Perm Journal of Petroleum and Mining Engineering (Sep 2018)
The efficiency assessment of the “Cold Flow” method against the deposition of asphaltenes, resins and paraffins
Abstract
Mechanisms of formation of deposition of asphaltenes, resins and paraffins (DARP) are considered. Molecular diffusion based on the influence of the temperature gradient is the main mechanism for DARP formation. The analysis of existing methods against DARP is given. Modern methods of DARP prevention that affect the temperature gradient are aimed at maintaining the oil temperature above the crystallization temperature of paraffin. The cold flow method is an alternative control method which involves cooling the oil to a surrounding temperature. The purpose of the work is to assess the effectiveness of the cold flow method against DARP; its advantages and disadvantages are revealed. In order to assess the effectiveness of the proposed method. The sample of oil and produced water was taken at the pumping station. Using gas chromatography, the fractional composition of an oil sample was determined using the SimDis method. Using a calibration table, a component composition of oil up to C52 was calculated using values of boiling point and equations of fluid state were formed in PVTsim software. Rheological studies of the transported oil are carried out. Based on results of laboratory studies in OLGA software package, a hydraulic calculation of the pipeline was performed for various values of the flow temperature using the “Wax deposition” paraffin deposition module on the Matzain model. Thus, having the flow with temperature equal to the ambient temperature, in 10 days 5.6 kg of paraffin is formed on pipeline walls, whereas in the current conditions it is 100 kg. As a result, it is established that the effectiveness of the application of the cold flow method against DARP is 94 %. Proposed method can significantly reduce production costs associated with paraffin oil transportation.
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