Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Cornering water jet drill for creating horizontal holes in coal seams

Technical Report ·
OSTI ID:6898103

Sandia National Laboratories has developed a drilling system which uses high velocity water jets to make horizontal holes in coal seams accessed through vertical boreholes. For underground coal gasification (UCG), these horizontal holes can be drilled to create linking paths between vertical or horizontal process wells. Three test series have been conducted to study and improve the drilling system and, ultimately, to prove the viability of the concept. With the exception of a persistent string binding problem, which ultimately determined the hole depth, all drill system components either performed as designed or exhibited weaknesses which could be remedied with minor alterations. The cornering water jet drill (CWJD) concept was proven to be viable for drilling horizontal holes in coal seams. For distances greater than 50 ft (15.2 m), however, making the process a routine operation will require additional study and improvement. 12 references, 16 figures.

Research Organization:
Sandia National Labs., Albuquerque, NM (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6898103
Report Number(s):
SAND-84-0228; ON: DE84012895
Country of Publication:
United States
Language:
English