松辽盆地徐深气田火山岩气藏相态与渗流机理

通过徐深气田天然气气体状态方程( PVT) 性质、天然气饱和水汽量和地层水PVT性质测试及全直径岩芯分析的气藏启动压力、储层流速敏感性和应力敏感性评价, 探讨了火山岩储层渗流机理。结果表明: 徐深气田火山岩气藏中CO₂含量差别较大(最高达86.88% ) , 天然气分子量与CO₂含量呈正相关; 偏差系数、饱和水汽含量及地层水中天然气含量受地层温度、压力、天然气组成及地层水矿化度等影响; 火山岩气藏启动压力与束缚水饱和度和空气渗透率均呈幂指数关系; 储层呈气水两相流特征, 具有弱速敏性和较强的应力敏感性, 易造成储层渗透率伤害以及孔隙结构改变。

Phase behavior and seepage mechanism of volcanic gas reservoir in Xushen gas field of Songliao Basin

Through the testing of gas state equation ( PVT) property, saturated vapor quantity of natural gas and formation water PVT property, and the evaluation of reservoir starting pressure of full diameter core analysis, flow rate and stress sensitivity in Xushen gas field, the author have discussed the seepage mechanism of volcanic reservoir. The results show that the contents of CO2 changes greatly in Xushen volcanic reservoir ( the highest content as 86.88 % ). Molecular weight of natural gas is positively correlated with CO2 content. Deviation coefficient, saturated vapor quantity and natural gas content in formation water are influenced by formation temperature, pressure, gas composition and mineralization degree of formation water. The starting pressure of volcanic gas reservoir shows exponential relationship with irreducible water saturation and air permeability. Reservoir is featured by gas-liquid two-phase flow with weak speed sensitivity and strong stress sensitivity, which may bring damage to reservoir permeability and variation to pore structure.