Practical Knowledge of Nitrogen Foam Technology in Horizontal Well Plugging Releasing of Zhengzhuang Block

As the drainage process continues, the low-yield problem of horizontal well stoppage is becoming more serious in Zhengzhuang block. By trying to adopt nitrogen foam technology, we solve the problem of stoppage on horizontal well, and discuss the applicability of the technology in Zhengzhuang block. We draw the following conclusion: physical properties of the reservoir and permeability are poor, so nitrogen foam may experiences great resistance when foam advances forward in the horizontal section of the plugged well and returns stemming to the surface, thus the blocking effect is affected. The horizontal well of the open hole which can not withstand downhole pressure fluctuations and cause the collapse of coal seam, thus the level of blockage is more serious. It is not applicable for solving the problem of horizontal well stoppage by nitrogen foam technology. The horizontal wells for glass fiber reinforced plastic screen can solve the collapse of horizontal section coal seam. For the low permeability, the new idea of nitrogen reaming, draining hole and post-nitrogen foaming is proposed, and the effect of increasing gas production in field applications is significant.