气井井下双节流油嘴设计方法

安装一个节流油嘴存在的最大弊端是节流前后压差很大，造成节流油嘴密封部件很容易失效，这就是目前井下节流仅在浅井中得到广泛应用，而在中深井中应用受到限制的原因之一。为了解决此问题，提出了安装双节流油嘴，并建立了双节流油嘴的设计模型。研究结果表明，该模型能真实反映双节流油嘴井下节流井筒流动动态；双节流油嘴可以减少每个节流油嘴的压差，从而减少损坏的可能性；双节流油嘴位置必须满足节流后不生成水合物，较浅一个节流油嘴下入位置必须在较深那个节流油嘴温降基本恢复的位置才能进行节流。

DESIGN OF DOWNHOLE DOUBLE-THROTTLING CHOKE FOR GAS WELLS

The biggest disadvantage of installing a choke is that great pressure difference exists between before and after the choke, which tends to cause choke seal failure. That is why the downhole choke is often used only in shallow wells at present, but its application in medium or deep wells is restricted to some degree. To solve this problem, this paper introduced a kind of double throttling choke, and also built up its designing model. The investigation results show this model can reflect the actual double choked wellbore flow behavior, and the double throttling choke can reduce the pressure difference across each choke so as to reduce the possibility of choke damage. This paper also suggests that the double throttling choke should be located in such a way that no hydrates will be produced after throttling, and the shallower choke should be set at such a depth where the temperature drop effects of the deeper one have been diminished.