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Amplitude Variation with Offset (AVO) is a technique that has been widely used as a reliable indicator of hydrocarbon expressions in seismic data. The technique uses mathematical approximations and approaches in order to estimate variations in seismic amplitude as a function of incidence angle, and related them to lithology and pore-fluids. In this study, a new AVO attribute is presented. The Energy-weighted AVO attribute uses Zoeppritz approximations and exploits the fact that hydrocarbon-bearing sediments show anomalous seismic responses relative to their backgrounds. The new AVO attribute emphasizes this hydrocarbon-associated effect and attenuates the background signal. In addition, the fact that the attribute integrates the signatures of conventional AVO attributes (intercept × gradient) with seismic data makes the discrimination of hydrocarbon anomalies from other anomalies caused by anomalous lithologies such as coal, carbonates or salt, straightforward. More interestingly, the new attribute can be applied to both prestack and poststack data. This indeed would solve several problems and difficulties encountered with prestack data, as prestack data are generally less readily available, and have a much lower signal to noise ratio. The process has been examined using synthetic data generated from Zoeppritz equations, and then applied to real prestack and poststack data. At all stages, promising results have been derived and the hydrocarbon effect and extent could be successfully predicted, also the AVO effect of hydrocarbons could be investigated even in the poststack data.

Searching for hydrocarbon reserves in deep subsurface is the main concern of wide community of geophysicists and geoscientists in petroleum industry. Exploration seismology has substantially contributed to finding and developing giant fields worldwide. The technology has evolved from two to three-dimensional method, and later added a fourth dimension for reservoir monitoring. Continuous depletion of many old fields and the increasing world consumption of crude oil pushed to consistently search for techniques that help recover more reserves from old fields and find alternative fields in more complex and deeper formations either on land and in offshore. In such environments, conventional seismic with the compressional (P) wave alone proved to be insufficient. Multicomponent seismology came as a solution to most limitations encountered in P-wave imaging. That is, recording different components of the seismic wave field allowed geophysicists to map complex reservoirs and extract information that could not be extracted previously. The technology demonstrated its value in many fields and gained popularity in basins worldwide. In this review study, we give an overview about multicomponent seismology, its history, data acquisition, processing and interpretation as well as the state-of the-art of its applications. Recent examples from world basins are highlighted. The study concludes that despite the success achieved in many geographical areas such as deep offshore in the Gulf of Mexico, Western Canada Sedimentary Basin (WCSB), North Sea, Offshore Brazil, China and Australia, much work remains for the technology to gain similar acceptance in other areas such as Middle East, East Asia, West Africa and North Africa. However, with the tremendous advances reported in data recording, processing and interpretation, the situation may change.

Vertical Seismic Profile (VSP) surveying is a vital tool in subsurface imaging and reservoir characterization. The technique allows geophysicists to infer critical information that cannot be obtained otherwise. MVSP is a new MATLAB tool with a graphical user interface (GUI) for VSP shot modeling, data processing, and interpretation. The software handles VSP data from the loading and preprocessing stages to the final stage of corridor plotting and integration with well and seismic data. Several seismic and signal processing toolboxes are integrated and modified to suit and enrich the processing and display packages. The main motivation behind the development of the software is to provide new geoscientists and students in the geoscience fields with free software that brings together all VSP modules in one easy-to-use package. The software has several modules that allow the user to test, process, compare, visualize, and produce publication-quality results. The software is developed as a stand-alone MATLAB application that requires only MATLAB Compiler Runtime (MCR) to run with full functionality. We present a detailed description of MVSP and use the software to create synthetic VSP data. The data are then processed using different available tools. Next, real data are loaded and fully processed using the software. The data are then integrated with well data for more detailed analysis and interpretation. In order to evaluate the software processing flow accuracy, the same data are processed using commercial software. Comparison of the processing results shows that MVSP is able to process VSP data as efficiently as commercial software packages currently used in industry, and provides similar high-quality processed data.

Seismic attributes along with seismic inversion are used to study a challenging reservoir facies from Boonsville field in north central Texas. Two thin reservoirs, Upper Caddo and Lower Caddo, separated by a nonproductive thin limestone formation are investigated. Seismic was not an unambiguous indicator of the Caddo reservoir. The Caddo event exhibits doublet character reflections when productive facies are present. However, this character proved to be a false diagnostic of the Caddo reservoir. Wells drilled on interpreted doublet reflections turned out to dry holes penetrating two thin limestone units instead. First, some modern poststack processing techniques are used to remove incoherent noise and improve the data resolution and interpretability. Seismic instantaneous attributes (i.e., amplitude, phase, and frequency) are then calculated to infer seismic expressions of the reservoir and the limestone formations. Next, spectral decomposition is performed to study the frequency responses of the different lithotypes. Interestingly, the attribute images and frequency maps could distinguish between the different investigated units. However, some limestone units show up similar to the Lower Caddo formation in the frequency images. Model-based acoustic impedance inversion is carried out on seismic lines spanning both zones. Acoustic impedance sections reveal that producing wells and dry wells penetrate different formations. The cosine of instantaneous phase attribute along with impedance sections supports the above interpretations and displays more clearly where the Caddo reservoir is traversed and where it is not. This study demonstrates that integration of modern poststack processing and novel seismic attributes can lead to extract more key information about challenging reservoirs with less ambiguity.

Stacking process in seismic data processing is a simple and powerful tool commonly used to remove undesired random noise and enhance signal to noise ratio. Basically, the process averages traces from prestack gathers (angles or CDPs) so that they present normal-incidence reflections in stack sections. Experience has showed that hydrocarbons-bearing sediments are generally characterized by anomalous amplitude changes relative to their background from an offset to another. This can result in interesting seismic expressions in the stack section that can help identify reservoirs and delineate their extensions. This paper investigates the conceptual assumptions behind stacking and amplitude variation with offset (AVO). A new attribute is presented and used to detect and extract anomalies associated with hydrocarbon sand reservoirs from their background. The attribute has been examined on real datasets from different fields. The seismic-weighted instantaneous energy attribute showed excellent results in delineating bright spots associated with shallow gas accumulations as well as revealing stratigraphic features of two productive sand-filled channels. Indeed, the paper provides a new insight into seismic stack data analysis and interpretation.

Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) data were analyzed for the Nohwa deposit area, Korea. The data were calibrated to reflectance using crosstalk correction and atmospheric correction and then used to map pyrophyllite distribution in surface by using band math, combination of Spectral Angle Mapper (SAM), and Matched Filtering (MF) technique. Results from two methods show generally close agreement with the existing alteration map. However, some pixels extracted by band math were vegetation areas not associated with pyrophyllite. In contrast, combination of SAM and MF could detect more accurately areas associated with pyrophyllite than band math. Furthermore, the regional distribution of high-grade and low-grade pyrophyllite in the Nohwa deposit area could be differentiated by combination of SAM and MF. Classification map, according to pyrophyllite grade, using ASTER data is likely to provide ancillary information in development of open-pit mine.

The Oyu Tolgoi porphyry Cu–Au deposits, Southeastern Gobi, Mongolia, are estimated to be among the world's largest reserves. Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) reflectance and emissivity data were used to map distribution patterns of hydrothermal alteration and igneous rocks, and to locate areas with potential mineral deposit in the Oyu Tolgoi region. To obtain more accurate information for the detection and classification of minerals, pre-processing such as crosstalk correction and additional radiometric correction was performed. The shortwave infrared band ratio logical operator (SWIR-BRLO) models and matched filtering were used to map alteration zone and minerals in the Oyu Tolgoi region. These results were fairly consistent with mineralogical information of previous researches. In addition, we identified mineral potential areas with characteristics similar to the Oyu Tolgoi Cu–Au deposits. In particular, in the northwestern part of the OT North Pluton, an extensive area predicted to be an argillic zone was newly detected. ASTER Level 2B surface emissivity data was effectively used for lithological mapping of the Oyu Tolgoi region. The new thermal infrared band ratio logical operator (TIR-BRLO) models could detect areas showing emissivity features of quartzose and alkalic rocks. These results indicate that despite some limitations, ASTER data can provide basic information in the initial steps of ore deposit exploration, or when mapping the distribution of altered, quartzose and igneous rocks, especially in areas where direct field survey is difficult.

Over the last few decades, many porphyry Cu deposits have been discovered in southeastern (SE) Mongolia. In particular, the Gurvansayhan and Mandalovoo island arc terranes, have high potential for ore deposits. Regional mineral mapping of these terranes using data from the Landsat Enhanced Thematic Mapper Plus (ETM+) and the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) have provided new geological information on the metallogenic province, revealing potential mineral deposits for future explorations. Iron oxides/hydroxides with high ETM+ band 1/3 ratio values occur extensively in Quaternary deposits located at the boundary between the Gurvansayhan and Mandalovoo island arcs terranes and basins. The high average band ratios (>1.35) registered for the porphyry Cu and Au deposits and their occurrences are associated with iron oxidation which originates from the erosion and weathering of ore zones. Regional mapping of the island arc terranes using the ASTER shortwave infrared (SWIR) logical operators showed circular or semicircular alteration patterns which usually cluster along faults. The mineral assemblages mapped by the ASTER SWIR analysis in five major porphyry Cu districts can be divided into two types. The first type includes argillic, phyllic, and propylitic mineral assemblages, as exemplified by the Shuteen, Ikh Shankhai, and Oyu Tolgoi deposits. The second type of assemblage includes phyllic and propylitic mineral assemblages, as exemplified by the Kharmagtai and Tsagaan Suvarga deposits. Within the deposits of the first type, quartz was also mapped using the ASTER thermal infrared (TIR) mineral index. The difference between the two types may be related to the presence of a lithocap. The results of a field survey including spectral reflectance measurements in the Ikh Shankhai porphyry Cu district, showed a good correlation with the image analysis results.

The crystallization behavior of wollastonite glass-ceramics was investigated by means of X-ray diffraction (XRD) analysis and surface morphological observations, and the chemical compositions were evaluated by field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectroscopy (EDS). Various heat treatment temperatures (850, 900, 950, 1000 and 1050 °C) were used to obtain glass-ceramics of the ideal wollastonite crystal phase as well as optimum mechanical properties and chemical durability. From XRD, FE-SEM and EDS, the crystallization of acicular crystal phase in the matrix was achieved at heat treatment temperature of 1000 and 1050 °C, and wollastonite (CaSiO3) was found in the acicular type main crystal phase in the glass-ceramics. Various properties, such as density, compressive strength, bending strength and chemical durability were also examined. The mechanical properties of glass-ceramics obtained at the heat treatment temperature of 1000 and 1050 °C were superior to those obtained at the heat treatment temperature of 850 °C.

The basic concept behind seismic inversion is that mathematical assumptions can be established to relate seismic to geological formation properties that caused their seismic responses. In this presentation we address some widely used seismic inversion method in hydrocarbon reservoirs identification and characterization. A successful use of the inversion in real example from gas sand reservoir in Boonsville field, Noth Central Texas is presented. Seismic data was not unambiguous indicator of reservoir facies distribution. The use of the inversion led to remove the ambiguity and reveal clear information about the target

Seismic attributes are defined as any measured or computed information derived from seismic data. Throughout the last decades extensive work has been done in developing variety of mathematical approaches to extract maximum information from seismic data. Nevertheless, geoscientists found that seismic is still mature and rich in information. In this paper a new seismic attribute is introduced. Instantaneous energy seismic attribute is an amplitude based attribute that has the potential to emphasize anomalous amplitude associated with hydrocarbons. Promising results have been obtained from applying the attribute on seismic section traversing hydrocarbon filled sand from Alberta, Canada.

Blackfoot field, Alberta, Canada, has produced oil and gas from a Glauconitic compound incised valley-system. In this area channels can be filled with sands and/or shales. Differentiation of prospective channel sands and non-productive shales was always problematic due to the similarity in P-wave impedance of these two lithotypes. We study the spectral decomposition response to the hydrocarbons presence in the Glauconitic channel of Early Cretaceous age. From previous AVO analysis and modeling, a strong Class III AVO anomaly has been observed at the top of the porous sandstone in the upper valley, whereas shale had a very different AVO response. Furthermore, AVO inversion revealed additional information about lithology and fluid content in the channel. Our workflow starts from selecting a continuous horizon that was close and conforms to the channel interval; we then run spectral analyses for the channel area. Short Window Fourier Transform workflow could successfully image the channel's stratigraphic features and confirm results obtained from AVO analysis and inversion run on the data before being stacked. Additionally, the producing oil wells in the sand-fill channel were found to be correlating with high spectrum amplitude; while the dry wells in the shale-plugged channel fell in low amplitude anomaly.

This paper describes a seismic object detection method using supervised neural networks to combine seismic attributes and transform them into a single ‘object probability’ attribute. Unlike other widely used methods, the approach incorporates interpreter's knowledge into the well-known process of combination of multiple attributes. In fact, the interpreter decides the anomaly to be addressed and picks examples of anomalies for the neural networks. The approach completely relies on the interpreter to select the input attributes. However, the limitation that this approach has over other approaches is that it does not incorporate machine intelligence to validate attribute selection. Thus, the present study attempts to overcome this limitation and uses neural networks in the process. The integration of a neural network has played a key role in determining the type and number of attributes used in the prediction and, thus, gives the approach more reliability and confidence. Furthermore, with the help of the ne...

Amplitude Variation with Offset (AVO) is a technique that has been widely used and proved to be a reliable indicator of hydrocarbons expression in seismic data. The technique uses mathematical approximations and approaches to estimate variations in seismic amplitude as function of incidence angle and relate them to lithology and fluids saturating the rocks in subsurface. In this work we introduce a new seismic attribute to investigate AVO anomalies associate with hydrocarbons. The Energy-weighted AVO (EAVO) attribute uses Zeoppritz approximations and exploits the fact that hydrocarbons-bearing sediments would show anomalous seismic responses relative to their backgrounds. The attribute attempts to emphasize hydrocarbons-associated effect and attenuate background signal. Unlike other conventional AVO attributes, the new attribute can be applied to both prestack and poststack data. We apply the attribute to synthetic data generated using Zoepprtitz equation and then we examine it on real detest. Intersting results have been obtained.

The purpose of this study is to map pyprophyllite distribution at surface of the Nohwa deposit, Korea by using Advanced Spaceborne Thermal Emission and Reflectance Radiometer (ASTER) data. For this, combined Spectral Angle Mapper (SAM), and Matched Filtering (MF) technique based on mathematical algorithm was applied. The regional distribution of high-grade and low-grade pyrophyllite in the Nohwa deposit area could be differentiated by this method. The results of this study show that ASTER data analysis using combination of SAM and MF techniques will assist in exploration of pyrophyllite at the exposed surface.

In this paper, we applied electrical resistivity monitoring method to evaluate the cement grouting effect. There are a lot of ways to evaluate cement grouting effect. In order to do this evaluation in a great safety, high efficiency, and lower cost, resistivity monitoring is found to be the most appropriate technique. In this paper we have selected a dam site from Korea to acquire resistivity monitoring data and compare the results of inversion to estimate the cement grouting effect.

Decomposing the seismic data into its spectral components can provide vital stratigraphic and structural details that cannot be seen in the broadband data. The technique shows excellent results particularly in tertiary basins such as the Gulf of Mexico and West Africa on which it was first implemented. Therefore many interpreters worried that it would not work well in other environments. Surprisingly, the method showed interesting results in older and less porous rocks with less contrast between shale and sand as well, and in different areas around the world. In this study, spectral decomposition has been performed in order to identify stratigraphic features of Glauconitic oil sand channel of Early Cretaceous age in Alberta, Canada. We selected first a continuous horizon that was close and conforms to the channel interval; we then implemented spectral analyses for the interval that corresponds to the channel location. Short Window Fourier Transform workflow could successfully image the channel’s stratigraphic features. Moreover, the producing oil wells in the sand-fill channel were found to be correlating with high amplitude spectrum; while the dry wells in the shale-plugged channel fell in low amplitude anomaly. Furthermore, spectral decomposition could discriminate the regional geology from sand-fill channel in dry wells located in relatively low impedance area where the differentiation using Pimpedance was ambiguous.

This paper presents the results of the surface current velocity estimation using 6 Radarsat-1 SAR images and high frequency (HF) radar data acquired in west coastal area near Incheon, Korea. We extracted the surface velocity from SAR images based on the Doppler shift approach in which the azimuth frequency shift is related to the motion of surface target in the radar direction. The extracted SAR current velocities were statistically compared with the current velocities from the HF-radar data. The corrected SAR current velocity inherits the average of HF-radar while maintaining high-resolution mature of the original SAR data.

Recently satellite SAR techniques have become essential observation tools for various ocean phenomena such as wind, wave and current. The CMOD4 and CMOD-IFR2 models are used to calculate the magnitude of wind at SAR resolution with no directional information. Combination of the wave-SAR spectrum analysis and the inter-look cross-spectra techniques provides amplitude and direction of the ocean wave over a square-km sized imagette. The Doppler shift measurement of SAR image yields surface speed of the ocean current along the radar looking direction at imagette resolution. In this paper we report the development of a SAR Ocean Processor (SOP) incorporating all of these techniques. We have applied the SOP to several RADARSAT-1 images along the coast of Korean peninsula and compared the results with oceanographic data, which showed reliability of space-borne SAR based oceanographic research.