高温粗煤气环境下节流工具冲蚀磨损研究

Erosion and Wear of Throttling Tools in High Temperature and Coarse Gas Environment

在气井井下节流工艺中,节流器位于井筒适当位置,能实现气体的降温降压,简化采气流程,降低生产成本,提高经济效益。井下节流工具结构类似截面突缩装置,能使气体流速增加、压力降低。但在煤炭地下气化过程中,由于燃烧不充分,粗煤气中含有大量微小煤粉颗粒,会对节流工具造成严重冲蚀磨损,导致节流工具失效,产生井控安全风险。为此,设计出双节流孔结构的井下节流工具,仿真预测节流工具所面临的冲蚀磨损情况,分析内部流场特性,研究气体速度、颗粒直径、颗粒质量流量对节流工具内壁的冲蚀磨损影响,为后续实际使用提供指导。

In the downhole throttling process of gas wells,the throttling tool is located at an appropriate position in the wellbore,which can reduce the temperature and pressure of the gas,simplify the gas production process,reduce production costs,and improve economic benefits.The structure of the downhole throttling tool is similar to the cross-section shrinkage device,which can increase the gas flow rate and reduce the pressure.However,during the underground coal gasification process,due to insufficient combustion,the crude gas contains a large number of tiny pulverized coal particles,which will cause severe erosion and wear of the throttling tools,resulting in the failure of the throttling tools and creating well control safety risks.To this end,this article designs an underground choke tool with a double throttling structure,simulates and predicts the erosion and wear conditions faced by the throttling tool,analyzes the internal flow field characteristics and explores the effects of gas velocity,particle diameter,and particle mass flow on the tool.The investigated impact mechanism of erosion and wear on the wall surface of the pipe string will guide its subsequent actual use.