AVD—An emerging new marine technology for reservoir characterization: Acquisition and application

Geophysics ◽  
1999 ◽  
Vol 64 (4) ◽  
pp. 1153-1159 ◽  
Author(s):  
Colin MacBeth ◽  
Xiang‐Yang Li
Keyword(s):  
Reservoir Characterization ◽  
Seismic Anisotropy ◽  
Azimuthal Anisotropy ◽  
Seismic Profiles ◽  
Vertical Seismic Profiles ◽  
Seismic Sensors ◽  
Strike Direction ◽  
Using Data ◽  
Central North Sea ◽  
Future Work

Several significant developments in marine technologies in the past few years have resulted in the creation of acquisition techniques suited to azimuthal anisotropy analysis in the offshore environment. The developments have parallelled the evolution in the theory underlying the use of P-P and P-S amplitude versus direction (AVD) for seismic anisotropy estimation. The demands of such AVD methods for a wide azimuthal coverage have only recently been met. To guide future work, the AVD method has been assessed using data from intersecting streamer lines. Application of the method in this example permits an identification of the strike direction of hydrocarbon‐filled fractures within a chalk formation in the central North Sea. The results of this study provide confidence that the method is sufficiently sensitive to fractures and can help guide future analyses. The new generation of vertical cables, seabed seismic sensors, and walk‐away (and/or 3-D) vertical seismic profiles will eventually lead to high‐resolution anisotropy estimation in the offshore environment using this approach.

Vertical open fractures and shear‐wave velocities derived from VSPs, full waveform acoustic logs, and televiewer data

Geophysics ◽  
1993 ◽  
Vol 58 (6) ◽  
pp. 818-834 ◽  
Author(s):  
Frédéric Lefeuvre ◽  
Roger Turpening ◽  
Carol Caravana ◽  
Andrea Born ◽  
Laurence Nicoletis
Keyword(s):  
Shear Wave ◽  
Azimuthal Anisotropy ◽  
Stoneley Wave ◽  
Correlation Technique ◽  
Seismic Profiles ◽  
Vertical Seismic Profiles ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Full Waveform ◽  
Zero Offset

Fracture or stress‐related shear‐wave birefringence (or azimuthal anisotropy) from vertical seismic profiles (VSPs) is commonly observed today, but no attempt is made to fit the observations with observed in‐situ fractures and velocities. With data from a hard rock (limestones, dolomites, and anhydrites) region of Michigan, fast and slow shear‐wave velocities have been derived from a nine‐component zero offset VSP and compared to shear‐wave velocities from two full waveform acoustic logs. To represent the shear‐wave birefringence that affects the shear wave’s vertical propagation, a propagator matrix technique is used allowing a local measurement independent of the overburden layers. The picked times obtained by using a correlation technique have been corrected in the birefringent regions before we compute the fast and slow velocities. Although there are some differences between the three velocity sets, there is a good fit between the velocities from the shear‐wave VSP and those from the two logs. We suspect the formations showing birefringence to be vertically fractured. To support this, we examine the behavior of the Stoneley wave on the full waveform acoustic logs in the formations. In addition, we analyze the borehole televiewer data from a nearby well. There is a good fit between the fractures seen from the VSP data and those seen from the borehole.

Twelve years of vertical birefringence in nine‐component VSP data

Geophysics ◽  
2001 ◽  
Vol 66 (2) ◽  
pp. 582-597 ◽  
Author(s):  
Donald F. Winterstein ◽  
Gopa S. De ◽  
Mark A. Meadows
Keyword(s):  
Seismic Data ◽  
Azimuthal Anisotropy ◽  
Vertical Shear ◽  
S Wave ◽  
Seismic Profiles ◽  
Surface Reflection ◽  
Vertical Seismic Profiles ◽  
Reflection Seismic ◽  
San Andreas ◽  
Vsp Data

Since 1986, when industry scientists first publicly showed data supporting the presence of azimuthal anisotropy in sedimentary rock, we have studied vertical shear‐wave (S-wave) birefringence in 23 different wells in western North America. The data were from nine‐component vertical seismic profiles (VSPs) supplemented in recent years with data from wireline crossed‐dipole logs. This paper summarizes our results, including birefringence results in tabular form for 54 depth intervals in 19 of those 23 wells. In the Appendix we present our conclusions about how to record VSP data optimally for study of vertical birefringence. We arrived at four principal conclusions about vertical S-wave birefringence. First, birefringence was common but not universal. Second, birefringence ranged from 0–21%, but values larger than 4% occurred only in shallow formations (<1200 m) within 40 km of California’s San Andreas fault. Third, at large scales birefringence tended to be blocky. That is, both the birefringence magnitude and the S-wave polarization azimuth were often consistent over depth intervals of several tens to hundreds of meters but then changed abruptly, sometimes by large amounts. Birefringence in some instances diminished with depth and in others increased with depth, but in almost every case a layer near the surface was more birefringent than the layer immediately below it. Fourth, observed birefringence patterns generally do not encourage use of multicomponent surface reflection seismic data for finding fractured hydrocarbon reservoirs, but they do encourage use of crossed‐dipole logs to examine them. That is, most reservoirs were birefringent, but none we studied showed increased birefringence confined to the reservoir.

The effect of seismic anisotropy on reservoir characterization

2005 ◽  
Author(s):  
Said Amiri Besheli ◽  
Milovan Urosevic ◽  
Ruiping Li
Keyword(s):  
Reservoir Characterization ◽  
Seismic Anisotropy

Similarities between the Madeira and Canary Hotspots Revealed by Seismic Anisotropy from Teleseismic and Local Shear-Wave Splitting with the SIGHT Project

2021 ◽  
Author(s):  
David Schlaphorst ◽  
Graça Silveira ◽  
João Mata ◽  
Frank Krüger ◽  
Torsten Dahm ◽  
...  
Keyword(s):  
Shear Wave ◽  
Canary Islands ◽  
Delay Time ◽  
Seismic Anisotropy ◽  
Vertical Component ◽  
Mantle Flow ◽  
Crust And Upper Mantle ◽  
Length Scales ◽  
Flow Models ◽  
Using Data

&lt;p&gt;The Madeira and Canary archipelagos, located in the eastern North Atlantic, are two of many examples of hotspot surface expressions, but a better understanding of the crust and upper mantle structure beneath these regions is needed to investigate their structure in more detail. With the study of seismic anisotropy, it is possible to assess the rheology and structure of asthenosphere and lithosphere that can reflect a combination of mantle and crustal contributions.&lt;/p&gt;&lt;p&gt;Here, as part of the SIGHT project (SeIsmic and Geochemical constraints on the Madeira HoTspot), we present the first detailed study of seismic anisotropy beneath both archipelagos, using data collected from over 60 local three-component seismic land stations. Basing our observations on both teleseismic SKS and local S splitting, we are able to distinguish between multiple layers of anisotropy. We observe significant changes in delay time and fast shear-wave orientation patterns on short length-scales on the order of tens of kilometres beneath the western Canary Islands and Madeira Island. In contrast, the eastern Canary Islands and Porto Santo the pattern is much more uniform. The detected delay time increase and more complex orientation patterns beneath the western Canary Islands and Madeira can be attributed to mantle flow disturbed and diverted on small-length scales by a strong vertical component. This is a clear indication of the existence of a plume at each of those archipelagos, nowadays exerting a strong influence on the western and younger islands. We therefore conclude that a plume-like feature beneath Madeira exists in a similar way to the Canary Island hotspot and that regional mantle flow models for the region should be reassessed.&lt;/p&gt;&lt;p&gt;This is a contribution to project SIGHT (Ref. PTDC/CTA-GEF/30264/2017). The authors would like to acknowledge the financial support FCT through project UIDB/50019/2020 &amp;#8211; IDL.&lt;/p&gt;

Integrated reservoir characterization: Beyond tomography

Geophysics ◽  
1995 ◽  
Vol 60 (2) ◽  
pp. 354-364 ◽  
Author(s):  
Larry Lines ◽  
Henry Tan ◽  
Sven Treitel ◽  
John Beck ◽  
Richard Chambers ◽  
...  
Keyword(s):  
History Matching ◽  
Preferential Flow ◽  
Reservoir Characterization ◽  
Seismic Anisotropy ◽  
Flow Direction ◽  
Geophysical Methods ◽  
Reservoir Properties ◽  
Traveltime Tomography ◽  
Sonic Log ◽  
Primary Water

In 1992, there was a collaborative effort in reservoir geophysics involving Amoco, Conoco, Schlumberger, and Stanford University in an attempt to delineate variations in reservoir properties of the Grayburg unit in a West Texas [Formula: see text] pilot at North Cowden Field. Our objective was to go beyond traveltime tomography in characterizing reservoir heterogeneity and flow anisotropy. This effort involved a comprehensive set of measurements to do traveltime tomography, to image reflectors, to analyze channel waves for reservoir continuity, to study shear‐wave splitting for borehole stress‐pattern estimation, and to do seismic anisotropy analysis. All these studies were combined with 3-D surface seismic data and with sonic log interpretation. The results are to be validated in the future with cores and engineering data by history matching of primary, water, and [Formula: see text] injection performance. The implementation of these procedures should provide critical information on reservoir heterogeneities and preferential flow direction. Geophysical methods generally indicated a continuous reservoir zone between wells.

scholarly journals Lithospheric and sublithospheric deformation under the Borborema Province of northeastern Brazil from receiver function harmonic stripping

Solid Earth ◽  
2019 ◽  
Vol 10 (3) ◽  
pp. 893-905 ◽  
Author(s):  
Gaelle Lamarque ◽  
Jordi Julià
Keyword(s):  
Lithospheric Mantle ◽  
Seismic Anisotropy ◽  
Receiver Function ◽  
Seismic Station ◽  
Atlantic Coast ◽  
Shear Zones ◽  
Receiver Functions ◽  
Azimuthal Anisotropy ◽  
Northeastern Brazil ◽  
Borborema Province

Abstract. The depth-dependent anisotropic structure of the lithosphere under the Borborema Province in northeast Brazil has been investigated via harmonic stripping of receiver functions developed at 39 stations in the region. This method retrieves the first (k=1) and second (k=2) degree harmonics of a receiver function dataset, which characterize seismic anisotropy beneath a seismic station. Anisotropic fabrics are in turn directly related to the deformation of the lithosphere from past and current tectonic processes. Our results reveal the presence of anisotropy within the crust and the lithospheric mantle throughout the entire province. Most stations in the continental interior report consistent anisotropic orientations in the crust and lithospheric mantle, suggesting a dominant northeast–southwest pervasive deformation along lithospheric-scale shear zones developed during the Brasiliano–Pan-African orogeny. Several stations aligned along a northeast–southwest trend located above the (now aborted) Mesozoic Cariri–Potiguar rift display large uncertainties for the fast-axis direction. This non-azimuthal anisotropy may be related to a complex anisotropic fabric resulting from a combination of deformation along the ancient collision between Precambrian blocks, Mesozoic extension and thermomechanical erosion dragging by sublithospheric flow. Finally, several stations along the Atlantic coast reveal depth-dependent anisotropic orientations roughly (sub)perpendicular to the margin. These results suggest a more recent overprint, probably related to the presence of frozen anisotropy in the lithosphere due to stretching and rifting during the opening of the South Atlantic.

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