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The hydrastab is shorter (97") than currently available VGS tools, thereby ensuring maximum inclination control when using the hydrastab in conjunction with all types of downhole motors. In addition, the shorter tool reduces the distance between bit and motor when running the hydrastab below the motor e.g. in horizontal lateral sections. The hydrastab is two positional and operated from surface by means of reducing and then increasing pump flow. Unlike the older, mechanically actuated tools, no weight has to be applied to the string to move the tool from one position to the other. Because the hydrastab is hydraulically actuated, it is ideal for running above or below motors, the blade change being carried out without fear of stalling the motor or damaging the PDC bit. In addition, the hydrastab has a nominal pressure loss and does not compromise bit hydraulics when being run in either rotary or, motor based bottom hole assemblies. A further feature of the new tool is the significant increase in extended blade coverage, when compared directly against the other piston type tools currently on the market. The hydrastab is able to offer this additional stabilisation because the pistons are 3" in diameter and are spaced closely together. Crown length is reduced from the normal 24" to 20" and because of the increased piston size, it is possible to utilise a large internal dampening / return spring. The spring ensures that the pistons can not 'hammer' off the internal mandrel as the BHA rotates, thereby prolonging tool life and reducing rechargeable maintenance and servicing costs. Another feature of the hydrastab is the option of melon shaped pistons for use above or below motors. The close spacing and large diameter pistons allows the directional driller to run the same melon shape stabilizer blades generally preferred when running downhole motors. Unique hydrastab features: 20% increase in full gauge blade coverage Overall tool length is eight feet - making it the shortest vgs tool currently in the marketplace Length from box end to spiral blade is 32" - making it ideal for above/below motor and nearbit applications Patented hydraulic actuation system Pumps off to change gauge / pumps on to lock gauge 200-psi pressure differential which tells the driller the position the tool is in Over the hole / changeable choke unit which allows the driller to increase or decrease the pressure differential when required Internal cartridge unit for ease of servicing and efficient, cost-effective maintenance Optional surface read-out, thereby reducing the need for an offshore engineer
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