Turbine generator system and method

Abstract

In one embodiment, a wellbore power generation method includes causing a fluid to flow through a downhole turbine, and causing the turbine to rotate a generator. At least one of a turbine configuration and a flow rate of the fluid is selected to cause the downhole turbine to operate near its runaway speed, such that changes in load applied to the generator do not substantially affect a rotation rate of the downhole turbine.

1 . A wellbore power generation method, comprising: 
 causing a fluid to flow through a downhole turbine;    causing the turbine to rotate a generator; and    wherein at least one of a turbine configuration and a flow rate of the fluid is selected to cause the downhole turbine to operate near its runaway speed, such that changes in load applied to the generator do not substantially affect a rotation rate of the downhole turbine.    
   
   
       2 . The method of  claim 1 , wherein causing the downhole turbine to operate near its runaway speed comprises causing the downhole turbine to operate at a minimum of 75% of its runaway speed.  
   
   
       3 . The method of  claim 1 , wherein causing the downhole turbine to operate near its runaway speed comprises causing the downhole turbine to operate at a minimum of 85% of its runaway speed.  
   
   
       4 . The method of  claim 1 , wherein causing the downhole turbine to operate near its runaway speed comprises causing the downhole turbine to operate substantially at its runaway speed.  
   
   
       5 . The method of  claim 1 , wherein the downhole turbine generator is associated with a drilling tool and the fluid is a drilling fluid.  
   
   
       6 . The method of  claim 5 , wherein the drilling tool is selected from the group consisting of a MWD tool, a LWD tool, and a rotary steerable tool.  
   
   
       7 . The method of  claim 1 , wherein the generator comprises an electric generator.  
   
   
       8 . The method of  claim 1 , wherein the generator comprises a hydraulic pump.  
   
   
       9 . The method of  claim 1 , wherein the downhole turbine generator is associated with a producing well and the fluid is a production fluid.  
   
   
       10 . A wellbore power generation system, comprising: 
 a pump circulating a fluid through a downhole turbine to rotate a generator; and    wherein at least one of a turbine configuration and a flow rate of the fluid is selected to cause the downhole turbine to operate near its runaway speed, such that changes in load applied to the generator do not substantially affect a rotation rate of the downhole turbine.    
   
   
       11 . The system of  claim 10 , wherein the fluid operates the downhole turbine at a minimum of 75% of its runaway speed.  
   
   
       12 . The system of  claim 10 , wherein the fluid operates the downhole turbine at a minimum of 85% of its runaway speed.  
   
   
       13 . The system of  claim 10 , wherein the fluid operates the downhole turbine substantially at its runaway speed.  
   
   
       14 . The system of  claim 10 , further comprising a drilling tool associated with the downhole turbine generator and wherein the fluid is a drilling fluid.  
   
   
       15 . The system of  claim 14 , wherein the drilling tool is selected from the group consisting of a MWD tool, a LWD tool, and a rotary steerable tool.  
   
   
       16 . The method of  claim 10 , wherein the generator comprises an electric generator.  
   
   
       17 . The method of  claim 10 , wherein the generator comprises a hydraulic pump.  
   
   
       18 . The system of  claim 10 , further comprising a producing well associated with the downhole turbine generator and wherein the fluid is a production fluid.  
   
   
       19 . A wellbore drilling method, comprising: 
 drilling a wellbore with a drilling tool, the drilling tool comprising a downhole turbine driven by a drilling fluid flowing at a first flow rate;    causing the downhole turbine to operate near its runaway speed; and then    changing the flow rate of the drilling fluid to a second flow rate without removing the drilling tool from the wellbore, the second flow rate being different from the first flow rate by at least twenty-five percent.    
   
   
       20 . The method of  claim 19 , wherein causing the downhole turbine to operate near its runaway speed comprises causing the downhole turbine to operate at a minimum of 75% of its runaway speed.  
   
   
       21 . The method of  claim 19 , wherein causing the downhole turbine to operate near its runaway speed comprises causing the downhole turbine to operate substantially at its runaway speed.  
   
   
       22 . A power generation method, comprising: 
 causing a fluid to flow through a turbine disposed in a conduit; and    causing the turbine to rotate a generator; and    wherein at least one of a turbine configuration and a flow rate of the fluid is selected to cause the turbine to operate near its runaway speed, such that changes in load applied to the generator do not substantially affect a rotation rate of the turbine.    
   
   
       23 . The method of  claim 22 , wherein causing the turbine to operate near its runaway speed comprises causing the turbine to operate at a minimum of 75% of its runaway speed.  
   
   
       24 . The method of  claim 22 , wherein causing the turbine to operate near its runaway speed comprises causing the turbine to operate substantially at its runaway speed.