Wellbore Skin Effect Calculation using Temperature Measurements

Abstract

Methods and system to calculate a skin effect using wellbore temperature measurements are described herein. In a generalized method, data corresponding to wellbore characteristics, reservoir characteristics, and a preliminary pressure drop around a wellbore due to a Joule-Thomson (“J-T”) effect are obtained downhole. The data is then input into a wellbore fluid temperature model and/or a reservoir fluid temperature model to calculate a wellbore fluid temperature profile and/or reservoir fluid temperature profile, respectively. The calculated wellbore and/or reservoir fluid temperature profiles may be calibrated using fluid temperatures measurements in the wellbore. The calibration may involve comparing the calculated temperature profiles to the measured temperature profiles to ensure the difference between the two profiles does not exceed an error threshold.

1 . A method to determine skin effect around a wellbore, the method comprising:
 obtaining data corresponding to wellbore characteristics, reservoir characteristics, and a first preliminary pressure drop around a wellbore due to a heating or cooling effect;   inputting the data into a wellbore fluid temperature model to thereby calculate a wellbore fluid temperature profile;   calibrating the calculated wellbore fluid temperature profile using a measured wellbore temperature profile; and   determining a final pressure drop around the wellbore due to a heating or cooling effect using the calibrated wellbore fluid temperature profile, wherein the final pressure drop may be applied to determine the skin effect around the wellbore.   
     
     
         2 . The method as defined in  claim 1 , further comprising:
 inputting the data into a reservoir fluid temperature model to thereby calculate a reservoir fluid temperature profile; and   calibrating the calculated reservoir fluid temperature profile using a measured reservoir fluid temperature profile,   wherein the calibrated wellbore and reservoir fluid temperature profiles are used to determine the final pressure drop around the wellbore due to the heating or cooling effect.   
     
     
         3 . The method as defined in  claim 1 , wherein calibrating the calculated wellbore fluid temperature further comprises:
 comparing the calculated wellbore fluid temperature profile to the measured wellbore fluid temperature profile;   determining if a difference between calculated and measured wellbore fluid temperature profiles is within a threshold; and   if not within the threshold, inputting a second preliminary pressure drop into the wellbore fluid temperature model.   
     
     
         4 . The method as defined in  claim 2 , wherein calibrating the calculated reservoir fluid temperature further comprises:
 comparing the calculated reservoir fluid temperature profile to the measured reservoir fluid temperature profile, the measured reservoir fluid temperature profile being measured near a bottom of the wellbore;   determining if a difference between the calculated and measured reservoir fluid temperature profiles is within a threshold; and   if not within the threshold, inputting a second preliminary pressure drop into the wellbore and reservoir fluid temperature models.   
     
     
         5 . The method as defined in  claim 1 , wherein a formation test string is used to obtain the data. 
     
     
         6 . The method as defined in  claim 5 , further comprising deducting heat generated by the formation testing string when calculating the wellbore fluid temperature profile. 
     
     
         7 . The method as defined in  claim 2 , wherein a formation test string is not used to obtain the data. 
     
     
         8 . The method as defined in  claim 1 , further comprising performing a production or stimulation treatment analysis of the wellbore based upon the skin effect. 
     
     
         9 . A system to determine skin effect in a wellbore, the system comprising:
 one or more wellbore sensors communicably coupled to a processor; and   a memory coupled to the processor having instructions stored therein, which when executed by the processor, cause the processor to perform operations comprising:
 obtaining data corresponding to wellbore characteristics, reservoir characteristics, and a first preliminary pressure drop around a wellbore due to a heating or cooling effect; 
 inputting the data into a wellbore fluid temperature model to thereby calculate a wellbore fluid temperature profile; 
 calibrating the calculated wellbore fluid temperature profile using a measured wellbore temperature profile; and 
 determining a final pressure drop around the wellbore due to a heating or cooling effect using the calibrated wellbore fluid temperature profile, wherein the final pressure drop may be applied to determine the skin effect around the wellbore. 
   
     
     
         10 . The system as defined in  claim 9 , further comprising:
 inputting the data into a reservoir fluid temperature model to thereby calculate a reservoir fluid temperature profile; and   calibrating the calculated reservoir fluid temperature profile using a measured reservoir fluid temperature profile,   wherein the calibrated wellbore and reservoir fluid temperature profiles are used to determine the final pressure drop around the wellbore due to the heating or cooling effect.   
     
     
         11 . The system as defined in  claim 9 , wherein calibrating the calculated wellbore fluid temperature further comprises:
 comparing the calculated wellbore fluid temperature profile to the measured wellbore fluid temperature profile;   determining if a difference between calculated and measured wellbore fluid temperature profiles is within a threshold; and   if not within the threshold, inputting a second preliminary pressure drop into the wellbore fluid temperature model.   
     
     
         12 . The system as defined in  claim 10 , wherein calibrating the calculated reservoir fluid temperature further comprises:
 comparing the calculated reservoir fluid temperature profile to the measured reservoir fluid temperature profile, the measured reservoir fluid temperature profile being measured near a bottom of the wellbore;   determining if a difference between the calculated and measured reservoir fluid temperature profiles is within a threshold; and   if not within the threshold, inputting a second preliminary pressure drop into the wellbore and reservoir fluid temperature models.   
     
     
         13 . The system as defined in  claim 9 , further comprising a formation test string used to obtain the data. 
     
     
         14 . The system as defined in  claim 13 , further comprising deducting heat generated by the formation testing string when calculating the wellbore fluid temperature profile. 
     
     
         15 . The system as defined in  claim 10 , wherein a formation test string is not used to obtain the data. 
     
     
         16 . The system as defined in  claim 9 , further comprising performing a production or stimulation treatment analysis of the wellbore based upon the skin effect. 
     
     
         17 . A non-transitory computer-readable medium comprising instructions which, when executed by at least one processor, causes the processor to perform the method of  claim 1 .