Hello! I'm Ramzi
I'm currently a Research Geophysicist at the Imaging Geophysics department at Petroleum Geo-Services (PGS) in Weybridge, UK. My research focus are methods to improve seismic data processing and inversion. I work mainly on data conditioning, seismic imaging and full waveform inversion.
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Previously I was a Ph.D. student at King Abdullah University of Science and Technology (KAUST) within the Earth Science and Engineering program. I worked at the Seismic Wave Analysis Group (SWAG), and my research was supervised by Prof. Tariq Alkhalifah.
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During my Ph.D. I was working on implementing multiparameter inversion for vertical transverse isotropic (VTI) acoustic media using the scattering integral approach (the explicit computation of the update based on the sensitivity kernels). Extensions to more complex anisotropy can be one of the possible continuations of this research.
I obtained a Polytechnic engineering degree from Tunisia Polytechnic School in June 2009. Also, I got an M.S in Computational Mechanics from the same school in May 2010.
I'm a member of SEG and EAGE.
Ramzi Djebbi
Research Geophysicist
Imaging Geophysics, PGS
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Phone:
+44 (0) 7504060267
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Email:
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Address:
PGS, 4 The Heights, Brooklands, Weybridge
Surrey, KT13 0NY, United Kingdom
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Background image source: http://petrec.com.br
SKILLS
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Paper on "Hybrid frequency-domain full-waveform inversion using ray+ Born sensitivity kernels"accepted in "Geophysics" and available online.
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Paper on "Frequency domain multiparameter inversion for VTI media"accepted in "Geophysics" and available online.
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Now Research Geophysicist at Petroleum Geo-Services (PGS) UK.
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NEWS
EXPERIENCE
Sept. 2010- present
Research assistant
King Abdullah University of Science and Technology (KAUST), SAUDI ARABIA
Proposed a new method to compute the finite frequency traveltime sensitivity kernels which showed a potential application in isotropic/anisotropic seismic data inversion; Extended the proposed method to multi-parameter anisotropic wave equation tomography and came-up with an inversion scheme which reduces the inversion trade-off between the different anisotropy parameters.
King Abdullah University of Science and Technology (KAUST), SAUDI ARABIA
Developed course material, prepared quizzes and graded them for ErSE 260- Seismic Imaging course. Delivered tutorials on the use of Madagascar package for reproducible research in Exploration geophysics and scientific computing.
Applied Geophysical Research Group (OPERA), FRANCE
Analyzed the feasibility of a new method for pseudo-spectral wavefield extrapolation based on a phase-shift operator and Gabor decomposition.
Aug. 2014- Oct. 2014
Research Internship
Aug. 2009- Jan. 2010
Research Internship
Applied Mechanics and Systems Research Laboratory (LASMAP), TUNISIA
Implemented a robust method to automatically measure the mechanical properties of a fiber reinforced composite material using ultrasonic waves.
Feb.- June 2009
Engineering Graduation Project
ACOUSTICA, TUNISIA
Implemented a finite element code for numerical homogenization for composite materials; analyzed different types of material reinforcement configurations and designed a new biodegradable material with potential applications in orthopedic prosthesis production.
July- Aug. 2008
Internship
Nov. 2017- Present
Research Geophysicist
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​Sep. 2010- Oct. 2017
Research assistant
Petroleum Geo-Services (PGS), Weybridge, UK
Work on research and development on improving existing seismic data processing methods as well as developing new algorithms for data conditionning, seismic imaging and full waveform inversion.
King Abdullah University of Science and Technology (KAUST), SAUDI ARABIA
Proposed a new method to compute the finite frequency traveltime sensitivity kernels which showed a potential application in isotropic/anisotropic seismic data inversion; Extended the proposed method to multi-parameter anisotropic wave equation tomography and came-up with an inversion scheme which reduces the inversion trade-off between the different anisotropy parameters.
Jan.-May 2016
Teaching assistant
King Abdullah University of Science and Technology (KAUST), SAUDI ARABIA
Developed course material, prepared quizzes and graded them for ErSE 260- Seismic Imaging course. Delivered tutorials on the use of Madagascar package for reproducible research in Exploration geophysics and scientific computing.
Aug. 2014- Oct. 2014
Research Internship
Applied Geophysical Research Group (OPERA), FRANCE
Analyzed the feasibility of a new method for pseudo-spectral wavefield extrapolation based on a phase-shift operator and Gabor decomposition.
Aug. 2009- Jan. 2010
Research Internship
Applied Mechanics and Systems Research Laboratory (LASMAP), TUNISIA
Implemented a robust method to automatically measure the mechanical properties of a fiber reinforced composite material using ultrasonic waves.
Feb.- June 2009
Engineering Graduation Project
ACOUSTICA, TUNISIA
Implemented a finite element code for numerical homogenization for composite materials; analyzed different types of material reinforcement configurations and designed a new biodegradable material with potential applications in orthopedic prosthesis production.
July- Aug. 2008
Internship
CETA Engineering, TUNISIA
Contributed to the numerical and analytical study of stresses in concrete reinforced bridges and applied the European standards to design the bridge.
EDUCATION
2010-2017
Ph.D. Degree
King Abdullah University of Science and Technology (KAUST), SAUDI ARABIA
Major: Earth Science and Engineering
Dissertation: Multi-parameter analysis and inversion for anisotropic media using the scattering integral method
2009-2010
Master's Degree
TUNISIA POLYTECHNIC SCHOOL, TUNISIA
Major: Computational Mechanics
Thesis: Automation of the ultrasonic identification of a fiber reinforced composite material mechanical properties
TUNISIA POLYTECHNIC SCHOOL, TUNISIA
Polytechnic Engineering degree with focus on Mechanics and Structures Engineering
2006-2009
Bachelor's of Engineering Degree
RESEARCH
Traveltime sensitivity kernels using the unwrapped phase
The paper describes a new method to compute the traveltime sensitivity kernels. Unlike the cross-correlation or Rytov kernels, the unwrapped phase kernels do not have a hollow space along the ray-path. We showed that the unwrapped phase kernels are a generalization of the Rytov approximation ones and are more sensitive to small size scattering points.
PUBLICATIONS
JOURNAL PAPERS
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Djebbi R. and Alkhalifah T., [2020], Hybrid frequency-domain full-waveform inversion using ray+ Born sensitivity kernels. Geophysics 85 (4), R339-R347.
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Djebbi R. and Alkhalifah T., [2019], Frequency domain multiparameter inversion for transversely isotropic medium with a vertical axis of symmetry. Geophysics 84 (1), C1-C14.
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Djebbi R., Plessix R-E. and Alkhalifah T., [2017], Analysis of the traveltime sensitivity kernels for the acoustic vertical transverse isotropic medium. Geophysical Prospecting, 65 (1), 22–34.
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Djebbi R. and Alkhalifah T., [2014], Traveltime sensitiviy kernels for wave equation tomography using the unwrapped phase. Geophysical Journal International, 197 (2), 975-986.
CONFERENCE PAPERS
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Djebbi R. and Alkhalifah T., [2017], Frequency domain multi-parameter full waveform inversion for acoustic VTI media. 79th Annual EAGE meeting, EAGE Expanded Abstracts.
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Djebbi R. and Alkhalifah T., [2016], Hybrid frequency domain full waveform inversion using Born sensitivity kernels. 78th Annual EAGE meeting, EAGE Expanded Abstracts.
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Djebbi R. and Alkhalifah T., [2015], Gradient for the acoustic VTI full-waveform inversion based on the instantaneous traveltime sensitivity kernels. 85th Annual SEG Meeting, SEG Expanded Abstracts, 1430- 1435.
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Djebbi R. and Alkhalifah T., [2014], Analysis of the multi-component pseudo-pure-mode qP-wave inversion in vertical transverse isotropic (VTI) media. 84th Annual SEG Meeting, SEG Expanded Abstracts, 394-399.
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Djebbi R. and Alkhalifah T., [2014], 3-D waveform tomography sensitivity kernels for anisotropic media. 76th Annual EAGE meeting, EAGE Expanded Abstracts.
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Djebbi R. and Alkhalifah T., [2013], Finite frequency traveltime sensitivity kernels for acoustic anisotropic media: Angle dependent bananas. 83rd Annual SEG Meeting, SEG Expanded Abstracts, 4858-4862.
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Djebbi R. and Alkhalifah T., [2013], Wave equation tomography using the unwrapped phase: Analysis of the traveltime sensitivity kernels. 75th Annual EAGE meeting, EAGE Expanded Abstracts.
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Djebbi R. and Alkhalifah T., [2012], It Is Only a Banana- Traveltime Sensitivity Kernels Using the Unwrapped Phase. 74th Annual EAGE meeting, EAGE Expanded Abstracts.
Software
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Madagascar, Matlab, Mathematica, Sage, Maple
Operating Systems
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Windows, Unix and Mac OS
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Programming
C/C++, Fortran,
Python, OpenMp, MPI
Languages
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English, French and Arabic
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