Proppant flowback mitigation

Abstract

Proppant flowback during post-stimulation well clean up and production is a common occurrence in most hydraulically fractured wells. The production of the proppant from a propped fracture is related to the forces acting on the proppant pack during the well that is actively producing fluids. Flow rate and pressure data collected during the post-treatment flowback activity is used in simulating bottomhole (BH) production rates using a Gaussian solution scheme. The BH rate is distributed amongst the various perforation clusters while incorporating the effects of key hydraulic fracture characteristics in the presence of simulated effective bottomhole flowing pressures across different fluid entry points into the wellbore. The solution is updated at each time step during the simulation. The production allocation is then used in calculating effective flow velocities that are then compared with critical velocities to predict proppant flowback. Steps to mitigate or reduce the flowback are implemented.

What is claimed is: 
     
         1 . A method of fracturing a hydrocarbon well comprising:
 calculating one or more formation properties and one or more production rates associated with a wellbore;   calculating one or more flow pressures at different production sleeves of the wellbore;   determining pressure depletion for different zones of the wellbore using a simulator model, the simulator model determining the pressure depletion for the different zones based on a material balance equation considering the one or more formation properties;   generating, by the simulator model, a simulated flow velocity value based at least partly on the one or more production rates, the one or more flow pressures, and the pressure depletion;   determining, by the simulator model, that the simulated flow velocity value is within a predetermined threshold range of an actual flow velocity value;   forming a normalized production rate responsive to the simulated flow velocity value being within the predetermined threshold range of the actual flow velocity value, the normalized production rate formed by comparing the actual flow velocity value with a critical velocity value; and   optimizing mitigation of proppant production from the wellbore by controlling the normalized production rate.   
     
     
         2 . The method of  claim 1 , further comprising:
 generating a z-factor vs. depth lookup table for a plurality of fluid segments and time intervals, optimize mitigation of proppant production is based at least partly on the z-factor vs. depth lookup table.   
     
     
         3 . The method of  claim 2 , further comprising:
 calculating, by the simulator model, a formation volume factor (FVF) and a specific fluid for the plurality of fluid segments.   
     
     
         4 . The method of  claim 1 , further comprising:
 calculating, as a first output of the simulator model, a static column pressure of the wellbore.   
     
     
         5 . The method of  claim 4 , further comprising:
 calculating, as a second output of the simulator model, a tubular friction gradient of the wellbore.   
     
     
         6 . The method of  claim 1 , further comprising:
 calculating, by the simulator model one or more downhole production rates corresponding to the different production sleeves.   
     
     
         7 . The method of  claim 1 , further comprising:
 calculating, by the simulator model, the one or more flow pressures at different perforation clusters of the wellbore.   
     
     
         8 . The method of  claim 1 , further comprising:
 calculating, by the simulator model, a drawdown and fracture permeability of the wellbore.   
     
     
         9 . The method of  claim 8 , wherein calculating the drawdown and fracture permeability is based on determining a fracture width and a fracture conductivity. 
     
     
         10 . The method of  claim 9 , wherein calculating the drawdown and fracture permeability includes updating the fracture width and the fracture conductivity for a closed boundary case. 
     
     
         11 . The method of  claim 1 , wherein optimizing mitigation of the proppant production from the wellbore includes providing a recommended blowback guideline based on comparing the actual flow velocity value with the critical velocity value. 
     
     
         12 . The method of  claim 1 , further comprising:
 normalizing a plurality of flow velocity values across the different production sleeves; and   repeating a calculation to determine whether the simulated flow velocity value is within the predetermined threshold range of the actual flow velocity value.   
     
     
         13 . A method of fracturing a hydrocarbon well comprising:
 determining one or more production rates associated with a wellbore;   determining one or more flow pressures at one or more production sleeves of the wellbore;   generating, by a simulator model, a simulated flow velocity value based at least partly on the one or more production rates and the one or more flow pressures;   determining, by the simulator model, that the simulated flow velocity value is within a predetermined threshold range of an actual flow velocity value;   forming a normalized production rate, responsive to the simulated flow velocity value being within the predetermined threshold range of the actual flow velocity value, by comparing the actual flow velocity value with a critical velocity value; and   optimizing mitigation of proppant production from the wellbore by controlling the normalized production rate.   
     
     
         14 . The method of  claim 13 , further comprising:
 calculating s, the simulated flow velocity value is at least partly based on the formation properties.   
     
     
         15 . The method of  claim 14 , further comprising:
 using, by the simulator model, a material balance equation which considers the formation properties to determine pressure depletion for different zones of the wellbore.   
     
     
         16 . The method of  claim 13 , further comprising:
 calculating, by the simulator model one or more downhole production rates corresponding to the one or more production sleeves.   
     
     
         17 . The method of  claim 13 , further comprising:
 calculating, by the simulator model, the one or more flow pressures at one or more perforation clusters of the wellbore.   
     
     
         18 . The method of  claim 13 , further comprising:
 calculating, by the simulator model, a drawdown and fracture permeability of the wellbore.   
     
     
         19 . The method of any of  claim 18 , wherein calculating the drawdown and fracture permeability is based on determining a fracture width and a fracture conductivity. 
     
     
         20 . One or more tangible non-transitory computer-readable storage media storing computer-executable instructions for performing a computer process on a computing system, the computer process including:
 determining one or more production rates associated with a wellbore;   determining one or more flow pressures at one or more production sleeves of the wellbore;   generating, by a simulator model, a simulated flow velocity value based at least partly on the one or more production rates and the one or more flow pressures;   determining, by the simulator model, that the simulated flow velocity value is within a predetermined threshold range of an actual flow velocity value;   forming a normalized production rate, responsive to the simulated flow velocity value being within the predetermined threshold range of the actual flow velocity value, by comparing the actual flow velocity value with a critical velocity value; and   optimizing mitigation of proppant production from the wellbore by controlling the normalized production rate.