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| Paradigm™ Customer Newsletter, Vol.3
Ed.1 February 2010
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Paradigm Launches New StratEarth Training Course for Rock & Fluid Canvas 2009 Release
Paradigm is pleased to announce the creation of a new course for our users as part of the Rock & Fluid Canvas™ 2009 release. The new training course, Introduction to Paradigm™ StratEarth® for Well Correlation, is a two day course designed for geologists, petrophysicists, or other technical personnel interested in using StratEarth Rollup 1 for performing well correlation.
Procedures taught in the course include displaying a traverse, as a well section and a cross-section, editing a well display, interpreting stratigraphic markers, correlating interpretation from well to well, reviewing interpretation in the time migrated domain, printing plots, and saving images.
Prerequisites for the course include a background in geology, geophysics, or petrophysics, working knowledge of the operating system in use, and familiarity with Epos® applications such as the Paradigm Product Manager and Session Manager.
The course was officially launched in late 2009. Customers can register for this new course online. Paradigm has also released the new 2010 Training Catalog available on our training website. The training catalog gives a robust description of every course in Paradigm’s training portfolio.
Susan Lockhart
Technical Training Director
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Probing the subsurface with amplitude versus angle analysis - Rock & Fluid Canvas 2009 Paradigm Probe New Features
Asset geoscientists routinely make use of amplitude versus angle (AVA) inversion and analysis procedures at every stage of the reservoir cycle. These AVA procedures play a role in exploration (as direct hydrocarbon indicators), in appraisal and delineation (as lithology indicators), and in field development (as a fluid migration indicator). To understand how lithology and fluid changes impact the amplitude versus angle “signature “and to make this data and information available to interpreters in a convenient and transparent manner, you need a software solution that is rich in signal (seismic and well) analysis and that connects to the interpreters canvas so that this additional dimension of information can be incorporated into the earth model.
Paradigm™ Probe™ amplitude versus angle system was engineered to meet the challenges and expectations of the E&P community by combining processing, interpretation, visualization, modeling, and analysis tools with the best amplitude versus angle (AVA) science. By doing so, both seismic and geologic interpreters have the “bridge” to better understand the correlations and disparities between well log signatures and seismic amplitudes present in the interpretation deliverables. Additionally, Probe’s seismic inversion suite can be used to create a new set of volume deliverables (e.g. angle stacks, fluid factor, P and S wave reflectivities) to qualify amplitude anomalies and strengthen the interpreter’s prospecting, ranking, and delineation capabilities.
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| Fig. 1: Co-visualization of fracture density and coherence cube attributes. |
The Rock & Fluid Canvas™ 2009 version of Probe breaks new ground as an exploration and delineation tool with its support for the Azimuthal inversion of seismic data. Inversion is an ideal match for modern rich and wide azimuth seismic acquisitions that “sample” the directional dependence of amplitude as a function of the acquisition (source to receiver) azimuth. For many of the unconventional plays (e.g. shale gas), this advanced inversion capability allows geoscientists to generate new attributes (e.g. fracture orientation, anisotropic gradient, fracture density) that reveal stress orientations and intensity (Figure 1).
These attributes become part of the data asset portfolio for the placement of laterals. It also supports geosteering activities in these very topical reservoir plays.
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| Fig. 2: Well to seismic calibration utility. |
The Rock & Fluid Canvas 2009 versions of Probe also introduces expanded and advanced well to seismic calibration functionality, including support for multi-well operations such as wavelet extractions and synthetics generation (Figure 2).
These functionalities allow Probe users, for example, to explore different wavelet extraction options (e.g. time variant wavelets, new amplitude-phase split wavelet estimation methods) that result in improved synthetics generation, improved seismic to well calibration, and consequently improved AVA attribute quality and accuracy. Of particular importance to Probe users is the ability to use the well to seismic calibration utility to more easily perform angle dependent wavelet extractions and to carry out modeling and calibration operations in multi attribute mode. In this mode, wavelets can be extracted separately for each attribute, and modeling is then performed using these attribute-dependent wavelets.
Finally, Probe users will enjoy new data preconditioning options to improve AVA quality, including automatic flattening of main gather events (with interpolation shifts in between), wavelet unstretching to remove wavelet stretch due to NMO or migration operations, and improved fourth order NMO corrections for better handling of long offset data.
Duane Dopkin
Senior Vice President - Technology
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4D Modeling of Salt-Sediment Interactions During Diapir Growth
Challenges
Salt related structures hold a large economical interest in oil exploration, not only because they create traps or seals, but also because of their control on the development of reservoirs in adjacent sediments. Trusheim's (1960) study of salt diapirs in northern Germany showed that the stratal patterns adjacent to diapirs form two main sediment bodies (Figure 1A): the primary rim-syncline thins towards the salt pillow, whereas the secondary rim-syncline thickens towards the diapir, thus recording the transition from the pillow to the diapir. Geometrical reconstruction through time of the successive evolution stages is essential to constrain both the reservoir setting and strain, but also to propose a valid scenario as an input for basin modeling.
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Figure 1: A) Three-stage growth of salt dome (Trusheim 1960);
B) 3D analog model reproducing the setting up of the 3 successive rim-synclines (Rondon et al., 2006). |
Diapir growth
Figure 1B shows the evolution with time of a model based on the gravitational settling of the overburden, following the inception of the pillow by erosion. The first rim syncline follows the growth of the pillow. Flank rotation occurs due to the differential pressure gradient along the gently dipping diapir walls. The down building of the diapiric body is a late phenomenon, associated to a crestal graben parallel to the diapir elongation, and to the flank rotation, which is delayed by the rigidity of the overburden flank above the salt pillow.
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Figure 2: 3D evolution of a salt dome from North Germany, with a similar three stage evolution.
The kinematic scenario is obtained by the sequential restoration of the present day geometry with Kine3D-2 (Rondon et al., 2006). |
Thanks to GDF Suez and its subsidiary PEG-Lingen, we were given the opportunity to compare our modeling results to a real seismic case study. The 3D evolution of the salt structure is obtained by using Paradigm Kine3D-2 on the model built with GOCAD (Figure 2). The Late Permian salt evolves first as a salt pillow. When the first rim syncline reaches the basement, during the erosive stage of the Lower Cretaceous, it triggers the development of the second rim-syncline. The age of the initiation of growth coincides with that obtained during the study of the Gorleben salt diapir. The salt volume estimate computed from the 3D model shows a good correlation between the pillow withdrawal and the diapir growth, indicating a mostly closed system evolution.
Diapir pinching during contraction
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Figure 3: 3D model built with GOCAD illustrating the compression
of pre-existing silicon diapirs and restored using Kine3D. |
A complex pattern of salt diapirs and large folds shapes the southern Zagros province (Iran), at this point in time still an under-explored area. Analog laboratory experiments (Figure 3) are designed to better understand the mechanisms of diapir extrusion, and particularly the critical role of pre-existing salt structures (i.e. pillows and diapirs) in the localization and evolution of newly formed fold sequences. During shortening, pre-existing ridges and domes are pinched horizontally, forcing the silicone mainly upwards through the overburden layer (Figure 4). The fold pattern is directly controlled by the pre-existing salt structures: originally sub-circular diapirs will constrain the folding process to a smaller area. These salt-cored anticlines now exhibit a particular “peanut”-like shape.
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Figure 4: Comparison between folded and pinched diapirs
and a field case study from the Fars area, Iranian Zagros (Callot et al., 2007). |
We thank IFP and GDF Suez for authorizing this publication and the IFP and Paradigm teams who are in charge of the development and commercialization of the Kine3D suite.
For a list of references, please go here.
J.-P. Callot, D. Rondon, A. Arbaumont, J. Letouzey
IFP France
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