Pipe string device for conveying a fluid from a well head to a vessel

Abstract

A device including a pipe string device anchored to a sea floor. The device is configured to convey a fluid from a well head to a vessel during a drilling phase of a well. The fluid is located in the pipe string and needing, for well-technical reasons, to be given a flow boost. The pipe string that is anchored on the sea floor is provided with at least one injection point for a driving fluid.

1 . A device comprising a pipe string anchored to a sea floor and adapted to convey a fluid from a well head to a vessel during a drilling phase of a well, the fluid being located in the pipe string and needing, for well-technical reasons, to be given a flow boost, wherein the pipe string that is anchored on the sea floor is provided with at least one injection point for a driving fluid. 
   
   
       2 . The device in accordance with  claim 1 , wherein the at least one injection point comprises a fluid-operated ejector. 
   
   
       3 . The device in accordance with  claim 1 , wherein a mechanically working pump is connected to the pipe string. 
   
   
       4 . The device in accordance with  claim 1 , wherein the pipe string leads into a separator tank on the vessel. 
   
   
       5 . The device in accordance with  claim 1 , wherein the pipe string is anchored on the sea floor by an anchor and provided with a buoyancy body near a sea surface. 
   
   
       6 . The device in accordance with  claim 1 , wherein the pipe string is suspended from the vessel and connected to the well head by a flexible connection. 
   
   
       7 . A method comprising providing flow assistance to a fluid located in a pipe string during a drilling phase of a well, the fluid being conveyed by the pipe string from a well head to a vessel, wherein the method further comprises supplying the pipe string with a driving fluid that has a lower density than the conveyed fluid at at least one injection point located on the pipe string. 
   
   
       8 . The method in accordance with  claim 7 , further comprising supplying, at the at least one injection point, a driving fluid which has a lower specific gravity than the fluid being conveyed by the pipe string. 
   
   
       9 . A device comprising a pipe string assembly, wherein at least a substantial portion of the pipe string assembly is interposed in a sea between a sea floor and a surface of the sea, wherein the pipe string assembly includes at least one fluid ejector adapted to inject a driving fluid into the pipe string assembly to give a fluid contained in the pipe string assembly a flow boost to assist the fluid in the pipe string assembly to flow away from the sea floor towards the surface of the sea. 
   
   
       10 . The device of  claim 9 , wherein the pipe string assembly includes a plurality of fluid ejectors spaced along the pipe string assembly. 
   
   
       11 . The device of  claim 9 , wherein the pipe string assembly includes at least five fluid ejectors spaced along the pipe string assembly. 
   
   
       12 . The device of  claim 9 , wherein the pipe string assembly includes at least five fluid ejectors spaced along the pipe string assembly substantially spaced along the pipe string assembly in even intervals. 
   
   
       13 . The device of  claim 9 , wherein the pipe string assembly includes a plurality of fluid ejectors spaced along the pipe string assembly, wherein a lower fluid ejector, relative to a higher fluid ejector in a direction opposite the direction of gravity, is adapted to inject driving fluid into the pipe string assembly to supply a pressure to the fluid in the pipe string assembly to drive the fluid in the pipe string assembly to the higher fluid ejector. 
   
   
       14 . The device of  claim 9 , wherein the pipe string assembly extends from a location proximate a well head on the sea floor to a location proximate a buoyant vessel located on the surface of the sea, wherein a separator is located on the buoyant vessel, and wherein the separator is adapted to separate driving fluid from a drilling fluid in the pipe string assembly. 
   
   
       15 . The device of  claim 9 , wherein the device is adapted to control a return pressure at a well head located proximate the sea floor to which the pipe string assembly is connected. 
   
   
       16 . The device of  claim 9 , wherein the device is adapted to control a return pressure at a well head located proximate the sea floor to which the pipe string assembly is connected by adjusting a driving-fluid pressure of one or more of the at least one fluid ejector. 
   
   
       17 . The device of  claim 9 , wherein the device further comprises a mechanical pump in fluid communication with the pipe string assembly at a location proximate the sea floor, wherein the mechanical pump is adapted to increase a flow rate of fluid in the pipe string assembly. 
   
   
       18 . A method, comprising:
 obtaining the device according to  claim 9 ,   directing a drilling fluid in the direction of gravity from a location proximate the surface of the sea to a well head proximate the sea floor;   directing the drilling fluid directed to the well head to the pipe string assembly;   directing a driving fluid to one or more of the at least one fluid injector; and   driving the drilling fluid directed to the pipe string assembly in a direction away from the direction of gravity by injecting the driving fluid through one or more of the at least one fluid injector.   
   
   
       19 . The method of  claim 18 , wherein the pipe string assembly extends from the well head to a buoyant vessel located proximate the surface of the sea. 
   
   
       20 . The method of  claim 18 , wherein the pipe string assembly includes a plurality of fluid ejectors spaced along the pipe string assembly, wherein a lower fluid ejector is located lower than a higher fluid ejector located higher than the lower fluid ejector in a direction opposite the direction of gravity, the method further comprising injecting the driving fluid into the pipe string assembly using the lower fluid ejector to supply a pressure to the fluid in the pipe string assembly to drive the drilling fluid in the pipe string assembly to the higher fluid ejector.