Increased lifetime of chemical treatments is an important achievement both from an economical – field productivity issue as well as from an environmental point of view. Whatever type of reservoir potential enhanced treatment efficiency would be beneficial. Normally, this could be obtained by different strategies of employments, like precipitation squeezes, enhanced adsorption and bridging techniques.

However, in HPHT fields, e.g. field with temperature higher than 150°C, an additional obstacle would be the thermal stability of the chemicals. In nature, the thermal stability of products is often in conflict with or in contradiction to the property of high biodegradation, e.g. environmental friendliness.

In the present paper a new, multi-task method with a high throughput screening system for thermal ageing is presented. Combined with this set up is a new dynamic test-rig at HPHT conditions, directly testing the efficiency of the thermally aged products. Further analytical aspects of the degraded chemicals are analyzed on liquid-chromatographic mass spectroscopic, LC-MS, techniques. In order to gain more in-depth knowledge of the overall chemical efficiency, all data are evaluated using a multivariate analytical tool. This combined system is used for qualifying chemicals to be used in North Sea HPHT fields. Three scale inhibitor products, two classified as yellow and one classified as a red chemical, were evaluated for field application.

In this paper, the detailed experimental data and a new procedure for thermal ageing tests will be presented.

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