DESIGN APPROACH OF INVERTED PENDULUM DRILL ASSEMBLY

Inverted pendulum drill assembly is one kind of new drill assembly for well deviation control, it displays well packed hole character under the small deviation angle and high bit pressure guards. In order to correctly use this kind of drill assembly, the authors of the article take the 311.5mm well as example to study the design approach of inverted pendulum drill assembly and provide the basis for Inverted pendulum drill assembly optimized design. Through analyzing size paring of the stabilizer above and below drill collar, as well as the different pendulum length, it is recognized that suitably increasing drill collar size above stabilizer and reducing the drill collar size below stabilizer and increasing the color length between stabilizer and bit can enhance the well deviation control ability of inverted pendulum drill assembly. When designing the inverted pendulum drill assembly, big drill bit corner should be obtained if the drill collar between bit and stabilizer don't contact the borehole wall.