**Source**

**Conference**

**Theme**

**Author**

- Browaeys, Thomas J. (1)
- de Hoop, Maarten V. (1)
- Guillaume, Patrice (1)
- Lambaré, Gilles (1)
- Le Moigne, José (1)
- Leblanc, Olivier (1)
- Malcolm, Alison E. (1)
- Mitouard, Pierre (1)
- Montel, Jean Philippe (1)
- Prescott, Tony (1)
- Siliqi, Risto (1)
- Singleton, Scott (1)
- Smit, Dirk (1)
- Ursin, Bjørn (1)
- Vidal, Nicolas (1)
- Zhang, Xiaoming (1)
- Zimine, Serge (1)

**Concept Tag**

- amplitude (1)
- analysis (1)
- angle (1)
- AVO (1)
- Biondi (1)
- building (1)
- building technique (1)
- capture (1)
- condition (1)
- conditioning (1)
- coupling (1)
- dip-angle common-image gather (1)
- domain (2)
- effect (2)
- exploration (1)
- flexible approach (1)
- Fomel (1)
- gather (1)
- geophysics (3)
- Goloshubin (1)
- hoop (1)
- hydrocarbon (1)
- hydrocarbon detection (1)
- hydrocarbon reservoir (1)
- illumination (1)
- Imaging (3)
- impedance (1)
- inverse (1)
- inverse problem (1)
- inversion (1)
- Johnson (1)
- kinematic invariant (1)
- Korneev (1)
- Lambare (1)
- las vegas (1)
- list (2)
- locally coherent (1)
- mapping (1)
- material (1)
**meeting (5)**- menu (2)
- method (1)
- migration (1)
- model (1)
- non-linear geophysics (1)
- nonlinear (1)
- nonlinear effect (1)
- polygon (1)
- PreSDM (1)
- property (1)
- reflector (1)
- research (1)
- Reservoir Characterization (5)
- reservoir description and dynamics (5)
- RMO (1)
- SEG (3)
- seg las vegas (2)
- seismic data conditioning (1)
- seismic processing and interpretation (5)
- series (1)
- slope (1)
- stack (1)
- stretch (1)
- subsalt imaging (1)
- Taner (1)
- th annual international (3)
- tomography (1)
- trace (1)
- update (1)
- Upstream Oil & Gas (5)
- Wave (1)
- wave-equation migration (1)
- wavelet (1)
- Workshop (1)
- workshop organizer (1)
- Zhang (1)

**File Type**

If singly scattered seismic waves illuminate the entirety of a subsurface structure of interest, standard methods can be applied to image it. In many cases, subsalt imaging for example, a combination of restricted acquisition geometry and imperfect velocity models results in regions of the model that are not illuminated with singly scattered waves. We present an approach to use multiply scattered waves to illuminate such structures, and illustrate the method by creating images of the base of salt with an erroneous velocity model. This method builds upon past work in which methods to predict artifacts in imaging from multiply scattered waves have been developed and shares similarities with current techniques of imaging with surface-related multiples.

In this paper we discuss a method for subsalt imaging using internal multiples. Our approach extends the work of Malcolm and de Hoop (2005) by including illumination in a series representation that models the data as a superposition of different phases. By explicitly including illumination in the series representation we identify those multiples which carry information about regions of the subsurface not illuminated by singly scattered waves.

Imaging with internal multiples in the framework of the one-way wave equation requires a "multi-pass" approach reminiscent of the generalized Bremmer series (de Hoop, 1996). Turning waves are accounted for in such an approach as discussed by Xu and Jin (2006); Zhang et al. (2006); see also Hale et al. (1991). In the multi-pass approach, starting at the surface (or top), waves are first propagated downwards and then stored at each depth; in the second "pass", starting at the bottom, reflection operators derived from the estimated standard image are applied to the stored fields and the results are propagated, accumulatively, back upwards. For turning waves, or doubly scattered waves this up-going field is correlated with the saved down-going field to form an image of steeply-dipping reflectors (for doubly scattered waves this is similar to the work of Jin et al. (2006); Xu and Jin (2007)). For internal multiples the source-side up-going field is correlated with the receiver-side up-going field to form an image of e.g. the base of salt. A related method for imaging with surface-related multiples has been proposed by Berkhout & Verschuur (1994; 2006) in which one leg of the surface multiple generates a new primary wave with the source at the surface reflection point; similar techniques are also discussed in Guitton (2002). Another method for imaging with surface-related multiples with particular emphasis on reducing crosstalk between the two (or more) images is given in Brown and Guitton (2005). For surface-related multiples, this improves the range of scattering angles illuminated for a single data set and allows the imaging of a larger region. Interferometric techniques can be applied to multiples to allow standard migration techniques to be applied to the resulting data; this is discussed in Schuster et al. (2004); Jiang (2006); Jiang et al. (2007); Vasconcelos et al. (2007). Here we use internal multiples, recorded at the surface, to image around complicated structures, such as salt domes, to create an image of the base of salt using waves that have not passed through it.

coupling, geophysics, hoop, Imaging, inverse, inverse problem, list, meeting, menu, method, migration, Reservoir Characterization, reservoir description and dynamics, SEG, seg las vegas, seismic processing and interpretation, series, subsalt imaging, th annual international, Upstream Oil & Gas, Wave, Zhang

SPE Disciplines: Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)

Guillaume, Patrice (CGGVeritas Massy.) | Lambaré, Gilles (CGGVeritas Massy.) | Leblanc, Olivier (CGGVeritas Massy.) | Mitouard, Pierre (CGGVeritas Massy.) | Le Moigne, José (CGGVeritas Massy.) | Montel, Jean Philippe (CGGVeritas Massy.) | Prescott, Tony (CGGVeritas Massy.) | Siliqi, Risto (CGGVeritas Massy.) | Zhang, Xiaoming (CGGVeritas Massy.) | Zimine, Serge (CGGVeritas Massy.) | Vidal, Nicolas (CGGVeritas Massy.)

We present a fast turnaround strategy for building depth velocity models from kinematic invariants. Our approach is based on the concept of kinematic invariants describing locally coherent events by their position and slopes in the un-migrated pre-stack domain. 3D slope tomography can be based on kinematic invariants that fully characterize the events in terms of positioning and focusing. Kinematic invariants offer a versatile tool for velocity model building as they can be derived from dip and move-out picks made either in pre-stack depth migrated (preSDM) or pre-stack time migrated (preSTM) domains, or even in the unmigrated domain. Since the invariants are in the unmigrated domain, they only need to be picked once. The classical iterative velocity update made of several iterations of RMO picking, pre-stack migration and velocity update can thus be replaced by a more efficient sequential approach involving a single preSDM and a single residual move-out (RMO) picking followed by a non-linear tomographic inversion, should the quality of the initial PreSDM be appropriate for an automated volumetric picking.

building, building technique, domain, flexible approach, Imaging, kinematic invariant, Lambare, las vegas, locally coherent, meeting, model, PreSDM, Reservoir Characterization, reservoir description and dynamics, RMO, SEG, seismic processing and interpretation, slope, tomography, update, Upstream Oil & Gas, Workshop, workshop organizer

SPE Disciplines: Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)

A hydrocarbon reservoir in the subsurface is usually explored and monitored with geophysical techniques described and interpreted in a linear "approximation", i.e. the propagation, reflection and conversion etc. of these signals is treated in a linear way. This assumption has served the industry well for mapping subsurface structural information.

In a real setting we might find that despite the fact that physicists and mathematicians prefer the linear description because of its relative simplicity a lot of nonlinear elements (elastic, electric, etc.) are found which might alter the signal path for exploration and monitoring. In fact some of these nonlinear elements may actually lead to interesting effect allowing e.g. a more unique detection and delineation of fluids or other elements like faults. Examples are fractured systems, faults, two-fluid interfaces etc. which may lead to nonlinear or hysteretic or delayed behavior (e.g. if a fractured rock gets compressed it will behave nonlinear once the fracture surfaces touch, similar to a rubber foam, where elasticity initially depends on the air bubbles included, but at some point of compression the bubble walls touch and the bulk rubber will determine the properties; or the broken bell, which gives not a single sharp spectrum, but a wide variety of sidebands it literally "squeaks").

While nonlinear physics has been a fashion topic for quite some time, nonlinear effects in geophysics are rather a niche topic so far. To some extent they are discussed where large amplitudes (near surface effects or strong earthquakes) take place, but mostly geophysics operates in the "linear approximation mode".

Recently, several interesting bits and pieces were reported in geophysics:

- low frequency effects (passive and active, such as low frequency shadows or similar, see e.g. Goloshubin et al., Dangel et al. and other sources), for hydrocarbon detection and mapping
- nonlinear seismic mixing effects, reported by e.g. Beresnev et al., Khan et al. or Zhukov et al. for hydrocarbon detection and mapping
- theoretical and lab experiment reports and proposals, such as by Johnson et al. or Korneev et al., either predicting nonlinear geophysical effects or linking some of the above described low frequency effects to nonlinear mechanisms
- nonlinear electro-seismic, from Thompson et al., for hydrocarbon detection and mapping; this includes the concept of EM only nonlinear effects, too.
- nonlinear EM effects like induced polarization (electric charging hysteresis) for hydrocarbon detection and mapping

effect, exploration, geophysics, Goloshubin, hydrocarbon, hydrocarbon detection, hydrocarbon reservoir, Johnson, Korneev, mapping, material, meeting, non-linear geophysics, nonlinear, nonlinear effect, property, research, Reservoir Characterization, reservoir description and dynamics, seismic processing and interpretation, th annual international, Upstream Oil & Gas

SPE Disciplines: Reservoir Description and Dynamics > Reservoir Characterization > Seismic processing and interpretation (1.00)

Angle domain common image gathers display the image points depth location with respect to the incidence angle. The possibility of image gathers as a function of both the scattering angle and the dip angle of the reflector has recently been considered for Kirchhoff prestack migration to detect diffraction events and use the dip information to provide a new tool for migration velocity analysis. The theory has not been completed yet for wave equation prestack migration. We have found two different methods to construct the dip angle gather, the first from prestack wave equation migration, the second from zero offset/poststack migration.

In seismic imaging, common image gathers (CIG) constitute a tool of primary importance for amplitude versus offset (AVO), amplitude versus angle (AVA) and migration velocity analysis. The velocity analysis is conventionally performed by flattening the common offset or common incidence angle gathers (Brandsberg-Dahl et al., 1999). The display of common image gather as a function of scattering angle, rather than offset, offers numerous advantages (Xu et al., 1998). Prucha et al. (1999) set the method to perform the transformation from the offset domain to the scattering angle domain. The full extension to create incidence angle gathers from waveequation prestack migration (Sava and Fomel, 2003) uses the local offset in the image space and performs a Radon transform to display the common image gather as a function of the local scattering angle at the image point. During this process, the dip angles are implicitly stacked. Meanwhile, selecting only the dip in the vicinity of the geological dip improves the image by suppressing artifacts created for example by multipathing (Brandsberg-Dahl et al., 2003). In wave-equation prestack depth migration, the dip of reflectors influences both the quality of common incidence angle gathers and the velocity analysis (Biondi and Symes, 2004).

The concept of Kirchhoff migration in the scattering angle domain (Audebert et al., 2002) clarified the influence and contribution of different illumination dip angles to the result of the Kirchhoff integral. Steep dips, structural conflicting dips, and the presence of diffractor points in faulted sedimentary layers can create spurious artificial events and compromise the interval velocity analysis by generating image points dispersal. A way to detect the geological dip before stacking, in Kirchhoff prestack depth migration, was proposed by generating illumination dip gathers and panels (Qin et al., 2005). This dip selection procedure has been demonstrated to enhance both the coherency of the reflectors image on noisy 3D seismic land prestack data (Gulunay et al., 2007) and the quality of the AVA analysis on a real 2D dataset (Bernasconi and Re, 2005). Another application of interest is migration velocity analysis (Reshef and Rüger, 2005) using in particular the detection of diffraction events (Fomel et al., 2007). In wave-equation prestack migration, the relations to form the common scattering angle gathers are derived by using the connection between the local slowness vectors and the incidence and dip angles (Sava and Fomel, 2005, 2006). The geometry of the local slowness vectors are at the central point of the directional analysis in wave-equation imaging.

The demands that reservoir characterization place on seismic data far outweigh those of traditional structural interpretation. Because of this, gather conditioning is seen by many as a prerequisite to pre-stack inversion. This paper discusses three conditioning processes-signal/noise (S/N) improvement, stretch removal, and reflector alignment. It then seeks to document the improvements that these processes achieve in the gathers and in the inversion. Specifically, the gathers were measured for AVO fit using a 2-term Shuey equation and found to be improved by 20%. A comparison of wavelets extracted from the angle stacks found amplitude and phase spectra to be much more stabilized, even out to the far angle stack. The far angle stack seismic/synthetic inversion residuals showed a 40% drop in amplitude and completely different frequency and reflector character. Finally, the AI/SI cross-plot showed a much more compact signature that allowed lithology and pay discrimination. Conversely, the raw data cross-plot contained noisy data that entered into the area of the polygon where the pay signature lay. Geobodies captured from improperly conditioned data are thus (1) inflated in size, and (2) have lower impedances. These errors, in turn, lead to incorrect rock property and reserve estimations.

amplitude, angle, AVO, capture, conditioning, effect, gather, impedance, inversion, meeting, polygon, reflector, Reservoir Characterization, reservoir description and dynamics, seismic data conditioning, seismic processing and interpretation, stack, stretch, Taner, th annual international, trace, Upstream Oil & Gas, wavelet

Thank you!