Reflection tomography without picking

Whiting, Peter

doi:10.1190/1.1820116

Cited by 8 publications

(3 citation statements)

References 4 publications

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“…As discussed in the Introduction, one of the main disadvantages of traveltime tomography remains the trade‐off between velocities and depth determination. In order to constrain ray trajectories fully and to improve optimization, slope tomographic methods increase the tomographic data set (traveltimes) by including the additional information of wave polarization (Sword 1987; Hu and Menke 1992; Le Bégat and Farra 1997; Whiting 1998; Song, Every and Wright 2001). The method presented here, known as stereotomography (Billette and Lambaré 1998), is based on automatic detection and picking of locally coherent events that may represent primary reflections or diffractions.…”

Section: Methodsmentioning

confidence: 99%

Velocity model estimation for depth imaging: Comparison of three tomography methods on a 2D real data set

Bégat

Chauris

Devaux

et al. 2004

Geophysical Prospecting

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International audienceThe estimation of velocity models is still crucial in seismic reflection imaging as it controls the quality of the depth-migrated image, which is the basis of geological interpretation. Among the numerous existing methods for velocity determination, tomographic methods are very attractive for their efficiency and ability to retrieve heterogeneities of the medium. We present three tomographic methods in order to estimate heterogeneous velocity models from 2D prestack PP reflection data: a traveltime tomography in the time-migrated domain, a traveltime and slope tomography in the non-migrated time domain, and a slope tomography in the depth-migrated domain.The first method (traveltime tomography in the time domain) is based on continuous picked events, whereas the two slope tomographic methods, one in the time domain and the other in the depth domain, are based on locally coherent events, with no assumptions about reflector geometry or the unknown velocity field. The purpose of this paper is not to describe in detail the theoretical basis and implementation of the methods, but to apply and compare their output using the same marine real data set. Based on the estimated velocity models, the migrated images and the common-image gathers from the three processing routes, the relative strengths and weaknesses of the methods are discussed. Finally, similarities are indicated and potential alternative approaches are proposed

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Section: Methodsmentioning

confidence: 99%

Velocity model estimation for depth imaging: Comparison of three tomography methods on a 2D real data set

Bégat

Chauris

Devaux

et al. 2004

Geophysical Prospecting

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“…Such a manual and interpretative approach may be very difficult and time consuming in complex areas. Picking locally coherent events (coherent signals over a few traces) is thus a way to overcome this difficulty: only available information is picked, no interpretation is required, and local events can be automatically picked (Sword 1986; Whiting 1998). Diffractions can also be picked and used in the tomography.…”

Section: Surface Data Slope Tomographymentioning

confidence: 99%

“…2004), in this paper is included information of borehole transmitted data together with reflection data in a joint optimization process. Compared to traveltime tomography, slope tomography uses the slopes of locally coherent events in addition to traveltime data (Riabinkin 1957; Sword 1986; Billette & Lambaré 1998; Whiting 1998). The use of an event local slope in a gather (common shot or common receiver) provides a direct estimation of a component of the slowness vector.…”

Section: Introductionmentioning

confidence: 99%

Combining borehole and surface seismic data for velocity field estimation through slope tomography

Gosselet¹,

Bégat²

2009

Geophysical Journal International

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International audienceA joint traveltime and slope (or slowness) tomography method of marine surface reflections and walk-away transmitted arrivals is investigated. Based on our previous developments of 2-D isotropic slope tomography dedicated to reflection data, the transmitted arrivals are added into the inversion scheme. The results of the transmitted arrival tomography are compared to those of the joint (transmitted and reflected arrivals) tomography on synthetic data. Moreover, a quality control (QC) procedure is proposed. Finally, walk-away transmitted arrivals, surface reflected arrivals and joint tomography of both arrivals are applied on real data sets from Oseberg, North Sea. These data include 2-D surface and walk-away lines along the same direction. The resulting velocity fields are used for pre-stack depth migration, allowing us to conclude that joint inversion leads to significantly improved images both in terms of focusing and event location. A key point is that improvements are not restricted in the area covered by transmitted arrivals. As the number of available borehole receivers is small, this case study demonstrates the strong impact direct arrivals that may have on depth imaging

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