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Misra S.,Arcis Corporation | Chopra S.,Arcis Corporation
Leading Edge (Tulsa, OK) | Year: 2010

Accurate wavelet estimation is crucial in the deconvolution of seismic data. As per the convolution model, the recorded seismic trace is the result of convolution of the Earth's unknown reflectivity series with the propagating seismic source wavelet along with the additive noise. The deconvolution of the source wavelet from the recorded seismic traces provides useful estimates of the Earth's unknown reflectivity and comes in handy as an aid to geological interpretation. This deconvolution process usually involves estimation of a wavelet, before it is removed by digital filtering. Because the Earth's reflectivity and seismic noise are both unknown, the wavelet estimation process is not easy. Statistical methods estimate the wavelet using the statistical properties of the seismic data and are based on certain mathematical assumptions. The most commonly used method assumes that the wavelet is minimum phase and that the amplitude spectrum and the autocorrelation of the wavelet are the same as the amplitude spectrum and the autocorrelation of the seismic traces, within a scale factor, in the time zone from where the wavelet is extracted (stationary assumption). © 2010 Society of Exploration Geophysicists.


Hunt L.,Fairborne Energy | Reynolds S.,Fairborne Energy | Brown T.,Fairborne Energy | Hadley S.,Fairborne Energy | And 2 more authors.
Leading Edge (Tulsa, OK) | Year: 2010

These experiments illustrate that the AVAZ, VVAz, and curvature attributes correlate strongly with image log fracturedensity, and should be valid predictors of fractures in the Nordegg of this area. Similar observations were made using the microseismic data, a less direct validator of fracture prediction, also exhibited strong correlations. The large,spatially distributed sample size and similar support make microseismic events an intriguing data element to compare and cross-validate with surface seismic fracture predictors. The comparison of microseismic to surface seismic should be carried out with other data to determine if the results are repeatable. Further experiments may reveal how important the wellbore orientation and hydraulic fracture orientation were with reference to hmax and the orientation of the preexisting natural fractures. This work indicated that AVAz was the best single predictor of fracture density, although curvature attributes were almost as good. We also observed that despite the predictive correlations, significant scatter remained in the data comparisons. That scatter likely has implications to our data quality as well as the theoretical limitations of our methods. In consideration of this, we attempted to use com binations of the attributes in multilinear and crossplotting approaches. These results were most accurate when AVAz and curvature were used together. The advantage of using these attributes together may lie in the areas of validity for each attribute: AVAz can directly detect fractures, but may fail in hinge zones where multiple fracture sets are most likely to exist, while the curvature attribute identifies the hinge zones, but may not infer the fractures that exist in less obviously deformed areas. A surprising conclusion from this work was that the coherence attribute did not predict fracture density or microseismic event moments for the Nordegg in this area. For the kinds of fractures that exist in the Nordegg of this area, AVAz and curvature are a more useful combination than coherence and curvature, which have been used to advantage in other areas. © 2010 Society of Exploration Geophysicists.


Hunt L.,Fairborne Energy Ltd. | Reynolds S.,Fairborne Energy Ltd. | Hadley S.,Fairborne Energy Ltd. | Downton J.,CGGveritas | Chopra S.,Arcis Corporation
Leading Edge (Tulsa, OK) | Year: 2011

We propose scaling volume curvature measurements with material property estimates to produce a superior prediction of natural fractures. Curvature is one of many, indirect, fracture-inferring attributes. It does not detect fractures, but is causally related to them through the assumption that increasing curvature relates to increasing strain. There are many other variables that are causally related to fractures. We propose that it would be advantageous to create combinations of these causal variables with curvature. Some of the most well known and important causes of variations in natural fracture density are material properties relating to brittleness. Material properties are critical geologically at all scales, from large-scale regional studies to prospect-level inquiries because the properties may vary significantly within individual formations and between formations. These vertical and lateral changes in material properties may be important and should be considered in fracture estimation, along with curvature. There is a lack of clarity regarding exactly which material property is best from the perspective of physics and rock mechanics; however, we have chosen a combination of parameters that we argue is a starting point. Fortunately, material properties are routinely estimated with amplitude variation with offset (AVO) techniques, and there is little practical reason not to use them together with curvature to produce a more complete attribute inferring fracture density. The combination of these variables is a step in the direction of creating quantitative causal fracture prediction estimates. © 2011 Society of Exploration Geophysicists.


Chopra S.,Arcis Corporation | Marfurt K.J.,University of Oklahoma
SEG Technical Program Expanded Abstracts | Year: 2011

Over the last several years, seismic curvature attributes have been shown to be very useful in delineation of folds, flexures, and faults. Although many curvature measures have been introduced we find the most-positive and most-negative principal curvatures k1 and k2 to be the most useful. All other curvature measures can be derived from the two principal curvatures. For example, Hart (2002) and others have found the components of apparent curvature projected parallel to the dip azimuth and strike of a dipping plane to be useful in given tectonic and stress settings. In this study we describe the theory and application of Euler curvature, which is a generalization of the dip and strike components of curvature in any user-defined direction, to the interpretation of surface seismic data. This attribute is useful for the interpretation of lineament features in desired azimuthal directions, say, perpendicular to the minimum horizontal stress. If a given azimuth is known or hypothesized to be correlated with open fractures or if a given azimuth can be correlated to enhanced production or effective horizontal drilling, an Euler-curvature intensity volume can be generated for that azimuth thereby high-grading potential sweet spots. © 2011 Society of Exploration Geophysicists.


Chopra S.,Arcis Corporation | Marfurt K.J.,University of Oklahoma
SEG Technical Program Expanded Abstracts | Year: 2011

Since they are second-order derivatives, seismic curvature attributes can enhance subtle information that may be difficult to see using first-order derivatives such as the dip magnitude and the dip-azimuth attributes. As a result, these attributes form an integral part of most seismic interpretation projects. This conventional computation of curvature may be termed as structural curvature, as lateral second-order derivatives of structural component of seismic time or depth of reflection events are used to generate them. In this study, we explore the case of applying lateral second-order derivatives on the amplitudes of seismic data along the reflectors. We refer to such computation as amplitude curvature. For volumetric structural curvature we compute first-derivatives in the inline and crossline components of structural dip. For amplitude curvature we apply a similar computation to the inline and crossline components of the energy-weighted amplitude gradients, which represent the directional measures of amplitude variability. Application of amplitude curvature computation to real seismic data shows higher level of lineament detail as compared with structural curvature. The images are mathematically independent of each other and thus highlight different features in the subsurface, but are often correlated through the underlying geology. © 2011 Society of Exploration Geophysicists.


Chopra S.,Arcis Corporation | Hardage B.,University of Texas at Austin
Leading Edge (Tulsa, OK) | Year: 2010

Borehole geophysics is essential for exploration, assessment, and production of Earth's resources, in addition to carrying out fundamental studies on the Earth itself. Borehole-based technology encompasses activities ranging from coring to measurements such as logging, VSP, crosswell profiling, and passive seismic monitoring. Each of these disciplines has grown into an established branch of borehole geophysics. The idea behind all these measurements has been to obtain useful information about the geological environment that helps evaluate subsurface zones of interest. © 2010 Society of Exploration Geophysicists.


Van Der Baan M.,University of Alberta | Van Der Baan M.,University of Texas at Austin | Van Der Baan M.,Arcis Corporation | Fomel S.,University of Texas at Austin | And 2 more authors.
Leading Edge (Tulsa, OK) | Year: 2010

Kurtosis maximization by constant phase rotation is a useful tool for nonstationary phase estimation. Statistical phase analysis can be used to extract nonstationary seismic wavelets suitable for deconvolution, as a quality control to check deterministic phase corrections resulting from seismic-towell ties, and also as an interpretation tool. In the latter case, it can be employed to highlight areas of subtle stratigraphic variations in the local geology (including pinch outs, and variations in turbidite and coal sequences, meandering channels and carbonate reefs) or to "red flag" spatial variations in the character of the propagating wavelet. We advocate analysis of local phase character as a complementary tool to spectral decomposition for highlighting variations in local reflection characteristics. © 2010 Society of Exploration Geophysicists.


Chopra S.,Arcis Corporation | Chopra S.,University of Oklahoma | Marfurt K.J.,University of Oklahoma
Leading Edge (Tulsa, OK) | Year: 2010

Volumetric curvature is a well-established interpretational tool that allows us to image subtle faults, folds, incised channels, differential compaction, and a wide range of other stratigraphic features. The maximum and minimum curvatures define the eigenvalues of a quadratic surface. By definition (and based on eigenstructure analysis), the maximum curvature is defined as the principal curvature that has the larger absolute value. We find that the principal curvatures k1 and k2, where k1 ≥ k2, provide the simplicity of interpretation seen in kpos and kneg, but retain the robustness of kmax and k min in the presence of steep dip. Multispectral volumetric curvature attributes are valuable for prediction of fracture lineaments in deformed strata. Several applications of volume curvature have been completed in different geological settings, which are useful for different stratigraphic features, ranging from imaging of channel boundaries and small scale faults to highly fractured zones. Corendering volumetric curvature with coherence provides a particularly powerful tool. © 2010 Society of Exploration Geophysicists.


Trademark
Arcis Corporation | Date: 2014-08-19

Pre-stressed and precast stone and concrete products, namely, cladding for building exteriors, decking planks for walking and traffic surfaces, paving units, counter tops and detectable warning pavers; custom architectural precast building materials, namely, stone and concrete cladding for building exteriors, stone and concrete decking planks for walking and traffic surfaces, stone and concrete paving units, stone and concrete counter tops and stone and concrete detectable warning pavers; non-metal decking; non-metal-cladding for construction and building. Custom manufacturing of pre-stressed and precast stone and concrete products.


Trademark
Arcis Corporation | Date: 2013-08-19

Pre-stressed and precast concrete products; custom architectural precast building materials; non-metal decking; non-metal-cladding for construction and building; decking material made of cement. Custom manufacturing of pre-stressed and precast concrete products.

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