How to Develop a Comprehensive Scale Management Strategy and Use the Scale Risk Factor (SRF) for Chemical Optimisation

The Valhall field is located in the southern part of the Norwegian sector in the North Sea and has been producing for over 40 years. In more recent years there has been a number of issues caused by the presence of solids in the system and although barite scale was always known to be the main source, a thorough assessment of the problem was required. A project task force was set up in early 2023 to collate and review years of water chemistry data, solids analysis, Environmental scanning electron microscopy (ESEM), Infrared Thermography reports and other measurements to clearly establish the source of solids in the system and develop a field wide scale prediction model which covers over 60 mixing points from wellhead to water overboard. Thanks to this process the areas at higher risk of scale formation were identified and this provided the basis for scale inhibitor optimisation throughout the system. In addition to this analysis, a large volume of data that had been stored in various databases was also transferred to Power BI to improve data visualisation and allow faster detection of solids precipitation, easier root cause analysis and ultimately more effective scale management. Finally, a new calculation was used to quantify the scale risk more holistically and to compare the scaling potential in different parts of the system. This is called Scale Risk Factor (SRF) and is calculated using both Saturation Ratio (SR) and mass of scale predicted. Additional lab work is currently ongoing to produce a trendline which shows how the minimum inhibitor concentration (MIC) for a specific product change with variable SRF. This case study shows how accurate conventional scale predictions can be used in conjunction with data visualisation and a new parameter, the scale risk factor (SRF) to successfully optimise scale inhibitor injection and potentially reduce operating costs.