Method and apparatus for drilling wells
OwnerCyril Hindsinventor
Life of this patent
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Abstract
A well borehole is prevented from deviating from its intended vertical path as it is being drilled by use of a sub assembly which is eccentrically weighted with respect to its axis of rotation. Such a sub assembly can comprise a straight tubular member weight relieved along one side by, for example, forming a cavity within the heavy walls of the tubular member along the side of the collar. Thus, the eccentric weight is imposed upon the drill bit without providing any protrusions or elbows which are designed to bear on the wall of the borehole. Additionally, as the cavity is contained within the heavy walls of the tubular member, drilling fluids containing various debris cannot inhabit the cavity, thus maintaining a constant eccentric weight upon the drill bit.
Claims10
A drill sub assembly for connection in a drill string above a rotating drill bit comprising a sub adapted to be connected at its upper and lower ends respectively to the lower end of a drill collar and to a drill bit comprising:
- a sub having substantially parallel axis of symmetry in alignment with the drill string wherein the sub is eccentrically weighted with respect to a plane passing through an axis of rotation by at least one enclosed cavity positioned within the wall of the member.
The method of inhibiting deviation from vertical in drilling a borehole with a rotating bit on a drill string comprising:
- placing in the drilling string immediately above the bit an eccentrically weighted sub assembly, wherein the weight is eccentrically positioned with respect to the axis of rotation of the bit created by at least enclosed cavity contained within the wall of the sub assembly eccentrically positioned with respect to the axis or rotation of the bit;
- and rotating the bit while avoiding preferential bearing of any portion of the drill string against the wall of the borehole in the region of said eccentric weight.
Dependencies are inferred from the claim text.