组合段塞工艺解除凝析气井水锁伤害实验评价

Experimental evaluation of combination slug technique to get rid of water blocking damage in gas condensate wells

在凝析气井生产过程中,井底长期积液极易导致近井地带发生反渗吸水锁效应,形成水锁伤害,降低储层渗流能力,增大生产压差,严重影响气井产能的释放.以Y凝析气井为例,采用考虑反渗吸水锁的气井产能方程,分析反渗吸水锁效应对气井产能的影响,并采用“甲醇+酸+解水锁剂+氮气吞吐”组合段塞工艺方式,开展Y井长岩心解除水锁效果实验评价.实验结果表明,气井无阻流量随着反渗吸水锁侵入深度的增大而急剧降低,“甲醇+酸+解水锁剂+氮气吞吐”组合段塞解除水锁效果很好,渗透率恢复倍数达到6.2.

In the process of the production of condensate gas wells,long-term liquid loading can easily lead to reverse osmosis water lock effect near wellbore area,which will form water blocking damage,lower the reservoir percolation ability,increase production pressure difference,and seriously affect the release of gas well production capacity.By taking condensate gas Y-well as an example,with the use of the gas well productivity equation considering the reverse osmosis water locking,the effect of reverse osmosis water entrapment on gas well productivity was analyzed.The combination slug technique of”methanol+acid+water locking agent+nitrogen huff and puff'’was adopted to carry out the experimental evaluation on the effect of lifting water locking in the long core of Y—well.The experimental results show that the open flow rate of the gas well decreases sharply with the increase of the penetration depth of the reverse osmosis water lock.The combination slug technique of”methanol+acid+water locking agent+nitrogen huff and puff'’has a good effect to get rid of water blocking damage,which will make the permeability recover to 6.2 times.