초록 ▼

A stabilized drill bit has a cylindrical main body, a formation cutting face at the lower end of the body, and means by which the upper end of the bit can be connected into a drill string. A drilling fluid flow passageway extends axially through the main body and provides flow of drilling fluid to t

A stabilized drill bit has a cylindrical main body, a formation cutting face at the lower end of the body, and means by which the upper end of the bit can be connected into a drill string. A drilling fluid flow passageway extends axially through the main body and provides flow of drilling fluid to the drilling face. A plurality of hydraulic actuated stabilizing members are arranged circumferentially about the throat and within the main body. Stabilizing members have a borehole wall engaging face thereon which can be retracted flush with the outer surface of the main body, and extended away from the main body face and into contact with the borehole wall, thereby stabilizing the drill bit as the bit is rotated while making hole. Hydraulic means is connected to the stabilizing members by which the members are progressively extended toward the borehole wall as the members become worn, and which normally prevents retraction of the stabilizing members so long as drilling fluid pressure is effected within the passageway. The stabilizing members are retracted when the drilling fluid is reduced to a predetermined value.

대표청구항 ▼

A stabilized drill bit comprising: a generally cylindrical main body having means at an upper end thereof for attachment to a driving means; a drilling face at the lower end of said main body; drilling cutters secured to said face; a throat formed through said main body for passage of drilling fluid

A stabilized drill bit comprising: a generally cylindrical main body having means at an upper end thereof for attachment to a driving means; a drilling face at the lower end of said main body; drilling cutters secured to said face; a throat formed through said main body for passage of drilling fluid to said face; flow restricting means positioned in the fluid path of the bit with said flow restricting means arranged to provide a fluid pressure drop therethrough; radially active stabilizing means for radially stabilizing said main body; means responsive to fluid pressure in said bit for applying outward force on said radially active stabilizing means and thereby moving said radially active stabilizing means into any one of a range of different extended positions; and blocking means for selectively preventing inward radial movement of said radially active stabilizing means from any of said extended positions upon application of radial force upon said main body opposed to said radially active stabilizing means sufficient to displace said fluid pressure in said bit.