| With the increase of oil demand, conventional oil already can not satisfy the needs of the development of production, to increase the extraction of high pour-point oil to fill the gap. But high pour-point and high viscosity of crude oil in the pipeline, not only increase the pipeline energy consumption, transportation process is complicated, and likely to occur tube and other accidents when pipeline condensing, affect the normal operation of the pipeline system. Therefore, how to effectively reduce the freezing point of crude oil, improve the flow characteristics of crude oil, determine the shutdown and startup of pipeline and crude oil convey process is particularly important.In this paper, the east China sea Bao Yun Ting BYT2well P14layer output of crude oil physical property parameters as the foundation. to make simulation of oil as the research object, to reduce the freezing point and viscosity of crude oil as the breakthrough point, study and formulate suitable for the east China sea Marine environment of high pour-point oil pipeline process. Determination wax, colloid and asphaltene content in crude oil, by rheological testing and analysis technology, as well as the simulation oil solidifying point. the related points, yield value and viscosity-temperature relationship, analyses the simulation of crude oil at different temperature range of phase change and rheological properties. On this basis, combining with the physical property of crude oil analysis, in order to add agent before and after solidifying point and the apparent viscosity of crude oil as the evaluation index, the coagulant screening test, obtained the optimum processing conditions of pour point depressant, determined simulated oil and diluted oil carbon number distribution. Using polarization imaging analysis system simulation for the oil and diluting agent after simulation oil micro wax crystal structure were observed.Temperature and pressure distribution along pipeline model is established, using OLGA software simulation analysis of the temperature dropping down along the change rule. Finally, using indoor visual flow loop device to simulating pipeline shutdown and restarting.Research shows that:use of Hui Zhou oil field provide sample HZ26-1and HZ32-3. according to the volume3:2synthetic simulated oil. simulated oil wax content and Bao Yun Ting BYT2well P14layer produce crude oil is same, solidifying point is32℃,5℃higher than the actual sample solidifying point, conform to the requirements of the experiments. Separate inject pour point depressant can’t obtain good effect, pour point depressant effect is obvious when diluted with condensate oil. The best pour point depressant (HYJN-04) can lower the sample oil solidifying point of12℃, satisfies the requirement of safe transportation (solidifying point is not higher than15℃). The best added dose is700ppm, heat treatment temperature is70℃. After dilution and inject pour point depressant simulated oil’s abnormal point is31.7℃, wax precipitation point is45.35℃, precipitation of wax crystal particle shape is bigger, and has the obvious trend of stay, wax crystal symmetry is better. During the running of pipeline along the temperature gradient is more and more small, from pipeline starting point to100km oil temperature close to the water temperature18℃, the temperature drop curve flattens out. Restart process, starting point and the end of the pipe pressure and temperature can fluctuate, pressure fluctuation is more obvious. Indoor plumbing experiment measured the start-up pressure corresponds to the actual pipeline pressure and OLGA software simulation results is consistent. |
PDF Full Text Request