Gas-tight connection for a casing or tubing inside a bore hole, consisting of a stem part provided with an external thread and a sleeve part provided with an internal thread matching the external thread, there being a groove in the thread area of the sleeve and/or stem part for accommodating a deformable sealing ring which, when the connection is screwed up, is defined and formed by the groove-root profile of the sleeve and/or stem part and by the thread profile of the other respective connecting part and in which the cross-sectional area enclosed by the groove-root profile of the sleeve and/or stem part and the thread profile of the other respective connecting part is kept constant over the course of the groove and is the same as or greater than the cross-sectional area of the deformable sealing ring before screwing. …<IMAGE>…
