Patent ID: 11860326
Assignee: INSTITUTE OF GEOLOGY AND GEOPHYSICS, CHINESE ACADEMY OF SCIENCES
Field: Measurement (Instruments)
Classification: CPC G | IPC G

Claim 6:
7. The fault characterization method for precise navigation of deep oil and gas based on image fusion as described in claim 1 is characterized in that the gradient amplitude attribute fault confidence region is obtained by:
set value of points with attribute points below a preset fault threshold to 0, while keeping values of other points unchanged;
process a grid with attribute points higher than the preset fault threshold through the ellipsoidal expansion method to obtain an expanded fault position data volume; specifically:
in a process of ellipsoid expansion, an ellipsoid is raised to a required height Δ h along a direction of a mean curvature radius of a corresponding point P1 of a ground point P0 on an original ellipsoid E1, so that the ellipsoid coincides with an elevation projection plane;
set R1 as the mean curvature radius of P0 on a foundation ellipsoid E1, and R2 as the mean curvature radius of P1 on an expanded engineering ellipsoid E2; a specific algorithm of R1 and R2 is:, {
  
   
    
     
      
       R
       1
      
      =
      
       
        
         M
         ·
         N
        
       
       =
       
        
         a
         1
        
        ·
        
         
          1
          -
          
           
            e
            2
           
           /
           
            (
            
             1
             -
             
              
               e
               2
              
              ⁢
              
               sin
               2
              
              ⁢
              
               B
               1
              
             
            
            )
           
          
         
        
       
      
     
    
   
   
    
     
      
       R
       2
      
      =
      
       
        
         R
         1
        
        +
        
         Δ
         ⁢
         h
        
       
       =
       
        
         a
         2
        
        ·
        
         
          1
          -
          
           
            e
            2
           
           /
           
            (
            
             1
             -
             
              
               e
               2
              
              ⁢
              
               sin
               2
              
              ⁢
              
               B
               2
              
             
            
            )
           
          
         
        
       
      
     
    
   
  
 

M and N represent a meridian radius of curvature of the original ellipsoid E1 and a radius of curvature of a prime vertical, al and a2 respectively represent a long half-axis of the foundation ellipsoid E1 and the long half-axis of the expanded engineering ellipsoid E2, e represent a first eccentricity of the ellipsoid, B1 and B2 respectively represent a geodetic dimensions of the reference point on the foundation ellipsoid E1 and the expanded engineering ellipsoid E2;
wherein:, {
  
   
    
     
      
       a
       1
      
      =
      
       
        
         R
         1
        
        ·
        
         (
         
          1
          -
          
           
            e
            2
           
           ⁢
           
            sin
            2
           
           ⁢
           
            B
            1
           
          
         
         )
        
       
       /
       
        
         1
         -
         
          e
          2
         
        
       
      
     
    
   
   
    
     
      
       a
       2
      
      =
      
       
        
         R
         2
        
        ·
        
         
          (
          
           1
           -
           
            
             e
             2
            
            ⁢
            
             sin
             2
            
            ⁢
            
             B
             2
            
           
          
          )
         
         
          
           1
           -
           
            e
            2
           
          
         
        
       
       =
       
        
         (
         
          
           R
           1
          
          +
          
           Δ
           ⁢
           h
          
         
         )
        
        ·
        
         (
         
          1
          -
          
           
            e
            2
           
           ⁢
           
            sin
            2
           
           ⁢
           
            B
            2
           
          
         
         )
        
       
      
     
    
   
  
 

due to the dense data points and linear shape of a fault data group, the dimensional changes after expansion are negligible, and B1≈B2, or a variable ‘da’ of the long half-axis is:

da=α2−α1≈Δh·((1−e2sin2B1)/√{square root over (1−e2)})

calculate an amount of change in the long half-axis to obtain a change in a volume of the ellipsoid; a position of the ellipsoid after the volume change is a position of the attribute point after expansion, and a value of a data point after the expansion is a average value of a data group a confidence region of the gradient amplitude attribute fault is obtained.