Patent ID: 7021404

Claim:
A method for coring through a wall of a bore hole which has been drilled previously in an underground formation, in order to carry out coring deviated transversely with respect to a longitudinal direction of the bore hole, the method being comprising: selecting a core barrel provided with a core bit having an inner gauge bore; arranging an internal guide within the core barrel, the internal guide comprising a material resistant to the abrasion of a bit; disposing the internal guide inside at least the inner gauge bore before beginning a deviated coring operation, the internal guide disposed such that the bit can move along the internal guide; extending the internal guide in front of the bit, according to a forward direction of coring thereof, with progressive deviation of the bit from the longitudinal direction towards the wall, following a desired deviated path direction; detachably fixing to the bit, and in front thereof according to its forward direction of coring, a destructible element, the destructible element made of a material operable to be destroyed by the bit in the process of deviated coring, and dimensioned to be disposed in the bore hole, fixing a guidance means within the destructible element to give a deviated path direction to the internal guide in front of the bit; initiating coring with the bit; and guiding the bit through cooperation between the inner gauge bore and the internal guide until the wall and the formation are penetrated to a desired depth following the deviated path.