Method for blocking outflow of petroleum or the like due to damage to subsea petroleum well steel pipe or the like

Abstract

The present invention relates to blocking a flow of crude oil or natural gas from a steel pipe for extracting the oil or the like that has been installed in the sea when the steel pipe is broken. When a steel pipe 4 for petroleum well in the deep sea is broken, a carrying pipe 6 is inserted from a hole 5 that is a broken point in the steel pipe 4 to a predetermined depth and is fixed. The carrying pipe 6 is an elongated pipe made of nonmagnetic material such as synthetic resin. The carrying pipe 6 has a diameter that is approximately one-half the diameter of the steel pipe 4 . A circular mesh plate 8 is hung at a tip portion of the carrying pipe 6. After that, magnetic particles 20 or the like having a diameter of several to several tens of millimeters are dropped from an upper opening 7 of the carrying pipe 6 in a randomly dispersed manner so as to cause the magnetic particles 20 or the like to magnetically adhere to the inner surface of the steel pipe 4 near the circular mesh plate 8 provided at the tip portion of the carrying pipe 6 and adhere to each other to form a mass. The outflow of crude oil is thereby suppressed. After that, concrete 24 is injected from the upper opening 7 of the carrying pipe 6 and cured, as a result of which the outflow of petroleum or the like is blocked.

1 . A method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like, the method comprising:
 when a steel pipe for petroleum or natural gas well that has been installed in the sea is broken, inserting an elongated carrying pipe made of nonmagnetic material such as synthetic resin from a hole that is a broken point in the steel pipe to a predetermined depth and fixing the carrying pipe, the carrying pipe having a diameter that is approximately one-half a diameter of the steel pipe, and a circular mesh plate  8  being provided at a tip portion of the carrying pipe;   after the carrying pipe has been fixed, dropping magnetic particles or the like having a diameter of several to several tens of millimeters from an upper opening of the carrying pipe in a randomly dispersed manner so as to cause the magnetic particles or the like to magnetically adhere to an inner surface of the steel pipe near the circular mesh plate provided at the tip portion of the carrying pipe and adhere to each other to form a mass, thereby suppressing the outflow of crude oil; and   after the outflow of crude oil has been suppressed, injecting concrete from the upper opening of the carrying pipe and curing the concrete.   
     
     
         2 . The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to  claim 1 , comprising:
 suspending in advance, inside the steel pipe for petroleum or natural gas well that has been installed in the sea, the elongated carrying pipe made of nonmagnetic material such as synthetic resin, so as to reach a position deeper than near the seafloor where the steel pipe is likely to break, the circular mesh plate being provided at the tip portion of the carrying pipe;   when the steel pipe is cracked or damaged, dropping the magnetic particles or the like having a diameter of several to several tens of millimeters from the upper opening of the carrying pipe in a dispersed manner so as to cause the magnetic particles or the like to magnetically adhere to the inner surface of the steel pipe near the circular mesh plate provided at the tip portion of the carrying pipe and adhere to each other to form a mass, thereby suppressing the outflow of petroleum or natural gas; and   after the outflow of petroleum or natural gas has been suppressed, injecting the concrete or the like from the upper opening of the carrying pipe and curing the concrete.   
     
     
         3 . The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to  claim 1 ,
 wherein the step of dropping the magnetic particles or the like in the elongated carrying pipe made of nonmagnetic material such as synthetic resin and suspended inside the steel pipe for petroleum or natural gas well that has been installed in the sea includes:   hermetically sealing the upper opening of the carrying pipe with an feeding equipment for feeding magnetic particles or the like so as to suppress an internal flow in the carrying pipe and   after the internal flow in the carrying pipe has been suppressed, dropping the magnetic particles or the like loaded into a feeding opening in the carrying pipe, whereby the magnetic particles or the like fall to a lower end of the carrying pipe without resistance, move along the flow of petroleum or the like in the steel pipe, reach a conical metal mesh attached to the carrying pipe, are blocked up by the conical metal mesh and magnetically adhere to the inner surface of the steel pipe, and a resulting adherent layer gradually grows downward so that the magnetic particles or the like reach the circular mesh plate provided at the tip portion of the carrying pipe, fill inside of the steel pipe and form a mass due to magnetic force, suppressing the outflow of petroleum or natural gas, and   wherein after the outflow of petroleum or natural gas has been suppressed, a ball valve or the like provided at an upper portion of the carrying pipe is opened and the concrete or the like is injected and cured.   
     
     
         4 . The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to  claim 1 ,
 wherein as the carrying pipe, a steel wire rope-reinforced polyethylene carrying pipe is used in which a plurality of flexible steel wire ropes are circumferentially disposed and buried inside a wall of the polyethylene pipe and each extends in an axial direction thereof, and is capable of sinking in the sea due to weight of the steel wire ropes.   
     
     
         5 . The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to  claim 2 ,
 wherein as the carrying pipe, a steel wire rope-reinforced polyethylene carrying pipe is used in which a plurality of flexible steel wire ropes are circumferentially disposed and buried inside a wall of the polyethylene pipe and each extends in an axial direction thereof, and is capable of sinking in the sea due to weight of the steel wire ropes   
     
     
         6 . The method for blocking an outflow of petroleum or the like due to damage to a subsea petroleum well steel pipe or the like according to  claim 3 ,
 wherein as the carrying pipe, a steel wire rope-reinforced polyethylene carrying pipe is used in which a plurality of flexible steel wire ropes are circumferentially disposed and buried inside a wall of the polyethylene pipe and each extends in an axial direction thereof, and is capable of sinking in the sea due to weight of the steel wire ropes