Patent ID: 9702216
Date: 2017-07-11
CPC Classifications: E21B

Claim:
1. A method for establishment of an annulus barrier in a subterranean well, wherein the well, at least in a portion where the annulus barrier is to be established, is provided with a casing, wherein the method comprises: (A) providing a plug in the well and along a longitudinal section thereof, wherein the plug, at least in a portion of the longitudinal section, covers substantially the entire cross-section of the well in such a manner that the plug covers both the inside and the outside of the casing; (B) removing a central through portion of the plug internally in the casing in such a manner that a through central opening is formed in the plug, and in such a manner that at least a cross-sectional section of the plug remains on the outside of the casing; (C) disposing and anchoring a connection pipe in the well, and internally in the casing, in such a manner that the connection pipe extends at least along a length of the remaining cross-sectional section; and (D) sealing, in a fluid-tight manner, a first annulus between the casing and the connection pipe, wherein (A) comprises: (A1) conducting a perforation tool down into the casing and to the longitudinal section where the plug is to be set; (A2) with the perforation tool, forming holes in the casing along the longitudinal section; (A3) with a washing tool, which is attached to a flow-through string and is conducted down to the longitudinal section, pumping a washing fluid down through the string and out into the casing via the washing tool; (A4) with a directional means connected to the washing tool, conducting the washing fluid out into a second annulus between the outside of the casing and a surrounding formation; and (A5) pumping a fluidized plugging material down through the string and out into the casing, thus also into the second annulus via the holes in the casing.