关键词: 水平井；立体开发；压裂水淹；产能损失；产能恢复 

Abstract: The development of multi-layer reservoirs using horizontal wells for primary well pattern often leads to the failure of effective production of a large number of high-quality reservoirs in the vertical direction. Volumetric development with horizontal wells can realize the effective production of potential layers vertically，offering a solution to this problem. However，in the case of volumetric development with horizontal wells，old wells often get flooded by fracturing fluid during fracturing because the well spacing between new and old wells is too small，resulting in greater productivity loss. In this paper，water flooded wells during fracturing in Z211 Volumetric Development Zone are studied to analyze the mechanism for old wells to get water flooded because of the fracturing of new horizontal wells， and to define the decisive factors causing the water flooded wells. The safety and environmental risks that may arise during the fracturing of new wells，as well as their monitoring techniques and means are elaborated. The countermeasures for mitigating safety and environmental risks and minimizing productivity loss are explained. The patterns of productivity loss and recovery after getting water flooded during fracturing are summarized，and the treatment countermeasures are put forward. The above work provides a basis for mitigating the safety and environmental risks during the execution of the same type of horizontal wells in the later stage in Z211 Volumetric Development Zone，minimizing the productivity loss of old wells，and improving the recovery degree of water flooded wells. 

Key words: horizontal wells；volumetric development；get waterflooded during fracturing；productivity loss；productivity recovery