结构参数对低压煤层气井用引射器性能影响研究

Study on the Influence of Structural Parameters on Ejector′s Performance Used in Low Pressure Coal Bed Methane Well

在煤层气田开采中后期,通常会出现压力下降不均衡、高低压气井相间分布、高压井限制低压井产量、压缩机压缩比增大等问题。为此,提出将高压井气体作为工作流体,利用其自身能量通过气体引射器来引射低压煤层气体。利用数值模拟对引射器内部流场分布特征进行研究,以引射系数为主要表征,重点讨论了气体喷嘴、喉嘴面积比和喉管长径比对气体引射器工作性能的影响规律,并确定了引射器最佳结构参数、最佳引射比。

In the middle and late stage of coalbed methane exploitation,the pressure drop is unbalanced and high and low pressure gas wells are distributed alternately.High-pressure wells limit the production of low-pressure wells while increasing the compression ratio of compressors.To deal with the issue,it is proposed to use high-pressure well gas as the working fluid and use its own energy to inject low-pressure coal seam gas through the gas injector.Numerical simulation was used to explore the distribution characteristics of the flow field inside the ejector with the injection coefficient as the main characterization.The influence rules of the gas ejector′s working performance were mainly discussed,including gas nozzle,throat nozzle area ratio and throat pipe length-diameter ratio.On this basis,the optimum structural parameters and the optimum ejection ratio of the ejector are determined.