TWI Gulf was engaged to identify the corrosive bacteria contaminated equipment across various assets and develop a criterion of probability (versus acceptable bacteria range for treated and untreated systems) and bio-mapping for each field, including recommendations for mitigating microbial-induced corrosion issues.
The number of Loss of Prime Containment (LOPC) incidents due to Microbial Induced Corrosion (MIC) is increasing predominantly in oil and gas assets. The source of corrosive bacteria is either produced fluids or re-injection fluids or supply/injection/wash water. To develop mitigation measures for the bacteria corrosion, it is necessary to identify bacteria (SRA/Methanogens/SRB/IRB/APB) contaminated equipment by conducting bacteria testing followed by bio-mapping of corrosive bacteria-contaminated areas. This testing will be conducted at all assets using external microbiology laboratory services.
The samples to be tested are mainly water samples and/or debris samples collected from the following locations:
a) Producing oil well heads, oil flowlines, oil pipelines, main oil lines, storage tanks
b) Supply, injection water clusters.
c) Produced Water Re-Injection (PWRI) lines
d) Service Water/Firewater
Quick Bacteria Testing
The quick corrosive bacteria testing is done using second generation ATP monitoring technologies for detection of all actively growing organisms in the system, using portable units “Luminultra” ATP monitoring kits at each asset.
The performance of the quick bacteria testing method adopted will be counter-verified through qPCR testing.
The quick testing technology (ATP technique) by counter-testing the same samples using qPCR technique for one sample each from oil system and water system prior to completing bulk testing at each asset.
Bacteria DNA (qPCR) Testing
The Quantitative Polymerase Chain Reaction (qPCR) testing will be collected at various fields and tested using Luminultra Genecount machine targeting microbes such as SRB/SRA/Methonogens/IRB/APB etc... (in line with NACE TM 0212 standard).
Data Analysis and Root Cause Analysis
TWI analyses the bacteria test data, identifies the source of corrosive bacteria; the type of major bacteria (Planktonic or Sessile); bacteria family species and its related impact on different metallic/non-metallic material of construction; root cause(s); analyses the severity in terms of Microbial Induced Corrosion (MIC) and recommends remedial measures to control the MIC issues at each asset.
Besides the Sulphate Reducing Bacteria also other Microbes play a role in MIC:
> Highly complex microbial/chemical process
> Key Role for Sulfate Reducing Prokaryotes, but also others:
>>Methanogens
>> Iron reducing/oxidizing bacteria
>> Acid Producing Bacteria
> Enhanced pitted corrosion rates at spots with biofilms & elemental sulfur
> Pitted corrosion difficult to predict
> Biofilm communities more biocide resistant
Mitigate by:
> Biofilm development mitigation by biocide
> Cathodic protection
> Regular pigging
> Inert lining and SS-piping
Reference and excerpt: De Bruijn, J. (2018, April). Reservoir Souring and MIC Measuring & Mitigating [PowerPoint]. Slide 13
![De Bruijn, J. (2018, April). Reservoir Souring and MIC Measuring & Mitigating [PowerPoint]. Slide 13]()
To learn more about how TWI Gulf can support, visit: https://www.twi-global.com/locations/middle-east/technical-services or contact us at Enquiries@twime.com.