M气田清管及停输再启动过程段塞流控制方法研究

发布时间：2018-01-05 11:30

本文关键词：M气田清管及停输再启动过程段塞流控制方法研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：M气田集输管道1号线由7段管线构成,高含硫湿气集输,大落差起伏,低洼处积液。顺序分段清管及停输再启动过程产生大量清管、启动段塞,易导致管线内水合物产生、集气总站内分离器溢流。借鉴国内外对气液混输管线进行段塞流控制的成功作法,本文优选清管作业方案、提出分离器控制方法、制定高含硫气田停输再启动方案的一般性方法及步骤、设计并改进相关段塞流抑制装置,主要研究工作如下:(1)对国内外多相流管线清管瞬态数学模型、天然气水合物形成条件动力学模型、典型清管工艺及方案、气液混输管线停输再启动工艺、段塞流控制装置研究现状进行调研。总结当前研究存在没有针对高含硫气田集输系统、段塞流控制方法单一等问题,分析高含硫气田与常规气田在清管作业、停输再启动操作等方面存在较大差异。(2)遵循M气田现场分段清管作业原则,研究1号线集输系统合理的清管管段顺序及相邻管段清管时间间隔,对清管过程中形成液塞体积及长度变化、进入分离器顺序进行跟踪,以分离器缓冲容积利用最大、一次清管作业过程持续时间最短为研究目标,优选出清管作业方案,提出缓冲容积降低措施。基于"临界清管方案",对集输系统水合物可能形成风险点进行识别,并对沿线水合物形成条件进行校核,设计并改进地面涡流装置,用于低洼处积液排出、段塞流控制,并对该装置应用效果进行分析。(3)基于M气田现场"清管+涂膜"作业工艺,为抑制作业过程输量变化对净化厂脱硫装置影响,保证硫磺回收环节产品质量,研究出清管、涂膜两项作业过程持续时间最短的清管方案。基于"极限清管"方案,推荐美国Northern Natural Gas公司研发的便携式低洼处积液排出装置,用于1号线积液排出、冰堵防止,论证分析装置的适应性,对积液排出效果进行预测。(4)针对1号线末端大落差管线清管过程产生的水击危害,优选了清管前的吹扫方案,优化了吹扫气量、吹扫时间、清管过程推球气量,控制清管液塞量,减缓液塞对集气总站设备冲击,对分离器控制方法进行了研究,缩短紧急排液时间,提高分离器分液效率。对常用旁通清管器进行改进研究,设计了防止清管液塞回流的旁通通道,增设清管器速度控制腔体、清管器前端液塞吹扫腔体,对旁通清管器在M气田末端管线的清管过程进行模拟,分析清管效果。(5)提出适用于高含硫气田安全停输时间计算方法,分析了不同工况下安全停输时间变化规律,计算了 1号线D管段不同输量、起点温度、环境温度下安全停输时间,基于安全停输时间内,进行了多种启动方案下参数变化的规律研究,采用输量分阶段变化法,控制气量增加速率,比选出防止启动段塞形成的最优方案,形成高含硫气田停输再启动方案制定的一般性方法及步骤。
[Abstract]:Line 1 of M gas field gathering and transportation pipeline is composed of 7 sections of pipeline, high sulfur moisture gathering and transportation, large drop fluctuation, accumulation of liquid in low-lying place. A large number of pigging and starting slug are produced in the process of sequential pipe-clearing and shutdown and restarting. It is easy to cause hydrates in the pipeline and the separator overflow in the gas collecting station. Using the successful method of slug flow control for the gas-liquid mixed pipeline at home and abroad, this paper optimizes the operation scheme of selecting and cleaning pipes, and puts forward the separator control method. The general method and steps of stopping and restarting scheme of high sulfur gas field are formulated, and the relevant slug suppression device is designed and improved. The main research work is as follows: 1) transient mathematical model of pipeline cleaning at home and abroad for multiphase flow pipeline. Dynamic model of gas hydrate formation condition, typical pipe-cleaning process and scheme, stop-down and restarting process of gas-liquid mixed pipeline. The current research status of slug flow control unit is investigated. It is concluded that the current research does not aim at the problems of gathering and transporting system of high sulfur gas field and single control method of slug flow, and analyzes the pipeline cleaning operation of high sulfur gas field and conventional gas field. According to the principle of section cleaning in M gas field, the reasonable sequence of pipe-clearing section and the time interval between adjacent pipe-cleaning sections in the gathering and transportation system of Line 1 are studied. The volume and length of the liquid slug formed in the process of pigging were followed up in the order of entering the separator. The maximum use of the buffer volume of the separator and the shortest duration of the first pigging operation were the research objectives. Based on the "critical clearance scheme", the possible risk points of hydrate formation in gathering and transportation system are identified, and the formation conditions of hydrate along the route are checked. The surface eddy current device is designed and improved, which can be used to discharge the accumulated fluid and control the slug flow in the low-lying area. The application effect of the device is analyzed. 3) based on the "pipe cleaning film" operation process in M gas field. In order to restrain the influence of the change of transport quantity during operation on the desulfurization unit in purification plant and ensure the product quality of sulfur recovery link, the cleaning pipe was studied. The shortest duration of the two operations of film cleaning program. Based on the "limit pipe cleaning" scheme. It is recommended that the portable low-lying drainage device developed by Northern Natural Gas Company, USA, be used for the discharge of accumulated fluid in Line 1, prevention of ice blockage, and demonstration of the adaptability of the analysis device. Forecast the efflux effect. 4) aiming at the damage of water hammer caused by the pipe cleaning process at the end of line 1, the paper optimizes the blowing scheme before cleaning pipe, optimizes the amount of air blowing and the time of blowing sweep. In the process of pipe-cleaning, the volume of ball gas is pushed, the amount of liquid slug is controlled, the impact of liquid plug on the equipment of gas collecting station is slowed down, the control method of separator is studied, and the time of emergency discharge is shortened. To improve the separation efficiency of the separator. To improve the commonly used bypass purge, designed the bypass passage to prevent the backflow of the slug, added the speed control chamber of the cleaner, and blew the cavity at the front end of the pipe-clearing device. This paper simulates the pipe-cleaning process of by-pass pipe-cleaner at the end of M gas field, and analyzes the effect of pipe-cleaning. 5) A method for calculating the safe shutdown time of gas field with high sulfur content is put forward. The change rule of safe shutdown time under different working conditions is analyzed, and the safe shutdown time of D pipe section of Line 1 is calculated under the different transportation quantity, starting temperature and environment temperature, based on the safe shutdown time. In this paper, the law of parameter change under various start-up schemes is studied. The method of phase change is adopted to control the rate of increase of gas volume, and the optimal scheme to prevent the formation of starting slug is selected. The general methods and steps for the formulation of stopping and restarting scheme of high sulfur gas fields.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE832.3

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