Patent ID: 8511377

Claim:
A non-rotating downhole sleeve adapted for open hole drilling and/or centralization in a casing or on a casing in a wellbore, the downhole sleeve comprising: a tubular body made from a molded polymeric material and having an inside surface adapted to surround a drill pipe or casing, the inside surface of the tubular body having circumferentially spaced apart axially extending grooves positioned between substantially flat bearing surface regions for contacting the outer surface of the drill pipe or casing, the axial grooves allowing drilling fluid to circulate therethrough to form a non-rotating fluid bearing upon circulation of fluid between the tubular body and the drill pipe or casing, characterized in that: the tubular body has a plurality of helical blades integrally formed with the polymeric tubular body and projecting from an outer surface of the tubular body, the helical blades having outer surfaces adapted for contact with the casing or an open hole drilled in formation below a casing exit, the blades providing a flow path for fluid passing between the blades, the flow path passing through the wellbore between upper and lower ends of the tubular body, in which the helical blades have a blade height (h) and an average blade width (w) such that during rotation of the sleeve a minimum of two blades are positioned to contact the casing exit, the blades have a generally parallel and helical spacing having an average distance between blades which is substantially equal to the average width (w) of the helical blades.