Abstract: The invention relates to a rock-cutting tool and a method for manufacturing this tool, which comprises knives comprising a layer of polycrystalline synthetic diamond (PSD), a diamond impregnation layer with diamond particles and bonding cobalt, characterized in that the PSD layer is supported directly, along a planar interface, on the diamond impregnation layer whose interface surface is planar by machining and with which the diamond particles are flush.

Abstract: The invention relates to a rock-cutting tool and a method for manufacturing this tool, which comprises knives comprising a layer of polycrystalline synthetic diamond (PSD), a diamond impregnation layer with diamond particles and bonding cobalt, characterized in that the PSD layer is supported directly, along a planar interface, on the diamond impregnation layer whose interface surface is planar by machining and with which the diamond particles are flush.

Abstract: Stabilizer-reamer for drilling string characterized in that it comprises a mixture of diamond impregnated inserts, the mixture comprising cutting diamond impregnated inserts and wear resistant diamond impregnated inserts, said wear resistant diamond impregnated inserts having smaller diamond grain size and higher diamond concentration than said cutting diamond impregnated inserts.

Abstract: Stabilizer-reamer for drilling string characterized in that it comprises a mixture of diamond impregnated inserts, the mixture comprising cutting diamond impregnated inserts and wear resistant diamond impregnated inserts, said wear resistant diamond impregnated inserts having smaller diamond grain size and higher diamond concentration than said cutting diamond impregnated inserts.

Abstract: A bit for drilling wells has a front face with radial blades having cutting elements distributed around the front face. A space for forming a core is situated at the center of the front face. A cavity is provided for evacuating the core towards a periphery of the bit. At least a portion of the cavity is situated between adjacent blades. The cavity is delimited by two lateral surfaces and a clearance surface set back with respect to the front face, and the cavity is open in a direction opposite the clearance surface. The bit may be used in methods for drilling wells and makes it possible to rapidly drill wells of great depth in all types of rock without the risk of clogging.

Abstract: A bit for drilling wells has a front face with radial blades having cutting elements distributed around the front face. A space for forming a core is situated at the center of the front face. A cavity is provided for evacuating the core towards a periphery of the bit. At least a portion of the cavity is situated between adjacent blades. The cavity is delimited by two lateral surfaces and a clearance surface set back with respect to the front face, and the cavity is open in a direction opposite the clearance surface. The bit may be used in methods for drilling wells and makes it possible to rapidly drill wells of great depth in all types of rock without the risk of clogging.

Abstract: The invention relates to a bit for drilling wells comprising:—a front face,—a plurality of radial blades (2) provided with cutting elements (3), the blades being distributed around the front face,—a space (4) for forming a core (10), the space being situated at the centre of the front face,—a cavity (5) for evacuating the core towards the periphery of the bit, the cavity being situated between two adjacent blades. The invention also relates to a method for drilling wells using the bit. The invention makes it possible to rapidly drill wells of great depth in all types of rocks without the risk of clogging.

Abstract: A drill bit as used in particular in the oil well drilling field comprising a central body (2), cutting blades (3) protruding with respect to the body (2), both at the front of this body according to a drill direction and at the sides of this same body (2), and cutting elements (9) divided over an outer front surface (10) and over an outer lateral well sizing surface (11) comprised by each blade (3), wherein there are provided as cutting elements: in a central area (13) of the front surface (10), on at least one blade (3): at least one synthetic polycrystalline diamond compact cutting disc (12), and in a remaining area (14) of the front surface (10) of this blade, situated beyond said central area (13) with respect to the rotation axis, and on the other blades: thermally stable synthetic diamonds and/or impregnated diamond particles.

Abstract: A drilling tool including a drilling head equipped with cutting edges and fitted with several shock-absorption elements, of which at least one part is made of an elastomer material. Each shock-absorption element having a block incorporating one portion inserted inside a receptor housing formed on the tool surface, and a portion which projects outward beyond the receptor housing.

Abstract: An integral tool bit for drilling a rock formation, including a cemented metal carbide holder (30) attached to the tool and joined, e.g. soldered, to a plate (34) in the form of a cylindrical disc made from polycrystalline diamond particles and having a side wall (40), and a substantially flat free surface (36). The plate (34) is positioned so that the plane of its free flat surface (36) is at an acute angle (.alpha.) to a line (N) normal to the surface (25) of the rock formation, and the angle is directed in the same direction as the forward direction (F) of the drill bit so that the plate engages the rock formation with its side wall (40).

Abstract: Hardfacing to protect wear surfaces of drill bits and other downhole tools having coated diamond particles dispersed within and bonded to a metallic matrix deposit. The coating on the diamond particles may be formed from materials and alloys such as particles, tungsten carbide, and tungsten carbide/cobalt and cermets such as metal carbides and metal nitrides. The coated diamond particles are preferably sintered and have a generally spherical shape. The coated diamond particles are pre-mixed with selected materials such that welding and cooling will form both a metallurgical bond and a mechanical bond within the solidified metallic matrix deposit. A welding rod is prepared by placing a mixture of coated diamond particles, hard particles such as tungsten carbide/cobalt, and loose filler material into a steel tube.

Abstract: Hardfacing to protect wear surfaces of drill bits and other downhole tools having coated diamond particles dispersed within and bonded to a metallic matrix deposit. The coating on the diamond particles may be formed from materials and alloys such as particles, tungsten carbide, and tungsten carbide/cobalt and cermets such as metal carbides and metal nitrides. The coated diamond particles are preferably sintered and have a generally spherical shape. The coated diamond particles are premixed with selected materials such that welding and cooling will form both a metallurgical bond and a mechanical bond within the solidified metallic matrix deposit. A welding rod is prepared by placing a mixture of coated diamond particles, hard particles such as tungsten carbide/cobalt, and loose filler material into a steel tube.

Abstract: A pair of stabilizers are placed in a string of drill pipe having a drill bit or a coring bit at its lower end, the placement of the stabilizers being such that the distance (d1) between the midpoint (mean transverse section) of the gauge surface of the bit and the midpoint (mean transverse section) of such first stabilizer bears a relationship to the distance (d2) between the midpoints of the two stabilizers. The ratio of d1 to d2 (d1/d2) should be between 1/1.5 to 1/5, and preferably between 1/2 and 1/3, with d1 being maintained less than five feet, preferably less than three feet. In one embodiment, the drill bit and the two stabilizers are formed in a monoblock.