Patent ID: 7168147
Filing Date: 2007-01-30
Classification: E21B,F16J,Y10T

Abstract:
1. A method of sealing between a rotating and a static component of a subterranean drilling tool, comprising: (a) molding an annular seal having an inner diameter surface and an outer diameter surface and being from an elastomeric material of generally uniform composition and curing the seal to provide a property that is at a substantially uniform selected level throughout the seal; then (b) exposing the seal to an environment to form a property gradient on at least one of the surfaces of the seal wherein the property changes progressively from a surface level at said one of the surfaces to the selected level without essentially changing the composition of the elastomeric material; (c) forming a seal gland between the rotating component and the static components of the tool; and (d) placing the seal in the seal gland with one of the surfaces in contact with the rotating component and the other surface in contact with the static component.