自进式旋转射流钻头破岩效果

利用有限的排量实现高效的破岩效率并尽可能增大径向水平井眼的延伸能力是实施新型径向水平井技术的关键,射流钻头的性能是该关键技术要解决的首要问题。在多孔射流钻头的基础上,设计研制了自进式旋转射流钻头,分析了其工作原理,并通过试验对自进式单孔旋转射流钻头、自进式单孔直旋混合射流钻头、自进式多孔旋转射流钻头以及自进式多孔直旋混合射流钻头随时间、射流压力和喷距的破岩钻孔规律进行了研究。研究结果表明:当喷距范围为9~12 mm、射流压力为20~35 MPa时,在相同的射流压力和喷距条件下,自进式多孔直旋混合射流钻头的破岩效果优于自进式多孔旋转射流钻头,其中1+4孔的多孔直旋混合射流钻头的破岩效果最好。设计得到的新型射流钻头可以提高径向水平井的钻进速度。

Rock breaking efficiency of the self-propelled swirling jet bit

To achieve high rock breaking efficiency using the limited discharge rate and increase the extension capacity of radial horizontal wellbore is a key to perform new radial horizontal well technology. The performance of jet bit is the primary problem solved by this key technology. Based on the multi-jet bit, the authors developed a self-propelled swirling jet bit, and analyzed its working principle. Based on experiments, a study was conducted on the rock breaking and drilling laws of jet bits with the changes in time, jet pressure and standoff distance, including self-propelled swirling single-hole jet bit, self-propelled straight-swirling single-hole jet bit, self-propelled swirling multi-hole jet bit and self-propelled straight-swirling multi-hole jet bit. The results indicate that when standoff distance is 9-12 mm and jet pressure is 20-35 MPa, and under the same conditions of standoff distance and jet pressure, the rock breaking efficiency of self-propelled straight-swirling multi-hole jet bit is better than that of self-propelled swirling multi-hole jet bit, and that of self-propelled straight-swirling multi-hole jet bit (1+4 holes) was optimal. The designed new jet bit is able to improve the drilling rate of radial horizontal well.