ORIENTED BENT SUB
The oriented sub is a major power deflection tool having a fixed angle (a) deviated from low end thread of the bent sub to axial line of drill stem, the power drill tool under the application of oriented sub give the bit a constant lateral force to ensure that the bit can cut on the well wall laterally and further drill into a curved well trace.
Operation method-oriented sub:
After the bit and oriented sub are connected and screwed, detecting of the angle between the big water hole of bit and oriented key of oriented sub shall be done;
After run in drill tool, calculate out the azimuth of big water hole of bit according to the azimuth of oriented key determined at a single point by drift indicator;
Change the big water hole of bit into required azimuth, then lock in rotary and start pump drilling to cut in;
During deflecting, taking a way that deflect while lightly pressing and crowning of drill to help deflection;
After deflected for 2 to 3 meters, drill in 4 to 5 meters with lightly pressure and rotating slowly;
Repeat above operation for several times, when the angle of deviation is up to the expected requirement deflecting in can be done smoothly by reducing of drill pressure and increasing of rotating speed.