井底岩屑磨料脉冲射流室内实验研究

提高深部复杂地层机械钻速，迫切需要发展新型高效破岩钻井技术。在分析现有技术的基础上，指出发展新型复合射流钻井技术是提高深部地层石油钻探效率的一个重要途径。提出了井底岩屑磨料脉冲射流钻井的技术构想，设计了相关的工具，分析了井底岩屑磨料脉冲射流破岩、辅助破岩的机理，进行了后混合磨料脉冲射流破岩室内实验研究。结果表明:冲蚀体积随泵压增大而增加，存在破岩的最佳喷距、磨料浓度和磨料粒径；在较低浓度下，后混合磨料脉冲射流的冲蚀性能较接近于前混合磨料脉冲射流；引入外部流体后射流的动压力增大了7%，脉冲幅值提高了1.5倍。研究结果为井底岩屑磨料脉冲射流钻井工具的研制和相关技术的开发提供了依据。

Study on the lab experiment of pulsed abrasive water jet using bottom hole cuttings

Based on theoretical analysis of current technologies, it is pointed out that developing high-efficiency drilling methods on the basis of new combined water jet is a good approach. A concept of pulsed abrasive water jet drilling technology, using bottomhole cuttings, is put forward, and the corresponding drilling tool is designed. The rock-breaking mechanism, assisted rock-breaking mechanism of this new drilling technology is analyzed, and the lab rock-breaking experiment of post-mixed pulsed abrasive water jet is carried out. The results show that the erosion volume grows with the increment of pump pressure, there are best rock-breaking jet length, abrasive concentration and particle size. In low concentration, the erosion energy of post-mixed pulsed abrasive jet is close to the pre-mixed pulsed abrasive jet. After the external fluid is drawn in, the jet dynamic pressure increases by 7%, while pulse amplitude increases by 150%. The above research lays solid foundation for the development of drilling tools with pulsed abrasive water jet using cuttings and related technology.