case study of offshore oil field

1. Case Study by Cong-Yu Kea et. al.
A pilot study on large-scale microbial enhanced oil
recovery (MEOR) in Baolige Oilfield
Presented By
Aakash Jangid
Mumne Tamuk
Vishal Sahu
Submitted To
Dr. Akhil Agarawal
Department of Microbiology

2.  Oil is one the most widely utilized fuel
 However, 70% of the total petroleum hydrocarbon reserves are highly
viscous, making them incompatible with processing.
 Heating consumes a significant amount of energy, and diluents such as
water have some logistical challenges.
 Microbial-enhanced oil recovery (MEOR) is a promising tertiary recovery
process used to enhance oil extraction from subsurface strata.
 MEOR is a biotechnology that utilizes biogas, biosurfactants, and
biopolymers produced by, and degradation by subsurface fermentation
process of microorganisms for enhancing oil production from substratum
reservoir.
Introduction

3.  Baolige Oilfield in China
 Study was carried out in four fault-blocks (namely, B19, B38, B48
and B51)
 The surface area of the four fault-block is approximately 20.8 km2
with original oil in place of 35 × 106 tons.
 This investigation included results from the oilfield’s 78 injection
wells and 169 oil production wells.
Sampling site

4. Isolation and characterization of
bacterial strains
Batch growth conditions
Determination of surface tension and
interfacial tension
Emulsifying activity
The determination of bacterial density
Results
Microbial injection and performance
monitoring in field tests
Core flooding tests
Methodology

5. Isolation and characterization of bacterial strains
 120 mL medium was prepared consisted of (wt.%): glucose 2.0%,
peptone 0.05%, yeast extract 0.05%, urea 0.05%, ammonium sulphate
0.05%, potassium dihydrogen phosphate 0.5%, magnesium sulphate
0.02%, and sodium chloride 0.01%,
 20 ml brine + 10 g crude oil + 120 ml medium in 500ml conical flask
 Incubated at 50 degree celcius temperature for 5 days at 180 rpm
 0.1 mL culture broth spread on LB agar plates and incubated at 50 °C
for 48 hr
 The pure colonies were obtained by repetitive streaking on LB agar
medium
 Genomic dna isolation and pcr then sequencing to get phylogenic tree

6. Batch growth conditions
 Batch growth experiments were performed,
 100 mL LB medium at different temperatures (20–60 °C) at 200 rpm.
 48 hr incubation
 The optical density at 600 nm (OD600) was measured using the
spectrophotometer.
Determination of surface tension
and interfacial tension
 Surface tension was Measured using surface tensiometer DST-100 at 25°C
 Interfacial tension of crude oil/water systems were determined using a Spinning
Drop Video Tensiometer at 50°C

7. Emulsifying activity
 The emulsifying activity of fermentation broth was determined at 25 °C
 supernatant liquid + equal volumes of crude oil for 2 min,
 settled at room temperature for 24 h
 The emulsification index (E24) was calculated
The determination of bacterial
density
 The samples of from oil wells were diluted serially
 The bacterial density were then counted by the flat colony counting method Each
dilution was plated in on a nutrient agar plate
 Incubated at 37 °C for 24 h.
 The number of CFU was determined.

8. Core flooding tests
(i) Core tube filling and
water saturation
(ii) Oil saturation and
water flooding
(iii) Microbial flooding.

9. Microbial injection and performance
monitoring in field tests

10.  The injected bacteria solution was prepared by diluting the
fermentation liquid, which contained 8 log10 cfu/mL after 8 h
fermentation, with 1 (wt.)% nutrient solution.
 operation started on May 2012
 injected through the 78 injection wells over a period of 40–60 days
at a total volumetric flow rate of 2275 m3 /d
 controlled at 6.5 log10 cfu/mL and 1.0%
 followed by a typical water flooding process
 Repetation after bacterial concentration got decline

11. Characterisation of the activities of exogenous bacteria
Results

12. Interpretation: Suggested that the six strains isolated were
facultative anaerobes. Strain LC was found to be the most active at
almost all the temperature levels.

13. Interpretation : Six strains significantly reduced the interfacial tension
between oil and water (> 70%).
All of six strains and their mixtures reduced the viscosity ranging from 25%
to 44%. Both Mixed strains 1 & 2 showed higher reduction than individual
strains, with reductions of 38% and 56%, respectively

14. Optimisation of nutrient concentration
Interpretation : The bacterial density increased approximately linearly extending
from 7.9 to 8.9 log10 cfu/mL when the nutrient concentration changed from 0.1% to
1.0%. The gas production increased significantly as well with increase in nutrient
concentration, surface tension of the fermentation liquid decreased from 54.5 to
35.2 mN/m

15. Core flooding based MEOR
Interpretation : Average MEOR for the different cores was 8.625

16. Pilot study in the oilfield
Interpretation : 2.1×105 t of crude oil incretment
water cut reached 65.8% from 78.5%

17. Conclusion
 The mixtures of strains tested in laboratory core flooding based MEOR
confirmed their higher MEOR performance, i.e., MEOR levels of 9.1% and
13.2%, respectively, compared to that of any single strain ranging from
7.0% % to 8.7%.
 The pilot field study achieved a significant MEOR, that was 210,000 tons
of crude oil cumulatively produced over 43 months in 169 production
wells using the selected strain mixture under the laboratory based
optimal conditions.
 Can be potentially applied in other oilfields with similar geological and
physical conditions, for large-scale MEOR process design and operations.

18. Reference
All the data had been taken from the following research paper
Cong-Yu Ke, Guo-Min Lu, Yong-Bin Li, Wu-Juan Sun, Qun-Zheng Zhang, Xun-Li
Zhang, A pilot study on large-scale microbial enhanced oil recovery (MEOR) in
Baolige Oilfield, International Biodeterioration & Biodegradation,Volume
127,2018,Pages 247-253,ISSN 0964-8305,
https://doi.org/10.1016/j.ibiod.2017.12.009.
(https//www.sciencedirect.com/science/article/pii/S0964830517313100)