降压开采过程中凝析油气相渗实验研究

EXPERIMENT RESEARCH ON CONDENSATE OIL/GAS PHASE PERMEABILITY DURING PRESSURE DROPPING PRODUCTION

目前凝析油气相渗曲线实验测试方法有常规模拟油气替代测试和真实平衡凝析油气测试两种,国内外还没有测量凝析气藏在降压开采过程中凝析油气相渗曲线的相关报道。文章给出了降压相渗实验测试方法,选用Q69-5井的平衡凝析油气和真实岩样进行了平衡凝析油气相渗曲线、降压相渗曲线和常规油气相渗曲线测试,并对3种相渗曲线进行了对比研究。研究结果表明:①降压相渗测试和岩心衰竭实验测试得到的凝析油饱和度具有相同的变化趋势,但前者的数值低于后者;②降压相渗实验测试过程中,凝析油开始析出后出现凝析油饱和度急剧上升和平衡气相相对渗透率急剧下降的现象,当压力降至最大反凝析压力后,凝析气的蒸发作用和平衡气驱作用可使近井地带的渗透性得到部分恢复;③降压相渗曲线比常规油气相渗曲线和平衡凝析油气相渗曲线明显向右偏移,其气相相对渗透率比常规测试和平衡油气测试得到的气相相对渗透率要高。

At present, common testing methods for condensate oil/gas phase permeability curve include conventional analog oil/gas substitute testing and real balance condensate oil/gas testing and there have been no reporting on condensate oil gas phase permeability curve measuring during pressure dropping production of condensate gas reservoir. This paper introduces the experimental testing method for pressure dropping phase permeability, describing balance condensate oil/gas phase permeability curve testing, pressure dropping phase permeability curve testing and conventional oil/gas phase permeability curve testing conducted of balance condensate oil/gas and real coring taken from Well Q69-5 as well as comparative study of three permeability curves. The study indicates that condensate oil saturation obtained from pressure dropping phase permeability testing and coring depletion testing show identical changing tendency with the value of the former lower than the latter; ② a drastic condensate oil saturation rise and sharp balance gas relative permeability drop occurred when condensate oil began to precipitate and when pressure dropped to the Max. anti-condensate pressure, evaporation of condensate gas and balance gas drive restored part of permeability in area near the well; ③ pressure dropping phase permeability curve is obviously on the right to conventional oil/gas phase permeability curve and balance condensate oil/gas phase permeability curve and its gas phase relative permeability is much higher than those obtained from conventional testing and balance oil/gas testing.