Subsurface closure of oil or gas riser pipe from deposit - with automatic activation in event of explosion or substantial shock at surface

摘要

An installation for obtaining petroleum or natural gas through a borehole pipe (1) that reaches from the surface down into an oil or gas deposit, has, at the surface, a closure in the form of a valve (2) or similar device. At some distance down in the pipe there is an additional closing device (3) consisting of a shut-off valve and its actuating mechanism (4). This mechanism is fitted with a release mechanism (5) that responds to flow signatures that vary from the normal ones and, if the variations reach a predetermined value, it shuts the closing device. The several variants claimed include the additional closing device (3) being at least 15m below the surface. USE/ADVANTAGE - The danger of oil or gas escaping as a result of accidental or war damage, and causing environmental harm or economic loss, is avoided by simple means.