四川气田采气井口装置承载能力分析

采气井口装置由于均匀腐蚀和点蚀的作用，其承载能力会缓慢下降，采用有限元法，对承载能力进行计算和分析，得出采气井口装置所能承受的极限载荷及其承载能力随使用时间的增长而下降的规律；将计算分析结果与四川气田现场使用资料进行对比后得出了“采气井口装置能够承受压裂酸化施工中一定范围内的超负荷压力”以及“采气井口装置承载能力下降速率低于地层压力下降速率”两个重要结论。目前，采气井口装置的选用原则是采气井口装置安装选取的额定压力级别通常是介质压力的1．3倍～1．5倍。

ANALYSING THE LOAD-BEARING CAPABILITY OF GAS PRODUCTING WELLHEADS EMPLOYED IN SICHUAN GAS FIELD

This paper presents both the limiting values and the decline law of load-bearing capability of gas -producting wellheads employed in Sichuan gas field. These values and curves of load-bearing capability are derived from a series of calculations and analyses by means of Finite Element Method. Comparing the results of calculation with the formation pressure decline laws, two conclusions are obtained in the paper, one is the gas producting christmas tree can tolerate more than rated pressure to some extent when fracture acidizing, the other is the decline rate of load-bearing capability is slower than the formation pressure decline rate. The data of this paper can be used as a reference to the management and operation of wellheads in the fields.