Theoretical analysis and design of hydro-hammer with a jet actuator: An engineering application to improve the penetration rate of directional well drilling in hard rock formations

PLoS One. 2018 May 16;13(5):e0196234. doi: 10.1371/journal.pone.0196234. eCollection 2018.

Abstract

Rapid horizontal directional well drilling in hard or fractured formations requires efficient drilling technology. The penetration rate of conventional hard rock drilling technology in horizontal directional well excavations is relatively low, resulting in multiple overgrinding of drill cuttings in bottom boreholes. Conventional drilling techniques with reamer or diamond drill bit face difficulties due to the long construction periods, low penetration rates, and high engineering costs in the directional well drilling of hard rock. To improve the impact energy and penetration rate of directional well drilling in hard formations, a new drilling system with a percussive and rotary drilling technology has been proposed, and a hydro-hammer with a jet actuator has also been theoretically designed on the basis of the impulse hydro-turbine pressure model. In addition, the performance parameters of the hydro-hammer with a jet actuator have been numerically and experimentally analyzed, and the influence of impact stroke and pumped flow rate on the motion velocity and impact energy of the hydro-hammer has been obtained. Moreover, the designed hydro-hammer with a jet actuator has been applied to hard rock drilling in a trenchless drilling program. The motion velocity of the hydro-hammer ranges from 1.2 m/s to 3.19 m/s with diverse flow rates and impact strokes, and the motion frequency ranges from 10 Hz to 22 Hz. Moreover, the maximum impact energy of the hydro-hammer is 407 J, and the pumped flow rate is 2.3 m3/min. Thus, the average penetration rate of the optimized hydro-hammer improves by over 30% compared to conventional directional drilling in hard rock formations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Equipment Design / standards*
  • Groundwater / chemistry*
  • Humans
  • Mechanical Phenomena
  • Minerals / metabolism*
  • Models, Theoretical*
  • Water Supply / standards*

Substances

  • Minerals

Grants and funding

The research work was financially supported by the National Natural Science Foundation of China (51674050) to YPL, the National Science and Technology Major Project of China (Grant No. 2016ZX05043005 & 2016ZX05045004) to YPL, the State Key Research Development Program of China (Grant No. 2017YFC0804202, 2016YFC0801402 & 2016YFC0801404) to YPL, the Project funded by China Postdoctoral Science Foundation (Project NO. 2017M612916) to JFH, the Project funded by Chongqing Postdoctoral Research Foundation (Project NO. Xm2017068) to JFH, and the Fundamental Research Funds for the Central Universities (Project No. 106112015CDJZR245520 & 106112017CDJXY240001) to YJL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.