sukdmig3d.su.main

su 的源代码库

SUKDMIG3D - Kirchhoff Depth Migration of 3D poststack/prestack data	

 	sukdmig3d datain= dataout= [parameters] 			

 Required parameters:							
 ttfile	 file for input tttables			       	

 Optional Parameters:							

 datain=stdin	 file for input seismic traces				
 dataout=stdout file for common offset migration output		
 crfile=NULL    file for cos theta and ray paths                       

   The following 17 parameters describe tttables: (from ttfile header)	
 fxgd= or from header (f1)		first x-sample in tttable	
 nxt= or from header (ns)		number of x-samples in tttable	
 dxgd= or from header (d1)		x-interval in tttable 		
 fygd= or from header (f2)		first y-sample in tttable 	
 nyt= or from header (ntr)		number of y-samples in tttable	
 dygd= or from header (d2)		y-interval in tttable		
 ixsf= or from header (sdel) 	        x in dxgd of first source	
 nxs= or from header (nhs) 		number of sources in x		
 ixsr= or from header (swdep) 	        ratio of source & gd spacing    
 iysf= or from header (gdel)	        y in dygd of first source 	
 nys= or from header (nvs)		number of sources in y          
 iysr= or from header (gwdep)	        ratio of source & gd spacing    
 fzs= or from header (sdepth/1000)	first depth sample in tttable	
 nzs= or from header (duse) 		number of depth samples in tttable
 dzs= or from header (ep/1000)		depth interval in tttable	
 nxgd= or from header (selev)		x size of the traveltime region 
 nygd= or from header (gelev)		y size of the traveltime region 
 multit= or from header (scalel)       number of multivalued traveltime

   The following two parameters are from data header			
 dt= or from header (dt)	time sampling interval of input data	
 ft= or from header (ft)	first time sample of input data		
 dxm= or from header (d2)      mid point spacing of input data         

 Default: output is 5 times finer in depth and 2 times finer in lateral
 fzo=fzs	z-coordinate of first point in output trace		
 dzo=0.2*dzs	vertical spacing of output trace (5 times finer)	
 nzo=5*(nzs-1)+1 number of points in output trace (5 times finer)	",	
 fxo=fxgd	x-coordinate of first output trace	 		
 dxo=0.5*dxgd	horizontal spacing of output trace (2 times finer)	
 nxo=2*(nxgd-1)+1 number of output traces (2 times finer)		
 fyo=fygd	y-coordinate of first output trace			
 dyo=0.5*dygd	horizontal spacing of output trace (2 times finer)	
 nyo=2*(nygd-1)+1 number of output traces (2 times finer)		

 Default: poststack migration						",	
 fxoffset=0		first offest in output in x			
 fyoffset=0		first offest in output in y			
 dxoffset=99999	offset increment in output in x	 		
 dyoffset=99999	offset increment in output in y			
 nxoffset=1		number of offsets in output in x		
 nyoffset=1		number of offsets in output in y		",	
 xoffsetmax=99999	x-maximum absolute offset allowed in migration 	
 yoffsetmax=99999	y-maximum absolute offset allowed in migration  
 xaper=nxt*dxgd/2.5	migration lateral aperature in x		
 yaper=nyt*dygd/2.5	migration lateral aperature in y		
 angmax=60             max angle to handle                             
 fmax=0.25/dt          max frequency in the data                       
 jpfile=stderr		job print file name 				
 pptr=100		print verbal information at every pptr traces	
 ntrmax=100000		maximum number of input traces to be migrated	
 ls=0                  point =0 line source =1                         

 Notes:								
 1. Traveltime tables were generated by program SUTETRARAY (or other	
    ones) on very sparse tetrahedral model, with dimension nys*nxs*nzs 
    *nyt*nxt.                                                          
 2. Input seismic traces must be SU format and can be any type of 	
    gathers (common shot, common offset, common CDP, and so on).	", 
 3. Migrated traces are output in CDP gathers if velocity analysis	
    is required, with dimension nyoffset*nxoffset*nyo*nxo*nzo.		", 
 4. If the offset value of an input trace is not in the offset array 	
    of output, the nearest one in the array is chosen. 		
 5. Memory requirement for this program is about			
    [nys*nxs*nzs*nyt*nxt+nyoffset*nxoffset*nxo*nyo*nzo+	       	
    nys*nxo*nzo*nyt*nxt]                                               
 6. Input traces must specify source and receiver positions via header	
    fields tr.sx and tr.gx, as well as tr.sy and tr.gy. Offset is 	
    computed automatically.						

 Disclaimer:								
 This is a research code that will take considerable work to get into	
 the form of a a production level 3D migration code. The code is	
 offered as is, along with tetramod and sutetraray, to provide a starting
 point for researchers who wish to write their own 3D migration codes.



 Author:  Zhaobo Meng, 01/10/97,  Colorado School of Mines 

 Trace header fields accessed: ns, dt, delrt, d2
 Trace header fields modified: sx, gx