暂堵剂形状对裂缝封堵影响规律的实验研究

Experimental study on influence law of temporary plugging agent shape on fracture plugging

许江文 张谷畅 李建民 王涛 程家麒 王博

中国石油新疆油田分公司工程技术研究院，新疆 克拉玛依 834000 中国石油大学（北京），北京 102249 中国石油大学（北京）克拉玛依校区石油学院，新疆 克拉玛依 834000）

Research Institute of Engineering Technique, Xinjiang Oilfield Company, PetroChina, Karamay 834000, China China University of Petroleum, Beijing 102249, China College of Petroleum, China University of Petroleum (Beijing) at Karamay, Karamay 834000, China

水平井多级压裂过程中，压裂液倾向于流入优势射孔簇，造成段内改造不均。裂缝暂堵是解决该难题的有效手段，但目前尚未明确暂堵剂形状对裂缝封堵的影响规律，造成裂缝封堵效果不稳定。文中首先利用高承压裂缝封堵实验装置，考虑裂缝宽度、裂缝壁面形态和暂堵剂配方，深入研究了暂堵剂形状对裂缝封堵的影响规律；然后进一步利用可视化粗糙迂曲裂缝暂堵剂运移实验装置，研究了不同形状暂堵剂的运移及架桥过程。研究结果表明：1）相同裂缝壁面形态及裂缝宽度下，纤维封堵比粉末起压速度更快；2）相同裂缝壁面形态下，裂缝宽度较小时，球形颗粒架桥封堵快，裂缝宽度较大时，圆柱形颗粒架桥封堵快；3）相同暂堵剂配方下，裂缝宽度较小时，不同裂缝壁面形态下起压速度差异不大，但裂缝宽度较大时，裂缝壁面形态对起压速度影响较大；4）暂堵剂架桥封堵经历纤维或粉末逐步吸附在裂缝表面、裂缝过流断面减小、颗粒暂堵剂架桥、纤维或粉末填充、形成致密封堵层5个过程。

 During multi-cluster fracturing in horizontal well section, fracturing fluid tends to flow into the dominant channel, resulting in uneven stimulation in the horizontal well section. Temporary plugging fracture can effectively solve the problem. However, influence law of temporary plugging agent shape on fracture plugging is not clear, and the plugging effect on fracture is unstable. In this work, the influence law of the temporary plugging agent shape on the fracture plugging is systematically investigated considering fracture width, fracture surface morphology and temporary plugging agent formula through the high pressure fracture plugging experimental facility. Moreover, the migration and bridging process of temporary plugging agent in different shapes are studied through the visual observation system. The results show that: (1) with same fracture surface morphology and fracture width, the plugging speed of fiber is faster than pressure rising speed of powder; (2) with same fracture surface morphology, the plugging and bridging speed of the spherical particle is faster while fracture width is lower, the plugging and bridging speed of the cylindrical particle is faster while fracture width is high; (3) with the same temporary plugging agent, fracture surface morphology has negligible effect on pressure rising speed when the fracture width is low, while it has obvious effect when the fracture width is high; (4) the bridging and plugging of temporary plugging agent experienced the process of attachment of fiber or powder at fracture surface, decrease of cross section of fracture, the bridging of temporary plugging agent, infill of fiber or powder, and completely block of fracture.

10.6056/dkyqt202206019