Abstract: A method of sealing a well comprises creating one or more openings in a tubing installed in a wellbore, in a location for a well seal; using a wireline to locate a stinger in that location; setting the stinger in that location; and forming a seal in the well in that location, by injecting sealant through said stinger.

Abstract: A method of plugging a well includes providing a tubing in a wellbore, wherein in a location for a well plug, the tubing is provided with an internal cable section placed inside of the tubing and/or an external cable section placed outside of the tubing, the external cable section including a fluid-tight cable suitable for forming a sealing part of the well plug, and forming a plug in the well in the location for the well plug without pulling the tubing from the wellbore.

Abstract: A method and apparatus for determining the location of a material located behind an obstruction. A plurality of acoustic resonators (6) having a known resonant frequency are dispersed in the material (3), the material to be located on a first side of the obstruction (2). An instrument (5) is provided at an opposite side of the obstruction to the material. The instrument emits an acoustic signal and measures a response. If the resonant frequency is detected, it is determined that the material is located substantially adjacent to the instrument. The apparatus may be used for determining the height of cement slurry located between a well casing wall and a borehole.