ACTUAL THEMES AND APPLICATIONS
* In the June 2010 News an Article of John Fanchi
Green Field Flow Modeling Workflow
Different workflows exist for designing, implementing and executing reservoir asset management projects. A typical workflow needs to identify project opportunities, generate and evaluate alternatives, select and design the desired alternative, implement the alternative, operate the alternative over the life of the project, including abandonment, and then evaluate the success of the project so lessons can be learned and applied to future projects. Reservoir flow models, which are also known as dynamic models, can play a significant role in comparing alternatives, selecting the optimum reservoir management plan, and assessing the success of the project as it is being implemented and operated. A modern flow modeling workflow for green fields is described below for an oil field.
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* In the May 2010 News an Article of Kurt Marfurt
SEISMIC ATTRIBUTE ILLUMINATION OF WOODFORD SHALE AND
FRACTURES. ARKOMA BASIN OK
Shale gas is one of the most promising unconventional resources
for hydrocarbon exploration and production. Open fractures in
shale provide critical porosity and permeability, while healed
fractures can be opened for hydrocarbon flow through
carefully-designed hydraulic fracturing programs.
Recent technical and economic advancement in horizontal drilling
techniques have made the Mississippian and Devonian Woodford Shale deposited over a large portion of the Midcontinent a significant
hydrocarbon play.
To date, the major use of 3D seismic data in the study of shale
gas reservoir has focused on (1) mapping natural fractures (and
karst) that can provide enhanced conduits for hydrocarbons (and
in the Barnett shale for water from the underlying Ellenberger),
and (2) mapping geo-mechanical brittleness and horizontal stress
directions for effective hydraulic fracture stimulation.
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* In the April 2010 News an Article of Gene Ballay
VISUAL BASIC
You can't depend on your eyes when your imagination is out of focus (Mark Twain).
Today’s sophisticated software offers unprecedented formation evaluation capabilities, but just as Mark Twain opined 100 years ago, the full benefit will not be achieved unless we have a clear understanding of the underlying inter-relationships, and a
focused vision with which to interpret the results.
Simple visual patterns can signal (and more)
* are (independent) laboratory measurements internally consistent with one another, and the wireline data,
* whether an interval is wet or hydrocarbon bearing,
* locally appropriate values for Rw, ‘m’ and ‘n’,
* is there a ‘short circuit’ risk to Sw(Archie).
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* In the March 2010 News an Article of Steve Hill
WHY 3D SEISMIC ?
3D seismic data is significantly more expensive than 2D seismic data. What do we obtain for the extra expense ? 2D data assumes no out-of-plane structure where surface locations of the 2D data define the “plane”. In other words, 2D data assumes no lateral variation in the reflectors perpendicular to the 2D plane.
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* In the February 2010 News an Article of Robert Garotta
SHEAR WAVES FROM VIBRATORS
Relationships between shear waves and vibrator sources are somewhat conflicting and amazing.
Manufacturers easily made the mass vibrating horizontally but the problem of the horizontal vibrator is coupling: inversed pyramids or vertical blades are necessary to transmit horizontal stresses.
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* In the January 2010 News an Article of Gene Ballay
STATISTICS ARE PLIABLE
Facts are Stubborn, Statistics are more Pliable: Mark Twain said it, and while we all realize it,the fact remains that in a busy environment the implications can slip past us. And the risk is
compounded when one recognizes that the default algorithms / display formats for some oilfield data, may lend itself to an improper numerical evaluation.
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* In the December 2009 News an Article of Tim Smith
THE LONG WAY TO A SUCCESSFUL SEISMIC INTERPRETATION
In 2007 BHP Billiton acquired a 2900 sq km leasehold in the northwest Florida shelf in water depths of about 1 to 1.25 km.
This acquisition was based on interpretation of a 12,000 km 2D seismic dataset which had been processed through pre-stack depth migration; these data became available in 2006.
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* In the November 2009 News an Article of Gene Ballay
SPLIT PERSONALITY
Carbonates and sandstones differ in a number of fundamental ways (Gene Ballay. 2005), with consequences that affect the techniques required for their evaluation (Chris Smart, 2003). One outcome of these differences is the likelihood of a multi-mode porosity system in carbonates, which in a manner akin to that thriller Dr Jekyll and Mr Hyde, can consist of pores that are almost art from a visual perspective, but become sinister when one is charged with correctly evaluating the reservoir.
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* In the October 2009 News an Article of Robert Garotta
WHAT TO EXPECT FROM VECTOR WAVEFIELDS ?
Multi-component experimentations started around forty years ago, using primitive acquisition or processing tools, when compared to the complexity of the shear mode propagation. Slow but substantial advances of the field techniques and digital processing now open the way to the real potential of multi-component technology provided the process respects all necessary conditions. Pure shear mode surveys are rare, multi-component technology presently considers PS mode in addition to the P mode.
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* In the September 2009 News an Article of Robert Garotta
DETECTION and COMPENSATION of the BIREFRINGENCE
The effects of birefringence or shear wave splitting on a single raypath recorded with a good signal-to-noise ratio can be easily described and formalized, offering a way of deriving birefringence attributes: natural orientation, percentage of azimuthal anisotropy and differential attenuation.
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* In the July 2009 News a new Article of Gene Ballay
ROLLING the DICE
There are two basic ways in which the issue of uncertainty can be characterized; partial derivatives of the expression of interest (Sw in this situation) and Monte Carlo simulation. At the simplest level, they complement one another, and since each are easily coded into an Excel spreadsheet, we routinely perform both, as a QC cross-check.
The deterministic derivative approach ..........
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* Filling with Petrophysical Properties
* In the June 2009 News the Paper of Helene Beucher and
Didier Renard: FILLING WITH PETROPHYSICAL PROPERTIES
One of the main challenges of geostatistics in reservoir characterization is to populate a portion of 3-D earth model with its petrophysical properties. This operation must be carried out while still honoring the information available along well logs: in our jargon,
we say that it must be conditional.
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* In the May 2009 News the Paper of Gene Ballay
Multidimensional Petrophysical Analysis in
the Reservoir Description.
During the development of the Shaybah Field in the Empty
Quarter of Saudi Arabia, a number of wells were cored and logged with a routine open-hole suite of tools (density-neutron, sonic-resistivity), and then later (but preproduction) logged with
a pulsed neutron tool.
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* The March 2009 second article of Robert Garotta:
About Gamma ratios and their combinations
The ratio between the compressional to shear velocities
(Gamma or Γ = Vp/Vs) is a key parameter in the
combination of P and S (or PS) data. It can be derived in
several ways. The most obvious are the ratio between the S
to P propagation times between associated events (Γ T) and
the ratio between P to S normal moveout velocities (Γ V).
Comparing P and S (or P and PS) seismic amplitudes also
gives access to Gamma ratio (ΓA).
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*The March 2009 Article: Gene Ballay and the uncertainty concepts in Petrophysics
Risky Business
We all realize that our evaluations can be no better than the data, and model, allow.
At the simplest level we often select Optimistic, Expected and Pessimistic parameter estimates, and bound the result accordingly.
It is, however, relatively simple to address the uncertainty question in a more comprehensive, quantitative fashion, and better identify where to focus time, and money, in search of an improved evaluation.
As carbonate (rather than shaly sand) petrophysicists, our Sw estimates are typically compromised by uncertainty in the Archie equation attributes.
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*Which Depth Imaging Method Should You Use?
A Roadmap In The Maze of 3D Depth Imaging.
- A Contribute of Biodo Biondi to our discussion -
Today’s explorationist is confronted with a large array of three dimensional depth imaging options, ranging from a variety of Kirchhoff implementations to a variety of waveequation
implementations. Historically, the choice of a depth migration algorithm was simple: Kirchhoff was the only practical option. This has changed. Advances in computing and clever algorithms
have made waveequation migration an economically feasible alternative. With so many choices, making the right choice of imaging method for a given objective can be a daunting task.
We briefly examine the origins of the various imaging methods, describe their relative approximations, and assess their relative merits and applicability.
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*Good News and Bad News - The January 2009 Newsletter
When observed, mud filtrate invasion likely signals that the formation has at least some amount of permeability. At the simplest level, and assuming a contrast in Rmf & Rw, there may be SP development, which in the presence of potassium feldspars, or uranium, can allow one to identify a reservoir that would not be clear on the GR, and can even offer an estimate of Rw.
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*Testing, Testing 1,2,3 The October Newsletter. Gene Ballay
Pressure profiles provide important, basic information on reservoir fluids and rock continuity, and in some locales are vital to an accurate interpretation.
· Fluid typing, via determination of the fluid pressure gradient
· Fluid contact placement, via observation of pressure gradient changes, Reservoir continuity, via identification of similar, but offset, pressure gradients.
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* Testing, Testing 1,2,3 The September Newsletter II
on Formation Pressure Profiles . Gene Ballay
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* Determinismus and/or Artificial Intelligence for Pattern Recognition ? Hansruedi Frueh
Artificial Intelligence Methods for Pattern Completion and Interpretation, AI Methods for Applications in the field of Geosciences.
An interview with Hansruedi Frueh, instructor for
the course: " The Logic of Neural Networks for the Petrophysical,
Seismic and Facies Estimation ". DOWNLOAD
* Two for One. On the August 2008 GeoNeurale Newsletter :
A routine suite of open hole logs, that includes both porosity and resistivity, has the potential to provide not one, but two, independent evaluations of the formation. DOWNLOAD
*Double Duty on the side of Carbonates.
GeoNeurale issues its first Newsletter: "Double Duty with The
Old and The New". A communication platform among
Geoscientists on Carbonate Petrophysics. DOWNLOAD
*GeoNeurale presents the widest and most advanced research project ever planned on the Bavarian Malm. The project covers a multidisciplinary integrated program of special seismic, petrophysical and surface measurements and the application of new derived analytical and processing methods focused on the interpretation of the structural and facies attributes to maximize the efficiency of geothermal projects.
*Petrophysics and Geostatistics: New analytical methods
*The Malm Research as a top priority.
*Application of Neural Networks to the Estimation and Classification of petrophysical related properties for
reservoir analysis.
*Multilayer Perceptrons and NN architectures for the Estimation
and mapping of petrophysical properties.
*Supervised methods training sets from core porosity, GR
for modeling the Porosity log.
*Defining Electrofacies: Supervised and Non-Supervised
Approaches
*From Bivariate to Multivariate Statistics: Electrofacies classification.
*Integration of Petrophysical Analysis with Neural Networks. |