MIC in Long Oil Pipelines: Diagnosis, Treatment and Monitoring

ISMOS 3Calgary, Alberta

June 14, 2011

Gary Jenneman, Jennifer Harris and Robert Webb

300 km 70 km 7 km 5 km

Organic AcidsAceticPropionicButyric

Inorganic SolidsBaSO4

FeS

ProducedWater

Pitting in the first 70 Km70 km 7 km 5 km

Pitting

Oil Pipeline

Terminal

GasesCO2

H2S

Bacteria

10°C

Production Platform

Problem

Is it MIC?

• Biological– Are environmental conditions conducive to microbial growth and

metabolism?

• Chemical– Are environmental conditions such that abiotic mechanism could

explain observed rates?

• Metallurgical– Are corrosion products and features characteristic of MIC present?

• Operational– Have changes occurred that may enhance the activity of

microorganisms?

MIC does not produce any unique type of corrosion and there are no definitive tests or specific observations that can be used to detect MIC.

B. J. Little

Temperature Gradient

ProductionPlatform

Oil Terminal

Zone of active pitting

Distance - Km

Analyte Units 1/27/05 2/9/05 2/24/05 3/14/05

pH ---- 5.9 6.2 5.5 6.0

Susp. Solids > 0.45 μ mg/l 340 490 300 161

Total Organic Carbon mg/l 830 852 662 1370

Total Sulfide mg/l 0.5 0.7 0.7 <1

Soluble Fe mg/l 30 26 43 28

Phosphorus as PO4 mg/l 6.1 18.1 7.3 5.5

Calcium mg/l 710 860 5660 1190

Potassium mg/l 340 260 410 390

Magnesium mg/l 160 250 400 530

Sodium mg/l 9100 13200 16200 13900

Strontium mg/l 80 120 160 120

Ammonium mg/l 27 42 51 48.4

Chloride mg/l 14200 22000 29800 26400

Sulfate mg/l 90 155 280 610

Methanol mg/l 10 30 80 1010

Ethanol mg/l 15 5 49 145

Acetaldehyde mg/l 1 7 22 140

Acetic Acid mg/l 350 760 700 630

Propionic Acid mg/l 145 240 130 40

Butyric Acid mg/l 15 11 14 9

• Chemical analyses of water from pig runs.

Disc Pig

0

20

40

60

80

100

120

140

Inte

ns

ity (

cp

s)

10 20 30 40 50 60 70 802theta (degrees)

GG-39048-70-2 |ÒÖRef ined Pattern

BackgroundPtn: Mullite (3-2)

Ptn: Cristobalite - alphaPtn: Quartz

Ptn: Ba75,Sr25 SulfatePtn: Paraf f in

Ptn: Iron - alphaPtn: Na/Ca Plagioclase

Ptn: HalitePtn: Corundum

Ptn: HematitePtn: Quartz

Ptn: CalcitePtn: Magnetite

Rietveld Refinement Results-209334Mullite – Al6Si2O13 19 wt %Corundum – Al2O3 1 wt %Cristobalite – SiO2 4 wt %Quartz – SiO2 11 wt %Na/Ca Plagioclase 11 wt %Calcite – CaCO3 7 wt %Halite – NaCl 4 wt %Magnetite – Fe3O4 1 wt %Iron – Fe 2 wt %(Ba0.75,Sr0.25)SO4 40 wt %

NOTE: The solids appear to be a mixture of high-

strength proppant, formation fines, iron oxide scale.

Also, the Barium Strontium Sulfate could be

NORM scale, not the drilling mud additive Barite.

XRD of Pig Sludge Solids

0.00E+00

1.00E+07

2.00E+07

3.00E+07

4.00E+07

5.00E+07

6.00E+07

Cells/mL

Mar-05

Apr-05

May-05

Jun-05

Jul-05

Aug-05

Sep-05

Oct-05

Nov-05

Live/Dead Bacteria Counts in Pig Water by Microscopy

Live

Dead

Total

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

1.00E+05

MPN/mL

Mar-05

Apr-05

May-05

Jun-05

Jul-05

Aug-05

Sep-05

Oct-05

Nov-05

Bacteria in Pig Water by Culture Media (30C)

GAB

GAnB

SRB/lac

SRB/lac

SRB/FA1.00E+00

1.00E+01

MPN/mL

Mar-05

Apr-05

May-05

Jun-05

Jul-05

Aug-05

Sep-05

Oct-05

Nov-05

Bacteria in Pig Water by Culture Media (60C)

GAB

GAnB

SRB/lac

SRB/lac

SRB/FA

Bacteria Analyses in PL Pig Water

1.00E+00

1.00E+01

1.00E+02

1.00E+03

1.00E+04

MPN/g

Mar-05

Apr-05

May-05

Jun-05

Jul-05

Aug-05

Sep-05

Oct-05

Nov-05

Bacteria in Pig Sludge by Culture Media (30C)

GAB

GAnB

SRB/lac

SRB/lac

SRB/FA1.00E+00

1.00E+01

1.00E+02

MPN/g

Mar-05

Apr-05

May-05

Jun-05

Jul-05

Aug-05

Sep-05

Oct-05

Nov-05

Bacteria in Pig Sludge by Culture Media (60C)

GAB

GAnB

SRB/lac

SRB/lac

SRB/FA

1.00E+001.00E+011.00E+021.00E+031.00E+041.00E+051.00E+061.00E+071.00E+08

Cells/g

Mar-05 Apr-05 May-05

Bacteria in Pig Sludge by Phospholipid Fatty Acid

PLFA

1.00E+04

1.00E+05

1.00E+06

1.00E+07

1.00E+08

1.00E+09

Cells/g

Mar-05

May-05

Jul-05

Sep-05

Nov-05

Total Bacteria in Pig Sludge by qPCR

Eubacteria

IRB/SRB

bssA

Cat

Bacteria Analysis in Pig Sludge

Community Structure of PL Pig Sludge by PLFA Analyses

DateBiomass Community Structure (% total PLFA)

Cells/g FirmicutesAnaerobicGram (–)(TerBrSats)

Proteo-Bacteria(Monos)

AnaerobicMetal Reducers(BrMonos)

SRB/Actino-mycetes(MidBrSats)

General(Nsats)

Eukaryotes(Polyenoics)

3-14 7.73x107 39.1 9.7 1.1 1.1 49.0 0.0

5-09 2.59x106 46.4 7.5 0.0 0.0 46.1 0.0

March 14Sludge sample

Sequence results from bands excised from Figure 5 (March 14). Similarity indices above .900 are considered excellent, .700-.800 are good, and below .600 are considered to be unique sequences.

DGGE of PL Pig Sludge – Mar. 14

May 9Sludge sample

Sequence results from bands excised from Figure 5 (May 9). Similarity indices above .900 are considered excellent, .700-.800 are good, and below .600 are considered to be unique sequences.

DGGE of PL Pig Sludge – May 9

Biometabolite Analysis

• 23 putative hydrocarbon biometabolites were identified.

• Biometabolites of the biodegradation of aromatic HC were especially prevalent (5 to 7 µM).

• Biometabolites for the anaerobic biodegradation of aromatic HC (e.g, BTEX) were also detectable.

• Evidence for anaerobic biodegradation of n-alkanes (e.g., fumarate addition products) were only weakly detectable.

Operational Considerations

• Soured reservoir• History of MIC in upstream pipelines• Velocity - < 1.5 m/s• Presence of solids – scale, suspended solids• Water slugging• Oxygen• 3rd party lines

Is it MIC?

• Microbiological, chemical, metallurgical and operational evidence suggest that MIC is a likely mechanism.

Biocide/Mitigation Program

0

0.5

1

1.5

2

2.5

3

Glu

tara

ldeh

yde

(mg/

L)Glutaraldehyde residuals in pig

envelope water by GC-ECD.

Effect of pH and Brine Composition on Stability of 550 ppm Glutaraldehyde at 60C.

0.0%

10.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

100.0%

0 10 20 30 40 50 60

Time (hours)

% G

luta

rald

hyde

Rem

aini

ng

pH 6 - PBS

pH 7 - PBS

pH 8 - PBS

pH 6 -PW

pH 7 - PW

pH 8 - PW

Synthetic seawater was amended with:

Water type [glut]0, ppm T (C) % degrad, 24h

Field sample 1000 60 90

Field sample 300 60 85

Synthetic PW 1000 50 80

from McGinley et al., SPE OFC Symposium (2011)

Screening of Components

Water type NH4+ % degrad

Synthetic PW None 10

Synthetic PW 10 ppm 40

Synthetic PW 100 ppm 81

Modified Synthetic PW, 55 ° C, 24h

from McGinley et al., SPE OFC Symposium (2011)

Screening of Components

* Complete Synthetic PW has 100 ppm ammonium

Sample [NH4+] other % degrad

1,2,3 -- 0, 0, 8

4 100 ppm 20

5 -- 595 ppm EG 0

6 100 ppm 595 ppm EG 30

7 -- 390 ppm AcOH 12

8 100 ppm 390 ppm AcOH 45

9 -- 49 ppm boron 14

Amended Instant Ocean, 55 °C, 24 hrs

from McGinley et al., SPE OFC Symposium (2011)

Successful Mitigation Measures

• Increase CO2 inhibitor concentration• Remove sources of oxygen ingress.• Increase continuous biocide concentration (GA/QAC)• Batch biocide and batch corrosion inhibitor every 5th week

following aggressive pit cleaning tool.• Scale inhibitor injection

Acknowledgments

• The authors would like to thank ConocoPhillips for the opportunity to present this work.