Wax Deposition Characteristic Research Of Crude Oil Pipeline

Study on wax deposition and operating cost of Huatugou-Geermu pipeline was performed in the paper, including laboratory test, programming and result analysis.Basic physical properties and rheological behaviors were determined through laboratory test on crude oil sample of Qinghai crude oil. Basic data were provided for building wax deposition model programming. In addition, pipe flow wax deposition test device was used to study wax deposition characteristics of Qinghai crude oil. With laboratory test result, wax deposition model of Qinghai crude oil was built.Wax precipitation in pipeline was predicted with wax deposition program of Qinghai crude oil. Calculation methods of parameters for friction resistance, oil temperature distribution along the pipeline, radial temperature gradient on pipeline wall, shearing stress on pipe wall, wax molecular concentration on pipe wall were listed in the paper. The two different flow patterns, namely Newtonian fluid and Non-Newtonian fluid were taken into account in the program. Main data about Huatugou-Geermu oil pipeline were embedded in the program, including station elevation, station spacing, etc. Some other data would be input according to actual demand, such as output, inlet and outlet oil temperature at different seasons, soil temperature, etc.Wax deposition, operating cost, and optimized pipeline cleaning period were simulated with the program. Factors such as operating temperature, transportation output, soil temperature, were individually viewed to study their effect on pipe waxing. With consideration of the four factors that influencing wax deposition rate, namely viscosity of crude oil, concentration gradient of wax molecular on pipe wall, temperature gradient on pipe wall, and shearing stress on pipe wall, to analyze the reasons. Further analysis was focused on effect on pipeline waxing on power cost, fuel expenditure, and pipe cleaning cost to determined effect of pipe waxing on pipeline operating cost, and finally determined the optimized pipe cleaning period under different service conditions.