Azimuthal offset‐dependent attributes applied to fracture detection in a carbonate reservoir

Feng Shen; Jesus Sierra; Daniel R. Burns; M. Nafi Toksöz

doi:10.1190/1.1468596

Azimuthal offset‐dependent attributes applied to fracture detection in a carbonate reservoir

Geophysics ◽

10.1190/1.1468596 ◽

2002 ◽

Vol 67 (2) ◽

pp. 355-364 ◽

Cited By ~ 29

Author(s):

Feng Shen ◽

Jesus Sierra ◽

Daniel R. Burns ◽

M. Nafi Toksöz

Keyword(s):

Seismic Data ◽

Small Variation ◽

Carbonate Reservoir ◽

P Wave ◽

Fracture Detection ◽

Multiple Signal Classification ◽

Fracture Orientation ◽

Amplitude Versus Offset ◽

Strike Direction ◽

Amplitude Versus

Offset‐dependent attributes—amplitude versus offset (AVO) and frequency versus offset—are extracted from 2‐D P‐wave seismic data using the multiple signal classification technique. These attributes are used to detect fracture orientation in a carbonate reservoir located in the Maporal field in the Barinas basin of southwestern Venezuela. In the fracture normal direction, P‐wave reflectivity is characterized by a large increase of amplitude with offset (large positive AVO gradient) and a large decrease of frequency with offset (large negative frequency versus offset gradient). In the fracture strike direction, P‐wave reflectivity shows a scattered variation in AVO but a small variation in frequency with offset. Our results also show that the reservoir heterogeneity can lead to large variations of AVO signatures and that using azimuthal offset‐dependent frequency attributes can help lessen the ambiguity when detecting fracture orientation.

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Processing Wide Azimuth P-Wave Seismic Data for Fracture Detection

10.3997/2214-4609-pdb.28.c7 ◽

2000 ◽

Author(s):

A. Pelham

Keyword(s):

Seismic Data ◽

P Wave ◽

Fracture Detection

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Fault whispers: Transmission distortions on prestack seismic reflection data

Geophysics ◽

10.1190/1.1444733 ◽

2000 ◽

Vol 65 (2) ◽

pp. 377-389 ◽

Cited By ~ 21

Author(s):

Paul J. Hatchell

Keyword(s):

Seismic Data ◽

Seismic Waves ◽

Shallow Gas ◽

Seismic Reflection Data ◽

Reflection Data ◽

Amplitude Versus Offset ◽

Velocity Changes ◽

Transmission Distortions ◽

Amplitude Versus ◽

Buried Faults

Transmission distortions are observed on prestack seismic data at two locations in the Gulf of Mexico. These distortions produce anomalous amplitude versus offset (AVO) signatures. The locations of the distortion zones are determined using acquisition geometry and ray tracing. No obvious reflection events, such as shallow gas zones, are observed at the predicted locations of the distortion zones. Instead, the distortion zones correlate with buried faults and unconformities. It is postulated that the distortions are produced by velocity changes across buried faults and unconformities. The distortions result from an interference pattern resulting from seismic waves arriving from different sides of the faults. A simple model is developed to explain many of the characteristics of the distortion pattern.

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Quartic reflection moveout in a weakly anisotropic dipping layer

Geophysics ◽

10.1190/1.2159047 ◽

2006 ◽

Vol 71 (1) ◽

pp. D1-D13 ◽

Cited By ~ 17

Author(s):

Vladimir Grechka ◽

Andrés Pech

Keyword(s):

General Formula ◽

Anisotropic Medium ◽

Seismic Data ◽

Wave Reflection ◽

P Wave ◽

Weak Anisotropy ◽

Effective Anisotropy ◽

Isotropic Solid ◽

Strike Direction

Deviations of P-wave reflection traveltimes from a hyperbola, called the nonhyperbolic or quartic moveout, need to be handled properly while processing long-spread seismic data. As observed nonhyperbolic moveout is usually attributed to the presence of anisotropy, we devote our paper to deriving and analyzing a general formula that describes an azimuthally varying quartic moveout coefficient in a homogeneous, weakly anisotropic medium above a dipping, mildly curved reflector. To obtain the desired expression, we consistently linearize all quantities in small stiffness perturbations from a given isotropic solid. Our result incorporates all known weak-anisotropy approximations of the quartic moveout coefficient and extends them further to triclinic media. By comparing our approximation with nonhyperbolic moveout obtained from the ray-traced reflection traveltimes, we find that the former predicts azimuthal variations of the quartic moveout when its magnitude is less than 20% of the corresponding hyperbolic moveout term. We also study the influence of reflector curvature on nonhyperbolic moveout. It turns out that the curvature produces no quartic moveout in the reflector strike direction, where the anisotropy-induced moveout nonhyperbolicity is usually nonnegligible. Thus, the presence of nonhyperbolic moveout along the reflector strike might indicate effective anisotropy.

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Seismic data processing for amplitude‐versus‐offset analysis

10.1190/1.1892540 ◽

1988 ◽

Author(s):

Jeffrey R. Resnick

Keyword(s):

Data Processing ◽

Seismic Data ◽

Seismic Data Processing ◽

Amplitude Versus Offset ◽

Amplitude Versus

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Amplitude preservation of Radon-based multiple-removal filters

Geophysics ◽

10.1190/1.2243711 ◽

2006 ◽

Vol 71 (5) ◽

pp. V123-V126 ◽

Cited By ~ 16

Author(s):

Ethan J. Nowak ◽

Matthias G. Imhof

Keyword(s):

Radon Transform ◽

Seismic Data ◽

Transform Domain ◽

Multiple Reflections ◽

Avo Analysis ◽

Amplitude Versus Offset ◽

Amplitude Preservation ◽

Amplitude Versus

This study examines the effect of filtering in the Radon transform domain on reflection amplitudes. Radon filters are often used for removal of multiple reflections from normal moveout-corrected seismic data. The unweighted solution to the Radon transform reduces reflection amplitudes at both near and far offsets due to a truncation effect. However, the weighted solutions to the transform produce localized events in the transform domain, which minimizes this truncation effect. Synthetic examples suggest that filters designed in the Radon domain based on a weighted solution to the linear, parabolic, or hyperbolic transforms preserve the near- and far-offset reflection amplitudes while removing the multiples; whereas the unweighted solutions diminish reflection amplitudes which may distort subsequent amplitude-versus-offset (AVO) analysis.

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Model-based amplitude versus offset and azimuth inversion for estimating fracture parameters and fluid content

Geophysics ◽

10.1190/geo2016-0196.1 ◽

2017 ◽

Vol 82 (2) ◽

pp. M1-M17 ◽

Cited By ~ 12

Author(s):

Jiao Xue ◽

Hanming Gu ◽

Chengguo Cai

Keyword(s):

Seismic Data ◽

Shear Fracture ◽

Influencing Factor ◽

Fractured Reservoirs ◽

Fracture Density ◽

Inversion Algorithm ◽

Fluid Content ◽

Fracture Parameters ◽

Amplitude Versus Offset ◽

Amplitude Versus

The normal-to-shear fracture compliance ratio is commonly used as a fluid indicator. In the seismic frequency range, the fluid indicator lies between the values for isolated fluid-filled fractures and dry fractures, and it is not easy to discriminate the fluid content. Assuming that the fracture surfaces are smooth, we use [Formula: see text], with [Formula: see text] and [Formula: see text] representing the normal fracture weakness of the saturated and dry rock, to indicate fluid types, and to define a fluid influencing factor. The fluid influencing factor is sensitive to the fluid properties, the aspect ratio of the fractures, and the frequency. Conventionally, the amplitude versus offset and azimuth (AVOA) inversion is formulated in terms of the contrasts of the fracture weaknesses across the interface, assuming that the fractures are vertical with the same symmetry axis. We consider fractures with arbitrary azimuths, and develop a method to estimate fracture parameters from wide-azimuth seismic data. The proposed AVOA inversion algorithm is tested on real 3D prestack seismic data from the Tarim Basin, China, and the inverted fracture density show good agreement with well log data, except that there are some discrepancies for one of the fractured reservoir sections. The discrepancies can be ascribed to neglect of the dip angle for the tilted fractures and the conjugate fracture sets, and to the validity of the linear-slip model. The fractured reservoirs are expected to be liquid saturated, under the assumption of smooth fractures. Overall, the inverted fracture density and fluid influencing factor can be potentially used for better well planning in fractured reservoirs and quantitatively estimating the fluid effects.

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ANALISIS AMPLITUDE VERSUS OFFSET (AVO) MENGGUNAKAN PARAMETER PETROFISIKA LAMBDA MU RHO (LMR) DAN EXTENDED ELASTIC IMPEDANCE (EEI) UNTUK KARAKTERISASI RESERVOAR KARBONAT

TEKNOSAINS: MEDIA INFORMASI SAINS DAN TEKNOLOGI ◽

10.24252/teknosains.v14i1.13330 ◽

2020 ◽

Vol 14 (1) ◽

Author(s):

Harsano Jayadi ◽

Icha Untari Meidji ◽

Yusniati H Muh Yusuf

Keyword(s):

Data Analysis ◽

Carbonate Reservoir ◽

Fluid Accumulation ◽

Inversion Result ◽

Amplitude Versus Offset ◽

Elastic Impedance ◽

Liquefied Gas ◽

Amplitude Versus

The research that refers to the characterization of carbonate reservoir to identify lithology and fluid had been done to the Baturaja Formation in South Sumatera Basin. The method used is analyzed of Amplitude Versus Offset (AVO) by utilizing the petrophysics parameter of Lambda Mu Rho (LMR) and Extended Elastic Impedance (EEI). The goal of the research is to find out the comparison of the application of petrophysics parameter LMR and EEI to characterization carbonate reservoir, besides finding a prospect location or proposed well. The result of data analysis of Al-Fatah well shows that the carbonate reservoir position with liquefied gas is located deeper around 350 meters with a thickness of around 7.62 meters. Interpretation of seismic from inversion result by using the petrophysics parameter of LMR and EEI shows the presence of a prospect location to the CDP 4253 up to 4301, which is carbonate reservoir with fluid accumulation (gas).

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Analisis AVO untuk Mengetahui Penyebaran Hidrokarbon Berdasarkan Faktor Fluida (Studi Kasus Lapangan “H” Formasi Talang Akar Cekungan Jawa Barat Utara)

INDONESIAN JOURNAL OF APPLIED PHYSICS ◽

10.13057/ijap.v3i02.1276 ◽

2016 ◽

Vol 3 (02) ◽

pp. 209

Author(s):

Muhammad Nur Handoyo ◽

Agus Setyawan ◽

Mualimin Muhammad

Keyword(s):

Seismic Data ◽

Class Iii ◽

Avo Inversion ◽

Amplitude Versus Offset ◽

Attribute Analysis ◽

Fluid Factor ◽

Inversion Analysis ◽

Amplitude Versus

Amplitude versus offset (AVO) inversion analysis can be used to determine the spread of hydrocarbons on seismic data. In this study we conducted AVO on reservoir layer Talang Akar’s formation (TAF). AVO inversion results are angle stack, normal incident reflectivity (intercept), gradient and fluid factor. Angle stack attribute analysis showed an AVO anomaly in the reservoir TAF layer, amplitude has increased negative value from near angle stack to far angle stack. The result of crossplot normal incident reflectivity (intercept) with gradient indicates reservoir TAF layer including Class III AVO anomaly. While the analysis of fluid factor attribute has a negative value thus reservoir TAF layer indicates a potential hydrocarbon.

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