气井水合物实时监测预警系统研究

气井井口温度较低时井筒内易生成水合物，为了避免测试时冻堵井下油管事故的发生，设计了与现场数采设备相配合的实时监测预警系统。以井口附近地面管线监测点实时传输的压力、温度及流量数据为依据，应用井筒多相流理论计算气井沿程压力温度分布，与图解法所形成的天然气水合物P-T图相比较，进而判断是否达到水合物生成条件，并计算可能存在水合物的井段，由此进行报警并采取及时的预防措施。系统中包含了所涉及开井与关井井筒压力温度计算、天然气水合物生成预测、预警预防设置3部分。编制的软件经现场实践可达到实时监测的目的。最后，给出在集成化实时监控下预防气井水合物的对策。

Research on monitoring and alarming system for hydrate in gas wells

When the wellhead temperature for gas wells is low, freezing accident in wellbore could happen because of hydrate generation. Through designing the monitoring and alarming system, the freezing accident can be avoided. The pressure and temperature distribution along wellbore is computed through multi-phase flowing theory, based on the data acquired from the wellhead. Comparing to the hydrate P-T Graph by the picture interpreting means, the results can judge the situation of the hydrate and show the depth range with the hydrate in gas wells, so that the system can monitor and alarm hydrate. The system contains three main functions: calculating the pressure and temperature in wellbore during production and well shutting; forecasting hydrate generation; design of alarming and prevention. The software made up by these methods can realize the aim to real-time monitor and alarm hydrate. Finally, the software of the system is shown with the suggestion to avoid hydrate during gas well testing and production.