Abstract: A well apparatus includes a bottom hole assembly (BHA) comprising a cutting structure at one end of the BHA, a whipstock assembly for selectively deflecting the BHA to form a deviated wellbore, a whipstock connector releasably connecting the whipstock assembly to the BHA, and a whipstock support member extending between the BHA and the whipstock assembly and spaced from the whipstock connector.

Abstract: A well apparatus includes a bottom hole assembly (BHA) comprising a cutting structure at one end of the BHA and a whipstock assembly for selectively deflecting the BHA to form a deviated wellbore. The apparatus further includes a whipstock connector releasably connecting the whipstock assembly to the BHA and a whipstock support member extending between the BHA and the whipstock assembly and spaced from the whipstock connector.

Abstract: A window milling system can include a window mill having selectively retractable and extendable blades, and a whipstock assembly having a receptacle therein, the window mill being secured relative to the whipstock assembly the blades are received in the receptacle. A method of cutting a window through a wellbore lining can include cutting through the lining with a window mill, then retracting blades of the window mill, and then outwardly extending the blades in a whipstock assembly, thereby securing the whipstock assembly to the window mill. A window mill can include multiple blades adapted for cutting through a wellbore lining, the blades being outwardly extendable relative to a body of the window mill in a well. Another method of cutting a window through a wellbore lining can include a window mill drilling a wellbore outward a substantial distance from the window after the window mill cutting through the lining.

Abstract: A window milling system can include a window mill having selectively retractable and extendable blades, and a whipstock assembly having a receptacle therein, the window mill being secured relative to the whipstock assembly the blades are received in the receptacle. A method of cutting a window through a wellbore lining can include cutting through the lining with a window mill, then retracting blades of the window mill, and then outwardly extending the blades in a whipstock assembly, thereby securing the whipstock assembly to the window mill. A window mill can include multiple blades adapted for cutting through a wellbore lining, the blades being outwardly extendable relative to a body of the window mill in a well. Another method of cutting a window through a wellbore lining can include a window mill drilling a wellbore outward a substantial distance from the window after the window mill cutting through the lining.

Abstract: A casing exit joint with an easily milled and low density barrier. A casing exit joint for use in drilling a lateral wellbore outwardly from a parent wellbore includes a generally tubular window structure having a window formed through a sidewall of the structure. An outer sleeve is disposed external to the window structure, so that the sleeve overlies the window. A hardenable substance supports the sleeve against deflection toward the window. A method of drilling a lateral wellbore extending outwardly from a parent wellbore includes the steps of: providing a casing exit joint including a hardenable substance positioned in a sidewall of the casing exit joint; then installing the casing exit joint in the parent wellbore; and then cutting through the hardenable substance in order to provide access for drilling the lateral wellbore.

Abstract: A casing exit joint with an easily milled and low density barrier. A casing exit joint for use in drilling a lateral wellbore outwardly from a parent wellbore includes a generally tubular window structure having a window formed through a sidewall of the structure. An outer sleeve is disposed external to the window structure, so that the sleeve overlies the window. A hardenable substance supports the sleeve against deflection toward the window. A method of drilling a lateral wellbore extending outwardly from a parent wellbore includes the steps of: providing a casing exit joint including a hardenable substance positioned in a sidewall of the casing exit joint; then installing the casing exit joint in the parent wellbore; and then cutting through the hardenable substance in order to provide access for drilling the lateral wellbore.