致密砂岩气藏水锁伤害及对产能的影响

为了评价致密砂岩气藏水锁伤害对储层的影响程度,设计了适于测定致密砂岩水锁伤害的试验方法,开展了室内试验研究,并分析了水锁伤害对气藏产能的影响。研究表明:致密砂岩束缚水饱和度较高,平均为47.67%,水锁伤害率平均为76.49%,水锁伤害严重。渗透率越低的岩心,水锁伤害越严重。水锁伤害主要发生在含水上升的初期阶段,水锁伤害率随含水饱和度的增加而增加的幅度越来越小;水锁伤害对产能的影响较为显著。水锁发生后,气体产能下降幅度超过了60%;水锁伤害半径越大,对产能的影响也越大,影响程度达到17.78%。致密砂岩储层水锁伤害要以预防为主,因此,油气田现场要适时地采取措施防止水锁伤害的发生,并建立合理的气井生产制度。

Water Blocking Damage for Tight Sandstone Gas Reservoirs and Its Effect On Productivity

In order to evaluation the extent of the gas reservoir impact of water blocking damage for tight sandstone,method of testing water blocking damage for tight sandstone was designed,then carried out experimental research in laboratory,and the relationship between productivity and water blocking damage was analyzed. Study shows that irreducible water saturation is so high that its average value up to 47.67%,and water blocking damage rate average value up to76.49%,the lower the permeability,the more serious the damage by water blocking. Water blocking damage mainly occurred in initial stage of water increasing,and water blocking damage rate is increasing with water saturation increases,but the increase rate tends to be reduced. Water blocking damage has much influence on productivity,and even reached more than 60%. The larger the water blocking damage radius,the more serious the damage by water blocking,and the impact extent even up to17.78%.However,the most important is to prevent the water blocking damage for tight sandstone gas reservoir. Based on the above analysis,it is necessary to take proper measures to prevent the occurrence of water blocking,and reasonable system of shale gas well production is established.