西南石油大学学报(自然科学版)

• 石油与天然气工程 • 上一篇    下一篇

抑制水合物冻堵的天然气开井动态模拟研究

岑康1 *,江鑫1,杨静2,朱远星1   

  1. 1. 西南石油大学土木工程与建筑学院,四川成都610500
    2. 中国石油集团工程设计有限责任公司西南分公司,四川成都610000
  • 出版日期:2016-02-01 发布日期:2016-02-01
  • 通讯作者: 岑康,E-mail:cenkangxt@126.com
  • 基金资助:

    国家安监总局科技项目(2012 387)。

Dynamic Simulation of the Open Process for Natural Gas Wells to#br# Inhibit Hydrate Freeze-plugging

CEN Kang1*, JIANG Xin1, YANG Jing2, ZHU Yuanxing1   

  1. 1. School of Civil Engineering and Architecture,Southwest Petroleum University,Chengdu,Sichuan 610500,China
    2. Southwest Branch of China Petroleum Engineering Co. Ltd.,Chengdu,Sichuan 610000,China
  • Online:2016-02-01 Published:2016-02-01

摘要:

针对天然气井工艺管道在开井过程中极易产生水合物冻堵的问题,采用Dynsim 软件建立了开井工况动态模
拟模型,讨论了开井流量、工艺管道敷设方式与保温层厚度、节流调节方案对节流后温度压力的影响,分析了开井过程
中外界热交换的动态变化特征及对开井过程的影响,提出了加热炉前工艺管道优化设计与开井过程水合物优化控制
方案。结果表明:开井流量对水合物生成风险具有重要影响,开井流量越小,水合物生成风险越大,但不管开井流量
如何调整,井口工艺管道内均存在水合物生成风险;在保证下游出口超压在可接受范围的前提下,应通过同时调节各
级节流阀或主要调节二级与三级节流阀来尽量增大开井流量,并配合注醇、加热等方式来避免在工艺管道中生成水合
物;井口至加热炉前的工艺管道宜采用埋地敷设方式,埋地敷设管道无需保温,而架空敷设管道宜加保温措施。

关键词: 天然气井, 开井, 动态模拟, 水合物, 优化设计

Abstract:

The hydrate freeze-plugging phenomenon is easy to occur in pipelines during the open period of natural gas wells
especially for wells with high pressure. The dynamic characteristics and optimal hydrate control schemes during well opening
period,however,have not been studied systematically. So the specific dynamic models have been established to analyze
the dynamic characteristics during well opening period by Dynsim package. The influences of the fluid flowrate,installation
modes of pipelines,thickness of thermal insulation layer as well as throttling regulation schemes on throttling temperature and
pressure during well opening period have been discussed by using the dynamic models. The dynamic characteristics of heat
transfer between fluid in pipelines and ambient environment during well opening period have also been analyzed. In addition,
the optimal control schemes for hydrate inhibition during well opening period and optimization design for pipelines have also
been put forward in the paper. The results demonstrate that the fluid flowrate during well opening period has dramatical influence
on the risk of hydrate formation in pipelines. And no matter how to regulate the fluid flowrate during well opening period,
hydrate formation risk in pipelines exists all the time,especially when the flowrate remains small. In order to avoid hydrate
formation in pipelines,the fluid flowrate during well opening period should be increased as large as possible by regulating
different throttle valves simultaneously or regulating the secondary and tertiary throttle valves mainly. Meanwhile,necessary
measures like alcohol injection or heating should be done to mitigate the risk of hydrate formation. Furthermore,it is suggested
that the pipelines between wellhead and heating furnace should be buried underground without thermal insulation layer,whereas
other overhead pipelines should be covered by thermal insulation layer.

Key words: natural gas well, well opening, dynamic simulation, hydrate, optimization design

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