摘要
通过分析凝析气藏的相图,建立了凝析液饱和度随压力降的变化规律,并回归得出了相应的公式;同时通过对气体压缩因子、黏度随压力、温度的变化,建立了这些参数和无因次压力的关系;在双重介质地层假设的基础上,建立了在试井过程中凝析气相对渗透率随凝析液饱和度变化的凝析气藏试井解释数学模型,采用隐式迭代的方法进行了求解并进行了参数敏感性分析;结果表明:凝析液的饱和度对凝析气藏试井的压力及压力导数曲线有着很大的影响,早期由于凝析液的析出,阻碍了气藏的流动,导致压力及压力导数曲线上升;在凝析液饱和度达到峰值之后,随着凝析液的挥发,凝析气的相对渗透率逐渐恢复,压力及压力导数曲线又回归到正常的径向流位置;由于裂缝和基岩之间的压力差,使得裂缝弹性储容比在测试过程中发生变化,进而影响了压力及压力导数;窜流系数和裂缝弹性储容比的变化决定了窜流段发生的早晚和程度;而基岩中气体黏度的变化使得窜流的发生稍微滞后。
According to the analysis for the pT-phase diagram of condensate gas reservoirs ,the formulation that describes the variation of the volume of liquid versus pressure is established.And based on the relations of compressibility factor and viscosity of the gas versus pressure ,the relations of these parameters versus dimensionless pressure are also built.On the basis of dual porosity theory,the well test interpretation model which considers the variation of krg versus the volume of liquid is also established and resolved by the implicit method numerically.The results show that the volume of liquid affects the pressure and pressure derivative greatly.At the early time,the krg is decreased and the pressure and pressure derivative increase accordingly due to the liquid dropout.When the volume of the liquid reaches the maximum,further reduction in pressure causes the vaporization process.So the krg increases and the pressure and pressure derivative resort to the normal radial flow finally.Due to the pressure difference between fracture and matrix,the elastic storativity ratio is also changed during the test,which affects the pressure and pres.sure derivative.The inter-porosity flow factor and the elastic storativity ratio determine the occurrence time and the degree of the inter-porosity flow.The change of gas viscosity in matrix makes the occurrence of inter-porosity flow be at a little later time.
出处
《中外能源》
CAS
2007年第4期37-42,共6页
Sino-Global Energy
关键词
裂缝性油藏
凝析气藏
饱和度变化
弹性储容比变化
黏度变化
试井解释
naturally fractured reservoirs
condensate gas reservoirs
variation of liquid saturation
variation of elastic storativity ratio
variation of gas viscosity
well test interpretation
