Abstract: This invention relates to a wire line core barrel inner tube assembly capable of travelling longitudinally within a drill string toward and away from a drill bit carried on the lower end of the string, the drill string having an annular landing shoulder therein. The inner tube assembly includes an elongated body having an annular landing shoulder adapted to co-operate with and seat on the landing shoulder of the drill string when in use. The body has a valve chamber defined therein and inlet and outlet ports leading from the valve chamber to the exterior of the body on opposite sides of the landing shoulder. These define a by-pass passage through which drilling liquid passing along the drill string must flow on its way toward the bit when the landing shoulder of said body is seated on the landing shoulder of the drill string. The valve chamber has a valve seat therein and a valve closure is located within the valve chamber.

Abstract: A stabilized drill string component includes an elongated tubular body. This body comprises a tubular stabilization section and at least one further tubular section. These tubular sections are integrally joined together in axially aligned relation. The stabilization section is much shorter than the further tubular section or sections but has a somewhat greater diameter than the latter such that the stabilization section can assist in stabilizing the drill string component during drilling by way of contact with the wall of the well bore. The wearing surfaces of the stabilization section are of substantially harder material than that of the further tubular section or sections thereby to provide substantial resistance to wear.