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Reflector dip in terms of traveltimes squared

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Proceedings Papers

Paper presented at the 2015 SEG Annual Meeting, October 18–23, 2015
Paper Number: SEG-2015-5807160
.... Simultaneous inversion for dipping boundaries and tilted TI anisotropy with unknown tilt axes leads to strong nonuniqueness. We therefore must make some assumptions about the anisotropy symmetry axes. I assume that anisotropy axes are perpendicular to the dipping reflectors. This is called a dip-constrained...
Proceedings Papers

Paper presented at the 1992 SEG Annual Meeting, October 25–29, 1992
Paper Number: SEG-1992-1275
... ABSTRACT No preview is available for this paper. dip-dependent divergence correction divergence correction correction reflection point horizontal reflector amplitude conventional divergence correction traveltime reservoir characterization reflector raypath francesca fazzari...
Proceedings Papers

Paper presented at the 2011 SEG Annual Meeting, September 18–23, 2011
Paper Number: SEG-2011-3017
..., a one way traveltime map that does not reflect directly the source/receiver setup associated with our typical surface seismic reflection ex- periment. For horizontal reflectors, such travelimes in homogenous media is given by a simple hyperbolic sur- face. To include both midpoint and offset, more ex...
Proceedings Papers

Paper presented at the 1996 SEG Annual Meeting, November 10–15, 1996
Paper Number: SEG-1996-1487
... Analysis of normal-moveout (NMO) velocity can provide valuable information for traveltime inversion in anisotropic media. Here, we present a general NMO equation that describes azimuthally-dependent reflection moveout of pure modes from both horizontal and dip- ping reflectors in arbitrary anisotropic...
Proceedings Papers

Paper presented at the 1995 SEG Annual Meeting, October 8–13, 1995
Paper Number: SEG-1995-1409
...- scribed in the previous section is just a way of measuring traveltime errors At.. The traveltime errors At are required to compute the perturbation Aw in reference slowness as shown in equation (2). Figure 8: For a reflector of dipping angle a plane wave sat- isfies Snell s law. To simplify the RMO...
Proceedings Papers

Paper presented at the 1988 SEG Annual Meeting, October 30–November 3, 1988
Paper Number: SEG-1988-0909
.... If the migration velocity is V, the equation of the ellipse is equation 1. If the imaging velocity is changed from v to v,, the image of the dipping reflector will move as shown in Figure 1, and will be tangent to an ellipse described by equation 2. v.t=&T&-Ty (2) The traveltime is Sxed since we consider the image...
Proceedings Papers

Paper presented at the 2012 SEG Annual Meeting, November 4–9, 2012
Paper Number: SEG-2012-0009
... models and some one-layered models with analytically described reflectors. It can be used in place of the exact moveout. However, it has two limitations: (i) It cannot be used for VSP geometry, or for direct or for reflected traveltimes because the time-distance function t(x) is not even in the case...
Proceedings Papers

Paper presented at the 1996 SEG Annual Meeting, November 10–15, 1996
Paper Number: SEG-1996-1987
... for hyperbolic velocity determination. Kinematics of zero=offset rays. The analytic derivation of zero-offset traveltime in the case of a dipping reflector embedded in a constant velocity Earth is the base for the expression of the DMO operator. With this assumption, the zero-offset traveltime is a simple...
Proceedings Papers

Paper presented at the 1995 SEG Annual Meeting, October 8–13, 1995
Paper Number: SEG-1995-0348
... given by and is the interval vertical velocity. For dipping reflectors, when expressed in terms of ray parameter p, NMO velocity is also given by a similar rms relation (Alkhalifah and Tsvankin, 1995). where is the interval NMO velocity as a function of vertical time (migrated time), and to(p) is zero...
Proceedings Papers

Paper presented at the 1996 SEG Annual Meeting, November 10–15, 1996
Paper Number: SEG-1996-1731
... dmo processing formalism ocpde coefficient reflection reservoir characterization continuation incidence angle curvature amplitude dmo offiet traveltime true amplitude dmo geophysics reflection coefficient amplitude reflector fomel asymptotic analysis dmo upstream oil...
Proceedings Papers

Paper presented at the 1995 SEG Annual Meeting, October 8–13, 1995
Paper Number: SEG-1995-1204
... ABSTRACT No preview is available for this paper. reflector dip migration transversely isotropic media media velocity gradient reflector migration error reservoir characterization larner anisotropy parameter algorithm anisotropy geophysics reflection alkhalifah gradient...
Proceedings Papers

Paper presented at the 2012 SEG Annual Meeting, November 4–9, 2012
Paper Number: SEG-2012-0507
... of the DSR formula valid for media with the symmetry axis normal to the dip of the reflector (DTI). The accuracy of this approximate solution is enhanced using Shanks transform to a point where the errors are extremely small for practical anisotropic values. Under this assumption, we also do not need...
Proceedings Papers

Paper presented at the 2009 SEG Annual Meeting, October 25–30, 2009
Paper Number: SEG-2009-0211
...-square fitting of any NMO approximation, which will provide a more stable and accurate result. From walkaway VSP data, virtual reflected traveltimes are created, using each receiver as a virtual horizontal reflector. Traveltimes are approximated using several three-term functions (Blias, 2009...
Proceedings Papers

Paper presented at the 1992 SEG Annual Meeting, October 25–29, 1992
Paper Number: SEG-1992-0974
... a dipping reflector in a constant-velocity medium. The derived moveout relation expresses traveltime-squared as a power series in offset; the f-lc TZO formulation itself is based on the hyperbolic ap- proximation to the derived moveout relation. This level of approximation avoids having to deal with cubic...
Proceedings Papers

Paper presented at the 1996 SEG Annual Meeting, November 10–15, 1996
Paper Number: SEG-1996-1866
... for the same amount of anisotropy. The reference curve is always cal- culated with ANRAY based on a model with an horizontal reflector and the same amount of anisotropy as the other two curves. For each dip (10, 20) the ANRAY calculation represents the real messurement. Fig 5: Separation for 15% TIV anisotropy...
Proceedings Papers

Paper presented at the 2004 SEG Annual Meeting, October 10–15, 2004
Paper Number: SEG-2004-1089
... and emergence angle terms that would otherwise contribute to a large error. The method is illustrated by synthetic data containing flat and dipping reflectors in depth dependent velocity media. analytically efficient true-amplitude weight exposition equation constant velocity approximation sand...
Proceedings Papers

Paper presented at the 2005 SEG Annual Meeting, November 6–11, 2005
Paper Number: SEG-2005-0116
... that required forth-order traveltime derivatives ex- ist. Pech et al. (2003) also derived a weak anisotropy ap- proximation for transversely isotropic layer with a tilted symmetry axis above a plane dipping reflector. They demonstrated that A 4( a ) can change sign and form in- tricate cloverleaf patterns...
Proceedings Papers

Paper presented at the 2009 SEG Annual Meeting, October 25–30, 2009
Paper Number: SEG-2009-3620
..., is derived in Appendix A. A truncated Taylor expansion of the squared traveltime from equation (12) around d = 0 and h = 0 is equivalent to equa- tion (8). ACCURACY COMPARISONS Analytical Example The first example we use to compare the accuracy of different approximations is that of a circular reflector...
Proceedings Papers

Paper presented at the 1999 SEG Annual Meeting, October 31–November 5, 1999
Paper Number: SEG-1999-1358
... along traveltime isochrons (i.e. migration operators). Constructive interference occurs when the tangent to the migration operator matches the dip of the reflector at the imaging point, and destructive interference occurs otherwise, resulting in an image of the reflector. If the tangent matches the dip...
Proceedings Papers

Paper presented at the 1993 SEG Annual Meeting, September 26–30, 1993
Paper Number: SEG-1993-0616
.... Forward ray-tracing method We formulated an approach to estimate parameters of a layered earth model such as interval velocity, reflector depth, and dip by inverting reflected traveltime with constraints on dipping directions and depth to reflectors. We applied the shooting method (Lines, Bourgeois...

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