| 玄武岩内非均质性对地震资料的影响:印度德干圈闭的一个研究实例 |
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| 引用本文： | Dhananjai Pandey,Satish Singh,Martin Sinha,Lucy MacGregor.玄武岩内非均质性对地震资料的影响:印度德干圈闭的一个研究实例[J].应用地球物理,2007,4(3):183-193. |
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| 作者姓名： | Dhananjai Pandey Satish Singh Martin Sinha Lucy MacGregor |
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| 作者单位： | [1]Bullard Laboratories, Madingley Road, University of Cambridge, Cambridge, UK, CB3 0EZ [2]Laboratoire de G＇eosciences Marines, IPG Paris 4 Place Jussieu, 75252 Paris Cedex 05, France [3]SOES, National Oceanography Centre, Southampton, UK, SO 14 3ZH [4]Offshore Hydrocarbon Mapping Plc., Aberdeen, UK, AB23 8GD |
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| 摘 要： | Hydrocarbon exploration interests have renewed the need for developing new sub basalt imaging techniques. One of the most important problems encountered today is seismic imaging below basalt. In recent years, this problem appears to have been overcome partly by using long offset seismic data. However near offset data are yet to be fully utilised due to the complex waveform caused by the surface as well as internal heterogeneity of the basalts. The near normal incidence data, which influence the sub-basalt imaging, are highly useful to understand the internal structure within a basalt layer. The use of converted waves for such targets has been proposed as an alternative in a rather homogeneous basalt layer. With a few synthetic modelling exercises here we highlight the practical difficulties in dealing with more realistic and heterogeneous basalt flow. Full waveform seismograms are computed to understand the effects of intra-trappean sediments on the seismic data. A case study from the Deccan Traps of India is presented in this paper. First, we discuss the effects of intercalated sediments on the overall seismic image. Later, the sonic log data from the field are used to compute the full wave-field response using the reflectivity method and compared with the field data. The feasibility of using mode converted waves （P to S and vice-versa at the top and bottom basalt interfaces） for sub-basalt imaging in Kutch region is discussed through a series of velocity-depth profiles. By comparing with the field data we demonstrate that the effects of multiple thin layering within the basalt can strongly deteriorate the image we seek to interpret and exploit.
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| 关 键 词： | 玄武岩下成像 库奇 德干高原 反射系数 全波形模拟 |
| 收稿时间： | 21 June 2007 |
| 修稿时间： | 2007-06-21 |
The effect of intra-trappean heterogeneities on seismic data: A case study from the Deccan Traps |
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| Dhananjai Pandey,Satish Singh,Martin Sinha,Lucy MacGregor.The effect of intra-trappean heterogeneities on seismic data: A case study from the Deccan Traps[J].Applied Geophysics,2007,4(3):183-193. |
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| Authors: | Dhananjai Pandey Satish Singh Martin Sinha Lucy MacGregor |
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| Institution: | (1) Bullard Laboratories, University of Cambridge, Madingley Road, Cambridge, UK, CB3 0EZ;(2) Laboratoire de G’eosciences Marines, IPG Paris 4 Place Jussieu, 75252 Paris, Cedex 05, France;(3) SOES, National Oceanography Centre, Southampton, UK, SO14 3ZH;(4) Offshore Hydrocarbon Mapping Plc., Aberdeen, UK, AB23 8GD;(5) Present address: National Centre for Antarctic and Ocean Research, Goa, India |
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| Abstract: | Hydrocarbon exploration interests have renewed the need for developing new sub basalt imaging techniques. One of the most
important problems encountered today is seismic imaging below basalt. In recent years, this problem appears to have been overcome
partly by using long offset seismic data. However near offset data are yet to be fully utilised due to the complex waveform
caused by the surface as well as internal heterogeneity of the basalts. The near normal incidence data, which influence the
sub-basalt imaging, are highly useful to understand the internal structure within a basalt layer. The use of converted waves
for such targets has been proposed as an alternative in a rather homogeneous basalt layer. With a few synthetic modelling
exercises here we highlight the practical difficulties in dealing with more realistic and heterogeneous basalt flow. Full
waveform seismograms are computed to understand the effects of intra-trappean sediments on the seismic data. A case study
from the Deccan Traps of India is presented in this paper. First, we discuss the effects of intercalated sediments on the
overall seismic image. Later, the sonic log data from the field are used to compute the full wave-field response using the
reflectivity method and compared with the field data. The feasibility of using mode converted waves (P to S and vice-versa
at the top and bottom basalt interfaces) for sub-basalt imaging in Kutch region is discussed through a series of velocity-depth
profiles. By comparing with the field data we demonstrate that the effects of multiple thin layering within the basalt can
strongly deteriorate the image we seek to interpret and exploit.
Dhananjai Pandeyreceived his M. Sc. (Tech) in Exploration Geophysics from Banaras Hindu University in 1997, India followed by Doctorate degree
from University of Cambridge (2003), UK. His doctoral work was based on using long offset data from the Deccan Traps of India
for sub-basalt imaging. His major research interests are wide-angle seismic data modeling and inversion for crustal structure
determination. His professional experience includes both working in academic as well as industrial research. He has been working
as marine geophysicist at National Centre for Antarctic and Ocean Research, Goa, India. Presently he is working as post doctoral
researcher in geophysical computing at National Oceanography Centre Southampton, UK. |
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| Keywords: | Sub-basalt imaging Kutch Deccan Traps Reflectivity Full-waveform modelling |
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