US2020311178A1PendingUtilityA1

Three-dimensional elastic frequency-domain iterative solver for full waveform inversion

Assignee: SAUDI ARABIAN OIL COPriority: Aug 25, 2015Filed: Apr 13, 2020Published: Oct 1, 2020
Est. expiryAug 25, 2035(~9.1 yrs left)· nominal 20-yr term from priority
G01V 2210/67G06F 30/20G06F 17/11G06F 17/12G06F 17/142G06F 17/16G01V 99/005G01V 20/00
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Claims

Abstract

Certain implementations of a three-dimensional elastic frequency domain iterative solver for full waveform inversion can be implemented as a method in which frequency domain numerical simulation of elastic waves is per formed in three-dimensional (3D) media.

Claims

exact text as granted — not AI-modified
1 - 22 . (canceled) 
     
     
         23 . A computer-implemented method comprising:
 representing, by data processing apparatus, a three-dimensional (3D) elastic system in compliance form, the 3D elastic system representing 3D land media, the compliance form comprising   
       
         
           
             
               
                 Lu 
                 = 
                 
                   
                     
                       [ 
                       
                         
                           i 
                            
                           
                               
                           
                            
                           ω 
                            
                           
                               
                           
                            
                           
                             M 
                              
                             
                               ( 
                               
                                 x 
                                 , 
                                 y 
                                 , 
                                 z 
                               
                               ) 
                             
                           
                         
                         - 
                         
                           P 
                            
                           
                             ∂ 
                             
                               ∂ 
                               x 
                             
                           
                         
                         - 
                         
                           Q 
                            
                           
                             ∂ 
                             
                               ∂ 
                               y 
                             
                           
                         
                         - 
                         
                           R 
                            
                           
                             ∂ 
                             
                               ∂ 
                               z 
                             
                           
                         
                       
                       ] 
                     
                      
                     u 
                   
                   = 
                   f 
                 
               
               , 
             
           
         
       
       wherein u represents a velocity through the media, wherein M is an operator represented by 
       
         
           
             
               
                 M 
                 = 
                 
                   ( 
                   
                     
                       
                         
                           ρ 
                            
                           
                               
                           
                            
                           
                             I 
                             
                               3 
                               × 
                               3 
                             
                           
                         
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         
                           S 
                           
                             6 
                             × 
                             6 
                           
                         
                       
                     
                   
                   ) 
                 
               
               , 
             
           
         
       
       ρ is density, I 3×3  is an identical operator and S 6×6  is a matrix represented by 
       
         
           
             
               
                 S 
                 = 
                 
                   [ 
                   
                     
                       
                         a 
                       
                       
                         
                           - 
                           b 
                         
                       
                       
                         
                           - 
                           b 
                         
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         
                           - 
                           b 
                         
                       
                       
                         a 
                       
                       
                         
                           - 
                           b 
                         
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         
                           - 
                           b 
                         
                       
                       
                         
                           - 
                           b 
                         
                       
                       
                         a 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               , 
             
           
         
       
       a is an operator represented by 
       
         
           
             
               
                 a 
                 = 
                 
                   
                     λ 
                     + 
                     μ 
                   
                   
                     u 
                      
                     
                       ( 
                       
                         
                           2 
                            
                           
                               
                           
                            
                           μ 
                         
                         + 
                         
                           3 
                            
                           
                               
                           
                            
                           λ 
                         
                       
                       ) 
                     
                   
                 
               
               , 
             
           
         
       
       b is an operator represented by 
       
         
           
             
               
                 b 
                 = 
                 
                   ( 
                   
                     λ 
                     
                       2 
                        
                       
                           
                       
                        
                       
                         μ 
                          
                         
                           ( 
                           
                             
                               2 
                                
                               
                                   
                               
                                
                               μ 
                             
                             + 
                             
                               3 
                                
                               
                                   
                               
                                
                               λ 
                             
                           
                           ) 
                         
                       
                     
                   
                   ) 
                 
               
               , 
             
           
         
       
       c is an operator represented by 
       
         
           
             
               
                 c 
                 = 
                 
                   ( 
                   
                     1 
                     μ 
                   
                   ) 
                 
               
               , 
             
           
         
       
       λ and μ are Lame parameters, S 6×6  is compliance tensor C −1 , P is represented by 
       
         
           
             
               
                 P 
                 = 
                 
                   [ 
                   
                     
                       
                         0 
                       
                       
                         A 
                       
                     
                     
                       
                         
                           A 
                           T 
                         
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               , 
             
           
         
       
       Q is represented by 
       
         
           
             
               
                 Q 
                 = 
                 
                   [ 
                   
                     
                       
                         0 
                       
                       
                         B 
                       
                     
                     
                       
                         
                           B 
                           T 
                         
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               , 
             
           
         
       
       R is represented by 
       
         
           
             
               
                 R 
                 = 
                 
                   [ 
                   
                     
                       
                         0 
                       
                       
                         D 
                       
                     
                     
                       
                         
                           D 
                           T 
                         
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               , 
             
           
         
       
       wherein 
       
         
           
             
               
                 A 
                 = 
                 
                   [ 
                   
                     
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               , 
             
           
         
       
       wherein 
       
         
           
             
               
                 B 
                 = 
                 
                   [ 
                   
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                     
                     
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               , 
             
           
         
       
       wherein 
       
         
           
             
               
                 D 
                 = 
                 
                   [ 
                   
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                     
                       
                         0 
                       
                       
                         0 
                       
                       
                         1 
                       
                       
                         0 
                       
                       
                         0 
                       
                       
                         0 
                       
                     
                   
                   ] 
                 
               
               ; 
             
           
         
         determining, by the data processing apparatus, parameters corresponding to the media, dimensions of a computational domain to solve the compliance form and condition at a top boundary of the computational domain; 
         determining, by the data processing apparatus, one-dimensional (1D) background parameters of the media and a preconditioner solve the compliance form within the computational domain; 
         representing, by the data processing apparatus, an initial problem as a perturbation of the preconditioner; 
         iteratively performing, by the data processing apparatus, matrix-vector multiplication to solve the compliance form; 
         determining, by the data processing apparatus, a velocity distribution of the velocity through the media in response to iteratively performing the matrix-vector multiplication. 
       
     
     
         24 . The computer-implemented method of  claim 23 , wherein the 3D land media comprises heterogeneous media. 
     
     
         25 . The computer-implemented method of  claim 23 , wherein the 3D land media comprises isotropic media. 
     
     
         26 . The computer-implemented method of  claim 23 , wherein the 3D land media comprises a rock formation. 
     
     
         27 . The computer-implemented method of  claim 23 , wherein the 3D land media comprises a hydrocarbon reservoir. 
     
     
         28 . The computer-implemented method of  claim 23 , wherein determining the preconditioner comprises constructing the preconditioner as an inverse to the operator shown in the following equation: 
       
         
           
             
               
                 
                   L 
                   0 
                 
                 = 
                 
                     
                 
                  
                 
                   
                     i 
                      
                     
                         
                     
                      
                     ω 
                      
                     
                         
                     
                      
                     
                       
                         M 
                         0 
                       
                        
                       
                         ( 
                         z 
                         ) 
                       
                     
                   
                   - 
                   
                     P 
                      
                     
                       ∂ 
                       
                         ∂ 
                         x 
                       
                     
                   
                   - 
                   
                     Q 
                      
                     
                       ∂ 
                       
                         ∂ 
                         y 
                       
                     
                   
                   - 
                   
                     R 
                      
                     
                       ∂ 
                       
                         ∂ 
                         z 
                       
                     
                   
                 
               
               , 
             
           
         
       
       wherein the operator M 0  has the same structure as the operator M. 
     
     
         29 . The computer-implemented method of  claim 28 , wherein a complex damping function is introduced into the operator M 0 . 
     
     
         30 . The computer-implemented method of  claim 29 , wherein the complex damping function is represented by the following equations: a 0 (z)={circumflex over (β)}â 0 (z), b 0 (z)={circumflex over (β)}{circumflex over (b)} 0 (z), c 0 (z)={circumflex over (β)}ĉ 0 (z), {circumflex over (β)}=(1+iβ). 
     
     
         31 . The computer-implemented method of  claim 23 , wherein representing the initial problem as the perturbation to the preconditioner comprises representing the initial operator L as a combination of L 0  and δL, wherein representing the initial operator L as a combination of L 0  and δL comprises representing the initial operator according to the following equation: δL=−iω[M 0 (z)−M(x,y,z)]. 
     
     
         32 . The computer-implemented method of  claim 23 , wherein the matrix-vector multiplication is performed by the application of a parallel Fast Fourier Transform (FFT), a banded matrix solver, and an inverse FFT.

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