| 摘要 |
An improved directional drilling tool permits the control of the angle of drilling of a drill bit through the repeated placement or removal of a ball within the mudstream. The ball activates, clutch mechanism within the directional drilling tool. The clutch mechanism, controlled by the activated valve, locks the exterior of the directional drilling sub to a fixed angular orientation and activates a deflection cam to deflect a drive shaft so as to angle the bit, causing the bit and sub to drill at a controlled angle offset from the vertical. The unit is aligned and located using wire line measuring equipment of known design. Since the sub may be controllably set in a straight line drilling or an angle drilling position, it may be left permanently in position in a drill string significantly reducing the requirement to trip out the well bore during directional drilling and significantly increasing the flexibility available to the driller to deflect the direction of drilling while drilling is in progress. |
