Quick Links

CWP Seminars - 2013 Fall

CWP seminars discuss topics pertaining to our broad areas of research interests. These seminars are led by CWP faculty, students and, on occasion, by guest presenters. CWP seminars are held every Monday at 4 p.m. in the Green Center on the Colorado Scho8ol of Mines campus. Click here to see previous CWP Seminars.

Note: To view weekly seminar schedules of individual CWP teams, click a link below:

A-Team seminars

C-Team seminars

iTeam seminars

Steam seminars

 

Fall 2013 CWP seminars

Date Speaker(s) Title Abstract
12/9

No seminar - Final exam week at Mines

12/2

Ernst Niederleithinger

Ernst Niederleithinger

Ultrasonic experiments as scale models for seismic imaging

I will wrap up the work done during my time at CWP. I will start with an experiment I've made with Johannes Douma to evalute his Time Reversal + Deconvolution technique to backpropagate and focus engergy recorded from seismic events. Together with Chinaemerem Kanu I have started to work on localizing subtle changes in a concrete body. Inspired by Gerald Schuster's lecture, I evaluated the possibilities of Seismic Interferometry for ultrasonic inspection techniques. I will also discuss application ideas for Autofocusing (Filippo Broggini, Satyan Singh) to my work.

11/25

Farhad Bazargani

Farhad Bazargani

Generalization of the Backus-Gilbert focusing for elastic waves and unknown sources

The formulation of the Backus-Gilbert focusing method in the past has been dependent on many restrictive assumptions about the seismic source, e.g., source mechanism and time. I will reformulate and simplify the method so that these assumption are no longer required.

Ali Knaak

Ali Knaak

Use of controlled-source electromagnetics (CSEM)

The use of controlled-source electromagnetics (CSEM) to de-risk and find hydrocarbon reservoirs is restricted by the size of the target, low resolution, and the depth of the target. I have previously shown how the technique of synthetic aperture can be applied to CSEM data to increase the detectability of the reservoir. Today, I will show how we optimize the steering of the synthetic aperture sources. I will present results from synthetic data.

11/18

Shingo Ishida

Bruce VerWest

A broadband marine dataset for CWP

CGG has released to CSM a pair of co-located 2D lines, one conventional and one acquired with a variable depth streamer profile, for research on broadband imaging. The lines were acquired simultaneously with the same source and transition from deep to shallow water. Hence they have a variety or multiple issues ranging from simple deep water multiples to complex transition zones to short period shallow water multiples. The variable depth streamer has enhanced low and high frequency content due to the deeper portions of the cable and the notch diversity due to the variable depth profile. The pair allows a direct comparison of the broadband uplift for imaging and inversion.

Detchai Ittharat

Detchai Ittharat

3D asteroid acquisition and navigation design

A star coordinate is a multi-dimensional visualization technique used for many applications that acquire multi-dimensional data, such as in science, engineering, and business. A star coordinate technique represents the data with a point in the uniform domain along the axes. This technique is used to visualize and analyze the multidimensional data. In asteroid exploration and acquisition design, the data are multi-dimensional arrays and are not visible in the full dataset in the 3D-space representation. Conventional data storage includes the time of acquisition and x,y,z displacement field components. However, in the 3D asteroid acquisition design, the source and receiver locations, along with the orientation axis of an asteroid at the time of the exploration, are crucial information stored in the data. This information is used to locate the path of wave propagation. Thus, the data is acquired with at least 10 dimensional arrays. To visualize the multi-dimentional array of the data with full information is not feasiable with 3D visualization. Also, the goal of data visualization is to statiscally analyze and optimize the distribution of data on the uniform grid of the acquisition. The star coordinate technique sufficiently handles high-dimensional data and is easy to implement. Therefore, the star coordinate technique is useful for axis or dimensional analysis and is a desirable implementation in 3D acquisition design for asteroid exploration.

11/11

Elias Arias

Elias Arias

Implementing harmonic attributes

(Implementation of a paper authored by Turhan Taner and Sven Treitel)

 

The goal of geophysics is to produce data that tell us more about the subsurface lithology. Using Gabor-Morlet transforms and a special kind of neural network known as Self Organizing Maps (SOM), Taner and Treitel claimed to have been able to produce seismic lithology maps.

Through careful implementation of our own Gabor-Morlet transform and SOM, we aim to produce similar results as to those seen in the paper.

Chris Graziano

Chris Graziano

11/4

Nishant Kamath

Nishant Kamath

FWI for VTI media

Nishant and Oscar will discuss FWI for VTI media.

Nishant will briefly go over the formulation for velocity estimation and show some inversion results for transmission experiments.

Oscar will go over the theory for inversion of seismic moment tensor and source location (for a microseismic event).

 

Oscar Jarillo Michel

Oscar Jarillo Michel

10/28

Chinaemerem Kanu

Chinaemerem Kanu

Sensitivity kernel for time-lapse monitoring using multiply scattered waves: Numerical solution

Multiply scattered waves provide the potential for increased illumination or increased detectability of the weak perturbations presence within a medium. One of the proven use of the multiply scattered waves is in the detection of the weak time-lapse changes, such as velocity changes due geomechanical processes within the sub-surface or localized defects/cracks within mechanical structures. However, using multiply scattered waves to resolve localized weak changes within a medium requires the characterization of the distribution of the scattered waves within the medium. In this presentation, we explore the characteristics of sensitivity kernel that can be used to resolve weak changes within a scattering medium, the requirements for the kernel computation, and the behavior of the kernel with varieties of scattering models. Our sensitivity kernel is based on the intensity of the scattered waves.

Roel Snieder

Roel
Snieder

Properties of a wavefield in a focus

How does a wavefield behave in a focal point? This question is not just of academic interest, it is important for understanding imaging of microseismic events. I will show that the focal wavefield obtained by letting a wavefield converge on a point is different from the wavefield that is radiated from a source at that point in the sense that much of the pathology has disappeared.

10/21

Francesco Perrone

Francesco Perrone

Aspects of migration velocity analysis

Francesco will talk about some aspects related to migration velocity analysis, in particular the sensitivity to accuracy of the source signature and what happens if you have multiples in the image. FWI is very sensitive to the source signature; correlations between wavefields characterize both FWI and MVA, does this mean that MVA is also sensitive to the wavelet signature estimation? Multiples do not respect the migration model (single-scattering), how do they affect the gradient computed in MVA techniques?

Esteban Diaz

Esteban Díaz Pantin

Summer internship at BP

As the subject of my internship is restricted for the time being, I will talk about my experience at BP. Also, I will go through some of the work that BP has published over the last few years that I think is of interest to CWP. I will only use information from abstracts published at the SEG and EAGE conferences.

10/14

No seminar - CSM Fall Break

10/7

Ehsan Naeini

Ehsan Naeini

Seismic inversion

I will discuss various inversion algorithms used in industry for reservoir characterisation. I will also discuss the importance of rock physics and well data in this matter.

9/30

No seminar - oral summaries of SEG presentations attended by CWP students

9/23

No seminar - CWP attending 2013 SEG Annual Meeting in Houston, Texas

9/16

Tariq Alkhalifah

Tariq Alkhalifah

Unraveling waveform inversion with an eye on anisotropy

Fully simulating our seismic experiment with all its acquisition variables, medium properties and the physical behavior of waves to reproduce the observed seismic data is an objective we all seek to achieve. Notwithstanding the computational limitations we may encounter or the physical approximations we assume of the Earth behavior, inverting for the medium properties (i.e. seismic velocities) is our objective and the reason why we call this undertaking seismic inversion. In anisotropic media, the challenges are only enhanced. The multi parameter nature of the inversion forces us to be more aware and careful of the medium representation to avoid the unavoidable Null space. The choice of the parameterization really reduces the null space of the inversion only when we reduce the number of parameter we invert for. Finding a minimum set of parameters that can explain the data can lead to a better inversion.

9/9

Ali Knaak

Allison Knaak

Applications of synthetic aperture and steering to CSEM

Controlled-source electromagnetic (CSEM) surveys are being conducted in shallower water to find smaller reservoirs. This results in new difficulties in finding the targets. Some of the problems are shallow resistors (i.e. carbonates or gas hydrates) and poor lateral resolution. Synthetic aperture and steering are the techniques proposed to overcome these issues. I'll show some preliminary results from applying these techniques to synthetic CSEM data.

Farhad

Farhad Bazargani

Backus-Gilbert focusing in the time domain

The goal in focusing is to concentrate the wave energy at a specific time and location inside a medium. Various techniques have been devised to achieve this goal. Among them are time-reversal methods. The ability of time-reversal methods, such as reverse time migration, to focus wavefields inside heterogeneous media is bounded by limitations such as incomplete acquisition, limited bandwidth, and attenuation. To go beyond these limitations, I formulate wave focusing as an optimization problem in the time domain. Solving this optimization problem gives the needed signals for transmission to the medium to get an optimal focus at a desired target. I will demonstrate the new technique using numerical examples.

9/2

Pock

Detchai (Pock) Ittharat

Salt Inclusion Analysis using 3D seismic data, wells logs, synthetic seismogram, synthetic wells ties, and drilling reports in Gulf of Mexico prospects

Salt inclusions and sutures are well known events that cause drilling hazards when penetrating through the salt body in Gulf of Mexico prospects. Geophysical artifacts from 3D seismic imaging inside the salt body may lead to incorrect interpretation of salt inclusions and sutures location. Integrating the possible-inclusions-scanning method will increase confidence in drilling operations, realize cost savings and help in understanding the petroleum system of the prospects.

Yuting

Yuting Duan

Polarity correction and artifact removal in elastic migration

In elastic migration of OBS data using receiver-side water-layer multiples, artifacts due mainly to converted waves negatively affect the quality of images. These artifacts result from real and fake wave modes correlating with one another, and they must be removed during migration. Also, when imaging with PS and SP waves, there exists a polarity change at normal incidence so we cannot simply stack over shots. This issue also needs to be addressed during migration.

8/26

Dave Hale

Dave Hale

Seismic wavelets and warping

A seismic wavelet can be extracted from any transform that involves stretching or squeezing of seismograms. Examples include NMO correction (stretching) and PP-PS registration (squeezing), and these transforms are enhanced by the process used to extract the wavelet.

1st CWP seminar of the Fall 2013 semester (CWP administrative topics)

 

Previous CWP Seminars

2013

Spring

 

2012

Spring

Fall

 

 

Back to Top