Abstract: A wellhead is formed by extruding a plurality of tubular liners off of a mandrel into contact with an outer casing. The first tubular liner and mandrel are positioned within the wellbore with the tubular liner in an overlapping relationship with the outer casing. At least a portion of the tubular liner is extruded off of the mandrel into contact with the interior surface of the outer casing. The first tubular liner is extruded off of the mandrel by pressurizing an interior portion of the first tubular liner. Subsequent tubular liners are positioned in concentric overlapping relation and similarly extruded off of a mandrel into at least partial contact with the interior surface of the outer casing.

Abstract: A method of forming a cementitious plug in a well is disclosed. According to the method, a well is selected for treatment which lacks sufficient formation pressure to cause well fluid to naturally flow to the surface of the well. In addition, a formation penetrated by the well has unobstructed access between it and the surface. Having thus selected a well for treatment, a liquid slurry comprising a cementitious material, whose density is greater than the density of the well fluid, is introduced into the well. The slurry is permitted to drive the well fluid into the formation. Sufficient slurry is added to the well to fill the well to the surface. The slurry is then permitted to set into a hardened mass.