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In this paper we show how to obtain wax diffusivity and solubility in crude oils from deposition measurements in the cold finger device with stirring. We present a mathematical model in which the physical quantities are assumed to be space-independent in the bulk region of the device, because of agitation. Comparison with available laboratory results is provided, showing that the wax diffusivity values obtained in simulations are in agreement with data of field experiments.

We investigate the linear stability of a flow down an incline when the fluid is modelled as a "mollified" Bingham material. We perform a theoretical analysis by using the long-wave approximation method. The results show the existence of a critical condition for the onset of instability which arises when the Reynolds number is above a critical threshold that depends on the tilt angle and on rheological parameters. The comparison of our findings with experimental studies is rather satisfactory.

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In this paper we describe how to obtain wax diffusivity and solubility in a saturated crude oil using the measurements of solid wax deposit in the experimental apparatus known as cold finger. Assuming that migration of dissolved wax is primarily driven by thermal gradients, mathematical models are derived relating the deposit growth rate to the above mentioned quantities. We will investigate the case in which the oil is not agitated. The stirred case is studied in part II. Comparisons with available experimental data are performed and possible sources of errors are discussed.