeaviest components of the crude oil, molecular weight 500-1500.

Contains heteroatoms (O, S, N) and metals (Ni, V, Fe).

Polar molecules with high interfacial activity.

Strong tendency of self-aggregation.

Under unfavourable solvent conditions asphaltenes may precipiate as a solid phase.

Stabilises emulsions by forming a rigid, cross-linked interfacial layer.

Courtesy: Prof. J. Murgich

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Prediction of SARA-data by Partial Least Squares Regression (PLS)

ypred = f (X) = b0 + b1x1 + b2x2 +…+ bnxn

PLS

62

…

27

74

45

Saturates

yOil(n)

….

Oil(3)

Oil(2)

Oil(1)

2200nm….1103nm1102nm1101nm

Organize spectral data

X

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Oscillating pendant drop tensiometer

ε, Gibbs interfacial dilatational modulus, measure of interfacial rheology:

Addγεln

= dd iωηε +=

Small, oscillating area deformations:→ Elasticity and viscosity contribution can be separated.

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Elasticity of crude oil/water interfaces

-2.0

3.0

8.0

13.0

18.0

23.0

28.0

4 16 14 6 20 8 9 11 23 21 22 5 19

Crude oil no.

Elas

ticity

[mN

/m]

Elasticity, 0.002 ml/ml

Light crude oils/condensates

Most stableemulsions

Highest inasphaltenes

Demulsifier added

Demulsifier not added

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Critical Electric Field Emulsion Stability Cell

0

0.5

1

1.5

2

2.5

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Electric field [kV/cm]

Cur

rent

[mA

]Crude oil 3, WC 30%

I

II I II

ECrit

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Crude oil data matrixOrigin WC20

[KV/cm] WC30

[Kv/cm] S

[wt%] A

[wt%] R

[wt%] Asph. [wt%]

Elasticity [mN/m]

Density [g/cm3]

IFT [mN/m]

Mw [g/mole]

Visc.,25°C [kg/ms]

TAN

West Africa 0.58 0.47 47.9 36.5 15.2 0.4 11.5 0.914 20.5 234 18.7 1.10 North Sea 0.87 0.61 48.0 37.5 14.2 0.3 7.3 0.916 24.8 279 57.4 3.10

West Africa 2.00 0.68 41.2 36.4 20.4 2.1 7.8 0.916 26.4 310 143.0 1.50 North Sea 0.00 0.00 82.7 13.4 3.9 0.0 -1.1 0.839 37.1 166 1.8 0.69 North Sea 1.00 0.64 62.7 23.6 12.2 1.5 16.5 0.844 12.8 201 5.4 0.18 North Sea 0.91 1.03 45.5 37.1 16.0 1.4 3.7 0.862 31.9 244 14.5 0.02 North Sea 2.00 1.50 35.3 36.8 24.5 3.5 11.7 0.945 27.4 333 386.6 2.30 North Sea 0.55 0.45 56.0 29.6 14.1 0.3 6.7 0.850 24.7 216 6.6 0.17 North Sea 0.84 0.59 41.8 38.8 18.7 0.6 8.4 0.914 11.8 284 51.0 3.10 North Sea 0.53 0.33 50.9 34.6 14.0 0.5 5.0 0.885 22.8 234 11.6 2.70

West Africa 2.00 1.85 40.6 32.1 20.6 6.6 10.6 0.888 29.0 260 27.8 0.49 North Sea 0.00 0.00 79.8 16.5 3.6 0.1 -1.4 0.796 34.2 157 1.7 0.01

West Africa 0.61 0.45 57.3 27.9 13.5 1.3 - 0.873 24.6 235 17.7 0.50 North Sea 0.59 0.08 60.6 30.0 9.2 0.2 0.2 0.857 22.9 227 10.5 0.04

West Africa 0.85 0.40 42.4 36.1 20.5 1.0 9.2 0.921 16.2 295 105.8 3.60 North Sea 0.00 0.00 65.0 30.7 4.3 0.0 -0.6 0.796 27.6 142 1.2 0.02 North Sea 0.47 0.42 44.1 41.6 13.8 0.5 8.1 0.847 19.9 223 11.7 0.15 North Sea 0.93 0.43 50.3 31.4 17.5 0.7 14.8 0.898 19.5 249 19.1 1.20 North Sea 2.00 2.00 54.5 28.8 14.9 1.8 24.9 0.840 27.4 298 63.1 0.36

West Africa 0.91 0.72 55.4 28.3 12.9 3.4 5.6 0.873 19.0 248 15.3 0.44 France 2.00 1.70 24.4 43.4 19.9 12.4 12.9 0.939 13.4 303 278.9 0.20

Objective: Correlate emulsion stability to the physico-chemical properties.

Tool: Multivariate analysis (PCA, PLS).

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PLS regression on data matrix

Saturates

Aromatics

Resins

Asphaltenes

t1, NIR

t2, NIR

(S+Asf)/R+A)

R/(R+Asf)

Elasticity

Density

IFT

MW

TAN

ViscosityRe

g. Co

eff.

(ln E

critc

al)

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Saturates

Aromatics

Resins

Asphaltenes

t1, NIR

t2, NIR

(S+Asf)/R+A)

R/(R+Asf)

Elasticity

Density

IFT

MW

TAN

ViscosityRe

g. Co

eff.

(ln E

critc

al)

Saturates

Aromatics

Resins

Asphaltenes

t1, NIR

t2, NIR

(S+Asf)/R+A)

R/(R+Asf)

Elasticity

Density

IFT

MW

TAN

Viscosity

Saturates

Aromatics

Resins

Asphaltenes

t1, NIR

t2, NIR

(S+Asf)/R+A)

R/(R+Asf)

Elasticity

Density

IFT

MW

TAN

ViscosityRe

g. Co

eff.

(ln E

critc

al)

-0.1

-0.05

0

0.05

0.1

0.15

0.2

Correlation coefficient of predicted vs. measured plot: R2 = 0.93

Additional models:1. SARA + interfacial elasticity2. Near infrared spectroscopy data

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High-pressure NIR rig

x x

x x x x

x

Air cabinet

Personal computer

NIR spectrometer

Fibre optics

NIRcell

Cell 1

Cell 2

V1

V2

V3x x

x x x x

x

Air cabinet

Personal computer

NIR spectrometer

Fibre optics

NIRcell

Cell 1

Cell 2x

xx x

x x x

Air cabinet

Personal computer

NIR spectrometer

Fibre optics

NIRcell

Cell 1

Cell 2

V1

V2

V3x x

x x x x

x

Air cabinet

Personal computer

NIR spectrometer

Fibre optics

NIRcell

Cell 1

Cell 2

V1

V2

V3x x

x x x x

x

Air cabinet

Personal computer

NIR spectrometer

Fibre optics

NIRcell

Cell 1

Cell 2x

xx x

x x x

Air cabinet

Personal computer

NIR spectrometer

Fibre optics

NIRcell

Cell 1

Cell 2

V1

V2

V3

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Depressurisation of crude oil

0.4

0.6

0.8

1.0

1.2

1.4

1300 1400 1500 1600 1700 1800 1900 2000 2100 2200

Opt

ical

den

sity

300 bar → 160 bar

155 bar → 150 bar

Wavelength [nm]

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Reversibility of asphaltene aggregation

0.39

0.40

0.40

0.41

0.41

0.42

0.42

140160180200220240260280300320

Pressure [bar]

Opt

ical

den

sity

@ 1

600

nm

0.39

0.40

0.40

0.41

0.41

0.42

0.42

140160180200220240260280300320

Pressure [bar]

Opt

ical

den

sity

@ 1

600

nm

16h

72h

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Paper IHigh-pressure

separation rig

High-pressure separation rig

Crude Water

Emulsification

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0

50

100

150

200

250

300

350

40011->

1

11->

7

11->

1

11->

7

Pressure drop (bar)

Foam

hei

ght,

ml

Main results / Conclusions

Gas cap removed

→ no foam stability

0

10

20

30

40

50

60

70

80

90

100

0.0 5.0 10.0 15.0 20.0

Time [min]%

sep

arat

ed w

ater

11->1 bar (gas cap removed)

11->7 bar (gas cap removed)

11->1 bar

11->7 bar

Paper I

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Paper I


Coated gas bubble Foam formationDegassing

Gas bubbles that move upwards through the oil phase can remove surface active materialfrom the water interface, thereby improving coalescence and separation

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Patent


No clear influence on separation from CO2 release

Increased separation upon CO2release after 5 minutes

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Patent


Pressuredrop

Coalescence

Bubbles ruptures interface

Flotation Film drainage

Bubbles inside droplets

1

2

1) CO2 dissolved into the aqueous phase forms bubbles upon pressure reduction that ruptures the interface

2) 2) CO2 dissolved in the oil phase, propagates through the system ripping of surface active material from the oil-water interface

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Patent


• A polar gas, such as CO2, can in some cases accelerate the breaking of crude oil based emulsions

• The method is probably useful only for particle stabilisedcrude oil emulsions

• Improved performance if the water droplets are allowed to sediment to form a dense packed region

• The flotation effect is also valid for model oil systems

• The use of flotation can be effective in a gravitational separators, especially of batch type

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Method

Dissipative Quartz Crystal Microbalance (QCM-DTM)

– A QCM consists of a thin quartz disc sandwiched between a pair of electrodes

– Due to the piezoelectric properties of quartz, it is possible to excite the crystal to oscillation by applying an AC voltage across its electrodes

– Measures simultaneously change in frequency,f and dissipation, D

– When a thin film adsorbs to the sensor crystal the frequency decreases. If the film is thin and rigid the decrease in frequency is proportional to the mass of the film m

Cnf ∆−=∆

1:ligningsSauerbrey`

Paper III

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Paper III


• Resins dissolved in pure heptane adsorb onto a hydrophilic gold surface (2.3 mg/m3), and pack into a compact monolayer (figure)

• Increased aromatic content in the solvent, decreases the adsorption of resins: 50/50 heptane/toluene → 0.6 mg/m3 and hardly at all in pure toluene

• Studies show that resins are not able to desorb pre-adsorbed asphaltenes from the surface.

• Neither do they show any tendency to adsorb onto the asphaltene-coated surface

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Paper III


• Asphaltenes dissolved in 50/50 heptane/toluene (4.4 mg/m3) adsorb to a larger extent than the resins

• In pure toluene (7.1 mg/m3) the asphaltenes adsorb as aggregates in multilayers onto the surface (figure)

• A mixture of asphaltene and resins in 50/50 heptane/ toluene show a larger adsorption than only asphaltenes or resins

⇓• Likely that the resins and

asphaltenes adsorb as mixed aggregates

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R-COOH

R-COOH

RCOOH

R-COOH

R-COOH

R-COOH

(RCOO)2Ca

Gas

Oil

Water

Pressure releaseIncreased pH

(RCOO)2Ca

R-COOH

CO2

(RCOO)2Ca

Naphthenate Formation

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Naphthenate Formation

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Problems with Acidic Crudes

Precipitation of calcium naphthenate

Naphthenic acid corrosion

Emulsion stabilisation

Environmental problems

Lower price for acidic crudes

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Outline of Doctoral Work

Naphthenic Acid Chemistry• Partitioning between oil and water• Dissociation• Micellisation• Interfacial behaviour• Interactions with asphaltenes

Emulsion Stabilisation• Monolayers of naphthenic acids/naphthenates• Electrostatically stabilisation of o/w-emulsions• Stabilisation by combined D-phase (multilayer) and

asphaltene particles

Formation of Calcium Naphthenate• NIR is presented as a method for studying calcium naphthenate precipitation

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NIR measurements of mixtures of asphaltenes and different concentration of a naphthenic acid

-0.030

-0.025

-0.020

-0.015

-0.010

-0.005

0.000

0 200 400 600 800 1000 1200Time [min]

Optica

l densi

ty

0.125 wt%

No additive

1.25 wt%

3.25 wt%

6.25 wt%

12.5 wt%

0.125 wt% asphaltenes

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NIR measurements for 1.25 wt% of various naphthenic acids in asphaltene mixture

-0.030

-0.025

-0.020

-0.015

-0.010

-0.005

0.000

0 200 400 600 800 1000 1200Time [min]

Optica

l densi

ty

No additive

Fluka

North Sea

C42

CHOL

2C4

Inhibitor A

CNA

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Critical Electric Field Emulsion Stability Cell

0

0.5

1

1.5

2

2.5

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7Electric field [kV/cm]

Cur

rent

[mA

]Crude oil 3, WC 30%

I

II I II

ECrit

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L1 MicellesE Hexagonal LCD Lamellar LC L2 Reversed micellesF? Reversed

hexagonal LC

[LC = Liquid Crystal]

70°C

Phase diagram ”water–palmetic acid-sodium palmetate”

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Emulsion Stability9.8 ml (55.7wt%) n-decane4.2 ml (32.7wt%) water1.5 g (11.7wt%) [ Palmetic acid D-phase + asphaltenes ]

70°C

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.2 0.4 0.6 0.8 1

Asphaltene to modified D-phase ratio

Ecr

itic

al [

kVcm

-1]

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Method

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

1100 1300 1500 1700 1900 2100

Wavelength [nm]

Optica

l D

ensi

ty

Naphthenic acids dissolved in water; pH=11.5

Solution of CaCl2 added

Formation and growth of calcium naphthenate particles monitored with near infrared spectroscopy

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Formation of Calcium Naphthenate

0

0.1

0.2

0.3

0.4

0.5

0 10 20 30 40 50

Time [min]

OD

0.5

[Ca2+]=2.30E-2M [1a1C4]=1.56E-3M

[Ca2+]=2.10E-2M [1a1C4]=1.56E-3M

[Ca2+]=1.80E-2M [1a1C4]=1.56E-3M

[Ca2+]=1.80E-2M [1a1C4]=1.25E-3M

VODrOD ∝⇒∝ 6

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Solubility Products

1.0E-15

1.0E-14

1.0E-13

1.0E-12

1.0E-11

1.0E-10

1.0E-09

1.0E-08

1.0E-07

1.0E-06

160 180 200 220 240 260 280 300MW [g/mol]

Ksp

[M

3]

C18

C18*C16

C7a1

C51

a1C4

a1C4C51

1a1C4

C7a1

1a1C4

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FLUCHA II - Deliverables

Academic3 PhD Thesis4 MSc Thesis27 Refereed articles3 miscellaneous articles (without refereeing)1 edited textbooks ~25 presentations at national/international meetings in addition to the biannual reference group meetings

IndustrialHP DVMHP Instrumentation

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The Life after FLUCHA II

Harald Kallevik Statoil

Øystein Sæther Det Norske Veritas

Gisle Øye Ugelstad Laboratory

Inge Harald Auflem Statoil

Narve Aske Esso Norge

Trond Erik Havre Champion Servo

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Spin-off

Joint Industrial Programme Particle-stabilized emulsions/Heavy crude oils, 2003-2006• ABB • ChevronTexaco • Norsk Hydro • Statoil• BP • Petrobras • TotalFinaElf

Ugelstad LaboratoryFounding Members:• ABB • Champion Servo • ChevronTexaco • IFE• PFI • Norsk Hydro • TotalFinaElf • Statoil

Affiliated Members:• Akzo Nobel • Borregaard Lignotech • ScanWafer • SINTEF Energy Research• KSV • Technical University of Denmark

FLUCHA IIThank you for your attention

Aknowledgements:

- All the post docs and PhD candidates involved in the programme- All industrial sponsors; ABB, Norsk Hydro, Statoil and TotalFinaElf- The Research Council of Norway (NFR)- Statoil R&D Centre in Trondheim for access to the high pressure

instrumentation

FLUCHA


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No Slide Title · ¾ Development of sub sea centrifugal separator system (Framo Purification) ......

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