脉冲射流式液动冲击工具的研制及现场应用

目前,对于水力脉冲射流的研究主要集中在脉冲流场及其作用效果等方面,而在液动冲击与脉冲射流协同破岩方面则还是空白。为此,基于脉冲射流相关理论,将液动冲击提速与脉冲射流协同破岩有效结合起来,分析其工作原理与实现条件,研制了脉冲射流式液动冲击钻井工具,并通过室内试验和现场实验验证了该工具的破岩能力。结果表明:(1)冲击体质量小于60 kg时,该工具能够运行;(2)液动冲击与脉冲射流协同作用下的钻具组合破岩能力明显优于其他钻具组合的破岩能力,在水平钻进过程中,其提速效果更明显;(3)冲击效果由冲击体的质量和冲击频率决定,质量为30 kg的冲击体的冲击效果更好;(4)脉冲射流越大,其破岩能力越强,减小工具喷嘴的直径能够增大脉冲射流;(5)液动冲击对高硬度岩石的破碎具有更明显的加速效果,对于胶结程度较差的岩石,通过增大脉冲射流,可更大幅度地提高破岩速度。现场应用效果表明,液动冲击与脉冲射流协同作用下的钻具组合的机械钻速为2.52 m/h,较之于常规钻具组合,该工具平均提速可达72.5%。结论认为,该工具为解决深井与水平井钻进速度慢、压持效应明显与岩屑清理困难等问题提供了新的思路。

Development and field application of a pulse–jet hydraulic impactor

The current studies on hydraulic pulse jet mainly focus on the pulse jet flow field and its effect, but have never extended to the collaboration of hydraulic impact and pulse jet for rock breaking. In this paper, both hydraulic impact and pulse jet were combined effectively to develop a pulse–jet hydraulic impactor for drilling after analyzing the working principles and realization conditions. The rock breaking capacity of this tool was verified through laboratory experiments and field tests. The following results were obtained. First, the tool can run when the mass of the impactor body is less than 60 kg. Second, the rock breaking capacity of the drilling assembly under the synergistic action of hydraulic impact and pulse jet is obviously better than that of other drilling tools, and the tool is much more efficient than other tools in ROP enhancement. Third, the impact effect is dependent on the mass and impact frequency of the impactor and the impactor with the mass of 30 kg is better in impact effect. Fourth, the larger the impulse jet, the higher its rock breaking capacity is. The pulse jet can be increased by reducing the diameter of the tool's nozzle. Fifth, hydraulic impact can help accelerate the breaking of high-hardness rocks, and the breaking of less-cemented rocks can be greatly enhanced by increasing the pulse jet. Field application results show that the ROP of the drilling tool based on the collaboration of hydraulic impact and pulse jet is 2.52 m/h, which is 72.5% higher than that of conventional drilling assemblies. It is concluded that this developed pulse–jet hydraulic impactor provides a new idea to solve the problems in deep wells and horizontal wells, such as low drilling speed, obvious chip hold down effect and difficult cuttings removal.