A Summary of Part 1 and Introduction to 2 Our complex earth has a continuum all scales ordered heterogeneities. Ordered heterogeneities give rise three types seismic observations, depending upon the relationship between wavelength scale length heterogeneity: Reflections that arise from layers 3/8ths thick or greater. Azimuthal scattering, azimuthal attenuation, dispersion aligned with lengths ∼0.01 – ∼0.4 wavelength. anisotropy = variations traveltimes (and amplitude) show 90° variation...

The presence of vertically oriented fractures and/or unequal horizontal stresses has created an azimuthally anisotropic earth, in which shear‐wave (SH) data collected along the principal axes anisotropy display time and reflection amplitude anomalies. Amoco shot two crossing lines that were approximately parallel to orthogonal azimuthal anisotropy. At tie point, these SH a time‐variant mis‐tie. point also displays reflection‐coefficient anomalies, attributable dependent velocities. Field...

A reservoir characterization study of Upper Green River gas reservoirs in the Bluebell‐Altamont Field, Uinta Basin, Utah was completed August 1995 for U.S. Department Energy. The included acquisition two crossing 2-D, 9-C seismic lines, VSP, and evaluation P-wave S-wave responses to fractured reservoirs. Lynn et al. (TLE, 1995) reported amplitude variations with offset azimuth (AVOA) at reflectors associated this field, supporting observations shear‐wave birefringence multicomponent VSPs...

A naturally‐fractured gas reservoir in the Wind River Basin, Wyoming, is site of a Department Energy‐sponsored project to optimize seismic techniques for characterizing natural fractures (density, orientation). The target zone Lower Fort Union (LFU, depth 5400–10 000 ft, two‐way time ∼1.3–∼2 s), low porosity, permeability section which are necessary commercial production. Flow rates incompatible with matrix porosity and observed.

Recent observations from several walkaround, walkaway, and 3D VSPs various parts of the world have shown that anisotropy symmetry directions (or fracture orientations) estimated traveltime or velocity do not necessarily agree with amplitude attenuation analysis. We also consistently found in reservoir intervals is generally stronger than overburdens. argue this article that, instead reconciling differences between attributes, we should try to understand mechanisms use difference which may...

Reflection P- and S-wave data were used in an investigation to determine the relative merits strengths of these two sets characterize a naturally fractured gas reservoir Tertiary Upper Green River formation. The objective is evaluate viability P-wave seismic detect presence gas‐filled fractures, estimate fracture density orientation, compare results with estimates obtained from data. response vertical fractures must be evaluated at different source‐receiver azimuths (travelpaths) strike. Two...

In recent years multicomponent 3D seismic data have demonstrated their usefulness for characterizing fractured reservoirs. Many theoretical and field studies shown that variation of attributes (such as velocity, amplitude, frequency P-wave acquired along different source to receiver paths), can be used an indicator azimuthal anisotropy. Lateral heterogeneity encountered by the azimuth source-receiver raypaths could give rise variations in traveltime and/or transmission characteristics, thus...

Although seismic reflection data in batholithic terranes are scarce, datasets available to us from three different regions show surprising similarities. All profiles, one across Precambrian rocks Texas, and two Mesozoic batholiths California Nevada, strong subhorizontal reflections at depths of 6–10 km. These interpreted originate the base batholiths, indicate that these tabular shape. The large amplitudes require a marked contrast acoustic impedance (product velocity density) between...

Research Article| August 01, 1983 Depth migration and interpretation of the COCORP Wind River, Wyoming, seismic reflection data Heloise Bloxsom Lynn; Lynn 1Department Geophysics, Stanford University, Stanford, California 94305 Search for other works by this author on: GSW Google Scholar Spencer Quam; Quam George A. Thompson Geology (1983) 11 (8): 462–469. https://doi.org/10.1130/0091-7613(1983)11<462:DMAIOT>2.0.CO;2 Article history first online: 01 Jun 2017 Cite View This Citation Add to...

This case history is one of three field projects funded by the US Department Energy as part its ongoing research effort aimed to expand current levels drilling and production efficiency in naturally‐fractured tight‐gas reservoirs. The original stated goal for 3-D P-wave seismic survey was evaluate map fracture azimuth relative density throughout a gas reservoir interval. At Rulison field, this interval Cretaceous Mesaverde, approximately 2500 ft (760 m) lenticular sands, silts, shales....

Gas production in Bluebell‐Altamont Field northeastern Utah is from numerous sandstones and carbonates the Tertiary upper Green River Formation at depths of approximately 6500–8500 ft. The local geologic setting nearly flat‐lying sediments with no faulting observed target depths. field has a very gentle anticlinal closure (less than 50 ft). Matrix porosity permeability reservoir rocks are generally low, such that fracturing yields substantially higher rates. Consequently, seismic detection...

Editor's note: This article is the first of two parts that together form an abbreviated version Fall 2004 SEG/AAPG Distinguished Lecture. A PowerPoint presentation this material posted on SEG Web site. “The winds change” refer to much more than just anisotropic rocks whose seismic anisotropy provides insight into horizontal permeability anisotropy. The way we view our planet changing. now being studied as interaction four interlocking systems—the hydro-sphere, atmosphere, lithosphere, and...

PreviousNext No AccessSEG Technical Program Expanded Abstracts 1986Reflection shear‐wave data along the principal axes of azimuthal anisotropyAuthors: Heloise B. LynnLeon A. ThomsenHeloise LynnLynn Inc. and Leon ThomsenAmoco Production Co.https://doi.org/10.1190/1.1893037 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Permalink: https://doi.org/10.1190/1.1893037FiguresReferencesRelatedDetailsCited BySeismic...

ABSTRACT Seismic data in which anisotropy is observed have been used to detect and characterize the natural fractures, Bluebell-Altamont, Utah, field. We show an (azimuth-dependent) amplitude variation with offset (AVO) anomaly P-wave reflection seismic, attributable gas-filled vertical oriented substantiated by 9-component VSP.

The use of seismic anisotropy is a topic that has evolved dramatically in the last 25 years oil and gas industry. Even though physicists who study waves vibrations solids have taught us elastic properties rocks should be described by complex set functions parameters, many data processing were conducted assuming velocities subsurface isotropic, shear modulus was zero (that could treated as “a liquid”). “Isotropic” means value measured (e.g., velocity) same all directions (whether you consider...

A high-fold full-azimuth, full-offset 3D P-P reflection survey was acquired and processed for the purpose of characterizing a naturally fractured carbonate reservoir. The reservoir is thick carbonate, overlain by shale, which will flow oil with sufficient fracture network. on-going drilling completion program horizontal wells plus hydraulic stimulation. azimuthal seismic attributes were compared to ISIP (instantaneous shut-in pressure) gradients, taken as indicating minimum stress, other...

Potentials and limitations for acquisition processing are examined, given the industry's interest in quantifying orthorhombic anisotropy contained 3D P-P field data. A field-data case presents one aspect of azimuthal prestack amplitudes demonstrates these potentials. Careful amplitude analysis azimuth-limited near-offset migrated volumes reveals significant variations that consistent with calibration measurements.

Multiazimuth binning of 3-D P-wave reflection data is a relatively simple but robust way characterizing the spatial distribution gas‐producing natural fractures. In our survey, were divided into two volumes by ray azimuth (approximately perpendicular and parallel (±45° to dominant fracture strike) separately processed. Azimuthal differences or ratios attributes provided rough measure anisotropy. Improved imaging was also attained in more coherent fracture‐parallel volume. A neural network...

[Formula: see text], Q) of near‐surface strata. The azimuthal anisotropy revealed in these field experiments is the result a combination circumstances: unequal horizontal stresses (the data were collected near center San Andreas and associated fault systems), fabric introduced by depositional agent, stress‐aligned fluid‐filled microcracks, cracks, or pore spaces.

Significant and occasionally abrupt changes are observed of the P-P bright-amplitude azimuth as reflection angle stacks increased from small (7°) to large (37°), throughout a full-azimuth full-offset 3D survey. The far offset amplitudes Top/Carbonate (Top/Reservoir) did exhibit (HTI) cosine 2θ azimuthal variation expected. However, near offsets too contained reliable sizable variations that were NOT steady decrease (predicted by HTI). Natural fracture calibration data included Star Trak...

A high-fold full-azimuth full-offset 3D P-P reflection survey was acquired and processed for the purpose of characterizing a naturally fractured carbonate reservoir. The reservoir is thick carbonate, overlain by shale, which will flow oil with sufficient fracture network. calibration data natural fractures are: 1) logging-while-drilling (LWD) Star Trak™ resistivity image log in horizontal borehole, 2) micro-seismic (m-s) data. were through azimuthal prestack depth migration (PSDM),...

PreviousNext No AccessSEG Technical Program Expanded Abstracts 1995The effects of azimuthal anisotropy in P‐wave 3‐D seismicAuthors: Heloise B. LynnC. Richard BatesK. Michele SimonRichard Van DokHeloise LynnLynn Inc., C. BatesColeman Research Corp., K. SimonLynn and DokWestern Geophysicalhttps://doi.org/10.1190/1.1887379 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Permalink:...

PreviousNext No AccessSEG Technical Program Expanded Abstracts 2001Frequency dependent anisotropyAuthors: Evgeni M. ChesnokovJohn H. QueenAlexander A. VichorevHeloise B. LynnJohn HooperIrina O. BayukJohn CastagnaBaishali RoyEvgeni ChesnokovUniversity of Oklahoma, Norman, OK 73019, John QueenConoco Inc., Ponca City, 74602, Alexander VichorevInstitute Physics the Earth, Moscow, 123810, Russia, Heloise LynnLynn Inc. 14732 F Perthshire, Houston, TX 77079, HooperConoco Irina BayukInstitute...