Locally lumped equation of state fluid characterization in reservoir simulation

Abstract

In some embodiments, a method for locally lumped equation of state fluid characterization can include determining a set of components for the material balance calculations for a plurality of grid blocks of a reservoir. The plurality of grid blocks can experience different recovery methods between them. Lumping schemes can be determined for the plurality of grid blocks. Phase behavior calculations can be performed on the plurality of grid blocks, wherein different lumping schemes can be used across the plurality of grid blocks.

1 . A method for locally lumped equation of state fluid characterization, the method comprising:
 determining material balance components for a plurality of grid blocks of a reservoir, wherein different recovery mechanisms are experienced within different groups of grid blocks;   determining lumping schemes for the plurality of grid blocks; and   performing phase behavior calculations on the plurality of grid blocks wherein different lumping schemes are used across the reservoir.   
     
     
         2 . The method of  claim 1 , wherein determining material balance components comprises determining a fluid composition in the plurality of grid blocks by, performing a pressure, volume, temperature analysis of the grid blocks or groups of grid blocks. 
     
     
         3 . The method of  claim 1 , further comprising delumping phase compositions resulting from the phase behavior calculations. 
     
     
         4 . The method of  claim 3 , further comprising expressing properties of fluid properties of a grid block or group of grid blocks with respect to the material balance components of the grid block or the group of grid blocks. 
     
     
         5 . The method of  claim 1 , wherein determining lumping schemes comprises lumping the material balance components to pseudo-components such that each pseudo-component represents one or more material balance components resulting in a reduced quantity of pseudo-components. 
     
     
         6 . The method of  claim 5 , wherein the reduced quantity of pseudo-components are less than the quantity of material balance components. 
     
     
         7 . The method of  claim 1 , wherein performing phase behavior calculations on the plurality of grid blocks comprises wherein a first lumping scheme is used for a first grid block or group of grid blocks at a first time and a second lumping scheme is used for the first grid block or group of grid blocks at a second time. 
     
     
         8 . The method of  claim 7 ; further comprising changing a recovery mechanism for the first grid block or group of grid blocks between the first time and the second time. 
     
     
         9 - 14 . (canceled) 
     
     
         15 . A method for locally lumped equation of state fluid characterization, the method comprising:
 performing pressure, volume, temperature (PVT) characterizations for each recovery mechanism of a plurality of recovery mechanisms for a reservoir comprising a plurality of grid blocks and a plurality of delumped components;   assigning each grid block to a PVT characterization;   performing phase behavior calculations across the reservoir using different lumping schemes to generate phase compositions;   delumping the phase compositions; and   expressing the phase compositions with respect to the delumped components.   
     
     
         16 . The method of  claim 15 , further comprising dividing the reservoir into a plurality of groups of grid blocks, each group of grid blocks experiencing a different recovery mechanism. 
     
     
         17 . The method of  claim 15 , wherein performing the PVT analysis comprises developing equation of state (EOS) characterizations for each recovery mechanism. 
     
     
         18 . The method of  claim 15 , wherein each PVT characterization comprises a plurality of delumped components. 
     
     
         19 . The method of  claim 15 , further comprising determining material balance components from the PVT characterizations having a largest quantity of delumped components. 
     
     
         20 . The method of  claim 19 , further comprising conserving the material balance components for each grid block. 
     
     
         21 . A system comprising:
 a processor; and   a memory coupled to the processor, the memory storing processor-readable instructions, which, when executed by the processor, cause the processor to perform a plurality of functions, including functions to:   perform pressure, volume, temperature (PVT) characterizations for each recovery mechanism of a plurality of recovery mechanisms for a reservoir comprising a plurality of grid blocks and a plurality of delumped components;   assign each grid block to a PVT characterization;   perform phase behavior calculations across the reservoir using different lumping schemes to generate phase compositions;   delump the phase compositions; and   express the phase compositions with respect to the delumped components   
     
     
         22 . The system of  claim 21 , wherein the plurality of functions performed by the processor further include functions to divide the reservoir into a plurality of groups of grid blocks, each group of grid blocks experiencing a different recovery mechanism. 
     
     
         23 . The system of  claim 21 , wherein the plurality of functions performed by the processor further include functions to generate equation of state (EOS) characterizations for each recovery mechanism. 
     
     
         24 . The system of  claim 21 , wherein each PVT characterization comprises a plurality of delumped components. 
     
     
         25 . The system of  claim 21 , wherein the plurality of functions performed by the processor further include functions to determine material balance components from the PVT characterizations having a largest quantity of delumped components. 
     
     
         26 . The system of  claim 25 , wherein the plurality of functions performed by the processor further include functions to conserve the material balance components for each grid block.