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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Enhanced Oil Recovery
Unrecovered oil rangefrom 1-2 trillion barrels
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
World Average Oil Price
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Microbially Converting CO2 to CH4 in Depleted Reservoirs (from Maeda, 2009)
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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%
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Microbial Screening
Hydrocarbon Degrading Bacteria (HBD)
Microbes population>105 cells/ml (Bottle test)
Sulphate Reducing Bacteria (SRB) Not Detected (PCR)
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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)
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Bio-surfactant producing species: culture and assessment
Surface tension reduction: 24%
Emulsification improvement: 14%
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Bio-surfactant analysis
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Bio-surfactant analysis
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Bio-surfactant analysis
lipopeptide bio-surfactant-Amino Acid (Yellow)
MetaboliteStandar
d Sample
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Bio-surfactant analysis
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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).
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
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.
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Future work
In-situ experiments (Field Trials)
Further analysis of the metabolites
30th IEA Workshop and Symposium on EOR Sept. 21-23, 2009, Canberra, Australia
Thank You
Dr Keyu LiuResearch Team LeaderCSIRO [email protected]
Dr Xiaofang WeiResearch Institute of Petroleum Exploration and Development, [email protected]