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  • (PDF) Coal seismic surveying over near-surface basalts ,
    (PDF) Coal seismic surveying over near-surface basalts ,

    Figure 11 shows that four layers of basalt are present at depths of 30-33, 37-38, 39-43, and 48-70 m Within the basalts, the sonic velocities tend to be between 5 and 6 km∕s These basalts are inferred to be fresh and very hard Between the basalt layers, the caliper ,

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  • Enhancing subbasalt reflections using parabolic transformation
    Enhancing subbasalt reflections using parabolic transformation

    seismic processing and subbasalt fea- , is thickness of each layer Water Sediment Basalt Sediment Basement W S1 Ba S2 Bm V P (m/s) 1500 2200 4800 4000 5500 V S (m/s) 0 950 2600 2100 3200 Q P = Q S (-) 500 50 30 100 150 ρ (kg/m3) 1000 2000 2500 2400 2700 D (m) 1200 1200 2100 2500 Figure 3(a) Enlargement of data in Figure 2 (b) Velocities .

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  • 2D Long Offset Data Processing for Sub Basalt – A Case History
    2D Long Offset Data Processing for Sub Basalt – A Case History

    attenuation and strong internal scattering of seismic energy Application of the processing techniques innovatively applied on seismic profiles recorded with wide azimuths for imaging the sediments buried under basalt layers have been presented in this paper The aim of processing is to image the sub basalt

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  • Coal seismic surveying over near-surface basalts ,
    Coal seismic surveying over near-surface basalts ,

    (20m) Conventional seismic acquisition and processing of a 2D seismic line provided poor results However, up-going reflections from layers below the basalt are clearly evident in the VSP survey and pre-stack depth migration was able to improve the continuity of the reflectors beneath the basalt

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  • 1 Z-99 THE IMPACT OF DATA PRE-PROCESSING ON SUB ,
    1 Z-99 THE IMPACT OF DATA PRE-PROCESSING ON SUB ,

    to use standard offset seismic datasets for sub-basalt imaging (Ogilvie et al, 2001), the wave- Figure 1: Original data without pre-processing: brute stack after NMO and AGC The water-layer peg-leg multiples from TB (top basalt) and BB (base basalt) are quite strong Multiple patterns are divided into three CDP intervals (ranges A-C)

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  • Advances in seismic imaging through basalts: a case study ,
    Advances in seismic imaging through basalts: a case study ,

    New seismic reflection data have been used to image intra- and sub-basalt features beneath the Faroe–Shetland Basin in the North Atlantic, where the highly reflective top and base boundaries of flood basalts and their complex internal structure make successful seismic imaging difficult This study demonstrates that appropriate acquisition and processing of marine seismic data from hydrophone .

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  • Modelling complex near-surface features to improve ,
    Modelling complex near-surface features to improve ,

    se surface layers However, adverse near-surface conditions have the potential to significantly degrade the target seismic reflections In the coal industry, particularly in the Bowen basin, there are often near-surface basalt structures overl ying economic targets As

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  • Multiple attenuation in the deep-water settings ,
    Multiple attenuation in the deep-water settings ,

    The presence of basalt traps considerably complicates marine seismic data processing and hampers velocity model building and seismic imaging This can be explained with the three key factors Firstly, trap layers are inhomogeneous; hence, high frequencies are attenuated rapidly when traveling through them [Ziolkowski, 2003] Secondly, such .

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  • Seeing below the basalt – offshore Faroes - Gallagher ,
    Seeing below the basalt – offshore Faroes - Gallagher ,

    Dec 17, 2007· This thick basalt layer obscures the deeper potentially prospective sedimentary section Research has shown that basalt layers scatter the higher seismic frequencies (Pujol and Smithson 1991; Hobbs 2002) and deep towing of receiver cables can extend the seismic bandwidth towards lower frequencies (Ziolkowski et al 2002)

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  • Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic ,
    Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic ,

    Imaging below the basalt for hydrocarbon exploration is a global problem because of poor penetration and significant loss of seismic energy due to scattering, attenuation, absorption and mode-conversion when the seismic waves encounter a highly heterogeneous and rugose basalt layer The conventional (short offset) seismic data acquisition, processing and modeling techniques adopted by the oil .

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  • SUB-BASALT IMAGING: MODELING AND DEMULTIPLE
    SUB-BASALT IMAGING: MODELING AND DEMULTIPLE

    Seismic imaging of sub-basalt sedimentary layers is difficult due to high impedance of the basalt layer, the roughness of the top and bottom of the basalt layer and sometimes the heterogeneities within the basalt layer In this thesis we identify specific problems within the modern imaging technology which limit sub-basalt imaging The basic

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  • 38 SEISMIC PROPERTIES OF FLOOD BASALTS FROM HOLE ,
    38 SEISMIC PROPERTIES OF FLOOD BASALTS FROM HOLE ,

    in this study, with focuses on (1) evaluating the seismic characteris-tics of the flood basalt sequence by processing and inversion of sonic waveform data, and (2) conducting detailed log-core correlation, en-abled by high core-recovery and high-quality FMS imag STRATIGRAPHY OF HOLE 917A

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  • Seismic wave propagation through an extrusive basalt ,
    Seismic wave propagation through an extrusive basalt ,

    Apr 01, 2016· Layers of basalt flows within sedimentary successions (eg in the Faeroe-Shetland Basin) cause complex scattering and attenuation of seismic waves during seismic exploration surveys Extrusive basaltic sequences are highly heterogeneous and contain strong impedance contrasts between higher velocity crystalline flow cores (∼6 km s-1) and the lower velocity fragmented and weathered ,

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  • ZONGE GEOSCIENCES, INC - OpenEI
    ZONGE GEOSCIENCES, INC - OpenEI

    basalt layers Average velocities of 7,000 and 8,000 fps should capture the range of depths that would be expected here An average velocity of 7,000 fps is equivalent to 35 feet of depth per millisecond (0001 second) of seismic time 4 feet of depth per millisecond of seismic time is equivalent to an average velocity of 8,000 fps While we

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  • Columbia River Basalt Group - Wikipedia
    Columbia River Basalt Group - Wikipedia

    The Columbia River Basalt Group is the youngest, smallest and one of the best-preserved continental flood basalt province on Earth, covering over 210,000 km 2 (81,000 sq mi) mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada The basalt group includes the Steen and Picture Gorge basalt formations

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  • Sub-basalt imaging problems and the application of ,
    Sub-basalt imaging problems and the application of ,

    Dec 01, 2001· In the presence of thick, laterally extensive basalt layers, seismic reflection sections are typified by a high amplitude top basalt reflector and the absence of base-basalt and sub-basalt events From our tests, varying layer thickness and source frequency, a synthetic 2-D fractal model, which produces seismic similar to real sub-basalt .

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  • Determining the Basaltic Sequence Using Seismic ,
    Determining the Basaltic Sequence Using Seismic ,

    The first layer is a thin layer of very dry weathered basalt, with an average value of ρ = 8430 Ohmm, and at a depth ranging from 1 to 75 m The value of apparent resistivity in the second layer is about ρ >4000 Ohmm and at depth ranging from 75 to 20 m, which might be com-prised of fresh basalt The third layer has an apparent

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  • Breakthroughs in seismic and borehole characterization of ,
    Breakthroughs in seismic and borehole characterization of ,

    Jan 01, 2011· In this paper we summarize the acquisition and processing of the multi-component seismic swath, and present observations on the integration of P- and S- waveform sonic logs with information from resistivity-based image logs to determine regional and local stress tensors and to improve identification of subsurface basalt lithofaci 2 Seismic .

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  • Sub-basalt Imaging Using Broadside CSEM
    Sub-basalt Imaging Using Broadside CSEM

    below a basalt layer However, due to shape irregularities and het erogeneities with high velocity contrasts around and within the basalts, it can be challenging for seismic processing to image the base of the basaltic layer and details of what is below [For example, s ee Fliedner and White (2001) ]

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  • Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic ,
    Sub-basalt Imaging of Hydrocarbon-Bearing Mesozoic ,

    Mar 16, 2018· Imaging below the basalt for hydrocarbon exploration is a global problem because of poor penetration and significant loss of seismic energy due to scattering, attenuation, absorption and mode-conversion when the seismic waves encounter a highly heterogeneous and rugose basalt layer The conventional (short offset) seismic data acquisition, processing and modeling techniques adopted by ,

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  • Seismic imaging through the volcanic rocks of the Snake ,
    Seismic imaging through the volcanic rocks of the Snake ,

    quence of basalt flows originating from a series of vents The final site, Mountain Home, is located in a fault-bounded sed-imentary basin with both surface and buried basalt layers Here, we discuss surface and borehole results using vertical seismic profiling (VSP) and surface seismic methods to show

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  • Sub-basalt imaging in Padra Field, South Cambay Basin ,
    Sub-basalt imaging in Padra Field, South Cambay Basin ,

    seismic exploration Strong inter-bed multiples always mask the weak reflections coming from sub-basalt formations Severe scattering of seismic energy due to heterogeneity of basalt layer further complicates the problem which results in the

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  • Improvement of sub-basalt imaging using parabolic tau-p ,
    Improvement of sub-basalt imaging using parabolic tau-p ,

    presence of basalt flows covering potential hydrocarbon exploration targets Such basaltic layers (up to several kilometers of stacked flows) create enormous problems for imaging underlying structures using conventional seismic acquisition and processing methods Scattering from the

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  • Sub-basalt Depth Imaging Using Simultaneous Joint ,
    Sub-basalt Depth Imaging Using Simultaneous Joint ,

    The layer-stripping joint inversion and PSDM workflow is repeated iteratively to generate an improved image of the sub-basalt section when compared to time-domain results The successful first application of simultaneous PSDM-joint inversion of seismic and electromagnetic data for a sub-basalt imaging case suggests that the methodology could be .

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  • Acoustic waveform inversion of ocean-bottom node seismic ,
    Acoustic waveform inversion of ocean-bottom node seismic ,

    image a low velocity layer situated beneath a high velocity layer such as basalt In this paper, we show that early arrival waveform inversion (EAWI) has the ability to see the low velocity layer underneath the basalt using ONGC ocean-bottom node (OBN) seismic data As we have used only the PP data with constant density assumption, EAWI

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  • A refraction seismic transect from the Faroe Islands to ,
    A refraction seismic transect from the Faroe Islands to ,

    ial basalt flows, are found on many reflection seismic profiles [eg, Smythe, 1983; Morgan et al, 1989; Barton and White, 1997a, 1997b] Refraction seismic data provide evidence for thick lower crustal layers with high seismic velocities (>72 km/s) in the continent-ocean transition zone, interpreted as magmatic underplating, for example

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  • Seismic challenges in high impact Lower Tertiary ,
    Seismic challenges in high impact Lower Tertiary ,

    Seismic imagings of prospective reservoir targets in the region have been problematic due to extensive Tertiary basalt The basin lies in water depths ranging from approximately 200 m (656 ft) to more than 1,000 m (3,281 ft) and is divided into both UK and Faroe offshore territories, with the Faroe area covered in a thick layer of basalt

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  • Effect of flood basalt stratigraphy on the phase of ,
    Effect of flood basalt stratigraphy on the phase of ,

    Effect of flood basalt stratigraphy on the phase of seismic waveforms recorded offshore Faroe Islands Juerg Schuler 1, Philip A F Christie2, and Robert S White ABSTRACT The generation of short-period multiples between highly heterogeneous layers of basalt flows can strongly alter transmit-ted seismic wavefields These layers filter and .

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  • Study on the limitations of travel-time inversion applied ,
    Study on the limitations of travel-time inversion applied ,

    neous structure of the basalt layers scatter 100 the higher seismic frequencies of the source signal (Pujol and Smithson, 1991; Hobbs, 2002) The lack of penetration and the multiple scattering within the basalt layer obscures the potential seis-mic events generated bellow the basalt This could represent potentially prospective sedimentary .

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  • Sub-basalt imaging in the Faroe-Shetland Basin using CSEM ,
    Sub-basalt imaging in the Faroe-Shetland Basin using CSEM ,

    Much of the seismic energy is reected at the top basalt interface due to the large seis-mic impedance contrast An additional difculty are interbed multiples which develop as a result of interchanging layers of basalt and other rock types, such as volcanoclastics These layers can have very different seismic properties which leads

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