高气液比气井井下节流携液分析

摘要

Aiming at the key problem whether liquid-carrying capacity is better or worse after applying the downhole choke than before,this article selects high gas-to-liquid ratio（GLR） gas well with downhole choke as research target.Taking downhole choke as a function node,its pressure drop correlation and temperature drop correlation are set up using the node analysis.The minimum flow rate for the continuous removal liquids by Professor Li Min is presented to quantitatively describe its liquid-carrying capacity and then obtain the minimum flow rate profile.The case analysis shows the minimum flow rate profile includes typical 3 parts in distribution and has 3 maximum rates.So the gas production rate should be higher than the maximum value of them.And the minimum flow rate between the reservoir and the downhole choke is higher than that between the downhole choke and the wellhead.In other words,the less gas rate with a downhole choke can help liquid-carrying production from gas well,which proves the liquid-carrying capacity is better than that without the downhole choke.But there is a maximum flow rate at the downhole choke,which proves the liquid-carrying capacity of the choke is worse for the bigger velocity difference between the gas jet and its surrounding mixture.%针对井下节流是否有利于携液这一热点问题,以高气液比井下节流气井为研究对象,建立了以油嘴为函数节点的井下节流气井井筒压力温度数学模型,并引入李闽教授提出的椭球体携液临界气量模型来定量分析其携液能力,耦合得到了井下节流气井携液临界气量剖面。实例分析表明：井下节流气井携液临界气量呈典型3段分布,可能存在3个极大值,应取其最大值配产。产层至节流油嘴上游的临界气量明显大于节流下游至井口的值,表明节流后在较小的气量下就可携液生产,利于携液,而节流油嘴处存在一临界气量极大值,说明气体通过油嘴形成高速射流,与周围流速差增大,携液所需气量增加,不利于携液。