Technology Focus: Oilfield Chemistry (September 2016)
Authors: Wylde Jonathan 
Published: January 2017

Technology Focus

In years past, analytics in the oil field meant running iron and manganese counts to determine corrosivity in a system or measuring a phosphorous residual to determine a phosphonate scale-squeeze chemical-flowback profile. Today, this is a given and the techniques used to perform this can be found in most, if not all, technical service laboratories or even can be implemented directly in the field.

In the past decade, analytics in the oil field has grown to be a major discipline, integrally supporting the application of many different types of production chemicals and becoming viewed by some as a technology differentiator.

We are all aware of inductively coupled plasma spectroscopy and how it can determine the full cationic content of a produced water. I am sure, however, that not everyone is aware of the expanse of techniques now available to determine the presence of multiple chemistries in a single commingled produced-water sample.

As field developments become more and more complex, the need for differentiated analytical techniques becomes increasingly pronounced. Imagine the scenario in a deepwater production system where several wet trees tie into a common manifold and flow through a single flowline to a host facility. Each of the wells can be treated with a scale squeeze treatment of different chemistry, and techniques are now available to distinguish between these similar species. Bear in mind also that this situation can be complicated by the presence of additional chemistries injected into the flowline such as a further scale inhibitor, corrosion inhibitor, hydrate inhibitor, and paraffin or asphaltene inhibitor.

The featured papers summarize some of the state-of-the-art techniques in use today to quantify production-chemical content accurately and reliably and therefore manage the flow-assurance risks. These techniques include advanced high-pressure liquid chromatography coupled with mass spectrometry and time-resolved fluorescence. Many of these techniques have been available for some years, but use in the oil field was complicated by the high salt content and presence of other contaminants such as dissolved organics and acids. This has required a significant advancement in pretreatment techniques for the fluids being analyzed, such as selective-ion and desalination cartridges.

Readers are encouraged to research the suggested additional reading and take some time to delve into the references contained in these papers. This literature contains an extensive review of the history and current state of the art of analytical science for the oilfield chemist and engineer. JPT

Recommended additional reading at OnePetro: www.onepetro.org.

SPE 179908 Accurate Detection of Tagged Polymeric Scale Inhibitors in Oilfield Produced-Water Samples by Vesa Vuori, Kemira Oyj, et al.

SPE 179902 New Robust Analytical Development for Sulfonated Polymers in Oilfield Brines by Kirsty MacKinnon, Scaled Solutions, et al.

SPE 173744 Application of Advanced Mass-Spectroscopy Techniques for Improved Scale Management in Conventional and Subsea Fields by Steve Heath, DONG Energy, et al.

SPE 173712 Alkalinity in the 21st Century: An Improved Methodology for Carbonate Determination in Oilfield Brines by Russell A. Fisher, Baker Hughes, et al.