Reverse Circulation DTH Hammer Drilling Technique

The reverse circulation DTH hammer drilling technique is an important constituent part of the Multi-Tech air drilling technology, and more importantly, it is a major break through of air drilling technology. It is combined with DTH impacting breaking rock, flushing medium reverse circulation and continuous coring three advanced drilling techniques into one system, and naturally it has become an integrated high-tech drilling techniques. The hollow-through DTH, reverse circulation bit, and dual-wall drilling tool are constituted the center channel, then the flushing medium along with the center channel to form the reverse circulation, so it is realized the core transportation in the process of drilling and effectively solved the problem of the orifice dust pollution. At present, this drilling technology is developing rapidly along with the application filed which are gradually expanded, and it has got good applications in drilling engineering filed such as geological core exploration, water well drilling and foundation engineering.

Key technologies of reverse circulation DTH hammer drilling

1. Structural design on the hollow-through DTH hammer

The key of structural design on the DTH hammer is the hollow pore design. The center of hammer’s all parts is the hollow-through tube structure. The hollow-through pore and the pre-and-post air chambers are completely closed, and the inner tube formed the hollow-through pore are crossing all parts, with its the upper part connecting with the inner tube of drill pipe and the lower part cottage grafting drilling bit to form the reverse circulation channel. At the same time, the inner tube has gas distribution function.

2 Computerized emulation of DTH hammer

Firstly, using the basic theory and mathematical formula to build up the mathematical model. Secondly, based on the finite difference theory to develop the computer software. Finally, it is achieved the computerized emulation on hammer dynamic process, piston reciprocating motion law and hammer performance parameters. With the computer assisted the optimum design, the actual test parameters are highly anatomized with the computerized emulation parameters. The working performance is good, and the effective heat efficiency is high, and consequently design of hammer becomes scientific. It changes the traditional design methods, shortens the development cycle, saves the research cost and optimized the hammer performance.

Post time: Nov-28-2022