Plug for injecting fluid into rock formations or the like structures

摘要

A plug (4') for injecting fluid into rock formations or the like structures comprises a tubular body (1) with a one-way valve (3) in one end thereof and an annular sealing member (2) of flexible material, capable of limited axial movement, surrounding the tubular body (1). The sealing member (2) includes a lip or flange (6') for initial sealing and retention of the plug. When inserting the plug (4') into a borehole the flange (6') folds down and thus permits insertion of the plug. At the desired location for the plug. the tubular body (1) is pulled backwards somewhat and this causes the flange (6') to double back on itself so that the flange lies on the outside of the main body of the sealing member (2) and constitutes an initial sealing and retention of the plug (4'). Furthermore there is wedging engagement between the external surface of the tubular body (1) and the internal surface of the sealing member (2) causing radial expansion of the latter when the tubular body (1) is moved rearwardly. Upon introduction of an injection fluid through the plug and the valve (3), an over-pressure arises in the borehole and the tubular body moves further backwards and further increases the radial expansion of the sealing member (2) by said wedging engagement for final sealing and plugging of the injection hole. IMAGE