Monitoring Microorganisms in the Oilfield
13 Aug 2019
The Art of Sample Management
The monitoring of microorganisms in oil and gas process systems is paramount to understanding the threat from microbes and the efficacy of any microbiological controls in place (to learn more see our blog - Tiny but vicious - Microorganisms in the oilfield). Oil and gas installations are often situated in remote locations with limited access to onshore laboratories for sample processing. Sampling and testing for microbiology is time critical and therefore it is important to be able to carry out consistent sampling from various oil field systems to ensure that reliable results can be achieved.
Having robust sampling management will ensure that consistent results are obtained so, with this, system integrity and safe operation can be maintained.
It is therefore essential to consider all the options available in order to get samples to the laboratory without negatively impacting the analysis. This may include the careful planning of logistics, as well as developing onsite capabilities using various field-testing equipment to allow for rapid onsite analysis.
Confident decision-making on aspects such as health & safety or system integrity relies on quality data. The collection of reliable data depends on good sampling practice. Due to the nature of sampling in the oilfield environment, it can be challenging to ensure that samples for microbiological analysis are uncompromised.
The sampling methods deployed depend on the aim of the microbiological study, but it must always be undertaken in a consistent and repeatable manner. Proper, aseptic sampling techniques are extremely important in order to obtain accurate information, crucial to this is the sample point location and its condition.
The main factors to be considered are:
- Distance of sample point to location of interest (ideally 0.5 to 2.0m).
- Condition of sample point (e.g. any signs of corrosion which could falsify results).
- Sufficiently flushed/purged or perhaps continuously flowing (where appropriate).
- Well maintained and easy to access.
- Correctly identified (review drawings) to guarantee consistent sampling.
- Protecting the sampler from the sample and the sample from the sampler (gloves, wipes etc.).
- Is there an opportunity for sessile samples (surface samples)?
The above factors need to be evaluated in advance of the sample collection and any issues rectified in a timely manner.
Depending on monitoring requirements, samples may have to be preserved, stored anaerobically or refrigerated during transportation.
Due to these challenges any sampling regime should be coordinated in advance. Close relations with logistics, using tracking consignments and ensuring the laboratory is notified in advance will aid a smoother process. It may however not always be possible to achieve speedy transportation as required for microbiological samples due to the sampling sites or unforeseen problems. If this is the case, then other steps are required.
Sampling kits and analysis
An alternative option is to use in-field test kits. By sending the bacterial growth media bottles to the field in advance of the sampling it is possible to either fully or partially complete the microbial analysis onsite. These can be inoculated easily in the field and don't require a high level of technical competence, meaning the enumeration of the microorganism can start before the samples reach the laboratory (if they are being sent onshore) or incubated in the field. This will help to reduce the inaccuracy of aged and poorly collected/stored samples and improve data reliability.
These growth media test kits are available for targeted groups of concern within the various systems ranging from sulphate-reducing bacteria (SRB) to general heterotrophic bacteria (GHB) to nitrate-reducing bacteria (NRB) and many more.
On-site sampling and enumerations kits for various different types of microorganisms such as sulphate reducing prokaryotes (SRP) or general heterotrophic bacteria (GHB) and acid producing heterotrophic bacteria (APB) plus others.
When more advanced molecular methods are needed to fulfil the required monitoring of microbiological related issues, it is equally crucial to ensure samples are uncompromised during transportation. In these cases, easy to use preservation kits can be used, which will allow the samples to be sent from the field to the laboratory without compromising the quality of the samples ensuring reliable results are obtained.
Continuous awareness and control
Our team can advise on monitoring methods and programs as well as assisting with the collection and testing of oilfield samples. In order to fully understand the microbiological status of oilfield systems, it is important to have measures in place to allow for data to be monitored across all systems over time. This method of management can assist immeasurably in assessing the effectiveness of maintenance and treatment regimen. An example of this type of sample management is our in-house Bugtracker system; a unique online management tool providing planned monitoring, online result management and data trending versus the norm of periodic information from occasional sampling. In addition to the monitoring of planktonic microbiological numbers to gauge a threat to the system, it is also important to measure microbiological attachment to pipe surfaces (sessile) in order to highlight the potential risks, such as biofouling causing plugging or microbiologically influenced corrosion (MIC). Developed by Intertek, sidestream® biofilm monitors allow information on sessile microbiological populations to be gathered; a method that proves particularly valuable in (sea)water injection systems. Intertek can provide this monitoring system, along with all the consumables required to do the sampling.
Get in touch and learn more
Contact us to enquire about available products to help maintain microbiological control in your offshore installations.
Find out more about our upcoming Oilfield Microbiology training course.