Jun 2008 The Geomodeling Network Newsletter

June 2008
The Geomodeling Network Newsletter

Congratulations, if you have received this newsletter it means you have
signed up to be a member of ‘The Geomodeling Network’ on the popular
LinkedIn networking site. This newsletter is kindly sponsored by Blueback
Reservoir – a provider of 3D modeling services & solutions

The aim of the group is short and simple:

“To provide up to the minute independent advice, information and news on all
geomodeling related issues” it sounds easy when I put it like that – but just try
asking members for contributions and see how far you get .

All articles on the newsletter are contributions from fellow Geomodeling
Network members and represent their past experiences and/or opinions. If you
take a look at the makeup of our current members you will see that the group is
fairly diverse, being made up of oil company employees, independent
consultants and geomodeling software providers.

Each member is entitled to express their own opinions and ideas on the
Geomodeling Network and I hope that these articles will encourage open
discussions, where problems can be solved, advice can be offered and
technology can be reviewed.

If you would like to reply to any of the articles or ask any questions you have the
ability through LinkedIn to connect to the contributor then contact them directly
or reply to me and I will ensure that everyone is copied (unfortunately this is a
bit cumbersome as LinkedIn does not provide the ability to send a ‘reply to all’
email at the moment and I don’t really want to publish everyone’s email
address).

So, to business! On the next page you will find a listing of all the articles in this
first newsletter, I hope you enjoy it. If however you would like the format to be
changed for subsequent newsletters please let me know – all constructive
comments (good & bad) are welcome.

Welcome again,

Mitch Sutherland (group administrator)
mitch.sutherland@blueback-reservoir.com

Page 1 The Geomodeling Network – Sponsored by Blueback Reservoir www.blueback-reservoir.com

June 2008

Table of Contents

1. Member Articles, Reviews & Questions

A review of the new IRAP RMS Structural Modeling software Page 3
By Lynsey Anderson – Blueback Reservoir

Geomodeling from different perspectives (Geologists & Reservoir Engineers)
Page 5
Noelia Vera – TAQA Energy

Modeling high NTG fluvial sands in Petrel whilst keeping the reservoir
engineer happy! Page 6
Emilie Deloof – Perenco

One way to use the Petrel distance to object functionality as a trend for
modeling porosity Page 7
Juan Cottier – Blueback Reservoir

Assigning parameters in RMS using IPL Page 8
Edwin Meissner – Blueback Reservoir

2. New Geomodeling Technology
Roxar’s new structural modeling tools Page 10
Blueback/EMGS – EM Petrel plug-in tool Page 11

3. Career networking Page 12

4. Requests for newsletter No2 Page 13


June 2008

1. Member Articles, Reviews & Questions

Review of the new structural modelling module in IRAP RMS
Lynsey Anderson: Geologist at Blueback Reservoir (lynsey.anderson@blueback-
reservoir.com)

The new structural modelling system in Irap RMS (version 9) has recently been
used to build a framework of a structurally complex reservoir in the Central
North Sea. Previous attempts to build a fault model in another 3D modelling
package resulted in faults either being verticalised, inaccurate fault geometry
modelled or even faults being removed. The resulting 3D grid also had problems
initialising in the simulator. Due to time constraints, after two weeks it was
decided that an alternative approach was required to build a more structurally
accurate framework.

The same input data was used in both approaches (fault sticks) however Irap
RMS can use fault polygons, fault surfaces as well as control points for well
intersections. The first step is to use this data to create fault surfaces, the data
can be either specified as soft input (fault sticks to give general fault shape) or
hard input (well picks). There is a choice of algorithms (general or linear) and
the user can specify the grid increment and also apply a smoothing factor. Data
can be limited by using a tip-line polygon which surrounds the data and allows
for the fault surface to be extended or clipped. Once generated it is very quick
to QC in the 3D viewer, however it is not possible to edit these fault surfaces,
therefore it is recommended to either edit the input data first of all/ or take
some time to adapt the settings on the fault modelling job for specific faults.
However the default settings gave a reasonable result for a first pass.

The next stage in the modelling process is to specify the fault truncations; this
can be done either by specifying the truncations in the job panel, or in the 3D
view which was found to be a very powerful option. RMS remembers what
pieces of the faults have been deleted, so if a mistake has been made by the
user, it is very easy to restore the fault and apply a different fault truncation. In
the model there were 23 faults, many of which were either low angle, or


June 2008

truncated against several major normal faults as Y or inverted Y faults. The
geophysicist was pleased at how accurately the fault geometries were modelled,
which led him to do further interpretation and ask for more faults to be
included! There is also a very handy tool for QC’ing which allows the user to
systematically go through and check each fault with its intersections and
truncations, which is very useful for a model with lots of faults as the animate
view controls how the faults are displayed.

Once the fault surfaces and relationships have been defined, the horizons need
to be modelled. This is no longer a requirement to generate fault lines from the
intersections of the fault surfaces and horizons. The new horizon modelling also
removes the requirement for stratigraphic modelling as a separate step in the
workflow. This not only reduces the time taken but also ensures a more
integrated structural framework. Setting up the stratigraphy is relatively
straightforward and the user has the option to specify the input data as soft or
hard. RMS also produces points from the horizon data; these can be edited and
also used as input, which is great if data near the fault has to be ignored. It is
also possible to define several horizon modelling jobs and look at various
stratigraphic options.

A new 3D gridding algorithm has been developed to incorporate the new
structural modelling. This works in a similar way as the previous 3D gridder in
RMS. Users have the option to define control lines, whether the faults are
included as pillar or stair-stepped and the vertical resolution. The only drawback
is that all the faults in the structural model are included in the 3D grid; therefore
it is not possible to exclude smaller faults for example. However a second
“With their four horizon model could be built with the same settings by copying the job and
dimensional minds and in removing the unwanted faults. The grid quality tools are also available to allow
for QC’ing. The resulting 3D grid easily incorporated all the complexity of the
their interdisciplinary
structural framework, whilst creating a 3D grid without distorted cells or
ultra-verbal way, compromising the fault geometry.
geologists can wiggle out
of almost anything” In conclusion a structurally complex fault model and 3D grid was built which
satisfied the requirements from both the geophysicist and reservoir engineer, in
John McPhee
less than half the time compared to the previous model.


June 2008

Geomodeling from different perspectives
Noelia Vera: Reservoir Engineer at TAQA Energy (nverar@hotmail.com)

Why reservoir engineers insist in simplifying the reservoir model? Less faults,
less heterogeneity, less number of cells… in the same way as the geophysicist
wants to include any single interpreted fault in the model, every change of
facies...

As reservoir modeling packages offer more cross-disciplinary tools, the
geophysicist focus in the 2D, depth conversion and complex fault modeling
workflow, while the reservoir engineer wants to only model few faults and the
essential parameters affecting the well performance.

The engineer uses uncertainty to replicate the reservoir behaviour seen by
“Engineering is the art production, tries different transmissibility across faults, multiplies permeability
of modeling materials to match the Kh at the well test and will do anything to replicate flow rates and
pressures at the existing wells. Sometimes engineers go as far as changing the
we do not wholly
pore volumes across the field (so carefully modeled by the geologist) without
understand, into shapes even modifying other dependent properties, like permeability or water
we cannot precisely saturation, almost nothing matters as long history match is achieved.
analyse so as to
Different models can achieve the same history match. The best match will be the
withstand forces we one that does not divert too much from the geological property ranges and
cannot properly assess, honours the PVT and other dynamic input. This is the reason why the geological
in such a way that the and simulation grids should be feeding one each other if we want to understand
the reservoir as a whole, instead of only getting separate answers from each
public has no reason to
side of the workflow.
suspect the extent of our
The engineer wants to replicate the observed flow rates and depletion seen by
ignorance”
the historical data. This is the first step in the dynamic model before predicting
the production rates until the end of the field life. In the other hand the
Dr AR Dykes
geophysicist concentrates the efforts in giving a single answer, hoping to obtain
the true model, a static model that will replicate the subsurface at the smallest
detail.

Uncertainty in the geological model is necessary to allow the reservoir engineer
enough room to modify the static parameters in a way that they do not deviate
from the geological input data. From the engineer’s point of view, the ability to
estimate and quantify uncertainty, perform intelligent upscaling and have
seamless data transfer to and from the simulator is more valuable that the
software capabilities to model the most sophisticated structure. Most engineers
embrace stochastic/probabilistic methods for their ability to give different valid
answers without differing from the geological description.


June 2008

How to model high NTG fluvial sands in multi stacked reservoirs in
Petrel when my favourite reservoir engineer can only accept 10ft cells
grid??
Emilie Deloof: Development Geologist at Perenco (edeloof@ukperenco.com)

The lateral extension of the thin non reservoir intervals within each zone is a key
”Imagine we have data”
uncertainty for the production simulation.
Prof. Steven Gorelick
With very few well data, one cored well only, and, as usual, very limited time to
complete the study, this modelling exercise can be challenging. The reservoirs
are heavy oil bearing, with excellent properties (~18-20% poro, 200mD to
several Darcies on average for the net).

I have just only started on this project (was dealing with the “quiet” gas bearing
Rotliegendes sandstones before – so the project could not be more different !)

My strategy for now is:

collect information from papers across the entire basin and look at similar type
-
fields located 100s km away – luckily it seems the depositional environments are
broadly similar
model the net reservoir as pseudo facies using SIS – but there, lateral extension
-
of the non net facies ?? use different scenarios. As the NTG averages are high I
think the thin non reservoir intervals have very limited extension (also, they
cannot be correlated across the few wells in the area), so the sands are all
connected.
model porosity using SGS based on net reservoir statistics
-
apply poro-perm transform defined from the available core data
-

At this early stage of the project, I am working directly at the simulation grid
scale, not going through a geomodel grid then upscaling. This simplifies the
workflow, but could greatly impact on the properties distribution.

Any idea ? tips from your own experience ?


June 2008

How can you use the distance from a channel as a trend for porosity
modeling, i.e. how far from the channel edge (or centre), is the cell that
porosity should be modeled in?
Juan Cottier: Geologist at Blueback Reservoir (juan.cottier@blueback-reservoir.com)

I’ve pondered over the issue, but fail to find a really clever way if doing it… If
anyone of you has any good solutions, please share!!

Petrel does have a “Distance to object” function in geometrical modeling, but
that only applies to point, polygons, wells and maps (which gives only distance in
Z).

Channels are defined as a discrete parameter in the 3D grid and can’t be used
directly.

One way it can be done is the following way:

Model your channels as usual.
Export the property using GSLIB format and toggle on X;Y coordinates for
output. Take the resulting file into excel or similar and remove all points/lines
that doesn’t correspond to the channel facies. Use sort on facies code column,
then it’s easy.
Reload into Petrel as point data set. This point data set can then be used in the
Geometrical modeling process (Distance to object)

Drawbacks:

There are many points that define a channel in this method, i.e. not just edge or
centre…
The Distance to object process doesn’t seem to discriminate between
layers/zones so; the lateral distances are common for all depths of the model….
The last point could be fixed by exporting out channel facies zone by zone,
though…

So, if anyone has any other ways of solving this issue I’d love to hear.

“Most of you probably
don’t know what dikes
and joints are….at least
in the geological sense”
Prof. David Pollard


June 2008

Assigning parameters in RMS using IPL – useful if you do not have a
Facies or Petrophysical modeling modules.
Article – Edwin Meissner: Geologist at Blueback Reservoir (em@emgs.com)

If the Facies and Petrophysical modules are not available, this procedure is a
workaround which will enable you to create a property in a grid and assign
values to it. The values are assigned by using the region index to distinguish
between different parameter values which will then be assigned.

Below there are 5 ppt slides describing the process (full ppt is also attached) plus
an Excel spreadsheet (IPL_100_if_Resistivities_OK.xls) is also attached to help
you create the IPL script.

Assigning parameters in RMS
IPL based template + other updates

Edwin Meissner

Start a new project

1. Copy START_NEW_PROJECT -template from:
bollywood:ggusers3D_MODEL_BUILDERRMS
• Some standard horizons, which can be renamed
• Folder structure in general 2D data for Areamaps and Horizon generation
(no more ”Work” Horizon needed)
• Folder structure in clipboard for prospect outlines, Tx and Rx positons
• Colourtables
• Workflows

2. Rename it before opening it with RMS:
Tlahuan_Pemax_areamaps_120308_RMS9_02

Project_Client_short_description_DDMMYY_RMS9_projectversion


June 2008

Prepare Excel /open Office template

1. Copy template from:
https://emgs-docuwiki.emgs.local//dokuwiki/doku.php?id=
modelling:building_3d_model
Or from:
bollywood:ggusers3D_MODEL_BUILDERRMS

2. Save with a new name!

3. Fill in the Horizon names and the
desired resistivities. They should
be automatically converted to
conductivity values.

4. Go to the ”Export_IF_Statements”-
worksheet.

Excel/ Open Office template

5. Copy the whole column A from
the “Export_IF_statements”
worksheet
And paste it into the upper IPL
command edit window.

Two column page

• After creating the Grid, open the IPL-
Window either from double click on the
IPL Job in the workflow or (if not the
RMS – template was used to start the
project) in the Job Tab is also a IPL
icon.
• Paste the copied column of the excel-
template in the upper IPL window.
• Fill in the correct number of the grid; in
this case 3 (sometimes the gridnumber
does not change imeadiatly after
deleting one earlier grid, after saving
the project the grids are renumbered
from the beginning)
• Click execute
Grid models
• Save!  Done


June 2008

2. NEW GEOMODELING TECHNOLOGY

EMGS and Blueback Reservoir launch Bridge, an EM Integration tool for Petrel

Electromagnetic Geoservices (EMGS) and Blueback Reservoir have collaborated
to develop and launch a new decision-support tool for exploration professionals
called Bridge. Bridge has been created to help oil & gas companies find and
develop hydrocarbons more efficiently.

The new software enables the easy integration of electromagnetic (EM) data
with other geophysical and geological information, resulting in a clearer and
more complete understanding of the subsurface.

Terje Eidesmo, EMGS chief executive officer, said: “This is an important
milestone for EMGS and the industry. Bridge will enable our customers to
capitalise on the benefits of EM by allowing the easy integration EM information
with their workflows. By integrating EM data with conventional geophysical,
geological and well log information, our customers can improve their exploration
risking process and the assessment of a reservoir’s potential.”

Bridge is an EM plug-in for Petrel, one of the industry’s leading geological and
geophysical integration platforms. The launch of Bridge brings long-awaited EM
functionality to the standard Petrel workflow. Petrel was originally created and
developed by the founders of Blueback Reservoir.

“We have been working with the team who created Petrel. The heritage,
expertise and experience we bring from our respective fields is an endorsement
for Bridge and the increasing demand for EM integration by the industry bodes
well for the uptake of this product. The launch of Bridge also reaffirms our
leadership in the EM sector”, continued Eidesmo.

Jan Egil Fivelstad, Blueback Reservoir’s chief executive officer, commented: “EM
data adds great value for geoscientists, and Bridge will make this technology
more accessible and understandable. There has been a growing recognition
throughout the oil and gas industry of the need for extra functionality in
Page The Geomodeling Network – Sponsored by Blueback Reservoir www.blueback-reservoir.com
10

June 2008

interpreting EM data and as a result we expect the demand for this product to
continue to grow”.

For more information on this product please click on the following link:
http://www.blueback-
reservoir.com/index.php?option=com_content&task=view&id=57&Itemid=71

ROXAR – Next Generation Structural Modeling

It’s probably fair to say that most geomodelers with any long term experience
will have used IRAP RMS software at one point during their career. Indeed a lot
of you will be using it as we speak. So it’s good to see that Roxar are still
churning out quality products, a case in point being their new structural
modeling tool which was officially released at the end of 2007. I have attached
the following material from the Roxar website which highlights some of the
features of their new Structural Modeling solution:

• Improved Fault Geometry & Fault Intersection. New algorithms will create fault
surfaces that closely honor the input data while also allowing the user control.
Fault surfaces can be automatically adjusted to well picks, may die out laterally
or in depth, and can be truncated by unconformity surfaces.

Roxar’s structural modeling tools will also enable the widest range of antithetic
and synthetic fault intersections to be modeled, including Y faults, lambda faults,
K faults, as well as crossing conjugate or X faults. Fault truncations can be a
combination of automatic and interactively defined in 3D.

• Horizon modeling. Roxar’s new approach to horizon modeling is a faultblock
based approach, which provides an easy method for modeling repeat section due
to reverse faults. Horizon surfaces can be generated directly from interpreted
seismic data or calculated using well and thickness data.

• Improved 3D gridding. New 3D grid building, designed to work with the new
structural framework building, will ensure the building of the best quality grids.
Any selection of faults may be treated as pillar or stair-cased faults. Roxar’s
unique methodology used for stair-casing reverse faults also eliminates the
shadow zone problems often seen in corner point grids and maintains layer
connections across the fault blocks.
11

June 2008

For more information on the above Roxar software, please click on the following
link: http://www.roxar.com/structure/

(If you missed it there is an independent review of the new RMS structural
modelling software on Page 3)

3. Career Networking
You wouldn’t believe (or maybe you would) the number of agency headhunters
that have applied to join the Geomodeling Network. Personally I have no
problem granting them access to the group but if any of you have any issues
with this please let me know and I will go with the general consensus.

Bearing the above in mind, it’s worth noting that this group was set up with the
intention of informing its members about various employment opportunities, so
if your team is looking for people let me know and I will of course list these
opportunities on the next newsletter.

Being the group administrator and in a position of absolute power , I will kick
off the career’s part of the Geomodeling Network.

As you will have no doubt noticed from my email address I work for Blueback
Reservoir currently based in London. Blueback are continuously on the lookout
for talented geomodelers who are able to use Petrel or RMS and who possess
significant experience in the E&P industry.
Our consultants are in big demand throughout the UK, Norway, Europe and the
Middle East so we would be very interested in speaking to anyone who would
like to work for us.
For those that are interested or know someone that is, please click on the
following link for more details:
or
http://www.blueback-reservoir.com/index.php?option=com_content&task=view&id=54&Itemid=69
drop me an email on mitch.sutherland@blueback-reservoir.com

12

June 2008

4. Requests for the newsletter No2
“None of us is as smart
The current plan is to make this newsletter as regular as possible and I propose
as all of us” that a newsletter is sent out every 2 months. This will ensure that the content is
current and 6 newsletters a year shouldn’t really bog down your Outlook inbox
Ken Blanchard
too much.

This newsletter is only possible through the kind contributions of different
network members; however I do need more contributions from as many
different people as possible.

The current layout of the newsletter is my own design, so if you don’t like it or
would like to see it done differently please let me know and I will consider it for
the next issue.

In the meantime as a gentle way of requesting input for future newsletters, here
are some topics (which is by no means exhaustive) that you may like to
contribute towards:

1. Workflows/workarounds you would like to share
2. Technology reviews – who’s using Jewel Suite, Skua and Gocad and are they any
good?
3. Technology requests – what’s missing from your workflow
4. Company Geomodeling workflows – how does your company do it?
5. Uncertainty modeling – a hot topic that needs to be discussed

Fin

13

Jun 2008 The Geomodeling Network Newsletter

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Jun 2008 The Geomodeling Network Newsletter