Integrated production simulator based on capacitance-resistance model

Abstract

A well-based production simulator is provided, which predicts the quantity of fluids produced per phase, per well and per time as a function of operational field parameters. The invention combines a petroleum reservoir simulator with a petroleum production facility simulator to obtain an integrated model to quickly and accurately forecast production on a well-by-well basis. The efficiency of the petroleum reservoir simulator is derived from its unique formulation, which solves for the production well's flow rate rather than the petroleum reservoir pressure. The simulator properly represents viscous, capillary and gravity forces, as well as complex fluid descriptions, including three-phase black-oil formulations.

We claim: 
     
         1 . At a computer system including at least one processor and a memory, a computer-implemented method for modeling a petroleum production system, the method comprising:
 accessing one or more portions of first production system information from a capacitance-resistance model of the production system, the production system corresponding to at least one petroleum production reservoir;   accessing one or more portions of second production system information from at least one of a well-bore model, a flow line and a petroleum production facility;   generating an integrated production simulator using both the first and second accessed production system information; and   implementing the integrated production simulator to determine the quantity of fluids produced per phase over time as a function of one or more operational field parameters corresponding to the petroleum production system by identifying the flow rate for the production reservoir.   
     
     
         2 . The method of  claim 1 , wherein the integrated production simulator shows the flow of petroleum and aqueous fluids from the production reservoir through the petroleum production facility. 
     
     
         3 . The method of  claim 1 , wherein the one or more operational field parameters corresponding to the petroleum production system comprise well-head choke size and artificial lift parameters. 
     
     
         4 . The method of  claim 1 , wherein the determined quantity of fluids produced per phase over time as a function of one or more operational field parameters corresponding to the petroleum production system is further analyzed to determine whether additional operations are to be initiated on the petroleum production system. 
     
     
         5 . The method of  claim 4 , further comprising, upon determining that additional operations are to be initiated on the petroleum production system, analyzing the determined quantity of fluids produced per phase over time as a function of one or more operational field parameters corresponding to the petroleum production system to determine the degree to which the additional operations are to be performed. 
     
     
         6 . The method of  claim 1 , wherein identifying the flow rate for the production reservoir comprises identifying a production rate for at least one of a plurality of fluids in the petroleum production reservoir. 
     
     
         7 . The method of  claim 1 , wherein the integrated production simulator accounts for fluid flow in both the well-bore and the petroleum production facility. 
     
     
         8 . The method of  claim 7 , wherein the integrated production simulator further accounts for fluid compressibility, capillary forces and gravitational forces. 
     
     
         9 . The method of  claim 1 , wherein bottom-hole pressure for the petroleum production system is identified as an unknown element. 
     
     
         10 . The method of  claim 9 , wherein the integrated production simulator is configured to model the bottom-hole's dependence on one or more components of petroleum production system architecture. 
     
     
         11 . An integrated well-based production simulator system comprising:
 a capacitance-resistance (CR) simulator configured to represent the flow of one or more fluids in a petroleum production reservoir;   a well-bore simulator configured to represent the flow of one or more fluids in a well-bore; and   a surface facility simulator configured to represent the flow of one or more fluids through at least one of the following surface facilities: one or more pipelines, a production gathering facility, a separation facility, and an injection distribution facility;   wherein the integrated well-based production simulator is configured to provide a system-wide representation of fluid flow through the petroleum production reservoir, the wellbore and at least one of the one or more surface facilities.   
     
     
         12 . The integrated well-based production simulator system of  claim 11 , wherein the one or more fluids comprise petroleum and one or more aqueous fluids. 
     
     
         13 . The integrated well-based production simulator system of  claim 11 , wherein the one or more fluids flow to a separator that is configured to isolate each fluid phase. 
     
     
         14 . The integrated well-based production simulator system of  claim 13 , wherein the separator isolates the fluids into at least three fluid phases (oil, gas and water). 
     
     
         15 . The integrated well-based production simulator system of  claim 13 , wherein the fluid phases are analyzed as being compressible when providing a system-wide representation of fluid flow through the petroleum production reservoir. 
     
     
         16 . The integrated well-based production simulator system of  claim 11 , wherein capillary forces and gravity forces are analyzed when providing a system-wide representation of fluid flow through the petroleum production reservoir. 
     
     
         17 . The integrated well-based production simulator system of  claim 11 , wherein the integrated well-based production simulator incorporates one or more control mechanisms of the petroleum production reservoir including at least one of well-head choke size and artificial lift parameters. 
     
     
         18 . The integrated well-based production simulator system of  claim 11 , wherein the integrated well-based production simulator includes different levels of control including one or more of the following: tubing head pressure, flow-line pressure located at the well head upstream and downstream of the choke, and downstream pressures of flow-lines, manifolds or separators. 
     
     
         19 . The integrated well-based production simulator system of  claim 11 , wherein the integrated well-based production simulator implements a flow function to determine fluid flow for the integrated well-based production simulator system, the function comprising an analytical formula that expresses dependence on bottom-hole pressure to downstream pressure, flow rates and one or more operational parameters. 
     
     
         20 . The integrated well-based production simulator system of  claim 11 , wherein the integrated well-based production simulator implements a numerical model of a flow function to determine fluid flow for the integrated well-based production simulator system, such that the flow function comprises at least one of a simulator of wellbore flow dynamics and a surface facility simulator. 
     
     
         21 . The integrated well-based production simulator system of  claim 11 , wherein the integrated well-based production simulator implements a flow function to determine fluid flow for the integrated well-based production simulator system, the flow function comprising a table of pre-computed solutions. 
     
     
         22 . The integrated well-based production simulator system of  claim 11 , wherein the integrated well-based production simulator system includes a computer system. 
     
     
         23 . At a computer system including at least one processor and a memory, a computer-implemented method for generating a production forecast for individual production wells of a petroleum reservoir, the method comprising the following:
 accessing one or more operational parameters for a production well;   providing an integrated well-based production simulator by solving the following system of equations:
 (Eq. 7) p BH =f p     c1     , . . . , p     cm     facility (p DS , q o , q w ), where p c1 , . . . , p cm  comprise m independent operational parameters for the production well; 
 (Eq. 5) q t =j(p−p BH ), which links a total production rate to the reservoir pressure; and 
   
       
         
           
             
               
                 
                   
                     
                       
                         
                           
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       which provides a mass conservation condition over one or more fluid components written over the drainage volume of the production well, where V comprises the drainage volume of the production well; and
 the integrated well-based production simulator generating a production forecast for the production well using the accessed operational parameters. 
 
     
     
         24 . The method of  claim 23 , wherein the fluid components comprise water and oil. 
     
     
         25 . The method of  claim 23 , wherein the production forecast is generated without relying on assumptions about the individual production well.