Abstract: A method of forming a wellbore is disclosed. An inner string and an outer string are conveyed downhole. The inner string is attached to the outer string at a first location and the wellbore is formed. The inner stringy is attached to the outer string at a second location us hole of the first location and an annulus between the outer string and the wellbore is cemented without retrieving the inner string from the wellbore.

Abstract: A method of forming a wellbore is provided that in one embodiment includes conveying an inner string and an outer string downhole; attaching the inner string to the outer string at a first location and forming the wellbore; and attaching the inner string to the outer string at a second location uphole of the first location and cementing an annulus between the outer string and the wellbore, without retrieving the inner string from the wellbore.

Abstract: Apparatus for drilling and lining a wellbore is described herein. A method of drilling and lining a wellbore is also described herein. A liner hanger is provided, secured in use on a liner. The liner hanger is operable selectively to be set and unset. The liner hanger is adapted to support the liner within an existing casing when set and to release the liner from the casing when unset. A liner hanger setting tool is provided, secured in use on a drill string. The liner hanger setting tool is actuatable selectively to set and unset the liner hanger. The liner hanger setting tool is operable selectively to be activated and deactivated. The liner hanger setting tool is adapted to attach to the liner and/or liner hanger when activated, to support the liner, and to release from the liner and/or liner hanger when deactivated.

Abstract: A centralizer includes a centralizer body to be situated at the outer surface of a pipe string in the form of casing, liner, or the like used while drilling, the centralizer body being formed with a plurality of outer centralizer blades arranged in an inclined manner to the longitudinal axis thereof, wherein the centralizer body has an separate split inner tube secured to the pipe string by means of a press fit, and low friction inner surface of the centralizer body and separate center tube facing each other are made from low friction material.