Xiaofang Wei 1 Xingli Li 2 Keyu Liu 3 Yuehui She 4 Jing Wang 1 1 China University of Petroleum 2 GRI, Jiangsu Oilfield 3 CSIRO Petroleum 4 Yangtz University.

Xiaofang Wei1 Xingli Li2 Keyu Liu3 Yuehui She4 Jing Wang1

1 China University of Petroleum2 GRI, Jiangsu Oilfield

3 CSIRO Petroleum4 Yangtz University

MEOR Using Facultative Anaerobic Indigenous Consortia and Bio-surfactants

30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia

Acknowledgements

CSIRO WfO Flagship Biochemical Engineering Laboratory, CUP, Be

ijing Yijng Luo, Mang Lu, Peiwen Zheng, Zhongzhi Zhang

The Langfang Research Institute of Petroleum Exploration and Development, PetroChina

Core-flooding technical support


Presentation Outline

Background of the MEOR study Nutrient stimulation

MEOR screening and assessment Bacteria selection and metabolite analysis

Oil spreading and blood agar lysis methods Emulsification Interfacial tension (IFT)

Core flooding experiments Experimental procedure Results

Conclusions and Future work


Enhanced Oil Recovery

Unrecovered oil rangefrom 1-2 trillion barrels


World Average Oil Price


Oil Consumption (BP Statistical

Review, 2006)

Australia: 0.9 mbbl/day China: 7.0US: 20.6World: 82.5 US 1 cubic km oil / year

Australia China United States

1 kml l


EOR Portfolio NON-THERMAL

Miscible Chemical Imm. GasDrives Other

Flue Gas

CO2

Inert Gas

FOAM

MEOR

Surfactant

Polymer

Alkaline

Enriched Gas Drive

Slug Process

N2 Miscible

CO2 Miscible

Alcohol

ASP

Micellar

Emulsion

Vaporizing Gas Drive

MEOR is a rapidly growing EOR technique currently under laboratory research or field investigation


MEOR Mechanisms and Strategies

Acids, gas, solvents production Commonly made by carbohydrate fermentation Inject carbohydrates (molasses, etc.)

Selective plugging Create biofilms, cell mass and/or mineral precipitates Any nutrient could work: use nitrate as electron acceptor If reservoir has high divalent cation concentration, CO2

production may stimulate carbonate formation Hydrocarbon degradation

Inject electron acceptor and/or limiting nutrients (N, S, P, metals)

Biosurfactant production

Emulsifiers Periodic cycles of nutrient-excess and nutrient limitation


Microbially Converting CO2 to CH4 in Depleted Reservoirs (from Maeda, 2009)


Implementing MEOR (from McInerney,2009)

Not all reservoirs are candidates for MEOR Environmental conditions limit microbial

growth Recommendations:

Temperature: <80oC pH: 5-9 Salinity: <10% Depth: <2500 m API gravity: > 15o

Residual oil saturation: >25%


Background of the Reservoir Investigated

Characteristics of the Huatugou Oil Reservoir, Qinghai Oilfield, China

Production history: 1958-present EOR: Water-flooding Formation Water Salinity <2x104 ppm Reservoir P/T: 45℃ /22 MPa Fm water pH≤7 Low sulfate concentration


Microbial Screening

Hydrocarbon Degrading Bacteria (HBD)

Microbes population>105 cells/ml (Bottle test)

Sulphate Reducing Bacteria (SRB) Not Detected (PCR)


MEOR Screening

The Huatugou reservoir is a good candidate for MEOR

Relatively high microbe population: >105

(Cell counting) Low formation Water Salinity: <2x104 ppm Low reservoir T: 45℃ Suitable formation water chemistry: pH≤7 Low corrosion risk: no SRB detected


Nutrient Stimulation

Proper nutrient (Carbon Source: Reservoir oil)

Target facultative anaerobic indigenous consortia

Cell Population is up to 108 cells/ml Minor IFT and Viscosity changes Gas production observed


Bio-surfactant: species selection and identification

Two strains were selected and named as BIOS682-1 and BIOS682-2

Initial screening by the blood agar lysis method: positive

Screening using the oil spreading method Pure culture clear zone diameters : 4.5 cm and 4.8 cm Mixed culture clear zone diameter: 5.0 cm

Species identification using 16s RNA BIOS682-1: Brevibacillus agri (99% similarity) BIOS682-2: Brevibacillus levicki (95%, a possible new species)


Bio-surfactants: species culture and assessment

Mixed culture of two selected strains 5ml oil/50ml-medium cultured for 3 weeks at 45℃ Under facultative anaerobic condition (headspace filled with

N2) Oil-water separation

Oil was centrifuged at 5000 rpm for 10 min at room temperature Oil was extracted by using CCl4 (oil in water)

The surface tension Equipment: Contact Angle analyzer (DCA322)

Emulsification (Culture and reservoir oil 1:1 v/v) Emulsification maintained for 100 hrs after 15 min u/s bathing The ratio between emulsified oil and water measured


Bio-surfactant producing species: culture and assessment

Surface tension reduction: 24%

Emulsification improvement: 14%


Bio-surfactant analysis

Bio-surfactant of lipopeptide extraction protocol

centrifuged twice at 4°C @10,000 rpm for 20 min the supernatant was mixed with 6mol HCL @ pH=2 (24 hrs 4°C) The floccules were collected using centrifuge (4°C @10,000 rpm

for 20 min) The settlings were washed using acidic solution (pH=2), then dis

solved in weak alkali solution (pH=8) Extracted with DCM and methanol solution (v/v 3:1) Dried under vacuum at low temperature The primary products were dissolved in alkali solution (pH=8) The extraction was then dried under vacuum



Thin Layer Chromatography (TLC) Initial screening

Liquid Chromatography-Mass Spectrometry (LC-MS). The purified product was hydrolyzed for 14 hrs at

110 with 6N HCl in N2 chamber℃ Equipment: Agilent 1100 system

-Amino acid



Thin Layer Chromatography (TLC)

lipopeptide bio-surfactant (Pink): Qualitative analysis

Solution used is a mixture of n-butanol/alcohol/water(4:1:1)

Metabolite

Standard

Sample



lipopeptide bio-surfactant-Amino Acid (Yellow)

MetaboliteStandar

d Sample



Amino Acid contents in the metabolites

AA Content ( wt%) AA Content (Wt%)

Asp 0.163988 Val 0.092605 Glu 0.106928 Ile 0.073791 Ser 0.075391 Leu 0.086862 Thr 0.123527 Phe 0.036458 Arg 0.089804 Cys 0.038439 Pro 0.014291 Lys 0.012635 Ala 0.085284

Total Content (Wt%) 1.000003


4. Core-flooding Experiment

Core-flooding experiment design: T/P: 45℃/22 MPa Water-cut: 70% Incubation time: 3 days Injected volume: 2.5 PV of Cultured solution

Oil

Water

Microbes

Collector Core Holder


Synthetic Core Plugs for Core Flooding Experiments

Material: oil zone sandstone recovered from the producing well, DisintegratedCleaned Sieved to 30, 80 and 120 meshes, respectively

A two-layer heterogeneous sand packs with different permeabilities was constructed Layer 1: 2:2:1 mix of 30-80, 80-120 and >120 mes

hes Layer 2: 1:1 mix of 30-80 and 80-120 meshes


Core-flooding Experiment

η ＝ (B － A) － C B: final oil recovery % A: oil recovery % from 0.5 pv nutrient solution injection C: oil recovery % (Blank) from 0.5 pv synthetic formatio

n water injection η: incremental oil recovery (%)

No. Length (mm) Diameter (mm) Permeability(mD) Porosity (%)

D14 70.4 25.1 299.47 32.60

D20 73.5 25.1 301.29 32.39

Core plug properties


Results of core-flooding

No. Core

No. Culture Bacteria

Inoculums

Volume

(pv)

Injected

Volume

(pv)

Water-flooding

Recovery

rate%

MEOR

rate%

Incremental

Rate

(%)

1 D140 N/A N/A － 3.0FW 51.97

2 D200 N/A N/A － 3.0FW 53.46

3 D141 N/A A 0.5 2.5 FW 51.20 0

4 D201 N/A A 0.5 2.5FW 55.73 2.27

5 D142 N/A N/A － 3.0FW 54.62

6 D202 N/A N/A － 3.0FW 50.77

7 D143 A A 0.5 2.5Culture 64.51 11.05

8 D203 A A 0.5 2.5culture 62.72 9.26


Conclusions

The Huatugou reservoir in the Qinghai Oilfield is a good candidate for MEOR

The indigenous facultative anaerobic flora from the reservoir was stimulated by adding proper nutrients to promote their activities

The two indigenous aerobic species selected can co-metabolize well and produced more bio-surfactant than from a single strain in the reservoir

The two species identified by 16s RNA are Brevibacillus agri (BIOS682-1); and a possible new species in genus of Bacillus brevis (BIOS682-2).


Conclusions

The metabolites of BIOS682 contain low concentration of amino acids

An 11% incremental recovery was achieved using a combined microbial and biosurfactant solution injection.

The facultative anaerobic flora play an important role in peeling the oil form rock or breaking down the large oil drops.

The use of cultured solution with bio-surfactant and other metabolites is much more effective than the use of the indigenous microbes alone in recovering residual oil.


Future work

In-situ experiments (Field Trials)

Further analysis of the metabolites


Thank You

Dr Keyu LiuResearch Team LeaderCSIRO [email protected]

Dr Xiaofang WeiResearch Institute of Petroleum Exploration and Development, [email protected]

Xiaofang Wei 1 Xingli Li 2 Keyu Liu 3 Yuehui She 4 Jing Wang 1 1 China University of Petroleum 2 GRI, Jiangsu Oilfield 3 CSIRO Petroleum 4 Yangtz University.

Documents

huatugou oil reservoir

nutrient limitationmicrobially

metabolite analysis

electron acceptorif

laboratory research

co2 production

species selection

bacteria srb