Abrégé

The claimed invention concerns a method and tools for sealing insufficiently sealed annulus between well casing and borehole in water wells by injection of Bentonite slurry through valves inserted in the well casing wall into the borehole annulus. Creating a penetration in the well casing wall carries a risk that an obstacle outside the well casing prevents valves to be inserted. By melting the valve inserts through the well casing wall and fitting them with a recess to retain the melt-out section of well casing wall, it can be ensured they can be removed and replaced by a plug by the described tools. In fig. 3b; 301b: Wings to transmit rotational force; 302b: Ball track groove to transmit axial force; 303b: Threading; 304b: Valve seat; 305b: Ball; 306b: Spring; 307b: Plate; 308b: Seeger ring; 309b: Exit hole; 310b: Melt-out retaining cavity; 311b: Blunt edge; 312b: Melt-out retaining recess; 313b: Valve insert housing.

Classes IPC  ?

• E03B 3/15 - Maintien des puits en bon état, p. ex. par nettoyage, réparation, remise en étatMaintien ou accroissement de la capacité des puits ou des couches aquifères
• E21B 33/13 - Procédés ou dispositifs de cimentation, de bouchage des trous, des fissures ou analogues