Study On The Pigging Period Optimization Of The Lun-ku-shan Crude Oil Pipeline

Aiming at the wax precipitation characteristics and pigging optimization of Lunnan-Korla-Shanshan oil pipeline under different conditions(oil transportation temperature and throughout),this paper conducted indoor experimental measurement of viscosity,specific heat and wax precipitation of pipeline transported crude oil under different working conditions.Combined with the data of production and operation in field,MATLAB software is used for modularized program compiling and this paper carried out a both qualitative and quantitative analysis on the influence factors and laws of wax precipitationon Lunnan-Korla-Shanshan oil pipeline and did a further research on the optimized pigging period under the related conditions.Through the conduction of laboratory rheological testing experiment,the basic physical property parameters including density,condensation point,wax precipitation point,abnormal point and wax content of Lunnan-Korla-Shanshan pipeline transported crude oil are measured and the viscosity-temperature relational expressions under different temperature intervals are obtained through tests and analysis.Through the DSC testing experiment,the characteristic curve of wax crystal solubility and specific heat capacity curve are obtained and then the related function relation is obtained through fitting.The wax precipitation testing experiments under different conditions are carried out on the experimental device of pipe flow to measure the wax deposition content.According to the laboratory experimental results of rheology and wax precipitation of pipe flow,the wax deposition model of Lunnan-Korla-Shanshan pipeline transported crude oil is established.Based on the established wax deposition model,this paper investigated and analyzed the operation data in field of Lunnan-Korla-Shanshan oil pipeline and compiled the program modules of wax deposition and pigging period which can predict the wax precipitation situations of oil pipeline under different operating conditions(oil temperature,throughout and ground temprature)and qualitatively analyze the main factors influencing the wax precipitation characteristics of pipeline(viscosity,shear stress of pipe wall,solubility coefficient of waxy molecule,temperature gradient,etc.).Based on the wax precipitation prediction result,the program module for pigging period of oil pipeline is compiled to calculate the optimized pigging periods under different operating conditions which can provide theoretical guidance on the pigging technological operation of Lunnan-Korla-Shanshan oil pipeline and give some reasonable advices on the production and operation.