Two Tests You Need to Evaluate Paraffin Inhibitor Products:
New test methods enable customers to better predict paraffin inhibition product field performance
Published: May 2019
Author: Kelly Chichak
SI Group’s new test methods enable customers to better predict paraffin inhibition product field performance
As the outdoor temperatures in the Northern Hemisphere are increasing, some of us are thinking of summer but, many of us have already started planning for winter. The seasonal cycle has significant impact on oil producers and affect a broad range of chemical packages deployed during oil production. Typically, spring and summer are the months that winterized products are replaced with summer blends. But what if this wasn’t necessary, what if there was a product that could be used year round? Utilizing new test methods may help you find that product.
Paraffin Inhibitors Often Behave Like Candles
For good reason, paraffin inhibitor products behave like candles. When the temperature is hot a candle melts and flows, and, when the temperature is cold, well, they are candles. A final formulated paraffin inhibitor also flows when hot but the flow properties can drastically change when temperatures dip below freezing. Paraffin inhibitor formulations can be extremely sensitive to temperature swings and are one of the more challenging chemical treatment products to manage. SI Group has been developing new technologies focused on solving these low-temperature stability issues.
Questions to Ask When Considering Product Field Performance
An unanticipated change in flow of a paraffin inhibitor will compromise the application and performance of the product. The last thing that anyone wants to receive is that frantic call related to stability issues of a product that is currently in use in the field. But, let’s consider some questions to prevent future product failures:
- Were the right performance tests run?
- How should these products be tested for stability?
- How does stability evaluated in the lab translate to expected field performance?
- What’s missing, are there other tests that should be run to evaluate low-temperature stability?
The goal is ensuring that when paraffin products are stored undisturbed and are cycled under ambient conditions that range from 120°F to -40°F, they don’t turn into candles.
Getting Under the Surface with New Test Methods
SI Group recently developed and launched a new line of paraffin inhibitor products for use in low-temperature environments. When evaluating existing and new paraffin technologies, we found that the current test methods were falling short when it came to understanding how a product’s fluid properties change with temperature. The most relevant test would be to store a sample at the oilfield production site in the environment that it is used. But, that’s very difficult to arrange and often not feasible, as an alternative, we developed a benchtop test that monitors the change in flow behavior of a sample when the temperature is changed. For good reason, this test sounds a lot like a standard test method, ASTM D97, which is used to measure the pour point of fuel and lubrication products. The pour point is simply defined as the temperature at which a sample stops flowing but this pour point test only looks at the top surface of the sample and disregards what is happening under the surface.
Changing Perspectives to See the Fault in Traditional Test Methods
Like most pour point tests, only one temperature sweep is used to evaluate the flow properties of the sample and the test is considered completed once the sample freezes. For candles, if you looked at the top of a burning one you would assume that the candle is liquid but, if you simultaneously looked at the top, bottom, and side your opinion might change. Because of this, only a snapshot of the top portion of a product is evaluated with the D97 method and flow behavior can be incorrectly assessed. A different perspective will invariably provide different Under real world conditions a sample would be cycled through a series of daytime highs and nighttime lows. This was the type of test that was missing to effectively assess the static thermal cycling (STC) properties of paraffin inhibitors, a test that evaluates the bulk flow behavior as temperature is cycled. To develop this missing test, rheology was identified as a suitable platform, which is best described as a scientific discipline that studies how materials deform and flow.
Uncovering New Methods Using Rheology
Rheology is used across numerous industries to characterize a product’s flow properties, for example, rheology is used to assess the characteristics of ketchup, when standing undisturbed it must not flow but it must when you tap the bottle. This property of behaving like a solid under no stress but as liquid under stress is a key branch of rheology that we leveraged to develop our flow behavior tests.
Daytime Highs & Nighttime Lows Through Static Thermal Cycling (STC)
Our first test evaluates the pour point of a sample, and we describe it as the no-flow-point (NFP). The sample is sandwiched in between two plates. One plate oscillates while the other is fixed and the advanced electronics of the instrument can sense the state of the sample, either a liquid or a solid. In this test, the sample is exposed to an extremely small amount of stress to not disrupt the fluid’s three-dimensional structure but, enough to sense it’s state while the sample is cooled. By evaluating the temperature at which the sample transitions from a liquid to a solid, we measure the no-flow-point. As mentioned earlier, the missing test was a test that can accurately evaluate the change in flow behavior as a sample is cycled through daytime highs and nighttime lows. By running successive NFP measurements through a range of temperatures we developed our static thermal cycling (STC) test. Knowing the basics of the our rheological NFP and STC, it is now possible to choose the temperature range that is swept to probe the tendencies for a product to solidify under these controlled conditions. What the test now showed was that some paraffin inhibitor products would develop a new NFP that was different from the its initial NFP after being exposed to temperatures below freezing. This observation captured and important piece of information toward understanding product stability: by not evaluating relevant ambient temperature cycles a product could potentially and unexpectedly fail in the field.
Testing Paraffin Inhibitor Products with the Right Methods Can Prevent Many Unwanted Consequences
So, what does all this mean? It is commonly accepted that most paraffin inhibitors are expected to flow when hot. But, it isn’t as easy to predict the temperature at which they will change their flow behavior. Armed with this flow behavior test, we screen all of our paraffin inhibitor products for STC stability, and in the process, identify products that are suited for low-temperature environments. By properly qualifying paraffin inhibitor formulations for low-temperature conditions we help our customers avoid hidden costs due to low temperature product failures, and ultimately offering, products that:
- Will not need to be stored in hot rooms to maintain homogeneity and avoid the need for additional CAPEX investments
- Will avoid unwanted precipitation in storage tanks avoiding the need to deploy more rigorous and expensive cleaning practices
- Can be used throughout the entire year and avoid having to blend summer and winter formulations and avoid the added cost of transport logistics
- Will be able to maintain paraffin control year-round to allow for a more predictive and less frequent scheduled cleaning interventions such as pigging or hot oiling
Learn more about CERIFLOW 4600 series paraffin inhibitor products for low-temperature applications. Contact our team to order samples at email@example.com
About the Author:
Kelly Chichak is an innovative and creative research chemist with accomplishments in the design and synthesis of novel materials for a variety of markets including the oilfield industry. He has nearly 18 years of experience as a chemist, with much of his career focused on oilfield chemistry. Since joining SI Group in 2017, he’s focused his efforts on developing problem-solving flow assurance products. Kelly is originally from Canada and now resides in Upstate New York with his family.
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