An Operation Research Of Submarine Oil-Gas Mixed Transmission Pipelines

During the process of operation. the allocation of the two typical submarine oil-gas mixed transmission pipelines varies in the JZ25-1S field group. Simultaneously, the fluid properties in pipelines differ greatly from those data used in design, which causes great diversities of practical operation parameters from the data selected in the simulation calculation of design. Thus. it is necessary to take a research into the operation parameters under different proration conditions of various fluid properties to obtain the principles of pressure drop and temperature drop of pipelines properly. Furthermore, it is required to check the operation situation of the two pipelines under different ambient conditions since the parameters such as temperatures of seawater and soil change from winter to summer. Since the JZ25-1S field group is recognized as an abundant storage of high-quality light oil, it is necessary to figure out the maximum throughput of landing pipe under the different operational modes as the load of pipelines increases along with the rising of field production. As it is noted above, a research for the simulation of submarine pipelines is preceded to manage operation scientifically and effectively.Both crude oil pipelines and oil-gas mixed transmission pipelines are studied in this thesis. Through plenty of literature research, the research status about oil-gas mixed transmission pipelines is analyzed for the theoretical basis of submarine pipelines operation simulation. The experiments about physical properties of oil gathered from JZ25-1, JZ25-1S and JX1-1 oil field respectively and the commingled of those above are conducted, while the experimental results are analyzed and evaluated for more accurate data of oil properties used in simulation of submarine pipelines. Experimental studies about dehydration, selection of demulsifying agents, static dehydration without any agent dose, thermochemical static dehydration and electric dehydration of crude oil in JZ25-1 oil field are performed to provide theory support and technical guarantee of dehydration scheme design and production run. A mathematical model for the simulation of oil-gas mixed transmission pipelines as well as crude oil pipelines is built. Meanwhile, the numerical solution of this model is presented. With the application of results from oil physical property experiments, theory model and solution and the software PIPESIM into the research of the two typical oil-gas mixed transmission pipelines, the simulation calculation results under different operational modes are analyzed to obtain the operation rules and ultimate parameters of pipelines under various allocation situations. Based on this, whether the pipelines are qualified for the requirements of transmission process and practical production or not is analyzed to better master the operation parameters for the scientific basis of both routine management and implementation of measures in throughput increase of submarine pipelines.