Downhole turbine-driven system

Abstract

The present invention relates to a downhole system for performing an operation in a well downhole. The system comprises an elongated tubing string ( 3 ) for conducting fluid in the well; a turbine ( 7 ) driven by the fluid for driving a shaft ( 8 ); a generator ( 9 ) driven by the turbine by means of the shaft, a fluid-driven driving section ( 5 ) comprising a pump ( 6 ) driven by the fluid supplied through the shaft for propelling the fluid-driven driving section and the tubing string forward in the well, and an electrically driven driving section ( 10 ) comprising an electrical motor ( 11 ) powered by the generator ( 9 ) for propelling the driving section and the tubing string forward in the well, wherein the fluid-driven driving section ( 5 ) is arranged between the generator ( 9 ) and the electrically driven driving section ( 10 ).

1 . A downhole system for performing an operation in a well downhole, comprising:
 an elongated tubing string for conducting fluid in the well,   a turbine driven by the fluid for driving a shaft,   a generator driven by the turbine by means of the shaft, and   a fluid-driven driving section comprising a pump driven by the fluid supplied through the shaft for propelling the fluid-driven driving section and the tubing string forward in the well,   
       wherein the system further comprises an electrically driven driving section comprising an electrical motor powered by the generator for propelling the driving section and the tubing string forward in the well, the fluid-driven driving section being arranged between the generator and the electrically driven driving section. 
     
     
         2 . A downhole system according to  claim 1 , wherein the generator and the electrical motor are electrically connected through an electrical connection extending through the fluid-driven driving section. 
     
     
         3 . A downhole system according to  claim 1 , wherein the fluid from the tubing string is supplied to the pump of the fluid-driven driving section through a fluid channel extending through the turbine and the generator. 
     
     
         4 . A downhole system according to  claim 1 , wherein the driving section comprises propelling units contacting an inner surface of the well for propelling the driving sections forward in the well. 
     
     
         5 . A downhole system according to  claim 4 , wherein the propelling units are non-hydraulically driven units and driven by the electrical motor. 
     
     
         6 . A downhole system according to  claim 4 , wherein the propelling units are wheels contacting an inner surface of the well. 
     
     
         7 . A downhole system according to  claim 6 , wherein each wheel is arranged on a projectable wheel arm. 
     
     
         8 . A downhole system according to any of  claim 4 , wherein each propelling unit of the electrically driven driving section comprises an electrical motor powered by the generator. 
     
     
         9 . A downhole system according to  claim 1 , wherein the electrically driven driving section comprises a pump driven by the electrical motor for driving the electrically driven driving section forward in the well. 
     
     
         10 . A downhole system according to  claim 1 , wherein the electrically driven driving section comprises a rechargeable battery. 
     
     
         11 . A downhole system according to  claim 1 , further comprising a flow diverter for diverting at least part of the fluid from the tubing string into the well. 
     
     
         12 . A downhole system according to  claim 11 , wherein the flow diverter is arranged in a dispersion unit for dispersion of fluids, such as chemical reactants in the well. 
     
     
         13 . A downhole system according to  claim 1 , further comprising an inflation unit for shielding the driving section while a stimulation operation is performed or the well is treated with an acid or base containing fluid. 
     
     
         14 . A downhole system according to  claim 1 , further comprising a detachment unit for detaching the driving section from the tubing string.