Flattened Domain Research Articles

A MATLAB code package for 2D/3D local slope estimation and structural filtering

Local slope is an important attribute that can help distinguish seismic signals from noise. Based on optimal slope estimation, many filtering methods can be designed to enhance the signal-to-noise ratio of noisy seismic data. We present an open-source MATLAB code package for local slope estimation and corresponding structural filtering. This package includes 2D and 3D examples with two main executable scripts and related subfunctions. All code files are in the MATLAB format. In each main script, local slope is estimated based on the well-known plane-wave destruction algorithm. Then, the seismic data are transformed to the flattened domain by utilizing this slope information. Furthermore, the smoothing operator can be effectively applied in the flattened domain. We introduce the theory and mathematics related to these programs and present the synthetic and field data examples to show the usefulness of this open-source package. The results of local slope estimation and structural filtering demonstrate that this package can be conveniently and effectively applied to the seismic signal analysis and denoising.

Reconstructing Seismic Images and Creating Pseudo-3D Volumes: a Machine Learning Approach

We describe how machine learning can be used to solve a range of interpolation problems regularly encountered in post-stack seismic data. In all experiments we train a U-net type of deep learning model on examples extracted in good-quality data areas. The 2D or 3D input images utilized for our training set are manipulated such that the inputs exhibit the same kind of problems as observed in the areas with poor, or missing data. We repair these poor data areas by applying the trained model. We show examples of interpolating missing traces, decreasing the bin-size (quadrupling the number of traces), and replacing a bad data patch in an undershoot area. We also demonstrate that these trained models are generic interpolators that can be reused without retraining to solve similar problems in other data sets. Finally, we use the same technology to create pseudo-3D volumes from 2D data. We present two workflows: a direct transformation approach and a transformation that takes place in the flattened domain. The latter approach is more demanding as it involves interpretation followed by flattening and unflattening the data.

Miocene seismic stratigraphy and geomorphology of Bibiyana gas field, Surma Basin, Bangladesh

An integrated approach using a three-dimensional (3-D) seismic survey over the Chevron-operated Bibiyana field in Bangladesh along with petrophysical well data and cores provides new insights into the stratigraphic development of the Miocene–early Pliocene Ganges Delta. From this, a sequence stratigraphic model was constructed for the Bibiyana field that more accurately depicts the internal architecture of the reservoir units of the field. As of 2019, Bibiyana field was producing approximately 1.3 billion SCF/day of gas and accounted for more than 45% of Bangladesh’s daily gas supply. The 3-D seismic volumes covering the field area were stratigraphically flattened using multihorizon seismic flattening techniques. The well-log data were also flattened to enable the wells to be tied and visualized within the flattened domain. Core data from the field were examined, interpreted, and integrated into the stratigraphic model. Reservoirs at Bibiyana are divided into a series of sequence stratigraphic units, each recognized by a seismically defined sequence boundary at both the base and the top of the units. Two types of major reservoir sandstones were observed: (1) erosional remnants of shallow-marine, tidal sandstones below sequence boundaries and (2) channel sandstones at the base of incised canyons above sequence boundaries. The focus of this investigation was on the architecture of the main reservoir known as the BB60 series (Miocene Bokabil Formation), containing approximately 50% of the field reserves. The BB60 series reservoir is an erosional remnant below a major sequence boundary (SB60) sealed by the thick canyon-fill prodelta shale of the BB55 interval. Channelized sandstones and associated mass transport deposits are present locally at the base of the canyon and have reservoir properties that contrast with the underlying and adjacent shallow-water, tidal-dominated deltaic sandstones of the BB60 reservoir. Multihorizon flattening of the seismic and well data in concert with 3-D visualization reveals the complexly eroded canyon system, incised into the underlying tidal deltaic deposits of the BB60 series. Similar erosional patterns are present in the underlying BH series reservoirs (Miocene Bhuban Formation), and the conceptual model developed for the BB60 reservoir can be applied and aide the understanding of the deeper reservoirs that are less well imaged by the existing seismic data. The recognition that unconformities with overlying canyon-fill shales seal many of the reservoirs at Bibiyana is critical in understanding and modeling the reservoir architecture and performance over time.

Retraction notice: Iterative deblending using the POCS algorithmin the approximate flattened domain

Retraction notice: Iterative deblending using the POCS algorithmin the approximate flattened domain

Editor's note: Iterative deblending using the POCS algorithm in the approximate flattened domain

Editor's note: Iterative deblending using the POCS algorithm in the approximate flattened domain

Expression of Concern: Iterative deblending using the POCS algorithm in the approximate flattened domain

Expression of Concern: Iterative deblending using the POCS algorithm in the approximate flattened domain

Retracted: Iterative deblending using the POCS algorithm in the approximate flattened domain

Retracted: Iterative deblending using the POCS algorithm in the approximate flattened domain

Iterative deblending using the POCS algorithm in the approximate flattened domain

Abstract We proposed an improved method to eliminate the interference generated by simultaneous-source acquisition, which can help shorten the acquisition period and improve the quality of seismic data. An iterative mathematical framework is devised, which uses the projection onto convex sets algorithm to estimate the blending noise subtracted from the pseudo-deblended data to separate the blended data in an iterative way. Differently to the conventional method using the coherent-promoting operator only based on the curvelet transform, we combine the curvelet transform and the approximate flattened operator (AFO) to improve the deblended result, which can flatten seismic events approximately to preserve the details of useful signals. This is the first time that the AFO and the curvelet transform are combined to enhance the effect of the coherent-promoting operator and improve the performance of deblending. To display the advantages of the improved method, we use both simulated synthetic data and field data examples to compare and analyse the deblended results using our method and the conventional method, and confirm that the improved method can perform better.

Boundary First Flattening

A conformal flattening maps a curved surface to the plane without distorting angles—such maps have become a fundamental building block for problems in geometry processing, numerical simulation, and computational design. Yet existing methods provide little direct control over the shape of the flattened domain, or else demand expensive nonlinear optimization. Boundary first flattening (BFF) is a linear method for conformal parameterization that is faster than traditional linear methods, yet provides control and quality comparable to sophisticated nonlinear schemes. The key insight is that the boundary data for many conformal mapping problems can be efficiently constructed via the Cherrier formula together with a pair of Poincaré-Steklov operators ; once the boundary is known, the map can be easily extended over the rest of the domain. Since computation demands only a single factorization of the real Laplace matrix, the amortized cost is about 50× less than any previously published technique for boundary-controlled conformal flattening. As a result, BFF opens the door to real-time editing or fast optimization of high-resolution maps, with direct control over boundary length or angle. We show how this method can be used to construct maps with sharp corners, cone singularities, minimal area distortion, and uniformization over the unit disk; we also demonstrate for the first time how a surface can be conformally flattened directly onto any given target shape.

Enhancing seismic reflections using empirical mode decomposition in the flattened domain

Due to different reasons, the seismic reflections are not continuous even when no faults or no discontinuities exist. We propose a novel approach for enhancing the amplitude of seismic reflections and making the seismic reflections continuous. We use plane-wave flattening technique to provide horizontal events for the following empirical mode decomposition (EMD) based smoothing in the flattened domain. The inverse plane-wave flattening can be used to obtain original curved events. The plane-wave flattening process requires a precise local slope estimation, which is provided by the plane-wave destruction (PWD) algorithm. The EMD based smoothing filter is a non-parametric and adaptive filter, thus can be conveniently used. Both pre-stack and post-stack field data examples show tremendous improvement for the data quality, which makes the following interpretation easier and more reliable.

Free Word Order, (Non)configurationality, and Phases

The article argues that a particular implementation of phase theory makes it possible to account for seemingly contradictory facts of Hungarian that no other framework has been able to handle. Namely, (a) Hungarian word order is fixed preverbally and free postverbally. The fixed word order of a string is liberated when it is crossed by V-movement. (b) Grammatical phenomena sensitive to c-command provide evidence of both configurationality and nonconfigurationality. The proposal is based on the following assumptions: The derivation of the Hungarian sentence involves a lexical phase (PredP) and a functional phase (a TP or a FocP), both headed by the raised V. When the functional phase is constructed, the silent lower copies of the V and their projections are deleted, which results in the flattening of the phasal domain. Grammatical phenomena indicative of a hierarchical structure are interpreted on the hierarchical domain of the lexical phase, whereas those indicative of a flat structure are interpreted on the flattened domain of the functional phase. The sister constituents of the flattened domain of the functional phase can be linearized in a free order in PF.

Geodynamic implications of flattened tabular equigranular textured peridotites from the Bakony-Balaton Highland Volcanic Field (Western Hungary)

Abstract Peridotite xenoliths showing unusual tabular equigranular textures (addressed as flattened tabular equigranular) were found in Neogene alkali basalts from the Bakony-Balaton Highland Volcanic Field (Western Hungary), Carpathian-Pannonian Region. The olivines have a characteristic crystallographic preferred orientation (CPO) with [0 1 0]-axes perpendicular to the foliation and the [1 0 0]- and [0 0 1]-axes forming a continuous girdle in the foliation plane. Contrarily, the CPO pattern of orthopyroxene is much more scattered, although a single maximum can be observed in [0 0 1] axes subparallel to the plane of foliation. In case of olivine, the activation of (0 1 0)[1 0 0] and also probably (0 1 0)[0 0 1] is suggested. The deformation micro-mechanisms of orthopyroxenes are suggested to be a combination of intracrystalline glide on the (1 0 0)[0 0 1] system and some kind of other mechanism resulting in quite scattered patterns. We suggest that the unusual orientation patterns of olivines and orthopyroxenes are the result of the complex tectonic evolution of the region. The flattened tabular equigranular xenoliths represent a structural domain within the subcontinental lithospheric mantle beneath the volcanic field with particular seismic characteristics. The occurrence of flattened domains in the upper mantle may considerably influence the percolation and residence time of the mantle melts and fluids, which could promote or prevent melt/wall-rock interaction.

Targeting caveolae for vesicular drug transport

Caveolae are morphologically evident as omega-shaped invaginations of the plasma membrane with a diameter of 50–100 nm. They may also exist in a variety of other forms including flattened domains indistinguishable from the plasma membrane itself. At least in some cell types caveolae undertake transport functions including that of the endocytic and transcytotic movement of macromolecules, and indeed microbes and microbial toxins. Opportunities exist for basic and applied investigators working within the pharmaceutical sciences to exploit caveolae membrane interactions with the aim to develop of novel cellular or transcellular drug delivery strategies. This overview article will provide: pertinent information on the biology of the caveolae membrane system; review the various caveolae isolation methods; highlight some of the literature evidence showing that caveolae are functional with regard to macromolecule transport; discuss the role that caveolae could fulfill in the pulmonary absorption of therapeutic proteins from alveolar airspace to capillary blood following inhalational drug delivery, and finally review some very recent work showing proof-of-principle that caveolae domains can be targeted in a tissue-specific manner with highly selective ligands.

Scatter factor induces segregation of multinuclear cells into several discrete motile domains.

The effects of scatter factor, HGF/SF, on multinuclear MDCK epitheliocytes were examined. Multinuclear cells were obtained by blocking cytokinesis by low concentration of cytochalasin D; these large cells had discoid shape and did not move much on the substrate. Incubation of these cells with HGF/SF induced their profound reorganization: their cytoplasm was reversibly segregated into several individually moving motile flattened domains, termed lamelloplasts and connected with one another by cylindrical domains termed cables. One or several nuclei were present in many lamelloplasts, but some lamelloplasts were anuclear. Nuclei were absent from the cables. Lamelloplasts continuously formed actin-rich ruffles at their edges; their cytoplasm contained small actin bundles and numerous focal adhesions. In contrast, cable, had no ruffles or focal adhesions. Dense networks of vimentin and keratin intermediate filaments were present in lamelloplasts; bundles of filaments of both types were seen in the cables. Segregation was accompanied by redistribution of centrosomes from perinuclear zone into lamelloplasts. As a result each lamelloplast in segregated cell acquired individual complex of centrosome and radiating microtubules. The cables contained numerous parallel microtubules but never had centrosomes. This reorganization of microtubular system was essential for segregation as alterations of shape and actin cytoskeleton were prevented by microtubule specific drugs: colcemid and Taxol (paclitaxel). It is suggested that mechanism of segregation is based on activation of two types of opposite actin reorganization: formation of actin networks in lamelloplasts and their dismantlement in the cables. Spatial distribution of the domains in which these opposite types of reorganizations occur may be regulated by microtubular system. It is also suggested that mechanisms of HGF/SF-induced segregation may be closely related to the mechanisms of important physiological reorganizations of cells, such as polarization of pseudopodial activities in motile cells and cytokinesis.

Phase Morphology of High-Impact-Strength Blends of EPDM and Polypropylene. Knit-Line Behavior

Abstract The blend morphologies of injection moldings of high-impact-strength blends of EPDM or mixtures of EPDM and high-density polyethylene (HDPE) in polypropylene have been elucidated by the use of several classical microscopic techniques. It is demonstrated that, when present, HDPE is located within the EPDM phase, where it probably functions predominantly as a viscosity modifier. Within the core, the dispersed phase has an equilibrium globular shape, whose size can be related to impact strength. Elsewhere, the shape of the dispersed phase accurately reflects the shear forces of viscous flow through the mold cavity. In effect, these small domains serve as tracer elements and provide visual evidence and verification for previously postulated flow patterns. Fast, laminar flow through the center of the cavity to the advancing front and then in a curved path to the wall creates shear patterns such that the dispersed phase is in sheetlike or disk-shaped domains at the melt front and in rapidly crystallized regions near the cold mold wall. When knit lines are formed by union of two melt fronts, these flattened domains are oriented perpendicularly to the flow direction, where they prevent adequate matrix union and probably act as stress concentrators which can provide additional loss of knit line strength. Less easily dispersed, higher viscosity EPDM compositions are recommended where knit-line strength is required.