Vertical seismic profile results from the Kola Superdeep Borehole, Russia

Carr, Bradley J.; Smithson, Scott B.; Kareav, N.; Ronin, A.; Garipov, V. Z.; Kristofferson, Y.; Digranes, P.; Smythe, David; Gillen, C.

doi:10.1016/s0040-1951(96)00133-3

Cited by 13 publications

(7 citation statements)

References 28 publications

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“…(Veselov et al 1987;SKB report 1992). However, through the study of shallow VSPs (50-525 m) close to the deep borehole, Carr et al (1993) inferred the fast direction to be approximately N150"W, and also found this to be consistent with the orientation of the present-day surface fractures in the borehole region. The direction of the palaeostress (1800-2000 Ma) is north-east-south-west (Marker 1985).…”

Section: Inter Pre Tat10 N a N D Discussionmentioning

confidence: 77%

An analysis of shear waves observed in VSP data from the superdeep well at Kola, Russia

Digranes

Kristoffersen

Karajev³

1996

Geophysical Journal International

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S U M M A R YTwo VSPs have been analysed from the Kola superdeep borehole, located on the Kola Peninsula. The Kola borehole was drilled down to a depth of 12 260 m and VSPs were recorded in the interval 2150 to 6000 m. The VSPs sample the Proterozoic Pechenga complex, which consists of alternating metasedimentary and metavolcanic layers that range from greenschist to amphibolite-grade facies. The structural dip is 28-45' to the SSW, and a major shear zone (the Luchlompolsky fault) occurs at 4.5 km depth.The VSPs display strong transmitted-and reflected-mode converted energy from structural and lithologic boundaries. A kinematic (traveltime) ray-tracing modelling of the main compressional-(P-) and shear-(S-) wave events was performed to define the seismic boundaries. P-and S-wave velocities were estimated from the near-offset data, and V,/V, ratios were related to the lithology. A significant increase in the &/V, ratio is observed in the main shear zone at 4.5 km depth. Shear-wave splitting is identified by traveltime divergence (different apparent velocites) and orthogonal polarization of S phases in the far-offset VSP. The inferred polarization direction for the fast shear wave is N160"W, clearly observed below 4400 m depth. Two models are suggested to explain the observed shear-wave splitting: intrinsic anisotropy caused by aligned hornblende minerals in the amphibolite-grade facies; and vertical cracks aligned N160"W. The direction of crack alignment is not consistent with the present-day NW-SE maximum compressive stress field. However, it is consistent with the direction of the palaeostress, the direction of crack alignment at the surface and the fast direction obtained from analysis of shear waves in shallow VSPs. The velocity anisotropy is estimated to be 4-5 per cent with a local increase to 10 per cent in the Luchlompolsky fault zone.

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Section: Inter Pre Tat10 N a N D Discussionmentioning

confidence: 77%

An analysis of shear waves observed in VSP data from the superdeep well at Kola, Russia

Digranes

Kristoffersen

Karajev³

1996

Geophysical Journal International

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“…2006), and tube waves when stimulated (Jones 1993). P – S reflections, and also S – S reflections, are known to occur in crystalline massifs on fault zones concentrating fluids (Carr et al . 1996; Smithson et al .…”

Section: Discussionmentioning

confidence: 99%

“…Thus, a good correlation is observed between the P – S reflectivity of a fault and its potential hydraulic and tectonic activity. The elastic response of a fault seems to be strongly related to its porosity network and fluid conditions, that could imply in some cases a mechanical defect (Schoenberg 1980; Jones & Nur 1984; Lüschen et al 1993; Carr et al 1996; Harjes et al 1997; Harjes et al 1998; Smithson et al 2000; Rabbel et al 2004), although this phenomenon has never been satisfactorily explained by theoretical work. In addition to the fluid content, the anisotropy induced by the fractures in the damage zones of the faults could be of importance in the reflection coefficients (see among others Zillmer et al 1997).…”

Section: Discussionmentioning

confidence: 99%

3-D mapping of permeable structures affecting a deep granite basement using isotropic 3C VSP data

Place¹,

Sausse

Marthelot³

et al. 2011

Geophysical Journal International

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International audienceThis paper illustrates the efficiency of vertical seismic profiling (VSP) for the investigation of dipping and hydraulically conductive structures affecting a granitic basement covered by sediments. A three-component (3C) VSP data set has been acquired in the GPK1 and EPS1 wells of the Soultz-sous-Foreˆts enhanced geothermal system (EGS) located within the Upper Rhine Graben (URG). Our study focuses on the isotropic processing of profiles acquired with vertical vibrator P and their subsequent interpretation. Mainly P-S converted reflections are identified from the analysis of the 3C records. These P-S conversions occur on steep permeable faults that are positioned in space by traveltime modelling. These faults cut the granite basement in several hectometric-scale blocks, and represent the main fluid paths between the boreholes. These faults are thought to be inherited from late Variscan and Alpine deformation periods, reactivated by the current stress field. When properly processed and interpreted, VSP allow the scale gap between surface and borehole data to be bridged

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“…The largest part of this project was a 3‐D reflection survey with the KTB at its center. The combination of borehole measurements and seismic surveys at the surface is a feature of a number of scientific deep drilling projects such as those at the Siljan impact structure in Sweden [ Juhlin , 1990], at the Kola superdeep borehole in Russia [ Carr et al , 1996; Ganchin et al , 1998], and at the SG4 borehole in the Urals in Russia [ Juhlin et al , 1997]. The purpose of the combination is to relate the reflections, visible in the seismic data, to the physical parameters and the lithology of the rocks in the borehole, determined from logs and from drill cores and cuttings.…”

Section: Introductionmentioning

confidence: 99%

Seismic reflections from the crystalline crust below the Continental Deep Drilling Site KTB: Modeling and inference on reflector properties

2002

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[1] The three-dimensional (3-D) reflection-seismic data set ISO-89 3D was recorded near the deep borehole KTB in southeastern Germany. Reflections from the SE1 reflector and from the top of the Erbendorf body (EB) in the upper crystalline crust can be identified in 5-10% of the single-shot sections. The reflectors have been first identified in previous studies of stacked and migrated seismic data. In this paper the velocity and density variations of these two structures are estimated in a new way using true amplitude single-shot (vibroseis) data. The method uses the direct wave P g as a reference phase and models the amplitude ratios of the SE1 and EB reflections to P g . Modeling in this paper uses a combination of ray theory and the reflectivity method, and the SE1 and the top of the EB are assumed to be obliquely oriented 1-D structures. P g modeling shows that a depth-dependent velocity function within the uppermost crystalline basement explains the amplitudes and travel times of this phase with sufficient accuracy. The largest observed amplitude ratios SE1/P g and EB/P g are explained by laminated models with strong velocity contrasts and with reflection coefficients of magnitude 0.1-0.2 (SE1) and 0.05-0.15 (EB). The total thickness of the reflecting zones is less than $300 m. P g amplitude modeling requires low Q p factors (<100) to a depth of $1 km, whereas at larger depths, values of several hundred are necessary to keep the SE1 and EB velocity contrasts in realistic ranges. Both reflectors can be interpreted as cataclastic zones. For the SE1 this interpretation agrees with the view that it is a steeply dipping thrust fault which continues the tectonic Franconian Lineament into the upper crust. We assume that the EB is the fractured top of a high-velocity zone at depths below $10 km, known from earlier wide-angle measurements. Both reflectors have large weakly reflecting or nonreflecting parts. The SE1 is nonreflecting at the intersection with the KTB borehole.

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Vertical seismic profile results from the Kola Superdeep Borehole, Russia

Cited by 13 publications

References 28 publications

An analysis of shear waves observed in VSP data from the superdeep well at Kola, Russia

An analysis of shear waves observed in VSP data from the superdeep well at Kola, Russia

3-D mapping of permeable structures affecting a deep granite basement using isotropic 3C VSP data

Seismic reflections from the crystalline crust below the Continental Deep Drilling Site KTB: Modeling and inference on reflector properties

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