Recirculation Concentric Overburden Casing System Symmetrix casing bits
The eccentric reamer drill is an overburden drilling system designed for conditions where a cased hole is required. Collapsing holes tend to make overburden drilling expensive, with lost drilling equipment and down time.
The eccentric designed bit rotates outward and drills a larger diameter hole than the casing, avoiding cave-ins, wash-outs, and other problems common in normal drilling operations in soft and gravel-type strata or loose rock. Since 90% of the world's overburden drilling is in loose strata, potential utilization is enormous. After reaching the designated depth, the reamer-bit is retracted by reversing the direction of the rotation and by applying tension on the reamer-bit, which has a taper and will retract into the casing for easy removal of the entire drill-string. This leaves the casing in place for other applications or for removal at a later date. The method is designed for use with flush joint threaded pipe or welded-type casing and provides a bit size for a wide variety of different casing wall thicknesses.
ODEX ECCENTRIC CASING SYSTEM In the projects of drilling,drillers often meet with problems due to the loose land formation.These may cause troubles such as difficulty in drilling down,collapse of holes,damage of drilling tools,etc.To solve the problems,the best way is to use (ODEX)Overburden Drilling System which can prevent holes and drilling tools from damage,and support the holes by casing tubes.
General Introduction HOD90 HOD115 HOD140 Overburden casing system,ODEX system, Casing drilling system,eccentric casing system 1.drill in overburden unstable rock 2.one step to drill and follow casing 3.flexible to open or close 4.effecient below 300mm Design Principles: Make the casing follow easy and the equipment and operation simple Outstanding Advantages Simple structure,simple operation,reliable quality,retrievable drilling tools,long service life. Raw Material Steel: first class special alloy steel with high strength, heat resistance and wearable Carbide The best tungsten carbides from China are commonly applied. Tungsten carbide from European is also available.
Eccentric Reamer System Step-by-step 1. When drilling starts, the reamer swings out and reams the pilot-hole wide enough for the casing tube to slide down behind the drill bit assembly. 2. When the required depth is reached, rotation is reversed carefully, whereupon the reamer swings in , allowing the drill bit assembly to be pulled up through the casing. 3. Casing tubes that are to be left in the drill hole should be sealed at the bottom of the hole by means of cement grout or some other sealing agent. 4. Drilling continues to the desired depth in the bedrock using a conventional drill string.