Drilling of multilateral wells in reservoirs

Abstract

Disclosed are methods, systems, and computer-readable media to perform operations including: building a multi-layer transient model representing the reservoir based on a geological model; determining a location at the reservoir for placing the at least one multilateral well in at least one first simulation scenario executed by the multi-layer transient model; determining a lateral spacing between lateral sections of the at least one multilateral well and a number of lateral sections based on a first productivity index (PI) in at least one second simulation scenario executed by the multi-layer transient model; determining a well length for each lateral section of the multilateral well based on a second PI in at least one third simulation scenario executed by the multi-layer transient model; and drilling the multilateral well in the reservoir having the determined lateral spacing, the determined number of lateral sections, and the determined well length at the determined location.

We claim: 
     
         1 . A computer-implemented method for placing at least one multilateral well in a reservoir, comprising:
 building a multi-layer transient model representing the reservoir based on a geological model;   determining a location at the reservoir for placing the at least one multilateral well in at least one first simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces hydrocarbons at a target production rate at the determined location;   determining a lateral spacing between lateral sections of the at least one multilateral well and a number of lateral sections based on, at least in part, a first productivity index (PI) in at least one second simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces the hydrocarbons at the target production rate in each second simulation scenario;   determining a well length for each lateral section of the at least one multilateral well based at least in part on a second PI in at least one third simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces the hydrocarbons at the target production rate in each third simulation scenario; and   drilling the at least one multilateral well in the reservoir having the determined lateral spacing, the determined number of lateral sections, and the determined well length at the determined location.   
     
     
         2 . The computer-implemented method of  claim 1 , further comprising determining a spacing between the at least one multilateral well and an injection well based on a pressure response and a water cut response at the at least one multilateral well. 
     
     
         3 . The computer-implemented method of  claim 2 , further comprising:
 receiving multiple candidate spacings between the at least one multilateral well and the injection well;   performing a sensitivity analysis for each candidate spacing to obtain an injection pressure response and a water cut response at the at least one multilateral well; and   selecting the spacing from the multiple candidate spacings based on the injection pressure response and the water cut response.   
     
     
         4 . The computer-implemented method of  claim 1 , building the multi-layer transient model further comprising:
 providing reservoir data including one or more of geological data, geophysical data, petrophysical data, pressure, volume and temperature (PVT) data, reservoir initial conditions, fluid-contact data, reference point, capillary pressure, relative permeability and well data including one or more of a proposed multilateral well trajectory, an injection well trajectory, pressure response data, production rates to the geological model; and   performing Quality assurance and quality control (QAQC) of the multi-layer transient model with reference to the reservoir data and the well data.   
     
     
         5 . The computer-implemented method of  claim 1 , determining the location further comprising:
 executing a first simulation scenario with the at least one multilateral well placed at an initial location;   in response to the at least one multilateral well failing to satisfy the target production rate at the initial location,
 adjusting the initial location and iteratively executing a new first simulation scenario at adjusted locations until the at least one multilateral well satisfies the target production rate; and 
 determining that the adjusted location is the location for placing the at least one multilateral well. 
   
     
     
         6 . The computer-implemented method of  claim 1 , determining the lateral spacing between the lateral sections of the at least one multilateral well further comprising:
 receiving multiple candidate lateral spacings for the at least one multilateral well;   performing a simulation scenario for each candidate lateral spacing;   calculating the first PI for each candidate lateral spacing; and   selecting the lateral spacing from the multiple candidate lateral spacings based on the first PI.   
     
     
         7 . The computer-implemented method of  claim 6 , determining the lateral spacing between the lateral sections of the at least one multilateral well further comprising:
 prior to calculating the first PI, generating a log-log plot to identify a late radial-flow regime.   
     
     
         8 . The computer-implemented method of  claim 1 , determining the well length for each lateral section further comprising:
 receiving multiple candidate well lengths for the at least one multilateral well;   performing a simulation scenario for each candidate well length;   calculating the second PI for each candidate well length; and   selecting the well length from the multiple candidate well lengths based on the second PI.   
     
     
         9 . An apparatus comprising a non-transitory, computer readable, storage medium that stores instructions that, when executed by at least one processor, cause the at least one processor to perform operations comprising:
 building a multi-layer transient model representing a reservoir based on a geological model;   determining a location at the reservoir for placing at least one multilateral well in at least one first simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces hydrocarbons at a target production rate at the determined location;   determining a lateral spacing between lateral sections of the at least one multilateral well and a number of lateral sections based on, at least in part, a first productivity index (PI) in at least one second simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces the hydrocarbons at the target production rate in each second simulation scenario;   determining a well length for each lateral section of the at least one multilateral well based at least in part on a second PI in at least one third simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces the hydrocarbons at the target production rate in each third simulation scenario; and   drilling the at least one multilateral well in the reservoir having the determined lateral spacing, the determined number of lateral sections, and the determined well length at the determined location.   
     
     
         10 . The apparatus of  claim 9 , the operations further comprising determining a spacing between the at least one multilateral well and an injection well based on a pressure response and a water cut response at the at least one multilateral well. 
     
     
         11 . The apparatus of  claim 10 , the operations further comprising:
 receiving multiple candidate spacings between the at least one multilateral well and the injection well;   performing a sensitivity analysis for each candidate spacing to obtain an injection pressure response and a water cut response at the at least one multilateral well; and   selecting the spacing from the multiple candidate spacings based on the injection pressure response and the water cut response.   
     
     
         12 . The apparatus of  claim 9 , building the multi-layer transient model further comprising:
 providing reservoir data including one or more of geological data, geophysical data, petrophysical data, pressure, volume and temperature (PVT) data, reservoir initial conditions, fluid-contact data, reference point, capillary pressure, relative permeability and well data including one or more of a proposed multilateral well trajectory, an injection well trajectory, pressure response data, production rates to the geological model; and   performing Quality assurance and quality control (QAQC) of the multi-layer transient model with reference to the reservoir data and the well data.   
     
     
         13 . The apparatus of  claim 9 , determining the location further comprising:
 executing a first simulation scenario with the at least one multilateral well placed at an initial location;   in response to the at least one multilateral well failing to satisfy the target production rate at the initial location,
 adjusting the initial location and iteratively executing a new first simulation scenario at adjusted locations until the at least one multilateral well satisfies the target production rate; and 
 determining that the adjusted location is the location for placing the at least one multilateral well. 
   
     
     
         14 . The apparatus of  claim 9 , determining the lateral spacing between the lateral sections of the at least one multilateral well further comprising:
 receiving multiple candidate lateral spacings for the at least one multilateral well;   performing a simulation scenario for each candidate lateral spacing;   calculating the first PI for each candidate lateral spacing; and   selecting the lateral spacing from the multiple candidate lateral spacings based on the first PI.   
     
     
         15 . The apparatus of  claim 14 , determining the lateral spacing between the lateral sections of the at least one multilateral well further comprising:
 prior to calculating the first PI, generating a log-log plot to identify a late radial-flow regime.   
     
     
         16 . The apparatus of  claim 9 , determining the well length for each lateral section further comprising:
 receiving multiple candidate well lengths for the at least one multilateral well;   performing a simulation scenario for each candidate well length;   calculating the second PI for each candidate well length; and   selecting the well length from the multiple candidate well lengths based on the second PI.   
     
     
         17 . A system, comprising:
 one or more memory modules; and   one or more hardware processors communicably coupled to the one or more memory modules, the one or more hardware processors configured to execute instructions stored on the one or more memory modules to perform operations comprising:   building a multi-layer transient model representing a reservoir based on a geological model;   determining a location at the reservoir for placing at least one multilateral well in at least one first simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces hydrocarbons at a target production rate at the determined location;   determining a lateral spacing between lateral sections of the at least one multilateral well and a number of lateral sections based on, at least in part, a first productivity index (PI) in at least one second simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces the hydrocarbons at the target production rate in each second simulation scenario;   determining a well length for each lateral section of the at least one multilateral well based at least in part on second PI in at least one third simulation scenario executed by the multi-layer transient model, wherein the at least one multilateral well produces the hydrocarbons at the target production rate in each third simulation scenario; and   drilling the at least one multilateral well in the reservoir having the determined lateral spacing, the determined number of lateral sections, and the determined well length at the determined location.   
     
     
         18 . The system of  claim 17 , the operations further comprising determining a spacing between the at least one multilateral well and an injection well based on a pressure response and a water cut response at the at least one multilateral well. 
     
     
         19 . The system of  claim 18 , the operations further comprising:
 receiving multiple candidate spacings between the at least one multilateral well and the injection well;   performing a sensitivity analysis for each candidate spacing to obtain an injection pressure response and a water cut response at the at least one multilateral well; and   selecting the spacing from the multiple candidate spacings based on the injection pressure response and the water cut response.   
     
     
         20 . The system of  claim 17 , determining the location further comprising:
 executing a first simulation scenario with the at least one multilateral well placed at an initial location;   in response to the at least one multilateral well failing to satisfy the target production rate at the initial location,
 adjusting the initial location and iteratively executing a new first simulation scenario at adjusted locations until the at least one multilateral well satisfies the target production rate; and 
 determining that the adjusted location is the location for placing the at least one multilateral well.