LHSS-EOS在富含硫化氢凝析气藏动态相态特征分析中的应用研究

【作者】 刘萍；

【导师】 孙雷；

【作者基本信息】 西南石油大学 ， 油气田开发工程， 2006， 硕士

【摘要】 富含硫化氢凝析气藏有效、高效的开发一直以来都是复杂凝析气藏开发与开采过程中的一个探索性课题，发展和完善酸性凝析气藏安全高效开发配套技术，对于实现酸性凝析气藏的长期稳定生产有着十分重要的意义。 富含硫化氢凝析气藏属于含酸性气体的特殊气藏，它的开发既要求能获得较高的天然气采收率，又希望能获得较高的凝析油采收率，同时还要考虑到硫化氢等酸性物质的影响。受酸性凝析气藏流体特殊相态特性的影响，首先要找到适合于描述和分析富含硫化氢凝析气藏相态特性的状态方程，来解决其两相区特殊PVT性质，经典和非经典的状态方程要描述酸性油气藏流体都存在一定困难，但是比较发现，现有的状态方程模型基本可以满足工业需要，在经典的状态方程基础上进行改进的话，更能有效地解决富含H₂S的酸性凝析气藏油气体系的实际相态问题。同时还要解决轻烃回收的问题，即对富含硫化氢凝析气藏进行一体化动态相态分析，将地下、地面进行统一。因此，本文通过大量调研，总结了国内外对富含硫化氢凝析气藏的研究现状，针对其流体特殊的性质，开展更为有效的解决富含硫化氢凝析油气体系相态特征预测以及轻烃回收的技术方法研究，具有重要的实际意义。 本文在雷三气藏中21井、中40井两口典型井有代表性井流物样品的基础上，通过局部相图的实验测定和相态软件包的相图拟合计算，获得了气藏目前开采状态下的基础数据；同时运用油气两相相平衡理论基础，分别建立了油气体系静态和动态相平衡模型；动态相平衡模型中最重要的是动态相图预测模拟器，它通过对油气藏衰竭开采过程中采出井流物和地层剩余流体相图形态变化的预测，说明了凝析气藏反凝析过程对地层剩余流体和井流物露点压力的影响程度； 通过对相态实验结果的最优化拟合和流体热力学参数场的匹配，优选了适合于雷三气藏高含硫、低含凝析油型油气体系相态模拟计算的状态方程热力学模型，将一个改进的四参数三次状态方程（LHSS-EOS）应用于富含硫化氢凝析气藏地层烃类体系相态模拟计算，并与不同状态方程相对比，分析了不同状态方程的结构与适应性关系，得出结论是采用改进的LHSS四参数三次状态方程用于所研究的富含H₂S凝析气藏烃类体系可以得到更好的拟合效果。 另外，气藏流体整体相态模拟计算，对气藏不同开采期地面常温、深冷分离装置中的凝析油和轻烃产量进行了动态预测，获得了气藏衰竭开采期采出气中凝析油和轻烃产量的变化规律，为轻烃回收工艺流程的改造工程建设，回收工作制度的优选，轻烃产品结构分析及增压—膨胀制冷回收凝析油的可能性提供了参考依据；并通过凝析油气体系采收率的相态模拟计算，为数值模拟预测采收率的评价分析，提供了参比基础。更多还原

【Abstract】 It’s a difficult trial test to exploit complicated gas condensate reservoir effectively which highly containing H₂S all the time, a 雷三 o it’s significant to develop and consummate acidty gas condensate reservoir exploitation complete technology which can realize long-term settled production.The gas condensate reservoir which highly containing H₂S is a typic sour gas reservoir, the exploitation of it has to get high gas recovery, high condensate oil recovery ,a 雷三 o.the influence of sour gas like H₂S is a most important factor. we must find out a suitable equation-of-state to describle and analyses it’s phase behavior and to solve it’s typic PVT property in two-phase region. Neither classic nor non-classic equation of state is difficult to describe phase behavior of fluid.It’s found out that the existing state equation model can satisfy industry request,it can solve practical problem of this typic sour gas reservoir which highly containing H₂S more effectively through improving on the base of classical equation-of-state.At the same time,the light hydrocarbon recovering problem has to be resolved,making unitization dynamic phase state analyses about gas condensate reservoir which highly containing H2S,letting underground and ground be unified. So, through a great deal of studing,this paper has summarized existing research both home and abroad about gas condensate reservoir which highly containing H2S,developed effective reseach relative to it’s specific property.Based on the 雷三 gas reservoir media well 21 and 40,this paper has obtained gas reservoir present exploitation basic data though local phase graphic experimental determination and phase state software package phase diagram matching computation;meanwhile,this paper has established oil-gas system static state and dynamic phase equilibria model.In the dynamic equilibria model, the dynamic phase diagram prediction simulator is the most important part, it has explained the incidence about retrograde condensation to residual fluid and dew-point pressure.Though phase experimental result optimizing matching and fluid thermodynamic parameter field matching, this paper has optimized phase behavior simulation computational equation of state thermodynamic model which is suitable for 雷三 gas reservoir high in sulfur,low in condensate oil system. A advanced four parameters cubic equation of state（LHSS-EOS） has been used to simulate phase behair of a gas condensate reservoir hydrocarbon system which highly containing H₂S, compare LHSS-EOS with other equation, analyses the structure and flexibility of different equation-of -state, the result indicates that LHSS is better than other equation-of state in the critical region phase diagram computation of the gas condensate reservoir hydrocarbon system which highly high H₂S.In addition,the reservoir fluid bulk phase state simulation has proceeded dynamic prediction towards different production life,ground nomal temperature,condensate oil in cryogenic separation tackle and light hydrocarbon production rate,obtained condensate oil in depletion production gas and varied rule about light hydrocarbon production,it has offered reference frame for modification works of light hydrocarbon更多还原