Hydraulic Hammer Drilling Technology: Developments and Capabilities

TLDR

Percussion drilling was once seen as the best for hard rock, but most hydraulic hammer designs were inefficient (≈8 %) and limited to shallow boreholes; recent research suggests efficiency could rise to 70 %. The paper aims to explore how hydraulic hammer efficiency can be increased to 70 % by presenting its basic design principles and operational features. The authors describe the fundamental design principles and operational characteristics of hydraulic hammer systems. A new generation of hydraulic hammers achieves 40 % efficiency, enabling hard‑rock drilling to depths of 2000 m and beyond, and recent U.S. tests show advantages for coiled‑tubing drilling.

Abstract

Percussion drilling technology was considered many years ago as one of the best approaches for hard rock drilling. Unfortunately, the efficiency of most hydraulic hammer (HH) designs was very low (8 percent maximum), so they were successfully used in shallow boreholes only. Thirty years of research and field drilling experience with HH application in former Soviet Union (FSU) countries led to the development of a new generation of HH designs with a proven efficiency of 40 percent. That advance achieved good operational results in hard rock at depths up to 2000 m and more. The most recent research has shown that there are opportunities to increase HH efficiency up to 70 percent. This paper presents HH basic design principles and operational features. The advantages of HH technology for coiled-tubing drilling is shown on the basis of test results recently conducted in the USA. [S0195-0738(00)00101-1]