Mechanisms of mineral scaling in oil and geothermal wells studied in laboratory experiments by nuclear techniques.

Two independent nuclear methods have been developed and tested for studies of mineral scaling mechanisms and kinetics related to the oil and geothermal industry. The first is a gamma transmission method to measure mass increase with a 30 MBq source of 133Ba. The other method applies radioactive tracers of one or more of the scaling components. CaCO3-precipitation has been used as an example here where the main tracer has been 47Ca2+. While the transmission method is an indirect method, the latter is a direct method where the reactions of specific components may be studied. Both methods are on-line, continuous and non-destructive, and capable to study scaling of liquids with saturation ratios approaching the solubility product. A lower limit for detection of CaCO3 with the transmission method in sand-packed columns with otherwise reasonable experimental parameters is estimated to be < 1 mg in a 1 cm section of the tube packed with silica sand while the lower limit of detection for the tracer method with reasonable experimental parameters is estimated to < 1 µg in the same tube section. [ABSTRACT FROM AUTHOR]