Wellbore real-time monitoring and analysis of fracture contribution

Abstract

Methods and apparatus are provided for calculating production of each of a plurality of fractured intervals (or fractures) and monitoring changes in the fracture contribution with time. Such real-time monitoring and analysis may be performed by combining temperature distribution (and pressure) measurements, a real-time surface multiphase flow measurement, and an inflow model for each fractured interval (or fracture). In this manner, the industry may be able to understand the behavior of fractures and, in turn, optimize the number of stages (i.e., fractured intervals), the number of fractures, and the spacing between fractures and stages.

1 . A method for determining production of hydrocarbons, comprising:
 determining a temperature distribution associated with a plurality of fractured intervals or fractures disposed along a well;   measuring a total flow rate for the well;   modeling an inflow rate for each of the plurality of fractured intervals or fractures; and   allocating production of each of the plurality of fractured intervals or fractures based on the temperature distribution, the total flow rate, and the inflow rates.   
     
     
         2 . The method of  claim 1 , further comprising repeating the determining, the measuring, and the modeling within a period short enough to observe transient behavior of the plurality of fractured intervals or fractures. 
     
     
         3 . The method of  claim 1 , further comprising determining one or more pressure measurements for the well, wherein allocating the production is further based on the pressure measurements. 
     
     
         4 . The method of  claim 1 , wherein determining the temperature distribution comprises performing at least one of distributed temperature sensing (DTS) or array temperature sensing (ATS). 
     
     
         5 . The method of  claim 1 , wherein the measuring comprises measuring the total flow rate using a multiphase flowmeter. 
     
     
         6 . The method of  claim 1 , wherein at least one of the determining, the measuring, or the modeling is performed daily. 
     
     
         7 . The method of  claim 1 , wherein at least one of the determining, the measuring, or the modeling is performed continuously. 
     
     
         8 . The method of  claim 1 , wherein allocating the production comprises:
 determining a first temperature value at a first time for each of the plurality of fractured intervals or fractures;   determining a second temperature value at a second time for each of the plurality of fractured intervals or fractures;   calculating a delta temperature value for the second time for each of the plurality of fractured intervals or fractures by determining a difference between the first and second temperature values for each of the plurality of fractured intervals or fractures;   calculating a first ratio of the delta temperature value for the second time for each of the plurality of fractured intervals or fractures to a geothermal temperature;   comparing the first ratio for the second time to a maximum value of the first ratio over all previous times for each of the plurality of fractured intervals or fractures;   for each of the plurality of fractured intervals or fractures, designating the first ratio for the second time as the maximum value of the first ratio over all previous times if the first ratio for the second time is greater than a previously designated maximum value;   for each of the plurality of fractured intervals or fractures, calculating a second ratio of the first ratio for the second time to a currently designated maximum value of the first ratio over all previous times;   multiplying the second ratio for the second time with the modeled inflow rate corresponding to the second time for each of the plurality of fractured intervals or fractures;   summing results of the multiplication for each of the plurality of fractured intervals or fractures; and   determining an allocation factor by dividing the measured total flow rate corresponding to the second time by the sum.   
     
     
         9 . The method of  claim 8 , wherein the first time occurs before the hydrocarbons are produced. 
     
     
         10 . The method of  claim 8 , further comprising applying the allocation factor to the modeled inflow rate for each of the plurality of fractured intervals or fractures. 
     
     
         11 . The method of  claim 1 , wherein the total flow rate comprises a total gas flow rate and wherein the inflow rates comprise inflow gas rates. 
     
     
         12 . The method of  claim 1 , wherein the plurality of fractured intervals or fractures is located in a shale reservoir. 
     
     
         13 . A system for determining production of hydrocarbons, comprising:
 a temperature sensing device configured to determine a temperature distribution associated with a plurality of fractured intervals or fractures disposed along a well;   a flowmeter configured to measure a total flow rate for the well; and   a processing unit configured to:
 model an inflow rate for each of the plurality of fractured intervals or fractures; and 
 allocate production of each of the plurality of fractured intervals or fractures based on the temperature distribution, the total flow rate, and the inflow rates. 
   
     
     
         14 . The system of  claim 13 , wherein the plurality of fractured intervals or fractures is located in a shale reservoir. 
     
     
         15 . The system of  claim 13 , further comprising a pressure sensor configured to determine one or more pressure measurements for the well, wherein the processing unit is configured to allocate the production further based on the pressure measurements. 
     
     
         16 . The system of  claim 13 , wherein the processing unit is configured to allocate the production by:
 determining a first temperature value at a first time for each of the plurality of fractured intervals or fractures;   determining a second temperature value at a second time for each of the plurality of fractured intervals or fractures;   calculating a delta temperature value for the second time for each of the plurality of fractured intervals or fractures by determining a difference between the first and second temperature values for each of the plurality of fractured intervals or fractures;   calculating a first ratio of the delta temperature value for the second time for each of the plurality of fractured intervals or fractures to a geothermal temperature;   comparing the first ratio for the second time to a maximum value of the first ratio over all previous times for each of the plurality of fractured intervals or fractures;   for each of the plurality of fractured intervals or fractures, designating the first ratio for the second time as the maximum value of the first ratio over all previous times if the first ratio for the second time is greater than a previously designated maximum value;   for each of the plurality of fractured intervals or fractures, calculating a second ratio of the first ratio for the second time to a currently designated maximum value of the first ratio over all previous times;   multiplying the second ratio for the second time with the modeled inflow rate corresponding to the second time for each of the plurality of fractured intervals or fractures;   summing results of the multiplication for each of the plurality of fractured intervals or fractures; and   determining an allocation factor by dividing the measured total flow rate corresponding to the second time by the sum.   
     
     
         17 . The system of  claim 16 , wherein the processing unit is further configured to apply the allocation factor to the modeled inflow rate for each of the plurality of fractured intervals or fractures. 
     
     
         18 . The system of  claim 13 , wherein the temperature sensing device comprises a distributed temperature sensing (DTS) device or an array temperature sensing (ATS) device. 
     
     
         19 . The system of  claim 13 , wherein the total flow rate comprises a total gas flow rate and wherein the inflow rates comprise inflow gas rates. 
     
     
         20 . A system for determining production of hydrocarbons, comprising:
 means for determining a temperature distribution associated with a plurality of fractured intervals or fractures disposed along a well;   means for measuring a total flow rate for the well;   means for modeling an inflow rate for each of the plurality of fractured intervals or fractures; and   means for allocating production of each of the plurality of fractured intervals or fractures based on the temperature distribution, the total flow rate, and the inflow rates.