دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: the amount by which lines drawn through the centre of each cone of a bit fail to meet in the centre of the bit. For example, in a roller cone bit with three cones, three lines can be drawn through the centre of each cone and extended to the centre of the bit If these cone centrelines do not meet in the bits centre, the coles are said to be offset In general, bits designed for drilling soft formations have more offset than cones for hard formations, because offset affects the angle at which the bit teeth contact the formation. Since soft formations require a gouging and scraping action by bit teeth, high offset achieves the necessary action.

n: Refers to the situation that the axiss of cone dont convergence at the centre line of cone bit.

n: clastation

n: a roller cone bit each cone of which displays offset from a centre point when a line is extended through the middle of each cone. Offset roller cone bits are usually employed to drill soft formations. because the offset causes the teeth on the cone to gouge and scrape the formation. Gouging and scraping action is required to penetrate soft formations.

n: A kind of crushing ways of the cone bit to the bottom hole when drilling the soft formation.