水平井分段多簇压裂暂堵球运移封堵规律

Temporary plugging ball migration and plugging law of staged multi-clusterfracturing in horizontal wells

李婷婷 许文俊 王雷 江枫 张健鹏

长江大学石油工程学院，湖北 武汉 430100 油气钻采工程湖北省重点实验室，湖北 武汉 430100 西南石油大学油气藏地质及开发工程国家重点实验，四川 成都 610500

School of Petroleum Engineering, Yangtze University, Wuhan 430100, China Key Laboratory of Drilling and Production Engineering for Oil and Gas, Wuhan 430100, China State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China)

投球暂堵转向技术是水平井分段多簇压裂实现多簇裂缝均衡扩展的主要技术之一，由于暂堵球在水平井筒内的运移封堵规律尚不明确，该技术应用效果并不佳。基于此，文中采用CFD+DEM耦合方法建立暂堵球水平井筒运移封堵模型，分析暂堵球密度、施工排量、压裂液黏度、投球数、暂堵球直径和孔眼出口应力分布状态对暂堵球井筒运移封堵行为的影响规律，并结合室内实验结果验证模型的准确性。模拟结果表明：增大暂堵球密度与压裂液黏度，封堵效率先减小后增大，密度与黏度的转折点分别为1 300 kg/m³，20 mPa·s；增加施工排量与投球数，封堵效率持续增大，但增大幅度渐缓，排量达到16 m³/min后，封堵效率基本稳定，投球数为24个时暂堵球有效利用率最高；暂堵球直径越小，封堵效率越高，使用1.25倍孔眼直径的暂堵球坐封效果最佳；压裂段内应力非均匀分布导致各簇孔眼出口流速不同，合理的施工参数方案有利于增强单簇孔眼封堵效果与出口流速的正相关性。基于上述模型优选出的施工参数方案，现场应用效果良好，验证了模型的工程应用价值。

The ball-drop temporary plugging and steering method is one of the main technical means to realize the balanced expansion of multiple fractures of staged multi-cluster fracturing in horizontal wells. Because the migration and plugging law of the temporary plugging ball in horizontal wells is not clear, the application effect of this technology is not good. Based on this, this paper adopts CFD+DEM coupling method to establish the migration and plugging model of temporary plugging ball in horizontal wellbore, analyzes the influence law of temporary plugging ball density, construction displacement, fracturing fluid viscosity, ball quantity, ball diameter and stress distribution state at hole outlet on the migration and plugging behavior of temporary plugging ball in wellbore, and verifies the accuracy of the model combined with laboratory experimental results. The simulation results show that the plugging efficiency first decreases and then increases with the increase of temporary plugging ball density and fracturing viscosity, and the turning points are 1,300 kg/m3 and 20  mPa·s, respectively. When the construction displacement and ball count were increased, the plugging efficiency continued to increase, but the increase rate gradually slowed down. When the displacement reached 16 m³/min, the plugging efficiency was basically stable, and the utilization rate of temporary plugging balls was the highest when 24 balls were thrown. The smaller the diameter of temporary plugging ball is, the higher the plugging efficiency is. The best plugging effect is the temporary plugging ball with 1.25 times the hole diameter. The non-uniform distribution of stress in the fracturing stage leads to different exit velocity of each cluster hole. Reasonable construction parameter scheme is beneficial to enhance the positive correlation between the plugging effect of single cluster hole and exit velocity. The construction parameter scheme selected based on the above model has a good application effect, which verifies the engineering application value of the model.

10.6056/dkyqt202301024