Casing tube max outer diameter 115-350mm ODEX drill bits eccentric overburden casing system for deep water wells drilling

Working Steps:1. The overburden drilling system is consist of DTH hammer, eccentric designed reaming and pilot bit, guide device and casing. The eccentric bit reaming rotates outward to drill a larger hole so as to enable the steel casing enter the hole simultaneously. Rock dust is blown out of the hole through the casing pipe.2. After drilling to the specific depth, the reamer will be retracted by slightly reversing the rotation direction or by pulling the tool, and it is the time that drilling tools can be pull out.3. Pulling the casing up and meanwhile filling concrete or other things underthe hole.4. Using ordinary drilling bit can continuously drill the hole, while DTH bit can drill to the required depth.