基于灰色关联度的超临界二氧化碳直旋射流参数敏感性

Parameter sensitivity of supercritical CO_(2) swirling-round jet based on grey correlation degree method

超临界CO_(2)直旋射流综合了超临界CO_(2)流体破岩门限压力低、直射流能量汇聚能力强以及旋转射流受效面积大等优势,是高效开发非常规油气资源射孔作业的新方法。通过自主设计研发的超临界CO_(2)射流破岩系统和直旋混合射流喷嘴,基于灰色关联度的分析方法研究了射流参数和喷嘴结构参数对破岩效果的敏感性。结果表明:破岩深度的最优敏感性排序从高到低依次为射流压力、混合腔长度、叶轮中心孔直径、叶轮长度、喷射距离,随着射流压力逐渐增大破岩深度逐渐增大;随着混合腔长度的增大,破岩深度呈先增大后减小趋势;破岩孔径的最优敏感性排序从高到低依次为射流压力、叶轮中心孔直径、混合腔长度、叶轮长度、喷射距离,随着射流压力的增大,破岩直径的增大趋势逐渐减小,叶轮中心孔直径的增大会导致射流破岩直径的逐渐减小。研究结果应用到超临界CO_(2)直旋混合射流参数的设计中,满足了现场作业中对非常规天然气储层保护性开采的高要求,实现了科学、绿色开发非常规油气资源。

Combined swirling-round jet of supercritical CO_(2) is a new perforation method for high-efficiency development of unconventional oil and gas resources,which comprehensively integrates the advantages of low threshold pressure of supercritical CO_(2) fluid,strong swirling energy convergence ability and large effective area of rotating jet.With the help of the independently designed and developed jet rock-breading system and swirling-round jet nozzle of supercritical CO_(2),the sensitivities of the jet parameters and the nozzle structure parameters to the rock-breaking effect is studied based on grey correlation degree method.The results show that the optimal sensitivity order of rock breaking depth from high to low is the jet pressure,mixing chamber length,impeller center hole diameter,impeller length and jet distance,and the depth of the broken rock gradually increases with the rise of the jet pressure.With the increase of mixing chamber length,the depth of the broken rock increases firstly and then decreases.The optimal sensitivity order of the broken rock pore size from high to low is the jet pressure,impeller center hole diameter,mixing chamber length,impeller length and jet distance.With the increase of jet pressure,the increasing trend of the broken rock diameter decreases gradually,and the increase of the impeller center hole diameter will lead to the decrease of the broken rock diameter.The study results are applied in the parameter design of combined swirling-round jet of supercritical CO_(2),which meets the high requirements for protective exploitation of unconventional gas reservoirs in field operation and realizes the scientific and green development of unconventional oil and gas.