Influence Of Process Parameters And Equipment To The Flowing Security

Currently, researches of waxy crude oil pipeline flowing security technology made by domestic and foreign scholars are comprehensive and abundant. On the basis of the existing research, the efficient algorithm of pipeline shutdown and restart failure probability is explored. Including: using POD dimension reduction techniques to reduce the simulation time of the single restart process; using the new pipeline shutdown and restart pressure calculation model base on the Houska thixotropic model to describe the thixotropic of waxy crude oil accurately; using LHS sampling method to overcome the disadvantages of poor convergence of traditional Monte-Carlo sampling method and reduce the sampling numbers; Introducing the interference principle to solve the failure probability calculation and reduce the requirements of small probability to calculate the sample. Through the comprehensive application of various technologies, which not only makes the calculation time reduced obviously, but also makes the calculation model more accurately, the flow safety assessment software of high waxy crude oil pipeline is improved.Researches on the influence of parameters volatility to the waxy oil flowing security from the two processes of the shutdown and restart and pipeline operation is done. Through the simulation of Zhong-Chao pipeline, pipeline failure probability influenced by the shutdown time, discharge temperature, rate of flow, pipeline depth, ground temperature and other factors is analyzed. In addition, the factors sensitivity analysis and safety margin analysis has accomplished. A new concept of probability from unstable operating region to finally state is put forward to represent the pipeline deterioration state.In consideration of the flow safety requirements and the reliability of direct-heater performance, the risk assessment model for direct-heater(heater station) based on waxy crude flow safety is established. Main steps: automatic data screening and extraction of production report; calculation of average value and variance of relevant working condition parameters;calculation of the heater efficiency; inverse new outbound temperature distribution by random sampling; heater assessment based on minimum outbound temperature; improvement suggestions. According to these steps, a heater risk assessment software is developed and used to assess the relevant examples, the evaluation result close to the actual situation.