Abstract: A method is for zone isolation in a subterranean well. The well is provided with a pipe body at least in a portion. The method includes providing a plug over a longitudinal section of the well, the plug covering substantially the entire cross section of the well at least in a portion of the longitudinal section, so that the plug fills the inside, of a pipe body and an annulus between the outside of the pipe body and a surrounding well body.

Abstract: A method is for the combined perforation, cleaning, and the subsequent plugging of a longitudinal section of a well. The well is provided with two pipe bodies placed substantially concentrically. The method includes lowering a perforation tool into the innermost pipe body to the longitudinal section, forming perforations in both pipe bodies along the longitudinal section with the perforation tool, cleaning the longitudinal section with a flushing tool which is attached to a lower portion of a string allowing through-flow, pumping a fluidized plugging material down the string and into the innermost pipe body at the longitudinal section, and placing the fluidized plugging material in the innermost pipe body, and thereby also into the entire cross section of the well via the perforations within the longitudinal section. A flushing tool is for cleaning the longitudinal section of the well.

Abstract: A method is for establishing a new well path from an existing well, wherein the existing well, at least in a portion where the new well path is to be established, is delineated radially by a casing.

Abstract: A method is for establishing an annulus barrier in a subterranean well. The method comprises 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 a casing; 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; 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 sealing, in a fluid-tight manner, an annulus between the casing and the connection pipe.

Abstract: Methods and washing tools are described for combined cleaning of an annulus in a well across a longitudinal section (L1) of the well, and subsequent plugging of the longitudinal section (L1).