laboratory core flooding experiments using bio-surfactant and molasses: implications for microbial...

Laboratory core flooding experiments using Bio-surfactant and molasses: Implications for Microbial EOR

Mohammad Bahar, Keyu Liu, Abdul Rashid ,Xiaofang Wei, Tara Sutherland, Xiaoyi Wang, Manzur Ahmed, Phil Hendry, Dongmei Li, Se Gong, Herbert Volk, S. Razak, Wan Ata, A Azhan,M.RizalCSIRO Wealth from Ocean Flagshipand Petronas Research

30th IEA Annual Workshop and symposium on EOR -Canberra

Outline

• Background

• Objectives

• Materials and methods

• Results and discussion

• Conclusions


Oil Recovery Mechanisms

CONVENTIONAL RECOVERY

EOR

TERTIARYRECOVERYTERTIARY

RECOVERY

SECONDARYRECOVERY

SECONDARYRECOVERY

PRIMARYRECOVERYPRIMARY

RECOVERY NaturalFlow

NaturalFlow

Artificial Lift(Pump, Gas Lift, etc.)

Artificial Lift(Pump, Gas Lift, etc.)

WaterfloodWaterflood Pressure Maintenance(Water, Gas Reinjection)Pressure Maintenance

(Water, Gas Reinjection)

ThermalThermal SolventSolvent ChemicalChemical MEORMEOR

Adapted from the Oil & Gas Journal, Apr 23, 1990

OtherOther


EOR vs. Permeability

HydrocarbonMiscible

Nitrogen andFlue Gas

CO2

MiscibleSurfactantPolymer

Polymer

Alkaline

Fireflood

Steam Drive

EOR Method

Not critical if uniform

Not critical if uniform

High enough for good injection

Permeability (md)10 100 1,000

Good Possible Fair Difficult Not Feasible

MEOR

Dr. Larry Lake, Oilfield Review (Jan. 1992)


Oil Gravity vs. EOR Methods

0 10 20 30 40 50 60Oil Gravity oAPI

N2 & Flue GasN2 & Flue Gas

HydrocarbonHydrocarbon

CO2 - MiscibleCO2 - Miscible

Immiscible GasImmiscible Gas

Alkaline/Surfactant/PolymerAlkaline/Surfactant/Polymer

Polymer FloodingPolymer Flooding

Gel TreatmentsGel Treatments

MEORMEOR

Steam FloodingSteam Flooding

MiningMining

(Modified from J.J. Taber, F.D. Martin & R.S. Seright, 1997)


• Microbes can be introduced into oil reservoirs, and/or indigenous microbes can be stimulated with nutrients.

Potentials:• Changing fluid properties such as Density, Viscosity,

composition and IFT• Changing the rock properties such as wettability ,

permeability and relative permeability• Changing conditions of system (pressurize,

What is MEOR and its Potential on EOR?


Background: Can MEOR be a successful method for EOR?

With biosurfactant (above CMC)

S.M. Farouq Ali- University of Calgary-2003

Initial


Overview of CSIRO’s MEOR project

MicrobiologyMicrobial physiologyMicrobial metabolismsIsolation and culture

before and after Microorganisms treatmentsMeasuring fluid physical properties, such as density, viscosity and IFTMeasuring rock physical properties K, Krw, Kro, Measuring EOR

Organic GeochemistryDevelop analytical protocolidentify/quantify metabolites

ModellingAnalyse/verify experimental resultsBuild predictive model for MEOR Build reservoir model for field trial


• Monitor changes in oil and water physical properties after culture experiments

• Detect and quantify various by-products

- Gases- Bio-surfactants- Acids- Co-biosurfactants

- Polymer - Oil Degradation

• Select suitable nutrients to stimulate microbial growth and production of metabolites leading to MEOR

• Undertake core flooding experiments

Objectives


• Reservoir fluids from Off-shore Malaysian oil-field

- Depth: ~ 720 m

- Temperature: 50ºC

- Salinity: 2.3 %

- Mature, high water cut

- Reservoir Pressure: 940 Psia

Material and methods


Experiment : Core Flooding Setup


Experimental sequences

Oil

Water

Molasses

Water

Water

Measuring volume ofWater

OilGas

Core Holder


Effects of biosurfactant on water densitiesEffect of Bio-surfactant concentration on density of Bokor formation water

for Well 104 LS

0.99

0.995

1

1.005

1.01

1.015

1.02

0 10 20 30 40 50 60 70

Temperature (oC)

Den

sity

(g

m/c

c)

Base Case

Bio - Surfactant - 40 ppm

Bio-surfactant - 150 ppm

No effects


Effects of bio-surfactant on viscosity of Bokor formation water (104LS)

Effect of Bio-surfactant on viscosity of Bokor formation water

0.4

0.5

0.6

0.7

0.8

0.9

1

1.1

1.2

0 10 20 30 40 50 60 70

Temperature (oC)

Vis

cosi

ty (

cp)

No - Biosurfactant



H2O viscosity increases with BS concentrations


Effect of bio-surfactant (Surfactin) on IFT (104LS) at 50 °C

0

2

4

6

8

10

12

14

0 200 400 600 800 1000

Pressure (psi)

IFT

(d

ynes

/cm

)

No - Surfactant


Bio-Surfactant - 150 ppm 940psi


MEOR core flooding results

0.0

1.0

2.0

3.0

4.0

5.0

0.0 0.2 0.4 0.6 0.8 1.0 1.2Volume of Water Injected (pv)

% E

OR

4.1% MEOR

Sor=25.6%

Swir=14%; Primary oil recovery: 74.4%Soir=25.6%; incremental EOR: 4.1%


Which phenomena is more reliable?

Injecting Molasses

Increasing production 4%

?


What types of by-products were produced?

• Gases• Alcohols• Acids• Bio-surfactants• Micro-emulsion


Gases and swelling

• A large reduction in oil viscosity and small increase in water viscosity

The Young – Laplace Equation predicts an inverse relation of pressure drop with Swelling of Oil

21 R

1

R

1γΔP


Distribution of microbial gases

CO2 CH4 C2H6 C3H8 C4H10

Con

cent

ratio

n (p

pm)

• Stimulation by carbohydrates produced substantial amounts of CO2 and CH4 gases

• C2+ gases desorbed from oil?

0E+0

2E+4

4E+4

6E+4

8E+4

1E+5

1E+5

Molasses only Microbes with molasses Microbes without molasses


Microbial gases

Duration of culture (days)(Control)

2 2 4 7 9 11 16 18 21 310.0E+0

2.0E+4

4.0E+4

6.0E+4

8.0E+4

1.0E+5

CO2

CH4

Con

cent

ratio

n (p

pm)

• Very high amounts of CO2 and CH4 gases produced

• CO2 generation continued to increase until after 9 days

• CH4 generation continued to increase until after 11 days


Alcohols production

• Variable amounts of alcohols produced

• Generation continued to increase until after 16 days of culture

• A second cycle of moderate generation initiated after 18 days

ng/m

L of

wat

er

Duration of culture (days)

2(Control)

2 4 7 229 11 14 16 18 20

0

100

200

300

1-Butanol, 2- + 3-methyl

0

20

40

60

1-Pentanol

0

100

200

300

1-Propanol


0

200

400

600

Acetic acid

0

50

100

150

Propanoic acid

0

25

50

75

100

Butanoic acid, 2-methyl

ng/m

L of

wat

er

Duration of culture (days)

2(Control)

2 4 7 229 11 14 16 18 20

Acids production

• Variable amounts of acids produced

• Consistent with gases and alcohols, generation continued to increase until after 16 days of culture

• A second cycle of intense generation initiated after 18 days


Micro-emulsion experiment using co-surfactant


Low Concentration - Surfactant Adsorption

High Concentration - Self-Assembled Surface Aggregates

Moderate Concentration - Hemimicelle Formation

Surfactants at the Solid-Liquid Interface

Clay

Clay

ClayClay


Water dropletsOil rim

surfactantsSolubility of alcohol in micelles


w/o emulsion

Micelles

Bio-surfactants


Water droplets

Oil


Water droplets with oil rimOil droplets

in water droplets

5 m


Interfacial tension and capillary pressure

• Surfactant Reduce interfacial tension in small pore and reduce the capillary pressure in the system

R1=2

Y=2

P=(2*2)/2=2

R2=1

Y=1

P=(2*1)/1=2


Conclusions

• Microorganisms can change the threshold point of residual oil in reservoirs and to enhance oil recovery:

• Core flooding using 40 ppm surfactin enable 3% EOR• Core flooding using 0.875% molasses enable 4.1% EOR

• MEOR uses a combination of mechanisms to recover residual oils in reservoirs including

• Gas production can reduce oil viscosity• Biosurfactant production can reduce IFT • Solvents and biosurfactants can promote micro or nano emulsion• Produced biosurfactants may change the wettability of clay rocks

• MEOR could become a low cost environmental friendly EOR method in the future but more research is required

Contact UsPhone: 1300 363 400 or +61 3 9545 2176

Email: [email protected] Web: www.csiro.au

Thank you

Wealth from Ocean FlagshipMohammad BaharReservoir Engineer

Phone: 08 64368954Email: [email protected]: www.csiro.au/science/MEOR.html

laboratory core flooding experiments using bio-surfactant and molasses: implications for microbial...

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