Insight through modelling - NORSAR
Insight through modelling - NORSAR
Insight through modelling - NORSAR
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<strong>Insight</strong> <strong>through</strong> <strong>modelling</strong><br />
NEWSLETTER FROM <strong>NORSAR</strong> INNOVATION SUMMER 2009<br />
<strong>NORSAR</strong> Innovation<br />
builds on its success<br />
New representative in Brazil<br />
New office in Malaysia<br />
Valuable additions to sales<br />
team<br />
Integration of commercial<br />
services<br />
See page 2 for further details<br />
SeisRoX Integrated into Petrel<br />
<strong>NORSAR</strong> Innovation, the leading supplier of survey evaluation<br />
and design software is happy to announce that its innovative<br />
reservoir-to-seismic software, SeisRoX, is now integrated with<br />
Schlumberger’s Petrel package via the Ocean framework.<br />
See page 3 for comment on the impact of SeisRoX or visit our web site<br />
for further information.<br />
www.norsar.com<br />
Also in this issue:<br />
News - consolidation, innovation, expansion<br />
Advanced SED - assessing the value of COIL<br />
Editorial Comment - the value of the Petrel plug-in<br />
What’s New - an update on the current software<br />
Training and Development - new facilities, new courses<br />
News, publications, sponsorships
Time-Lapse<br />
Modelling<br />
Mapping the changes in the<br />
fluid and pressure distributions<br />
of a reservoir during production<br />
is a major objective in 4D<br />
seismic data analysis. Seismic<br />
<strong>modelling</strong> can be used as a<br />
guide for interpreting seismic<br />
changes during production.<br />
However, in most 4D projects<br />
a simple 1D seismic <strong>modelling</strong><br />
approach is used, disregarding<br />
the illumination and sampling<br />
characteristics imposed on<br />
the reservoir response as the<br />
seismic waves are transmitted<br />
by a pattern of sources,<br />
modified by the overburden<br />
structures, reflected in the<br />
reservoir and recorded by<br />
another pattern of receivers.<br />
SeisRoX now provides the<br />
potential to integrate the<br />
survey data, overburden<br />
properties, rock properties and<br />
fluid simulator data into the<br />
4D <strong>modelling</strong> scheme in a time<br />
efficient manner <strong>through</strong> the<br />
use of the ray based 3D PSDM<br />
simulator.<br />
Furthermore, SeisRoX is<br />
integrated with Petrel* to<br />
improve data transfer and<br />
close the Seismic to Simulation<br />
workflow.<br />
*Petrel is a mark of Schlumberger<br />
What’s New?<br />
Expansion of activities in<br />
Brazilian Market<br />
We are happy to welcome Carlos Eiffel<br />
Arbex Belem, principle of Ies Brazil<br />
Consultoria, as our Brazilian and South<br />
American representative. Ies Brazil<br />
will be assisted by Patricia Lugao<br />
of Stratalmage in the provision of<br />
technical support and consulting.<br />
New office in Kuala Lumpur,<br />
Malaysia<br />
The office, headed by Dr Mike<br />
Branston, will provide software<br />
sales and service project support to<br />
<strong>NORSAR</strong> Innovation’s clients in the<br />
Asian Pacific Region.<br />
“We are seeing a rapid broadening<br />
of our client base across the world.<br />
With the addition of this office to<br />
our existing representation in Oslo,<br />
Bergen, Houston, Beijing and Rio we<br />
feel we are well positioned to give our<br />
clients the service they have come to<br />
expect from <strong>NORSAR</strong> Innovation.”<br />
New Training Facilities<br />
A new training facility was opened<br />
at our head office in Oslo in the<br />
Autumn of 2008. The opening of this<br />
state of the art facility reaffirms our<br />
commitment to providing our clients<br />
with quality training. See the back<br />
page for details of upcoming courses.<br />
Software Releases<br />
Maintaining our commitment to<br />
provide world class maintenance<br />
and support, we continue to release<br />
regular software updates. We value<br />
our clients feedback and endeavour to<br />
incorporate many of their ideas in this<br />
process. If you would like to contribute,<br />
please contact us. See page 6 for<br />
a review of what has been recently<br />
added to the software.<br />
<strong>NORSAR</strong> Innovation reports<br />
record results for 2008<br />
The board of directors announced in<br />
their annual report for 2008 that the<br />
gross revenue for 2008 increased<br />
by 71% when compared to the same<br />
period in 2007.<br />
<strong>NORSAR</strong> Innovation continues<br />
to grow<br />
As a result of continuing demand for<br />
our software we have added to our<br />
sales team.<br />
Hugo Moen joins us as Sales Manager<br />
for Europe, Africa, Asia and Australia.<br />
(hugo.moen@norsar.com)<br />
Chris Watts joins us as Sales Manager<br />
for North and South America. (chris.<br />
watts@norsar.com)<br />
Integration of Commercial<br />
Services<br />
The commercial services department<br />
has now been fully integrated into<br />
<strong>NORSAR</strong> Innovation. The team looks<br />
forward to working with you to provide<br />
innovative solutions. See opposite<br />
Inversion, the next step for<br />
NSM<br />
Integrating inversion into the SeisRoX<br />
workflow. Watch this space!<br />
Continued sponsorship of some<br />
of the most exciting research<br />
programs around<br />
We pride ourselves on our<br />
commitment to R&D. One aspect of<br />
this is the sponsorship of research<br />
initiatives such as the Edinburgh Time<br />
Lapse Program, the CO2Sink program<br />
at Uppsalla University and the Wave<br />
Inversion Technology Consortium.<br />
More details on page 4
<strong>NORSAR</strong> Innovation releases<br />
advanced seismic simulation<br />
capability for Petrel<br />
The release of our SeisRoX plug-in<br />
gives Petrel* users new functionality and<br />
a level of integration and accuracy not<br />
previously available.<br />
Why include SeisRoX<br />
The key components within SeisRoX are<br />
a) comprehensive rock physics <strong>modelling</strong>,<br />
b) the inclusion of 3D illumination effects<br />
caused by the overburden and survey<br />
geometry, c) rapid simulation of 3D<br />
prestack depth migrated<br />
(PSDM) seismic cubes<br />
using an extremely accurate<br />
PSDM simulator (SimPLI),<br />
which incorporates the<br />
effects of illumination as<br />
well as lateral and vertical<br />
resolution.<br />
The SeisRoX plug-in to Petrel makes<br />
it possible to make a SeisRoX model<br />
directly from a Petrel simulation model,<br />
or a Petrel geo model, and write seismic<br />
data from the SeisRoX <strong>modelling</strong> back to<br />
Petrel.<br />
Illumination and Resolution Effects<br />
The Petrel user can now dramatically<br />
improve their synthetic seismic<br />
simulation by including the illumination<br />
and resolution effects of the overburden<br />
and survey geometry. The process takes<br />
a matter of moments and can be run<br />
from a standard PC or laptop.<br />
*Petrel is a mark of Schlumberger<br />
SeisRoX therefore provides an efficient,<br />
accurate and flexible simulation-toseismic<br />
workflow, truly bridging the gap<br />
between the reservoir and seismic.<br />
4D Analysis with <strong>NORSAR</strong> Seismic<br />
Modelling<br />
One of the many applications is an<br />
improvement in the history matching<br />
process during 4D analyses; by including<br />
the 3D illumination and resolution<br />
effects in the<br />
“The Petrel user<br />
can now dramatically<br />
improve their synthetic<br />
seismic simulation...”<br />
Including Rock Physics<br />
seismic simulation<br />
process you can<br />
ultimately improve<br />
the accuracy of your<br />
reservoir model.<br />
Further to this, the plug in can be used<br />
for the quantifiable evaluation of future<br />
seismic survey designs. Rock physics<br />
analysis can now be included in the<br />
evaluation of multiple acquisition designs<br />
and reservoir scenarios to ensure that<br />
you make the right acquisition decisions<br />
and maximize your ROI.<br />
Commercial<br />
Services<br />
Take a look at your turn<br />
around time. We offer<br />
flexible solutions from a<br />
turn-key illumination project<br />
to the building of models<br />
enabling you to conduct the<br />
geophysical analysis.<br />
Our team of experienced<br />
geophysicists provide a full<br />
range of services using<br />
<strong>NORSAR</strong>-3D, <strong>NORSAR</strong>-2D<br />
and SeisRoX.<br />
<strong>NORSAR</strong> Modelling Services<br />
include a number of tasks,<br />
such as:<br />
• 3D survey planning<br />
• 3D seismic illumination<br />
studies and attribute<br />
mapping<br />
• Simulation of synthetic<br />
seismograms including user<br />
specified multiples and peg<br />
legs<br />
• Building of 1D - 3D rock<br />
models in the reservoir zone<br />
• Pore fluid substitution<br />
using rock models<br />
• Estimating seismic<br />
parameters from rock/fluid<br />
models, including sensitivity<br />
analyses<br />
• Modelling seismic<br />
response for different<br />
reservoir scenarios including<br />
time-lapse feasibility studies<br />
• Target oriented model<br />
based imaging in the<br />
reservoir zone (PSDM)<br />
For more information<br />
services@norsar.com
An Eye on Research<br />
The Wave Inversion Technology<br />
Consortium (WIT) was<br />
established in 1997 with the<br />
goal of developing the most<br />
accurate and efficient target<br />
orientated <strong>modelling</strong> and<br />
imaging via seismic and acoustic<br />
methods. Today it consists of<br />
research teams from Germany,<br />
Brazil, Russia and Norway.<br />
<strong>NORSAR</strong> joined WIT as an<br />
research affiliate in 2007. In<br />
addition to actively participating<br />
in the research topics,<br />
<strong>NORSAR</strong> has donated up to 5<br />
full licenses of the <strong>NORSAR</strong><br />
Seismic Modelling Suite to<br />
the participants in the WIT<br />
Consortium (estimated value<br />
EURO 1,000,000) for use on<br />
research topics in the field of<br />
seismic exploration.<br />
Dr. Tina Kaschwich is <strong>NORSAR</strong>’s<br />
representative within the WIT<br />
consortium.<br />
“The consortium and <strong>NORSAR</strong><br />
have highly complementary<br />
research topics in the field<br />
of seismic exploration. Both<br />
organizations agree to build<br />
an exchange of scientific ideas<br />
and research results applicable<br />
to seismic exploration and<br />
production. This includes the<br />
exchange of scientists as well<br />
as MSc and PhD students, and<br />
the joint supervision of theses.<br />
This collaboration provides an<br />
excellent opportunity to get new<br />
insights and innovative solutions<br />
for the further development of<br />
seismic <strong>modelling</strong> software.”<br />
The University of Hamburg and<br />
<strong>NORSAR</strong> (WIT) have submitted<br />
an abstract to the EAGE subsalt<br />
imaging workshop in Cairo 15th<br />
- 18th November 2009.<br />
Advanced Survey<br />
Evaluation and Design;<br />
the benefit of COIL<br />
Arguably the biggest impact on the<br />
seismic industry in the last decade<br />
has been the advent of innovative<br />
survey acquisition designs to overcome<br />
complex imaging problems.<br />
Integral to the success of these<br />
surveys and the uptake by the industry,<br />
is the advanced survey evaluation<br />
and design (SED) studies that are<br />
conducted initially as proof of concept<br />
but ultimately to address the specific<br />
imaging challenges of an individual<br />
prospect.<br />
To illustrate a typical SED workflow<br />
we have used the <strong>NORSAR</strong> Seismic<br />
Modelling (NSM) software suite to<br />
compare the main marine acquisition<br />
designs available for a marine sub-salt<br />
reservoir. In this example a synthetic<br />
reservoir model was added to the well<br />
known SEG/EAGE salt model.<br />
The primary objectives of this study<br />
were a) to characterize the impact<br />
that the marine survey strategies<br />
have on the illumination of the target<br />
horizon, b) to assess and quantify the<br />
related improvement in seismic data<br />
quality and c) establish the relative ROI<br />
for each design.<br />
Key to the success of this study were<br />
the wavefront construction method<br />
used to trace the rays (the engine<br />
behind all NSM software), the ability to<br />
simulate accurate migration amplitudes<br />
along the target horizon (the SMA<br />
module within <strong>NORSAR</strong>-3D) and the<br />
rapid simulation of 3D PSDM data<br />
cubes at key points within the reservoir<br />
(SeisRoX - a new addition to NSM<br />
software suite).<br />
Illumination from WAZ survey. 4.9<br />
times the cost of NAZ<br />
Illumination from RAZ survey. 9.4<br />
times the cost of NAZ.<br />
Illumination from COIL survey. 3.7<br />
times the cost of NAZ.<br />
Illumination analysis shows the<br />
increased coverage gained by adopting<br />
the COIL approach. Cost analysis<br />
shows the improved ROI in comparison<br />
with the vessel intensive RAZ survey.<br />
The results from this study will be<br />
presented on our booth at all major<br />
exhibitions. Details on page 12.
The survey acquisition strategies<br />
modelled included conventional<br />
narrow azimuth (NAZ), wide azimuth<br />
(WAZ), rich azimuth (RAZ), shooting<br />
in circles (COIL) and ocean bottom<br />
node survey (OBN). Selected results<br />
can be seen opposite.<br />
Unique functionality within NSM<br />
allows the accurate estimation of<br />
migration amplitudes across the<br />
target horizon to aid the decision<br />
process. In addition, we can analyze<br />
the number of reflection points,<br />
reflection angles, aperture size<br />
(CMP-CRP) and recording time when<br />
assessing the relative virtues of the<br />
various survey strategies.<br />
Following the illumination analysis,<br />
the study was extended to include<br />
the resolution of the seismic data<br />
at key points within the reservoir.<br />
This analysis was conducted using<br />
SeisRoX. This new addition to the<br />
NSM software suite efficiently<br />
estimates PSDM seismic amplitudes<br />
without the need to predict and<br />
process synthetic seismic gathers.<br />
The COIL survey shows a dramatic<br />
improvement in the migration<br />
amplitudes across the target<br />
horizon. Looking at the PSDM data<br />
at key points of poor coverage<br />
beneath the salt it can be seen that<br />
the improved azimuthal coverage<br />
afforded by the COIL approach<br />
results in better imaging of the<br />
faults.<br />
As part of the SED, a cost analysis<br />
was performed for each survey,<br />
taking into account the number of<br />
shots in the survey, the number of<br />
vessels, expected infill, line change<br />
duration and technical downtime.<br />
However, we have not considered<br />
mob/de-mob time or any price<br />
uplift associated with proprietary<br />
technology. As can be seen the<br />
COIL technique has significant cost<br />
and imaging benefits over the other<br />
strategies for the given model.<br />
Summary<br />
The survey evaluation and design<br />
(SED) workflow presented takes<br />
advantage of the efficiency and<br />
accuracy of the ray tracing<br />
approach. Advance functionality<br />
within the <strong>NORSAR</strong> Seismic<br />
Modelling software has enabled the<br />
generation of results that provide<br />
diagnostic information needed to<br />
assess the merits of the key marine<br />
survey strategies. Information<br />
such as optimal survey orientation,<br />
amplitude distribution, number of<br />
reflection points and listening time.<br />
In addition, the use of the advanced<br />
PSDM simulator, has extend the<br />
analysis <strong>through</strong> the simulation of<br />
PSDM data at key depth points in a<br />
usable timeframe.<br />
Saudi Aramco and <strong>NORSAR</strong> will be copresenting<br />
a paper detailing a similar<br />
case study from the Red Sea at the<br />
upcoming Subsalt Imaging workshop<br />
in Cairo 15th - 18th November 2009.<br />
Anti-clockwise starting<br />
from top left: a)<br />
Illumination map for<br />
NAZ survey with salt<br />
overlain in grey. Key<br />
points on interest on<br />
the target are labelled.<br />
Equivalent for Coil<br />
survey is shown as<br />
insert. b) Synthetic<br />
reservoir model with<br />
key locations shown.<br />
c) Synthetic PSDM<br />
data generated for<br />
COIL with illumination<br />
vector plots, showing<br />
the azimuth and dips<br />
that can be illuminated<br />
with this survey. d)<br />
the equivalent for the<br />
NAZ survey. Note the<br />
improvement in the<br />
resolution of the faults<br />
in the PSDM data<br />
from the COIL survey.<br />
We can extend our analysis by generating synthetic 3D PSDM data for key points below the salt. Using SeisRoX<br />
we can incorporate the resolution and illumination effects from the overburden and survey and rapidly generate<br />
an accurate 3D PSDM data cube from the reservoir geo/simulation model. Further to this, we can analyze the<br />
illumination vectors to determine which dips and azimuths can be illuminated for this survey/overburden combination.
What is new in <strong>NORSAR</strong><br />
Seismic Modelling?<br />
Free 30 day<br />
software trial<br />
We offer a temporary licence<br />
to enable you to evaluate the<br />
software at your convenience.<br />
Discover the full range of<br />
functionality and ease of<br />
integration by using the test<br />
data and tutorial supplied.<br />
In addition you can run your<br />
current projects <strong>through</strong> the<br />
software with full access<br />
to the <strong>NORSAR</strong> software<br />
support team. This is an ideal<br />
way to assess the potential<br />
improvements that could be<br />
made to your next project.<br />
If you would prefer, we are<br />
happy to give a demonstration<br />
of the software at your<br />
offices.<br />
A review of this year’s major releases<br />
Version 5.3 introduces a new<br />
simplified and user-friendly way of<br />
defining the <strong>modelling</strong> project, new<br />
functionality in the Model Builder and<br />
improved ray code definition in the<br />
Wavefront Tracer. In addition the<br />
Illumination Map module has been<br />
upgraded with improved user interface,<br />
new functionality like attenuation maps<br />
and setup for easier parallelization.<br />
Project definition<br />
• Completely new module<br />
• Easy and user friendly setup<br />
• Preview of grids used as templates<br />
Model Builder<br />
• Load grid directly into the Model<br />
Builder<br />
• New function to remove zerothickness<br />
layers<br />
• Improved block cross-section plots<br />
Wavefront Common Shot Tracer<br />
• Improved user interface for General<br />
Ray Code setup and selection<br />
• Improved default values and warnings<br />
Illumination Map<br />
• Simplified and improved setup<br />
• Improved handling of converted<br />
waves<br />
• Option to include attenuation effects<br />
in the maps<br />
• Option to calculate constant<br />
impedance SMA maps<br />
• Event selection (all, first arrival, most<br />
energetic, shortest ray path)<br />
• Improved recover possibilities<br />
• Automatic splitting of IMG’s into subimgs<br />
to be run in parallel<br />
Illumination Map Utility<br />
• Improved handling of trimesh IMGs<br />
• Option to import external data, for<br />
example noise grids and add to an<br />
IMAP<br />
• Operations between maps on<br />
different IMGs
Version 2.0 sees SeisRoX mature into<br />
a highly advanced seismic <strong>modelling</strong><br />
package. Further integration with<br />
<strong>NORSAR</strong>-3D as part of the <strong>NORSAR</strong><br />
Seismic Modelling software suite provides<br />
additional <strong>modelling</strong> possibilities.<br />
SeisRoX cube models<br />
Extension of the SeisRoX reservoir model<br />
to include cubes as a model element. A<br />
SeisRoX model can consist of a set of<br />
cubes, a set of horizons or both cubes<br />
and horizons, all with property values<br />
attached to each node. This makes it<br />
easy to import and use external cubes<br />
in the SeisRoX <strong>modelling</strong>.<br />
Petrel plug-in<br />
A new plug-in for Petrel makes it possible<br />
to make a SeisRoX model directly from<br />
a Petrel simulation model or a Petrel<br />
geo model and write seismic data from<br />
the SeisRoX <strong>modelling</strong> back to Petrel for<br />
viewing and comparison.<br />
Cube Import<br />
New import function to import property<br />
cubes on SEG-Y format.<br />
Time/Depth functions<br />
Definition of time/depth functions<br />
is extended with an option to use a<br />
P-velocity cube as basis for the function.<br />
Fully integrated time domain<br />
All data elements and SeisRoX models<br />
can be defined and edited both in time<br />
and depth using a time/depth function<br />
transformation.<br />
Fully integrated time domain 3D viewer<br />
All elements can be plotted simultaneously<br />
in both the time viewer and depth viewer.<br />
Well handling<br />
More flexible import of well data and<br />
prediction of new logs based on depth<br />
trends.<br />
Handling of general surveys<br />
All <strong>NORSAR</strong>-3D surveys can now be<br />
sub-selected, plotted and used in the<br />
SeisRoX <strong>modelling</strong>. Sub-selection filtering<br />
based on X-offset and Y-offset is added.<br />
Illumination Vector improvements.<br />
Tighter integration between <strong>NORSAR</strong>-<br />
3D and SeisRoX makes it easier and<br />
more flexible to take into account survey<br />
sub-selection and PSDM filters when<br />
generating the Illumination Vectors. In<br />
addition a new plot option to compare<br />
Illumination Vectors is added.<br />
New SimPLI <strong>modelling</strong> options<br />
New options and improvements in<br />
the SimPLI <strong>modelling</strong> are introduced<br />
to simulate various amplitude effects,<br />
including geometrical spreading and<br />
transmission. In addition when selecting<br />
a pulse, a new option allows to simulate<br />
deconvolution by replacing the spectrum<br />
of the pulse by a white-spectrum.<br />
This release builds on the success of<br />
previous releases. Highlights of which<br />
include;<br />
Wells<br />
LAS format reader included. Prediction<br />
of Vp, Vs and Rho using logged geological<br />
properties and ROCKs.<br />
Rocks<br />
• Pressure correction using exponential<br />
velocity function.<br />
• The solids definition can be edited.<br />
• Import and use of external tabulated<br />
rocks.<br />
Survey<br />
• Sub select a survey based on survey<br />
configuration with filters on parameters<br />
such as indices (shot line, streamer,<br />
etc.), positions, offset, azimuth, etc.<br />
SeisRoX workflow<br />
• Handling of converted-wave ray code<br />
(PS) for homogeneous and layered<br />
background models.<br />
• Improved speed of the illumination<br />
vector generator<br />
• Cross-section plots of cubes<br />
NSM featured<br />
in Nucleus+<br />
PGS has extended the<br />
capabilities and scope of<br />
the Nucleus <strong>modelling</strong><br />
package to a new platform,<br />
known as Nucleus+, whilst<br />
maintaining the link with<br />
<strong>NORSAR</strong> Seismic Modelling<br />
(NSM).<br />
A project-based and project<br />
sharing capability is now<br />
offered, enabling greater<br />
flexibility and easier user<br />
access to libraries of<br />
results and files. A new<br />
tree structure during<br />
parameterization provides<br />
greater interactivity and<br />
the capability to execute<br />
several jobs in a workflow<br />
or batch manner. A “job<br />
builder” enables easier<br />
modification and revision<br />
later during projects.<br />
PGS distributes <strong>NORSAR</strong>-<br />
2D and <strong>NORSAR</strong>-3D as<br />
an integrated part of its<br />
NUCLEUS package<br />
The key values added to<br />
<strong>NORSAR</strong>-3D <strong>through</strong> the<br />
integration with NUCLEUS<br />
are:<br />
• Seismogram generation<br />
with full source-receiver<br />
directivity <strong>through</strong><br />
integration with the<br />
industry standard<br />
marine source <strong>modelling</strong><br />
software.<br />
• Simple, realistic and<br />
flexible acquisition<br />
geometry definition with<br />
the NUCLEUS survey/<br />
vessel concept.
Publications<br />
Resolution and Illumination<br />
analyses in PSDM: A raybased<br />
approach.<br />
Isabelle Lecomte. The Leading<br />
Edge, 2008, pp 650-663.<br />
Closer to real earth in<br />
reservoir characterization:<br />
a 3D isotropic/anisotropic<br />
PSDM simulator.<br />
Isabelle Lecomte and Tina<br />
Kaschwich. Expanded Abstracts,<br />
2008, SEG 78th Annual<br />
Meeting, Las Vegas.<br />
Using a 3D PSDM simulator<br />
to facilitate overburden and<br />
survey consistent <strong>modelling</strong><br />
of the 4D seismic response<br />
in the Norne field offshore<br />
Norway.<br />
Åsmund Drottning and Mike<br />
Branston. Expanded abstracts<br />
PETEX 2008, London.<br />
Image-ray tracing for joint 3D<br />
seismic velocity estimation<br />
and time-to-depth conversion<br />
Einar Iversen and Martin Tygel.<br />
Geophysics, 2008, vol,73. No3<br />
Ray tracing and<br />
inhomogeneous dynamic<br />
ray tracing for anisotropy<br />
specified in curvilinear<br />
coordinates<br />
Einar Iversen and Ivan Psencık,<br />
Geophys. J. Int. 2008, 174,<br />
316-330.<br />
This years key publications<br />
Closer to real earth in reservoir<br />
characterization: a 3D isotropic/<br />
anisotropic PSDM simulator.<br />
Isabelle Lecomte and Tina Kaschwich.<br />
Expanded Abstracts, 2008, SEG 78th<br />
Annual Meeting, Las Vegas<br />
1D convolution has proved to be a<br />
very valuable simulation tool in seismic<br />
exploration for decades. It is easy to<br />
understand and to program (cheap!),<br />
and in-house codes using this principle<br />
are numerous because the method<br />
is fast too. However, the underlying<br />
assumptions are very strong, i.e., a<br />
flat layered earth model. While 1D<br />
convolution uses a 1D time wavelet,<br />
the PSDM simulator is based on 3D<br />
spatial wavelets (PSF) depending on<br />
surveys, 3D models and wave type.<br />
The additional cost is negligible<br />
because the process is FFT-based and<br />
the alternative (<strong>modelling</strong> + processing)<br />
is far too expensive. In addition, the<br />
PSDM simulator can be extended to<br />
more complex background models,<br />
taking into account anisotropy and<br />
soon wave conversion. Various PSDM<br />
effects can also be easily added, as will<br />
be demonstrated, to better reproduce<br />
actual PSDM data. Applications to<br />
seismic inversion are on-going.<br />
“This goes far beyond the<br />
standard 1D poststack timeconvolution<br />
seismic simulators<br />
used in industry, adding proper<br />
3D illumination and resolution<br />
effects, including angledependency<br />
of both reflectivity<br />
and PSF.”<br />
Norne reservoir model courtesy of<br />
StatoilHydro. a) Location of two local<br />
PSDM targets in the reservoir model<br />
(water saturation is used for the color<br />
mapping). The 3D target will be used<br />
here. b) Location and geometry of<br />
the modeled surveys. 2D line (grey<br />
markers): the red square is the first shot<br />
and the blue line shows the streamer.<br />
3D survey (magenta markers): the<br />
magenta square is the first shot and<br />
the green lines show the streamers.<br />
Illumination plots showing both dips and<br />
azimuths of the potentially illuminated<br />
reflectors at the center of the target<br />
for a homogeneous background and<br />
with c) the 2D mono-streamer line,<br />
d) a 2D multi-streamer line (same<br />
multi-streamer configuration as for the<br />
3D survey), and e) the 3D grid with<br />
multistreamer acquisition.
Resolution and Illumination analyses in PSDM: A raybased<br />
approach.<br />
Isabelle Lecomte. The Leading Edge, 2008, pp 650-<br />
663.<br />
Ray-based approaches allow an efficient and flexible<br />
calculation of illumination vectors (difference of two local<br />
slowness vectors) at any image point in an imaging<br />
target, as a function of the survey, background velocity<br />
model, pulse, and wave phases. This can be done in<br />
isotropic and anisotropic media in complex background<br />
models, and wave conversion can be included. The<br />
illumination vector alone gives fundamental information<br />
in terms of dip and azimuth of potentially illuminated<br />
reflectors (the actual reflectors are not known). Each<br />
illumination vector corresponds to one potentially<br />
illuminated reflector: the one perpendicular to the<br />
illumination vector (Snell’s law). However, it is possible to<br />
go much further by introducing a frequency dependency<br />
to form the scattering wavenumber vectors. A mapping<br />
of the latter in the wavenumber domain will give the<br />
point-scatterer function (PSF), hence resolution of<br />
the PSDM system, after taking a Fourier transform<br />
“The workflow presented here has<br />
shown that more realistic 4D signals are<br />
obtained from the PSDM simulator compared<br />
to the 1D approximation”.<br />
to get back to the depth domain. This approach is<br />
data-independent, i.e., the illumination and resolution<br />
capabilities of a given combination of survey, model,<br />
pulse, and wave types can be calculated prior to any<br />
PSDM migration of actual data. Considering reflectors<br />
as sets of point scatterers acting as secondary sources<br />
in reflection seismic (Huygens’ principle), and knowing<br />
<strong>through</strong> the PSF (space-domain) or their corresponding<br />
scattering-wavenumber filters (wavenumber domain)<br />
how a point scatterer is imaged in PSDM, an efficient<br />
PSDM simulator has been developed. It works as a 3D<br />
prestack space-convolution method applying calculated<br />
3D PSFs to 3D reflectivity cubes (FFT-based imageprocessing<br />
approach). This goes far beyond the standard<br />
1D poststack time-convolution seismic simulators used<br />
in industry, adding proper 3D illumination and resolution<br />
effects, including angle-dependency of both reflectivity<br />
and PSF. Though key approximations are done here,<br />
such as the local plane-wavefront approximation in the<br />
calculation of the PSFs, and the use of the same PSFs<br />
for a size-limited reflectivity cube (target-oriented local<br />
imaging), extensions are possible. The first consists<br />
of considering curvature parameters calculated by ray<br />
tracing to extend the plane-wave approximation to higherorder<br />
approximations. The second consists of a spacedependent<br />
convolution where the PSFs are precalculated<br />
at the nodes of a cube and interpolated to get a better<br />
PSF estimate for each image point. However, the<br />
space-variant convolution is more time-consuming and<br />
an alternative is to use the actual local process in an<br />
iterative mode for several local adjacent targets, merging<br />
all resulting PSDM cubes at the end. Such a process<br />
is easy to parallelize on a multinode machine or on a<br />
cluster of computers. The actual version of the PSDM<br />
simulator is working in a “true-amplitude” mode, i.e., all<br />
scattering wavenumber vectors are attached with the<br />
same weight when mapping in the wavenumber domain.<br />
However, it is easy to consider other parameters<br />
calculated by ray tracing, such as traveltime, amplitude,<br />
attenuation, polarization, etc., to modify these weights<br />
and thus introduce various effects on the simulated<br />
PSDM results. These could be amplitude effects<br />
(especially to study some ad hoc corrections functions<br />
of traveltime), directivity pattern for both source and<br />
receiver, attenuation in the background model, and<br />
decomposition of the wavefield for multicomponent<br />
receivers (polarization needed).<br />
Using a 3D PSDM simulator to facilitate overburden<br />
and survey consistent <strong>modelling</strong> of the 4D seismic<br />
response in the Norne field offshore Norway.<br />
Åsmund Drottning and Mike Branston. Expanded abstracts<br />
PETEX 2008, London.<br />
An overburden and survey consistent PSDM simulator is<br />
proven to be a valuable tool for calculating the synthetic<br />
seismic response from complex reservoir geometries.<br />
Using real data taken from the Norne field we have shown<br />
that the SimPLI approach, where PSDM seismic amplitudes<br />
that include 2D / 3D illumination and resolution effects<br />
are used, is superior to a 1D approach where illumination<br />
and resolution constraints are ignored. What is more, the<br />
methodology behind SimPLI and the implementation of the<br />
technology means that the rapid evaluation of different<br />
survey configurations can be easily achieved. The workflow<br />
presented here has shown that more realistic 4D signals<br />
are obtained from the PSDM simulator compared to the<br />
1D approximation. This is so even in the Norne case with<br />
its geologically simple overburden. It is right to assume<br />
that as the overburden increases in complexity, the<br />
value of a survey and overburden consistent <strong>modelling</strong><br />
technique also increases. As the SimPLI method includes<br />
the resolution and illumination of the overburden it can<br />
provide more accurate seismic simulations thus leading<br />
to the generation of a better history match within the<br />
reservoir model.
Helping the next<br />
generation of<br />
geophysicists<br />
In 2008 <strong>NORSAR</strong> Innovation<br />
increased its cooperation with<br />
academic institutions in Norway<br />
by donating software licenses<br />
and courses worth about Euro 4<br />
Mil. to universities in Norway.<br />
“It is important for a Norwegian<br />
research institute to have a<br />
close and fruitful cooperation<br />
with academia, as we are in<br />
between academia and the<br />
industry” - Principal Researcher.<br />
“The oil industry, a main<br />
employer of new students in<br />
geophysics, will benefit from this<br />
in the end. It is surprising to see<br />
that while we are strengthening<br />
our support of education and<br />
research, major oil companies<br />
operating in Norway have cut<br />
back on their financial support<br />
of research in the Norwegian<br />
institute sector” - Anders Dahle<br />
Next Generation Oil and Gas<br />
magazine ask <strong>NORSAR</strong> about the<br />
future of Seismic Modelling<br />
“The ambition behind this project was<br />
to use our seismic <strong>modelling</strong> expertise to<br />
improve on the standard 1D convolution<br />
technique”.<br />
Q. How are companies using 3D<br />
seismic data to improve reservoir<br />
<strong>modelling</strong> techniques?<br />
AD. In recent years, increased<br />
emphasis has been placed on the<br />
use of sophisticated 3D Earth models<br />
in the decision process of the E&P<br />
cycle. However, the generation of<br />
such models relies heavily on well<br />
data which will always be limited by<br />
its inherent lack of spatial coverage.<br />
Therefore, the integration of 3D<br />
seismic data into the model to obtain<br />
a more accurate representation of the<br />
reservoir properties between the wells<br />
will remain a key challenge.<br />
The development and application of<br />
geostatistical methods in this area has<br />
improved the interpolation of reservoir<br />
properties between the wells but the<br />
need to QC the model <strong>through</strong> the<br />
simulation of synthetic seismic will<br />
remain a key aspect of the quality<br />
assurance process. It is therefore<br />
vital that the simulation of synthetic<br />
seismic from the reservoir model is as<br />
realistic as possible as in the majority<br />
of scenarios this simulated seismic<br />
data is compared directly with the<br />
acquired surface seismic. Improving<br />
the accuracy of the seismic simulation<br />
therefore has direct results on<br />
improving the validity of your model.<br />
Q. 3D seismic data gathering and<br />
<strong>modelling</strong> can be expensive. How<br />
can intelligent analysis make sure<br />
that you get the most out of this<br />
resource?<br />
AD. The current cost of seismic<br />
acquisition certainly justifies the<br />
expense of routinely using seismic<br />
<strong>modelling</strong> to ensure the quality of the<br />
end product. Using seismic <strong>modelling</strong><br />
to assess how the source and receiver<br />
configuration, azimuth contribution and<br />
known overburden is going to affect<br />
the overall quality of the seismic image,<br />
can help optimize the survey and<br />
avoid poor illumination issues and the<br />
additional expenses of re-shooting with<br />
revised survey parameters or indeed<br />
making poor decisions on incomplete<br />
data.
Really it is a way of accurately<br />
determining the value of the seismic<br />
survey before it is shot and is an<br />
effective way of reducing risk.<br />
Q. What are the on-going challenges<br />
for creating 3D <strong>modelling</strong>? How can<br />
technology solve these problems?<br />
AD. The development and integration of<br />
rock physics has gone a long way towards<br />
representing data in the formats required<br />
to move from the geological domain<br />
<strong>through</strong> the elastic domain and into<br />
the reflectivity domain. However,<br />
to date, the seismic simulators<br />
used at the end of this process<br />
are limiting the effectiveness of the<br />
3D Earth models in the E&P cycle<br />
because they are based around 1D<br />
convolution methods which do not<br />
take into consideration the effects<br />
of illumination and resolution caused<br />
by the survey and overburden.<br />
At <strong>NORSAR</strong> we believe that the inclusion<br />
of 3D illumination and resolution effects<br />
in synthetic seismic is vital for the<br />
accurate understanding of the reservoir.<br />
To achieve this we have developed a<br />
seismic simulator which is able to rapidly<br />
simulate local prestack depth migrated<br />
data that incorporates the 3D effect<br />
of overburden illumination as well as<br />
lateral and vertical resolution. This new<br />
technology is called SimPLI (simulated<br />
prestack local imaging) and has been<br />
built into a new software program,<br />
SeisRoX, which integrates this with<br />
comprehensive rock physics <strong>modelling</strong>.<br />
Q. How are your products and services<br />
assisting clients to create accurate<br />
and reliable models?<br />
AD. <strong>NORSAR</strong> is renowned for its Ray<br />
Tracing software. This has been primarily<br />
used for seismic <strong>modelling</strong> such as<br />
survey design, calculation of travel<br />
times and the generation of synthetic<br />
seismograms. However, with the launch<br />
of our new seismic simulator we are in<br />
an ideal place to bridge the gap between<br />
seismic and the reservoir. The ambition<br />
behind this project was to use our<br />
seismic <strong>modelling</strong> expertise to improve on<br />
the standard 1D convolution technique.<br />
While 1D convolution ignores survey and<br />
overburden effects and hence assumes<br />
perfect illumination at the reservoir level,<br />
<strong>NORSAR</strong> software takes into account<br />
the overburden and survey effects which<br />
affect the seismic energy while it travels<br />
to and from the reservoir. As a result,<br />
we can accurately reproduce the lateral<br />
and vertical resolution effects seen in<br />
the acquired seismic. What is more, it<br />
“...we believe that the<br />
inclusion of 3D illumination<br />
and resolution effects in<br />
synthetic seismic is vital for<br />
the accurate understanding of<br />
the reservoir.”.<br />
is truly 3D giving a much better match<br />
to the real seismic data.<br />
Our technology provides a rapid,<br />
integrated <strong>modelling</strong> solution which<br />
allows the reservoir modeller to better<br />
simulate synthetic seismic from their<br />
model and thus improve the accuracy<br />
and reliability of that model. Not only<br />
does this impact decisions on the validity<br />
of the model but <strong>through</strong> the integration<br />
of the survey and overburden, the<br />
modeler can determine the value of<br />
future seismic surveys.<br />
About Anders Dahle<br />
Anders Dahle has been involved<br />
with <strong>NORSAR</strong> since he joined as a<br />
research assistant in 1972 as part<br />
of his MSc thesis. In 1975 he left to<br />
work for AS Geoteam but returned<br />
in 1985 and has been at <strong>NORSAR</strong><br />
ever since. Appointed as Managing<br />
Director of the research institute in<br />
1999, Anders has over 37 years of<br />
experience in the seismic industry.<br />
A New Director<br />
On the 1st Jan 2009,<br />
Anders Dahle stepped<br />
down as Managing Director<br />
of <strong>NORSAR</strong> Innovation<br />
AS to be replaced by<br />
Åsmund Drottning.<br />
Anders was integral to the<br />
commercialization of <strong>NORSAR</strong><br />
software during his role as<br />
<strong>NORSAR</strong> Managing Director.<br />
It was under his tenure that<br />
the commercial daughter<br />
company, <strong>NORSAR</strong> Innovation<br />
AS (NIAS), was established in<br />
2005.<br />
When asked about his<br />
successor Anders was full of<br />
praise.<br />
“I feel Åsmund brings a<br />
great deal to the role of<br />
Managing Director of NIAS.<br />
He has a wide background<br />
in both seismic <strong>modelling</strong><br />
research and applied seismic<br />
<strong>modelling</strong>. In addition, he is<br />
a specialist in rock physics<br />
<strong>modelling</strong> which is important<br />
for the development of<br />
<strong>NORSAR</strong> seismic <strong>modelling</strong><br />
software.<br />
His experience in running<br />
both research and service<br />
projects and his knowledge<br />
of the oil and gas industry<br />
mark him out as a natural<br />
successor and I am sure<br />
that with these qualities the<br />
continued success of NIAS<br />
will be assured.”<br />
Anders moves on to become<br />
CEO of <strong>NORSAR</strong> and will<br />
continue to be involved with<br />
the commercial operations<br />
<strong>through</strong> his role as Chairman<br />
of the NIAS board.
User Meeting<br />
Your feedback counts.<br />
We pride ourselves on our<br />
research and development. We<br />
think it is important to keep our<br />
software dynamic such that it<br />
continues to evolve to meet the<br />
ever changing demands of our<br />
industry. We achieve this <strong>through</strong><br />
our internationally recognized<br />
research department, input<br />
from our commercial services<br />
department and most importantly,<br />
feedback from the largest user<br />
group, our clients.<br />
We are incredibly proud of the<br />
strong, personal relationships<br />
that we have developed over the<br />
years and the innovative software<br />
solutions that this has lead to.<br />
This coming fall we will be holding<br />
a user meeting at our main office<br />
in Kjeller, Norway. We see this as<br />
an opportunity for our clients to<br />
learn how other users are applying<br />
the software, find out what will be<br />
released in the short term and<br />
influence the direction the software<br />
will take in the mid to long term. If<br />
you would like to be involved please<br />
get in touch for details of dates<br />
and venue.<br />
sales@norsar.com<br />
www.norsar.com<br />
Training and Development<br />
These courses are suitable for both the new user and users with moderate<br />
experience who are looking to broaden their understanding and improve the<br />
efficiency of their current usage. The courses are held in Oslo or Houston.<br />
Introductory courses<br />
Practical training in <strong>NORSAR</strong>-2D,<strong>NORSAR</strong>-3D and<br />
SeisRoX.<br />
The courses are designed to give attendees a practical understanding of<br />
the functionality of the software. In addition emphasis is placed on practical<br />
exercises and problem solving with help and guidance from our experts.<br />
Private Courses<br />
If you are more than 4 in a group or if you prefer to attend a course at your<br />
own facilities ask for private onsite training courses tailored to your needs.<br />
Intermediate and Modular Courses<br />
This course is an extension of the <strong>NORSAR</strong>-3D introductory course. The main<br />
motivation for developing this course was...<br />
• to provide a way to repeat some key tasks<br />
• to bridge the gap between a controlled training situation with nicely<br />
prepared data and the advanced requirements for a real-life project<br />
• to gain in-depth understanding of pre-processing and <strong>modelling</strong> parameters<br />
and to learn how to tune them<br />
• to learn about potential pitfalls and possible workarounds<br />
It is for users who wish to have better control of work flows or attendees of the<br />
introductory course who want to rise rapidly to a commercial project standard.<br />
On the Road<br />
Held in our new,<br />
state of the art<br />
training facility.<br />
We will continue be present at the major exhibitions across the world. Join us<br />
to find out about new releases as well as what is in the research pipeline. In<br />
addition, join us for case study presentations and one to one trouble shooting<br />
sessions.<br />
Join us at:<br />
• SBGf 2009 Salvador 24th - 28th August<br />
• SEG 2009 Houston 25th - 30th October<br />
• EAGE Subsalt Imaging Workshop Cairo 15th - 18th November<br />
• GEO2010 Bahrain 7th - 10th March<br />
• EAGE 2010 Barcelona 14th - 17th June<br />
• SEG 2010 Denver 17th - 22nd October<br />
• PETEX 2010 London 23rd - 25th November