| abstract |
The invention provides a selective gel water plugging system and a preparation method for fracture-cavity oil reservoirs. The system includes: by mass percentage, 0.5-5.0% of the main gel agent (agent A), 0.5-5.0% of the gelling agent (agent B) and the remainder of water. The temperature resistance of the novel multifunctional gel water blocking system provided by the invention can reach above 150°C, and can exist stably in an aqueous solution with a salinity of up to 350,000 ppm, and has good salt resistance. In addition, the plugging agent still maintains strong plugging performance against the water phase after 20PV flushing, and the core plugged by the plugging agent is displaced by the oil phase, and the permeability of the basic core core within 2.0h All recovered to more than 90%, showing good plugging performance, which can meet the performance requirements of water plugging agent for carbonate reservoirs in Tahe Oilfield. |