Abstract: Multiple wellbores may be extended from a common, generally vertical wellbore and completed for conduction of fluids between said common wellbore and each of said wells by drilling the common wellbore, inserting a seal bore into the common wellbore below the junction of a deviated well with said common wellbore, inserting a whipstock and then drilling the deviated well. The whipstock is removed and a guide member is inserted into the common wellbore and secured to the anchor member. A dual packer is inserted in the common wellbore above the junction of the deviated well and is connected to the guide member to provide a slow passage into the wellbore located below the junction. A second tubing guide connector member is inserted into the common wellbore with a tubing string extending downwardly therefrom.

Abstract: Medium curvature deviated wellbores having a radius of curvature in the range of 200 feet to 400 feet are drilled with downhole drilling assemblies for drilling the curved wellbore portion and for correcting or holding the horizontal wellbore portion and which are connected to the end of a drillstem made up of elongated elastically bendable drillstem members which may be cyclically compressively stressed during rotation of the drillstem. The elastically bendable drillstem members are characterized by joint forming portions at opposite ends of an elongated tubular body and which are of a diameter which minimizes the tendency for the drillstem to buckle during drilling. Spaced apart stress bearing sleeves are attached to or integrally formed with the tubular body and are of a diameter greater than the body and preferably equal to the diameter of the tool joint portions.

Abstract: A method for completing a drainhole wellbore with casing but without conventional cementing of the casing wherein in the drainhole portion of the wellbore a casing string composed of alternating casing subs and external casing packer subs is employed, the external casing packer subs carrying an elastic member adapted to be expanded and form a seal between the exterior of the casing string and the wellbore wall, and one or more of the external casing packer subs is activated to expand the elastic member carried by same thereby providing for isolation of discreet segments of the casing string in the drainhole portion of the wellbore to allow for localized production and remedial treatments in the drainhole wellbore.