Operators in the oil and gas industry make extensive use of scale inhibitors to provide the level of flow assurance required to maximise safe and economic hydrocarbon production. For continuous and scale squeeze treatments, field operators need to verify the residual inhibitor concentrations regularly to ensure that the implemented scale management program remains effective. Sulfonated polymers are effective and widely used sulphate (barium, strontium, calcium) scale inhibitors, however detection of residual (less than 15 ppm) amounts has been problematic, leading to the use of an overdose on continuous applications or resqueezing before reaching the minimum effective dosage (MED) level.

The authors have developed a testing protocol that enables measurement of the residual concentration of polymeric scale inhibitors at the point of use and directly in produced water, providing a timely and accurate scale inhibitor concentration to the facility operator. Field operators with minimal training use sample preparation protocols that are minimized and standardized to determine polymer concentrations within 15 minutes down to 1 ppm active polymer. The testing protocol uses an aqueous liquid fingerprinting technology platform to detect a range of scale inhibitor products and provides direct field analysis for either continuous or scale squeeze application programs. Operators determine the residual scale inhibitor level at the point of use, eliminating the cost and time delay of shipping samples to a remote analytical laboratory.

We previously presented laboratory results of this technology (Johnstone et al. 2014). In this paper, we present the results of the performance of this system in actual field operation which was completed late 2014 at oil and gas production locations and validated at an analytical laboratory. The results demonstrate the benefits of the protocol in field applications in monitoring residual levels to a level of accuracy for polymeric scale inhibitors previously only achievable in fully equipped analytical laboratories.

This technology has been demonstrated to the oil and gas industry and has generated significant interest in a number of communities for which monitoring polymeric scale inhibitors at concentrations less than 5 ppm active is a business-critical activity. The validity of the protocol has been confirmed by ongoing work across a number of application areas, supporting the global industry challenge of scale control.

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