Abstract: A process is presented which produces at least one block of dense material constituted by hard particles dispersed in a binder phase, it being possible for the dense material to be enriched locally with binder phase by imbibition. The process includes bringing at least one imbibition area of a surface of the block, preferably coated with a coating material, into contact with an imbibiting material which locally enriches the block with binder phase. The block in contact with the imbibiting material is then subjected to a suitable thermal cycle constituted by heating, temperature maintenance and cooling. This serves to bring some or all of the imbibiting material and the binder phase of the block into the liquid state in such a manner that the enrichment with binder phase takes place solely through the imbibition area. The block is used in connection with the building of a drill bit or tool.

Abstract: A process is presented which produces at least one block of dense material constituted by hard particles dispersed in a binder phase, it being possible for the dense material to be enriched locally with binder phase by imbibition. The process includes bringing at least one imbibition area of a surface of the block, preferably coated with a coating material, into contact with an imbibiting material which locally enriches the block with binder phase. The block in contact with the imbibiting material is then subjected to a suitable thermal cycle constituted by heating, temperature maintenance and cooling. This serves to bring some or all of the imbibiting material and the binder phase of the block into the liquid state in such a manner that the enrichment with binder phase takes place solely through the imbibition area. The block is used in connection with the building of a drill bit or tool.

Abstract: The invention concerns a self-penetrating drilling method and a thrust-generating tool: the tool comprises N blades. Each blade comprised K drill cutters. The shapes, positions and orientations of said drill cutters are determined in the following manner: the kth drill cutter of the last blade drills, at the (q?1)th of the tool rotational cycle, a cut in the rock downstream of the one produced by the (k+1)th drill cutter of the first blade at the qth rotational cycle of the tool; the kth drill cutter of the nth blade drills, at the qth rotational cycle of the tool, a cut in the rock downstream of the one produced by the kth drill cutter of the (n+1)th blade at the qth rotational cycle of the tool; the normal to the leading edge of the drill cutter has a component along the axis of rotation oriented towards upstream.

Abstract: The invention concerns a method which includes the steps of: introducing into a pre-drilled portion of a well (16) a drilling system containing a drilling bit (11) assembled with tubular lining elements (15), an element for measuring the inclination and azimuth direction of the pre-drilled part of the well, an element for rotary friction (26, 27) against the wall of the pre-drilled part and an element capable of modifying the friction coefficient of the friction element against the wall; measuring the azimuth direction of the pre-drilled part of the well (16); and varying the friction coefficient of the friction element (26, 27) sufficiently to influence the azimuth direction of the next well portion to be drilled.

Abstract: The invention concerns a self-penetrating drilling method and a thrust-generating tool: the tool (1) comprises N blades (2a, 2b, 2c, 2d). Each blade comprised K drill bits (3a, 3b, 3c, 3d). The shapes, positions and orientations of said drill bits are determined in the following manner: the kth drill bit of the last blade drills, at the (q−1)th of the tool rotational cycle, a cut in the rock downstream of the one produced by the (k+1)th drill bit of the first blade at the qth rotational cycle of the tool; the kth drill bit of the nth blade drills, at the q?th rotational cycle of the tool, a cut in the rock downstream of the one produced by the kth drill bit of the (n+1)th blade at the qth rotational cycle of the tool; the normal to the leading edge of the drill bit has a component along the axis of rotation oriented towards upstream.

Abstract: The invention concerns a method which consists in: introducing into a pre-drilled portion of a well (16) a drilling system comprising a drilling bit (11) assembled with tubular lining elements (15), means for measuring the inclination and azimuth direction of said pre-drilled part of the well, means for rotary friction (26, 27) against the wall of said pre-drilled part and controlled means capable of modifying the friction coefficient of said friction means against the wall; measuring the azimuth direction of the pre-drilled part of the well (16); and varying the friction coefficient of said friction means (26, 27) sufficiently to influence the azimuth direction of the next well portion to be drilled.