US2011130966A1PendingUtilityA1

Method for well testing

Assignee: SCHLUMBERGER TECHNOLOGY CORPPriority: Dec 1, 2009Filed: Dec 1, 2010Published: Jun 2, 2011
Est. expiryDec 1, 2029(~3.4 yrs left)· nominal 20-yr term from priority
E21B 49/087
38
PatentIndex Score
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Cited by
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Claims

Abstract

The present document discloses techniques to perform an impulse well test for formation property estimation of subsurface reservoirs. It disclosures a method to obtain the optimum time range of a downhole isolation valve closure to achieve an acceptable depth of investigation for an impulse test and methodologies to optimize the execution of an impulse test using the simulated and measured real time bottomhole pressure data. It is emphasized that this abstract is provided to comply with the rules requiring an abstract which will allow a searcher or other reader to quickly ascertain the subject matter of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

exact text as granted — not AI-modified
1 . A method for well testing, comprising communicating fluid from the well into a chamber in connection with a well test; determining the optimal time to close an isolation valve connected to the chamber and isolating the chamber from the well. 
     
     
         2 . Method according to  claim 1 , wherein the optimal time to close the isolation valve is determined by using the liquid fluid length and total produced volume in the chamber. 
     
     
         3 . Method according to  claim 1 , wherein the optimal time to close the isolation valve is determined by obtaining the maximum valid test time after the isolation valve closure. 
     
     
         4 . A Method according to  claim 3 , wherein the valid test time after the closure of the isolation valve is given by: 
       
         
           
             
               
                 Δ 
                  
                 
                     
                 
                  
                 t 
               
               = 
               
                 
                   t 
                   p 
                 
                  
                 
                   
                     
                       exp 
                        
                       
                         ( 
                         
                           
                             2 
                              
                             L 
                           
                           - 
                           
                             
                               
                                 A 
                                 noise 
                               
                                
                               
                                 kht 
                                 p 
                               
                             
                             
                               3.53 
                               * 
                               24 
                                
                               μ 
                                
                               
                                   
                               
                                
                               
                                 BV 
                                 p 
                               
                             
                           
                         
                         ) 
                       
                     
                     - 
                     1 
                   
                   
                     
                       exp 
                        
                       
                         ( 
                         L 
                         ) 
                       
                     
                     - 
                     
                         
                       
                           
                         
                           
                             exp 
                              
                             
                               ( 
                               
                                 - 
                                 L 
                               
                               ) 
                             
                           
                            
                           
                             exp 
                              
                             
                               ( 
                               
                                 
                                   2 
                                    
                                   L 
                                 
                                 - 
                                 
                                   
                                     
                                       A 
                                       noise 
                                     
                                      
                                     
                                       kht 
                                       p 
                                     
                                   
                                   
                                     3.53 
                                     * 
                                     24 
                                      
                                     μ 
                                      
                                     
                                         
                                     
                                      
                                     
                                       BV 
                                       p 
                                     
                                   
                                 
                               
                               ) 
                             
                           
                         
                       
                     
                   
                 
               
             
           
         
         Where q is the flow rate before the pressure buildup, A noise  is the testing noise level, k is the permeability, h is the formation thickness, μ is the viscosity, B is the formation volume factor and L is the logarithmic cycle used for pressure derivative calculation, t p  is the producing time and V p  is the total produced volume. 
       
     
     
         5 . Method according to  claim 1 , wherein the optimal time to close the isolation valve is determined by obtaining the maximum depth of investigation after the isolation valve closure. 
     
     
         6 . Method according to  claim 1 , wherein the optimal time to close the isolation valve is determined by selecting the time that satisfies the minimum depth of investigation requirements for all possible variations of the permeability and skin factor for the underground formation surrounding the well. 
     
     
         7 . A method to design an impulse well test comprising providing a chamber for communicating with a fluid from the well wherein the chamber comprises an isolation valve and selecting a range of isolation valve closure times as a function of a targeted depth of investigation value within the underground formation surrounding the well. 
     
     
         8 . A method according to  claim 7 , wherein the targeted depth of investigation is determined using a measured real-time bottom hole pressure data. 
     
     
         9 . An apparatus usable in a well comprising:
 a tubular member including a chamber;   an isolation valve disposed in the tubular member to control fluid flow from the well into the chamber in connection with a well testing operation; and   means determine the optimal time to close the isolation valve and isolating the chamber from the well.   
     
     
         10 . Apparatus according to  claim 9 , wherein the tubular member comprises a coiled tubing. 
     
     
         11 . Apparatus according to  claim 9 , wherein the upper end of the chamber is directly connected to a production facility.

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