巴喀致密砂岩气藏水锁/水相圈闭伤害评价

Trapping damage evaluation for water locking/water phase of tight sand gas reservoir in baka

针对致密砂岩气藏储层特征,分析了水锁/水相圈闭伤害的机理与影响因素,利用巴喀致密砂岩气藏天然岩心,研究了储层渗透率、孔隙度、甲醇浓度、毛细管自吸地层水深度等因素对地层含水饱和度和伤害程度的影响。实验结果表明,随着储层中含水饱和度上升,气相渗透率明显下降,并在含水饱和度为0%～40%范围内下降幅度加剧;当含储层水饱和度超过60%的临界值时,会造成极强的水锁/水相圈闭伤害。这一结果对在气藏改造措施中合理控制含水饱和度具有指导意义。

In view of reservoir features of tight sand gas accumulation we have analyzed mechanism and affecting factor of water locking/water phase trapping damage,by means of natural rock core of tight sand gas accumulation in Baka,and researched factor on formation water saturation and damage degree effect,such as reservoir permeability,porosity,methanol concentration,capillary imbibition formation water,etc..Experiment results show with water saturation increase,gas phase permeability obviously decrease,within 0%～40%water saturation, intensively reduce scope.When reservoir water saturation exceed 60%critical value, and can cause greatly water locking/water phase trapping damage.The result has guide function for controlling reasonably water saturation in gas reservoir reclamation measures.