Estimation of kinematic wavefront characteristics and their use for multiple attenuation
Applied Geophysics, 1999
 Summary
Kinematic wavefront characteristics of primary reflected waves can be used to predict and attenuate surface-, as well as interbed multiples. In order to estimate kinematic wavefront characteristics directly from unstacked data the common-shot-point homeomorphic-imaging CSP HI. method can be applied. This macro-model-independent method is based on a new local moveout correction that depends on two wavefront parameters: the emergence angle and the radius of wavefront curvature of a reflected primary wavefront. These parameters can be estimated by optimizing the semblance correlation measure, calculated in the common-shot-gather along the travel time curve defined by the new moveout correction. In the case of local maxima in the semblance functional, an automatic maximization procedure might lead to a wrong estimation of these parameters. In order to avoid such a situation, we propose an interactive, horizon-based implementation of the CSP HI method, which allows manual picking of the optimal wavefront parameters along the seismic line. Afterwards, we use the estimated emergence angles for the prediction and attenuation of multiples, based on the simple but powerful idea that any multiple event can be represented as a combination of primaries.
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A Review of the MultiFocusing stacking method 2017 (Chinese)
ALL, ALL
Summary
考虑信噪比和分辨率的多焦点（MF）叠加方法近年来得到了广泛的应用。一方面采用双平方根时间差校正公式，解决了针距变化较大的问题，不需要进行切除处理，数据完整性最大化。另一方面，多聚焦叠加方法将属于不同的CMP道集的接收通道叠加，通过增加覆盖数量，大大提高了叠加剖面的信噪比和分辨率。本文主要研究平面多焦点，多点聚焦，球面多焦点，非双曲多焦点和多焦点叠加方法在多重预测中的应用，叠前信号增强，数据正则化和衍射成像及效果，系统地综述了多焦点叠加法并展望其发展趋势。.
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Tracking Fracture Corridors in Tight Gas Reservoirs: An Algerian Case Study
EAGE, ALL
Summary
The interpretation of faulted systems is an essential step in E&P business, from a proper understanding of
prospects to optimal development well placements. The identification of fractured zones within a reservoir,
usually characterized by sub-seismic faults, is often neglected, while it can add significant value to the
development of a project. The present case study is focused on the very prolific Algerian Ordovician tight
reservoir target. It highlights a structure at the end of an appraisal well campaign, where an integrated fracture
reservoir study had been performed in order to track efficiently subtle fault corridors.
The utilization of advanced seismic attributes using the MultiFocusing technique has proven valuable when
determining the detection and extension of fracture corridors within the reservoir. At the well locations, results
matched reasonably well with the fracture orientation and density interpreted from cores, borehole images and
DST interpretations. This approach has a great value when planning well trajectories, for production predictions,
and eventually for locating any future development wells in the area.
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Multi-Focusing imaging and regularization of an irregular 3D dataset in an urban environment
First Break, 2014
Marianne Rauch-Davies
Summary
The generalized approach of the MF method of moveout correction allows processing of data acquired with irregular acquisition design and is very useful in cases where the subsurface is highly complicated.
The core of the Multi-Focusing stacking, based on paraxial approximation and dynamic ray tracing, is its Fresnel-zone basis for defining the large number of traces used in the stacking procedure. The resulting traces have a more densely sampled source-receiver distribution about each output location which allows the output dataset to be easily regularized.
The MF method not only provides coherent stacking of seismic data with arbitrary source-receiver distribution, creating high-quality time images, but also yields enhanced and regularized prestack gathers. In areas where acquiring aregular 3D dataset is impossible due to difficult terrain or high
population density, conventional gathering and stacking often results in shallow gaps in coverage. Stacking these regularized,enhanced gathers can often ‘heal’ these gaps in coverage.
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Diffraction imaging applied to pre-existing 3D seismic data to map fracture corridors in an unconventional play
First Break, 2014
Marianne Rauch-Davies, Kostya Deev, Danil Pelman, Maria Kachkachev-Shuifer
Summary
The MultiFocusing imaging technology is able to describe not only reflection but also diffraction events from conventionally acquired seismic data and is performed in the pre-stack domain. By optimally summing diffracted events and attenuating specular reflections, an image that contains mostly diffraction energy is being generated. Synthetic and seismic studies are indicating a direct relationship between fracture density and intensity of the diffractivity. This phenomenon is being exploited to use seismic to directly map zones within unconventional/tight reservoirs that are naturally fractured. The MultiFocusing diffraction imaging methodology makes it possible to extract the weak diffractive element from the overall wave field and suppresses the strong specular events.
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