Numerical simulation of water lock damage in fractured well in low permibility reserviors
In order to find out the quantitative evaluation method of water lock damage in fractured gas wells,the mechanism of water lock damage in fractured wells was studied,the main controlling factors of water lock damage and its numerical simulation characterization method were defined.Taking S-1 well as an example,a fine fractured well model was established to simulate the formation process of water lock.The results show that:1)The main formation reason of water lock damage in fracturing wells is that part of the irreducible water is converted into movable water due to the poor flow capacity of fracturing fluid after gelout and the high flowback differential pressure,resulting in water lock damage;2)The damage radius of water lock is mainly concentrated in the area of 3～5 m near the fracture face;3)The reason why the solid acid hydrolysis water lock in well S-1 is ineffective is that the acid liquid did not break through the water lock pollution zone,and the water lock damage was aggravated by the influence of the injected liquid;4)The liquid nitrogen was injected by incremental pressure differential method to relieve the water lock.The water lock damage of well S-1 was relieved after 192 m3 liquid nitrogen was injected.The open flow rate of the well reached 3.2X 104 m3,and normal production was resumed.The application of this method can accurately evaluate the water lock damage and optimize the removal treatment of water lock,which has a guiding significance for the treatment of low-production gas wells after fracturing.
water lock damagedamage radiusnumerical simulationbackflow differential pressurestarting pressure
万方数据
维普
