static.m

基于matlab的反演程序,用于地球物理勘探中射线追踪及偏移成像程序.

function [recstat,shotstat] =static(depth, shotcoord, shotelev, recelev, uphole, datum, repvel,psd, v1rec, v2rec)
% Calculate the receiver and the shot static corrections according to a depth 
% and velocity model. Three static corrections: the weathering correction,
%  the elevation correction and the total correction.  
% The weathering correction correspond to the time needed to bring the 
% receiver or the shot at the base of the first layer using the depth and the
% velocity of the first layer.  In method 1, the elevation correction
% correspond to the time needed to bring back the shot or the receiver from 
% the base of the first layer to a flat datum using a replacement velocity. 
% In method 2, the elevation correction include the time to bring the shot or
% the receiver from the base of the first layer to a pseudo datum below the 
% first layer using the second layer velocity and the time to bring the shot
% or the receiver back to the final datum using a replacement velocity. 
% The total correction is a summation of the weathering and the elevation 
% corrections.


if (psd==0) % method 1

	% Weathering static computation
	hg = depth(2,:);
	wsrec = -hg./v1rec;

	hs = interpextrap(depth(1,:),depth(2,:),shotcoord);
	hs=hs';
	v1shot = interpextrap(depth(1,:),v1rec,shotcoord);
	v1shot=v1shot';
	wsshot = (-hs./v1shot) + uphole';

	% Elevation static computation
	
	repvel=repvel/1000;
	esrec = (datum-(recelev(2,:)-hg))./repvel;
	esshot = (datum-(shotelev-hs))./repvel;

else % method 2

	% Weathering static computation
	hg = depth(2,:);
	wsrec = -hg./v1rec;

	hs = interpextrap(depth(1,:),depth(2,:),shotcoord);
	hs=hs';
	v1shot = interpextrap(depth(1,:),v1rec,shotcoord);
	v1shot=v1shot';
	wsshot = (-hs./v1shot) + uphole';

	% Elevation static computation
	depthelev(1,:)=recelev(2,:)-depth(2,:);
	pseudo=min(depthelev);
	repvel=repvel/1000;
	esrec = (datum-pseudo)/repvel  -((recelev(2,:)-hg)-pseudo)./v2rec;
	v2shot = interpextrap(depth(1,:),v2rec,shotcoord);
	v2shot=v2shot';
	esshot = (datum-pseudo)/repvel  -((shotelev-hs)-pseudo)./v2shot;
end

recstat(1,:)=wsrec;
recstat(2,:)=esrec;
recstat(3,:)=wsrec+esrec;

shotstat(1,:)=wsshot;
shotstat(2,:)=esshot;
shotstat(3,:)=wsshot+esshot;

% Update menus
PMTsetmenus;