REPAIR METHOD FOR WELL WITH DEFECTIVE AREA WITH DISPLACED CASING STRING Russian patent published in 2014 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: during study of the defective area the diameter d of the inner narrowing is determined within the interval of displaced casing string area, a jet nozzle is run in at the surface pipe into the displacement interval and rock is washed out from the well along the whole length and perimeter of the displacement interval by a directed flow of the process fluid until the washed rock stops coming out at the well head. Then, the following arrangement is assembled on the well head in an upward direction: a perforated cone-plugged liner with the upper and lower positive centralisers with overflow channels and an outside cuff, a drillable packer. The packer is fixed rigidly to the liner; the cuff is installed to the liner below the lower centraliser. The assembled arrangement is run in at the work string to the defective area interval and the displaced parts of the casing string are centred so that the upper and lower centralisers are placed at a distance less than 1 m from the defective area interval; the drillable packer is seated and plugging of the defective area is carried out. The work string is removed and operations at the well are withheld till microcement hardens. The downhole propelling screw with a cutter is run in at the surface pipe, the drillable packer, the hardened cement, the cemented liner, the upper and lower centralisers, the cuff are removed from the defective area and the inner diameter D of the casing string is restored.

EFFECT: improving efficiency of repair, reducing specific amount of metal.

4 dwg