Resources - Geomage

Resources - Geomage Resources - Geomage

MultiFocusing based multiple attenuation

The proposed MultiFocusing based multiple attenuation procedure is valid for surface-related as well as for interbed types of multiples. It is robust and simple. It is easy to implement and it can predict all kinds of multiples defined by the picked corridors in the MF domain. The multiple suppression approach with MF attributes is not dependent on the regularity of the data.

TLE, 2012

Berkovitch Alex, Landa Evgeny

MultiFocusing 3D Diffraction Imaging

The new algorithm of 3D diffraction imaging is based on a MultiFocusing methodology and consists of optimal summation of seismic data in accordance with a diffraction-moveout formula. The diffraction-oriented stacked sections can be used for reliable interpretation of non-smoothed geological interfaces and for identification of local heterogeneities such as faults, karsts, fractures etc.

EAGE, 2012

Berkovitch Alex, Deev Konstantin, Pelman Danil, Rauch – Davies Marianne

How non-hyperbolic MultiFocusing improves depth imaging

Common-offset MultiFocusing can be considered as a method for full prestack wavefield analysis and imaging.
The method is based on a local MultiFocusing approximation for locally coherent seismic events and allows, for each trace and each time sample, an accurate estimation of the wavefield parameters (such as local wavefront curvatures, geometrical spreading and emergence angles in shot and receiver domains).

First Break, 2011

Berkovitch Alex, Landa Evgeny, Deev Kostya

MultiFocusing improves seismic data

The MultiFocusing method not only provides coherent stacking of seismic data with arbitrary source-receiver distribution to create high-quality time images, but it also has the potential to compute enhanced prestack seismic traces. This method uses a new MF move-out correction formula for approximation of the local moveout correction and is based on partial stacks along optimal travel-time trajectories.

EP, 2011

Landa Evgeny

Improved seismic imaging by using MultiFocusing technology

Multifocusing, as a non-CMP based imaging method, opens a new perspective for optimal approximation of the zero-offset sections.Stacked sections obtained by the MultiFocusing method are superior to those obtained by the conventional DMO/NMO processing: they are characterized by higher signal-to-noise ratio and better approximate the actual zero-offset sections. Parameters (wavefield attributes) estimated by the MultiFocusing method have clear geophysical interpretation and can be used for several important applications such as velocity model building, migration, structural and stratigraphic interpretation.

ALL, 2011

Landa Evgeny

MultiFocusing revisited – inhomogeneous media and curved interfaces

EAGE, 2010

Landa Evgeny, Keydar Shemer, Jan Moser Tijmen

MultiFocusing increases accuracy, resolution

The MultiFocusing method consists of stacking seismic data with arbitrary source-receiver distribution according to a new moveout correction formula. The MF travel-time curve provides a better approximation of actual reflection travel-time than the standard hyperbolic one. In particular, MF is very effective for processing and reprocessing low-fold CMP data due to MF’s noise suppression wavefield. Parameters obtained by the multifocusing method can be used for velocity model estimation and for time and depth migrations.

EP, 2009

Geomage Research Team

Diffraction imaging by MultiFocusing

MultiFocusing diffraction imaging propose a new technique for detecting local subsurface heterogeneities using diffraction MultiFocusing stack. The imaging is based on a new type of local time correction for diffraction travel-time curve parametrization. The DMFS method consists of optimal stacking of seismic data along actual diffraction traveltime curves. The stacking procedure produces a section in which diffractions are emphasized and specular reflections are illuminated. The diffraction MultiFocusing stacks can be used for reliable interpretation of nonsmoothed geologic interfaces and for identification of local heterogeneities such as faults, karsts, and fractures.

SEG, 2009

Berkovitch Alex, Belfer Igor, Hassin Yehuda, Landa Evgeny

Tyumen Conference MultiFocusing Paper

ALL, ALL

Berkovitch Alex, Belfer Igor, Meshbey Valentine, Cimbaluk Yuri

MultiFocusing as a method of improving subsurface imaging

TLE, 2008

Berkovitch Alex, Belfer Igor, Landa Evgeny

A revised interpretation of the Russkoye field, Western Siberia, using MultiFocusing technology

The integrated interpretation of well log data and seismic data processed by the new MultiFocusing technology allowed the revision of the identification of unconformity markers and internal structural details in the northern part of the Russkoye field. Facies of marine origin (clays), slope deposits (shales), as well as shelf and deltaic sands were identified with more certainty using seismic reflections and based stratigraphic sequences, determined from the log data (together with core studies).

First Break, 2008

Berkovitch Alex, Belfer Igor, Nekrasova Lubov, Korabelnikov Alexander, Kulikova Anna, Nevidimova Antonina

MultiFocusing: A New Method of Multifold Seismic Data Processing

MultiFocusing method consists of stacking seismic data with arbitrary source-receiver distribution according to a new moveout correction formula. The method is not dependent on the geological section model and consists of stacking seismic data with arbitrary source-receiver distribution near the central points. A higher SNR, due to the summation of a greater number of traces and the absence of stretch effect, delivers a significant increase in the signal-to-noise ratio for both deep and shallow reflections.

CSEG, 2008

Berkovitch Alex, Belfer Igor, Sydykov Kairat

Rosnedra MultiFocusing

ALL, 2007

Berkovitch Alex, Belfer Igor, Meshbey Valentine

Geomodel lecture

EAGE, 2007

Berkovitch Alex, Belfer Igor

Multiple prediction and attenuation using wavefront characteristics of multiple-generating primaries

This article explains a method of predicting the timing and moveout of a multiple so that its location in the t-r domain can be identified. If the t-r location of a given multiple is known, it can be attenuated. It is an interactive target-oriented “predict and subtract” attenuation method, whose objective is to remove multiples of any type (free surface, peg-leg, and interbed) .

TLE, 1999

Landa Evgeny, Keydar Shemer, Belfer Igor

Multiple attenuation in the parabolic ø – p domain using wavefront characteristics of multiple generating primaries

This is a new 2-D method for attenuation of both surface-related and interbed multiples in the parabolic ø-p domain. It is a combination of the prediction method based on wavefront characteristics of multiple generating primary reflections and the Radon transform–based method for multiple subtraction. The multiple reject areas are determined automatically by zeroing the multiple ellipse in the ø-p domain, or by comparing the energy on the traces of the multiple model and the original input data in the ø-p domain.

SEG, 1999

Landa Evgeny, Keydar Shemer, Belfer Igor

First arrival traveltime tomography: when simpler is better Multifocusing homeomorphic imaging Part 1. Basic concepts and formulas

Applied Geophysics, 1999

Berkovitch Alex, Gelchinsky Boris, Keydar Shmariahu

Multifocusing homeomorphic imaging Part 2. Multifold data set and multifocusing

Applied Geophysics, 1999

Berkovitch Alex, Gelchinsky Boris, Keydar Shmariahu

Application of MultiFocusing method for subsurface imaging

The MultiFocusing method consists in stacking seismic data with arbitrary source–receiver distribution according to a new MultiFocusing moveout correction. This method can produce a zero offset section superior to the NMO/DMO stacked section in an automatic manner. The method is particularly useful in situations of low fold and/or low signal-to-noise ratio.

Applied Geophysics, 1999

Landa Evgeny, Gelchinsky Boris, Keydar Shmariahu, Trachtman Pinchas

Homeomorphic imaging approach — theory and practice

Applied Geophysics, 1999

Gelchinsky Boris, Keydar Shmariahu

Multiple prediction using the homeomorphic- imaging technique

Geophysical Prospecting, 1998

Landa Evgeny, Keydar Shemer, Belfer Igor, Gelchinsky Boris

MultiFocusing 3D diffraction imaging for detection of fractured zones in mudstone reservoirs

Unconventional reservoirs have a unique set of problems. Most production wells are drilled horizontally through the reservoir rock and hydraulic fracturing is applied to increase permeability in the reservoir. The pre-drilling knowledge of natural fracture corridors and small offset faults is very important in this case. Seismic resolution from conventional reflection imaging is generally not sufficient to resolve such small scale rock properties. Diffracted waves are events generated by small scale subsurface heterogeneities and discontinuities (including fractures). Detection and imaging the diffractive component of the total wavefield opens a new perspective to find and characterize fracture zones in carbonate environment.

ALL, 2014

Alana Schoepp (Shell Canada Ltd.), Evgeny Landa (Geomage), Stephane Labonte (Shell Canada Ltd.)

Diffraction imaging applied to pre-existing 3D seismic data to map fracture corridors in an unconventional play

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.

Multi-Focusing imaging and regularization of an irregular 3D dataset in an urban environment

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.

First Break, 2014

Marianne Rauch-Davies

Tracking Fracture Corridors in Tight Gas Reservoirs: An Algerian Case Study

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.

EAGE, ALL

A Review of the MultiFocusing stacking method 2017 (Chinese)

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。.

ALL, ALL

Estimation of kinematic wavefront characteristics and their use for multiple attenuation

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.

Applied Geophysics, 1999