Dual circulation water hammer drilling system

摘要

A dual circulation fluid hammer drilling system (10) has a fluid hammer (12) which is coupled to a drill string (14). The system (10) utilizes a first fluid (16) and a second fluid (18). The first fluid (16) is delivered through the drill string (14) to drive or otherwise power the fluid hammer (12). The second fluid (18) is also delivered through the drill string (14) but in isolation of the first fluid (16) so they do not mix within the drill string (14). The second fluid (18) passes through a hammer bit (38) of the hammer drill (12) and is directed to flow out from a bit face (20). Thus when the system (10) is in use the second fluid (18) will flow across the bit face (20). The first fluid (16) also exits the drilling system (10) at the hammer drill (12). However the first fluid (16) exits upstream or up-hole of the bit face (20).