The Study Of Flowrate-Enhancement And Operation-Optimization Technology Of Dongxin Pipeline

As the deepening of the oil exploitation extent, it is an unreversed trend that the crude oil will become thicker and heavier. Great density, high viscosity and flow difficulty are the prominent characteristics of heavy oil resource, which severely restrict the transportation of thick oil. Based on the indoor rheological experiment, field drag reducer experiment and numeric model-building calculation, this thesis studied the viscosity-reduction and flowrate-enhancement technology of Dongxin pipeline.Firstly, indoor rheological research was done on the transportation oil of Dongxin pipeline. Then, 5 kind antifreezing agents and 5 kind viscosity reducers were selected based on the rheological characteristic.. EVA(2804) antifreezing agent with better modifying effect was chosen, and its modifying effect was certified by the indoor annulus experiment: the freezing point of Dongxin crude oil can be reduced to 5℃, and the viscosity reducing rate can be up to 9.51%.Secondly, field experiment was done along pipeline of the end of Dongxin pipeline(Guangrao Station) for EP viscosity reducer. The experiment had preferable flowrate-enhancement effect:the flowrate -enhancing rate of pipeline can reach 14.5%～20.8% .Finally, according to the analysis of current condition and primary parameters of Dongxin pipeline, flowrate-enhancement model and algorithm were built based on the experiment and theory. Dynamic programming method is an optimized mathematical method to solve optimization problems of multistage decision process, so according to the optimization principle, the whole pipeline was divided into several subprocess. Each subprocess was also an optimization problem, and recurrence equation was used to transfer these subprocesses successively. The final subprocess is the optimization process of the whole pipeline. According to this principle, an optimization running software for Dongxin pipeline was established, and technical and economic analysis was done on the result and project. Then the best flowrate-enhancement project for Dongxin pipeline was obtained, and the transportation capacity of 600×104 t/a of Dongxin pipeline was recovered.