“A Method and an Apparatus for Killing an Uncontrolled Oil-Gas Fountain at an Offshore Oil Platform Using a Telescopic Rod Assembly”

摘要

A method and an apparatus for killing of uncontrolled oil fountains include a series of rods with the first rod having the smallest diameter and successive rods having increasing diameters. Such telescopic assembly of rods is lowered into the well to cause gradual reduction in cross-sectional area available for oil flow discharge. Once sufficiently large rods are lowered into the well, the oil fountain discharge will be greatly diminished. A method of monitoring the conditions of lowering the rods into the well may utilize a weight measuring device mounted at the surface platform. In the case of killing the oil fountain based on the present method, such device will show the difference between the weight of the rods (pushing the entire assembly down) and the combination of various forces acting to push it up, including the reservoir pressure and the drag force from the flow of oil or a multiphase flow of various gases and fluids coming out from the well. Final sealing may be accomplished by pumping cement into a space formed between the well pipe and the rod assembly. A novel system for aligning the rods to the center of the well is also described. The present method is aimed at making killing of the well safe, fast and inexpensive so as to prevent heavy environmental and financial losses typically associated with dealing with offshore well blowouts. The present method relates to a method and system for the extinction or “killing” of an offshore oil well after an explosion or a blowout causing an uncontrolled fountain of oil fluids mixed with gas from the remaining part of the well. Often during drilling or well exploration in gas and oil wells, a gas kick may enter into the well space and then it begins to emerge in the annular space of the well, displacing and replacing the mud. If unnoticed, this phenomenon can bring hydraulic fracturing, loss of all liquid from the well into the reservoir, filling the well with gas and as a result an explosion and uncontrolled fountain. This may cause human casualties, environmental pollution and the creation of an uncontrolled fountain. This uncontrolled fountain is very difficult to suppress, because the wellhead is under enormous pressure. As offshore drilling on the continental shelves is progressing into deeper and deeper waters, the problem is many times more complicated when the explosion occurs in deep waters