Sealing riser in casing of burning oil or gas prodn. well - by driving access tunnel, boring transverse hole through riser, sealing riser, and fitting stop valve to control resumed flow

摘要

Below the ground, a working tunnel is driven that leads to the riser (3) so that a length of it is exposed and made accessible from outside. Work can then be done to seal off the riser. Two flanged half-shells (9, 10) together form a cylinder having extensions (14, 15) around the riser (3). These extensions are closed by the pressure-tight flanges (16, 17). The flange (17) has a pressure-tight bearing for the shaft (18), which has an external drive. The leading end of the shaft (18) has tools that include an auger bit (22) and cutter (21), and the arrangement is used to bore through the riser pipe (3) a transverse hole with the same dia. as that of the internal thread (30). USE/ADVANTAGE - Other methods of extinguishing such fires, by explosive or other means, are expensive, can be dangerous and may be unsuccessful. This method overcomes these drawbacks and provides for the resumption of controlled further flow from the riser.