Christensen, Inc.

David S Rowley

James T Aumann

Coy M Fielder

Bruce H Walker

Heino J Rohde

Lothar H Waldes

An improved coring device that incorporates a nonrotatable inner barrel disposed within the outer driving structure of the drill string which is coupled to a coring bit. A woven metal mesh sleeve is circumferentially mounted outside the inner barrel and tucked around its lower end. The lower end of the mesh sleeve in the inner barrel is in turn connected to a stripper tube which is pulled upwardly during the coring operation. As the core is cut by the coring bit and enters the inner barrel, the woven metal mesh sleeve is disposed about the core and constricts about the core when pulled upwardly by the stripper tube. The opposing end of the woven metal mesh sleeve is connected to a weight which serves to compress the metal sleeve when outside the inner barrel, thereby increasing its diameter to prevent binding or jamming.

Coring device with an improved core sleeve and anti-gripping collar

A composite drill collar for drilling bore holes in earth formations including a structural steel outer jacket having a lower end secured to a lower coupling connectable to a drill bit and an upper end secured to an upper coupling connectable to an adjacent drill collar thereabove. An annular heavy metal core of sintered tungsten is disposed in the jacket and is held in compression therein by preloading the lower and upper couplings against the ends of the core, which places the jacket in tension, causing the jacket to contract and grip the periphery of the core. The structural steel jacket has a thick wall to carry the bending, torsion, compression, tension and impact loads encountered in the drilling operation, so that such loads are not carried through the core, which has the purpose of increasing the overall density and mass of the composite drill collar, lessening considerably the tendency for a deviated well bore to be produced.

Composite heavy metal drill collar

The invention relates to the design of earth bore-hole drill bits employing shaped preform cutters containing hard abrasive materials, such as diamonds, the cutters being mounted in companion preformed sockets in a hard metal bit matrix.

Earth-boring drill bits

A diamond drill bit for drilling bore holes in earth formations having a body connectible to a drilling string, and provided with a matrix portion of hard metals in which diamonds are surface set at the outer gage portion and adjacent to the bit axis, the hard metal matrix having preformed grooves in which preformed diamond impregnated segments are inserted, which are a mixture of diamonds and hard metals, and secured to the matrix portion by brazing material. During bit rotation in the bore hole, the segments cut the major portion of the hole, the diamonds being dispersed throughout the mass of each segment for selective release from the segment as the diamonds become damaged and lost, thereby exposing new diamonds in the segment at a controlled rate, and thereby producing continual resharpening of the segments. As a result, the drilling rate of the bit is increased, as well as the length of hole drilled.

Drill bits embodying impregnated segments

The invention relates to the design of earth boring bits employing shaped preform cutters containing hard abrasive materials such as diamonds.

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Salt Lake City, UT, United States of America

David S Rowley