The reliable determination of water content in oil and gas (also known as water cut, BSW, or BS&W measurement) has posed a consistent and lasting problem for the oil and gas industry. In this article we will review the benefits of on-line water cut, vs a traditional, manual sampling strategy.
The most obvious of these, and often the most attractive to potential implementors of on-line watercut measurement is the simple advantage of decreasing labour-hours. Traditionally, every time a measurement was made, a sample from the pipeline had to be pulled manually and tested for water content via some form of measurement like a centrifuge or a titration device. Depending on the needs of the producer and the specifics of the production environment this process might be done many times per day, very quickly resulting in elevated labour costs for the producer.
Alternatively, an on-line watercut meter supplies a continuous, real-time readout from the pipeline, which means that the extent of time and effort required to get an accurate measurement is limited to simply checking the meter’s data.
The continuous measurement provided by an on-line water cut meter - as opposed to a one-time grab sample - offers other advantages as well. The foremost of these is accuracy. Due to a number of different factors, when pulling a sample from any oil production environment there is always a risk that the sample won’t be an accurate representation of the hydrocarbon in question. Maybe the water and oil aren’t mixing properly in the pipeline. Maybe a discrepancy in production resulted in a large bubble of water flowing past the sample point at the moment of measurement.
There are countless scenarios that could result in a non-representative sample, but an on-line meter mitigates these problems by measuring continuously - presenting an average over time, rather than a single data point. This is analogous to a shipment of lumber being sent out from a sawmill. Using the manual sampling strategy above, the inspector has to look at a single 2x4 to determine the quality of the entire shipment. Maybe they check every second piece of lumber, or maybe they check only one per batch, the fact remains that there is a leap of faith being made that the 2x4 you check is representative of the rest of the shipment. An on-line meter is different in that every piece of lumber is examined automatically as its loaded onto the truck.
A key downside to manual sampling is human error. As is the case with any non-automated task, there is always room for mistakes, as well as gaps in knowledge and procedure protocols. One of our technicians was once on site at a production facility where he was told that a Delta C unit wasn’t working properly, and was consistently displaying a different water content than the value being determined by the manual test being done with a centrifuge.
Upon further investigation, it was revealed that the technicians on the day shift had a completely different method for performing the centrifuge test than those on the night shift, resulting in a drastically different measurement every time. This is an extreme example, but it demonstrates that mistakes happen, and when dealing with manual tasks some degree of discrepancy is inevitable. The Delta C watercut meter, once calibrated, operates autonomously, effectively minimizing this problem.
All of these factors regarding on-line watercut meters result in a more consistent, stable, and accurate measurement. Which can be important for as many reasons as there are different applications.
Maintaining a strong handle on the amount of water present in hydrocarbons is essential on both ends of the custody transfer process - both for the customer, to ensure that they get exactly what they’re paying for as well as to the vendor, to leverage standards and regulations to ensure a maximization of profits.
Water measurement has powerful environmental implications as well, with a large percentage of oil spills being caused by corrosion in pipelines and shipping vessels. This corrosion is a direct result of unaccounted for water in the production process, so whether it is for economic, environmental, or logistical reasons, the proper management of water in the oil and gas industry is absolutely imperative.
In order for water to be managed it has to be measured, which is why, when dealing with the inevitable issue of measuring water in oil and gas, on-line measurement offers the most reliable, consistent,and cost-effective solution.
Delta C is a specialized water cut meter manufacturer based in Western Canada. They develop advanced capacitance technology for water cut metering and build field-ready water cut meters and sampling systems. Delta C’s expertise on watercut measurement in the oil and gas industry spans over 30 years, with a specialization in low PPM measurements.