Application Of Seismic Attributes Research Articles

Appraisal of reservoir quality for hydrocarbon-bearing deep-water Miocene sandstones incised valley, south-east Asian offshore Indus: An application of seismic attributes and instantaneous spectral porosity quantitative reservoir simulations

Incised marine valleys (IVS) are hot topics in exploring the stratigraphic oil and gas-bearing plays. Multiple channelized sandstone lenses at varying depths [m], thicknesses [m], and porosities [%] constrain seismic impedance. The presence of hydrocarbon-bearing resources affects the seismic impedance (density (g/cc) and velocity (m/s)). Therefore, a quantitative prediction has been carried out for determining the thickness [m], porosity [%], and depths [m] of laterally distributed channelized sandstone lenses (SLS) for IVS, Indus offshore Basin (IOB), Pakistan, using 2-D instantaneous spectral porosity quantitative modelling (2DSSM), continuous wavelet transforms-based (CWT) 2-D instantaneous spectral density modelling (2DSSDM), and spectral decomposition tools. The 2DSSM remained limited in predicting the number of channelized sandstone lenses and their quantitative stratigraphic attributes. The 45-Hz-based processing of conventional 2DSSM has resolved the two channelized sandstone lenses of the stratigraphic trap. The deepest channelized sandstone lens has attained 1–6 m thickness with a lateral extent of 3 km, within the porosity range of 18–33 %. The highest confidence level for predicted petrophysical attributes such as 13 m-thick pay zones, −0.08, −0.067, and −0.07 acoustic impedances [g/c.c.*m/s], and 28 % porosities with R2 > 0.85 have validated interpretations. The response of 45-Hz CWT waveform-based inverted density and thickness simulations has predicted the highest thicknesses and lowest densities of reservoir sandstones within the meandering channel belt of the deepwater depositional system. The predicted densities and thicknesses for the coarse-grained sandstone lenses of point bars were 1.8–1.9 g/cc and 15 m, respectively. In the same way, the quantitative estimates of predicted density and simulated thickness have shown a strong coefficient correlation (R2 > 0.80), which confirms the presence of gas-bearing prospects within the IVS. The facies-controlled migration is thought to be the movement of the reservoir facies of the point bars and channelled sandstone-filled lenses to the side.

The Application of Seismic Attributes in Fault Detection and Direct Hydrocarbon Indicator in Tomboy Field, Western-Offshore Niger Delta Basin

Seismic attribute analysis is important in subsurface data interpretation, such as seismic interpretation, which could involve seismic stratigraphic and structural interpretation. This interpretation is often hampered by seismic resolution and, sometimes, human inability to identify a subtle feature on the seismic. These factors have frequently led to the poor seismic interpretation of geologic features. Thus, an integral approach to studying structural patterns and hydrocarbon bearing zones using seismic attributes was carried out on the Tomboy field using 3D seismic data covering approximately 56 km2 of the western belt of the Niger Delta. The seismic volume underwent post-stack processing, which enhanced seismic discontinuities. A deep steering volume was first created, and several dip filters were applied to enhance faults in the study area. After that, curvature and similarity attributes were calculated on the dip-steered and fault-enhanced volume. These calculations show detailed geometry of the faults and zones of subtle lineaments. Six faults (F1, F2, F3, F4, F5 and F6) were identified and mapped. These faults range from antithetic to crest growth faults. Two major growth faults (F5 and F6) were revealed to dip in the northeast to southwest directions. A near-extensive crest fault (F4) appeared beneath the major faults. Although several minor fractures were displayed in the southern and central portions of the crest fault of the dipping seismic data, the southwest (F4) and growth fault, F6, are responsible for holding the hydrocarbon found within the identified closures. Using attributes on the seismic data increased confidence in mapping and interpreting structural features. Furthermore, energy attributes were used as Direct Hydrocarbon Indicators (DHI) to visualize viable areas within the study, which allows a more robust interpretation. Time slices were taken in regions of flat and bright spots. The spectral decomposition attribute was run on these slices to display areas of high amplitude reflection typical of hydrocarbon-bearing regions trapped mainly by regional to sub-regional growth faults. The surface attribute calculated on the generated surface shows that the field is predominantly controlled by faults serving as traps for hydrocarbon.

Synthetic transfer zone characterization using seismic attributes: An example from the Parihaka fault system in the Taranaki Basin, New Zealand

Synthetic transfer zones develop between fault segments that dip in the same direction, with relay ramps connecting the fault blocks separated by the different fault segments. The characteristics of the transfer zones are controlled by the lithology, deformation conditions, and strain magnitude. The Parihaka fault is a northeast–southwest-trending set of three major en echelon faults connected by relay ramps in the Taranaki Basin, New Zealand. The structure in the basin is defined by extension during two episodes of deformation between the late Cretaceous and Paleocene and between the late Miocene and recent. To better understand the evolution of a synthetic transfer zone, we studied the geometry and secondary faulting between the individual fault segments in the Parihaka fault system using structural interpretation of 3D seismic data and seismic attributes. This interpretation allows for a unique application of seismic attributes to better study transfer zones. Seismic attributes, such as coherence, dip, and curvature, are effective tools used to understand the detailed geometry and variation in displacement on the individual faults, the nature of secondary faulting along the transfer zones, and the relationship between the faults and drape folds. The seismic characterization of the fault system of Miocene to Pliocene age horizons highlights variations in the degree of faulting, deformation, and growth mechanism associated with different stages of transfer zone development. The coherence, dip, and curvature attributes indicate a direct correlation with structural parameters such as deformation, folding, and breaching of relay ramps. All three attributes enhance the visualization of the major and associated secondary faults and better constrain their tectonic history. The observed correlation between the seismic attributes and structural characteristics of transfer zones can significantly improve the structural interpretation and exploration workflow.

A reappraisal of legacy reflection seismic data from the western margin of the Kaapvaal craton, South Africa, with implications for Mesozoic-Cenozoic regional tectonics

The 150 km long, 6 s TWT, 2D seismic profile KBF03A, which was acquired in 1994 and lies near the western edge of the Kaapvaal craton in South Africa, has been reprocessed using standard reflection seismic processing methods. The results exhibit a significant improvement in the imaging quality of the subsurface features and an evident boost in the signal-to-noise ratio. The improved seismic data, combined with application of seismic attributes, integration with surficial geological and geophysical maps, and computation of velocity tomograms, has revealed previously undetected structural features within the supracrustal sequences underlying the profile. In particular, the Phanerozoic sediments found along the profile, comprising exclusively Kalahari Group and Dwyka Group deposits, are disrupted by multiple folds of varying wavelengths (~1–10 km) and variably oriented normal and thrust faults. Additionally, the effect of the Moshaweng fault, previously characterised as a listric fault extending to depths of >10 km, on the Phanerozoic sediments has been further constrained to suggest repeated extensional reactivations and a more recent (<1 Ma) inversion. Considerations of the eastern end of the profile have suggested links between some of the observed structural features and the nearby ~146 Ma Morokweng impact structure, the lateral expanse of which is poorly constrained in the literature. The collection of these newly imaged features is interpreted as evidence for multiple Late Mesozoic to Cenozoic tectonic events, including polyphasic reactivation of basement structures, under both extensional and compressional stress regimes. By analysing these newly detected features, our study not only provides new insight into the neotectonic evolution of the Phanerozoic sediments along the western margin of the Kaapvaal craton, but also demonstrates the utility in reprocessing legacy data and reveals its untapped potential.

НОВЫЙ МЕТОДИЧЕСКИЙ ПОДХОД К ОЦЕНКЕ ХАРАКТЕРИСТИК ПАЛЕОРУСЛОВЫХ ТЕЛ ПО РЕЗУЛЬТАТАМ АТРИБУТНОГО АНАЛИЗА В РАЗЛИЧНЫХ ГЕОЛОГИЧЕСКИХ УСЛОВИЯХ

The paper presents the results of studying the characteristics of paleochannel targets using seismic (3D) and well data based on the use of dynamic attributes. The paper demonstrates methodological approaches to the application of seismic attributes in the pay interval. As a result, the applicability of various attributes for the selection of paleochannels was analyzed. Effective thicknesses of the central channel, identified by attributes, were determined based on the spectral decomposition of the peak frequency. The results obtained are consistent with those obtained using well data based on geostatistical analysis. The methodological approach presented in the paper can be used in various oil and gas regions.

Application of Multi Attributes for Feasibility Study of Fractures and Structural Anomalies in Malaysian Basin

There have been lots of efforts to study the geological characteristics and structure of the Malaysian Basin. Faults and fractures are of great importance due to the role they can play affecting different phases of a hydrocarbon prospect life from exploration through production and even abandonment. Carbonate build-ups are another type of significant geological anomalies in the area; because they are proved to be promising prospects. Application of seismic attributes on three dimensional seismic data has been proved to be useful in the study of such features. Each attribute is based on certain property of the seismic data which itself is the result of relevant geological phenomena. In this paper, different seismic attributes that can emphasize on the aforementioned geological anomalies are used in Malaysian Basin. Based on the results and their comparison, it is seen that combination of the results of different attributes can provide a much more convenient outcome.

The Application of Seismic Attributes and Wheeler Transformations for the Geomorphological Interpretation of Stratigraphic Surfaces: A Case Study of the F3 Block, Dutch Offshore Sector, North Sea

This study was carried out in the Pliocene interval of the southern North Sea F3 Block in the Netherlands. This research paper demonstrates how an integrated interpretation of geological information using seismic attributes, sequence stratigraphic interpretation and Wheeler transformation methods allow for the accurate interpretation of the depositional environment of a basin, as well as locating seismic geomorphological features. The methodology adopted here is to generate a 3D dip-steered HorizonCube followed by chronostratigraphic analysis, 3D Wheeler transformation, and system tract interpretation. A dip-steered seismic attribute (similarity, dip, and curvature) was performed on each stratigraphic surface of interest and the isopach maps were generated for each stratigraphic surface to help identify the maximum deposition. The results of this study show that the similarity attribute is able to identify distinct stratigraphic features such as sand-waves and deep marine meandering channels. However, its lateral continuity is poorly understood, as the similarity attribute does not take into account the true geological dip and curvature of the surfaces. Structural features such as faults are not easily recognizable due to these reasons. However, the dip-apparent attributes are found to be very useful in identifying both the structural and stratigraphic features. The seismic dip map is then improved by rotating the dip measurements to user-defined azimuths. Such optimization has revealed the structural and stratigraphic features that are not clearly evident on the similarity and curvature attributes. The maximum curvature attribute is found to be useful in delineating faults and predicting the orientation and distribution of fractures and also in subtle structural features.

Application of seismic attributes for constraining Magnetotelluric Inversion

SUMMARY Unconstrained inversion of surface magnetotelluric data generates non-uniqueness solutions. Boundaries derived from seismic reflectively images have the potential to substantially improve MT inversion. Seismic should be highly beneficial where significant and strong reflectors can reasonably be associated with contrast in electrical conductivity across well-defined relatively continuous boundaries. We show how seismic reflections can assist in defining such inversion controls as the smoothness penalty across known boundaries. We apply and compare a range of cooperative inversion strategies using large scale co-located magnetotelluric and seismic reflection field data sets from the Carlin style gold district in Nevada USA.

Application of seismic attributes in structural study and fracture analysis of DQ oil field, Iran

The determination of the most unstable areas in oil fields is critical for addressing engineering problems of wellbore and sand production as well as geologic problems such as understanding dynamic constraints on hydrocarbon migration and fracture permeability. In this research work, coherency seismic attribute has been used for the determination of the most critical areas in terms of drilling stabilities in the DQ oil field, Iran. The results obtained have shown that the (1) predominant features are the SSE–NNW and N–S trends (2) the central part of the DQ structure shows the highest concentration of segment bundles, (3) the segment bundles seem to be aligned along some lineaments oriented SE–NW and SSE–NNW, and (4) on the eastern and western margins of the map there is an anomalous concentration of segments oriented E–W. It can be concluded that coherency attribute is a valuable tool for structural analysis highlighting those areas containing unstable features.

3D seismic attributes for structural analysis in compressional context: A case study from western Sichuan Basin

Compressional region usually forms complex thrust faults system, which is difficult to identify using traditional migration profiles. The successful application of three-dimensional (3D) seismic attributes analysis greatly reduces the difficulty, and improves the accuracy and efficiency of seismic interpretation and structural analysis. In this paper, we took Qiongxi area in the compressional region of western Sichuan as an example, using two 3D seismic attributes, coherence and instantaneous phase, to identify fault assemblages and variations both vertically and laterally. The results show that the study area mainly consists of NS-, NE- and NEE-trending faults. The NS-trending faults are the largest and have a component of sinistral slip controlling the formation of NEE-trending faults, while the NE-trending faults are intermediate in scale, formed earlier and were cut by the NS-trending faults. Our results demonstrate that using seismic attributes for structural analysis have the following advantages: (1) more details of major fault zones, (2) highlighting minor faults which are hardly traced in seismic migration cube, and (3) easier acquisition of accurate fault systems. The application of seismic attributes provides a new idea for deciphering fine and complicated structures, and will significantly contribute to the development of objective and precise geological interpretation in the future.

Application of seismic attributes and spectral decomposition for reservoir characterization of a complex fluvial system: Case study of the Carbonera Formation, Llanos foreland basin, Colombia

Hydrocarbon exploration in the Llanos foreland basin of eastern Colombia has traditionally focused on structural traps. However, in the past decade, the country’s oil demand has generated an increased interest in exploration for stratigraphic traps. We integrated [Formula: see text] of 3D seismic data volumes with eight wells in the Central Llanos area to assess the reservoir potential of the fluvial channel deposits of the Late Eocene–Oligocene Carbonera Formation in the Casanare Province. Distinguishing nonproductive, mud-filled channels from productive sand-filled channels is of economic importance for hydrocarbon exploration because both channel types can exhibit a similar seismic character. Our interpretation of the fluvial sandstone and the reservoir identification was based on 3D seismic attributes, including coherence, curvature, and spectral decomposition, and the analysis of fluvial geomorphology. Analysis of stratal slices through coherence, isofrequency amplitude cubes, and curvature cubes revealed (1) a northeast-trending meandering fluvial system with changes in the rivers’ paleoflow direction from southwest to northeast during the period of the Late Eocene to the Early Miocene, (2) development of prospective sandy point bars, scrolls, and sand bar deposits, and (3) channel ridges and bases accentuated by differential compaction dependent on the channel’s filling material. Based on our attribute analysis, we were able to characterize nonprospective mud-filled channels versus prospective sand-filled channels.

Application of Seismic Attributes Using Image Fusion for Small Structure Interpretation in Coalmine

The small structures can directly affect the admissibility of the coal seam, the mining schedule, cost and safety. Seismic attributes extracted from seismic data can be used to identify small structures; However, geophysical methods often have multiple solutions, this will make the results of interpretation become unreliable. In this paper we will use image fusion technology to fuse a variety of seismic attributes, and then make full use of the complementarity of different attributes to reduce the multiple solutions, and make the seismic attributes more accurately in predicting small structures in coalmine.

The Optimization and Application of Seismic Attribute – In Depicting Reservoir Sand Bodies

Right now the application of seismic attributes in China is almost only qualified. Given this situation 2D crossplot analysis, the unary linear regression method and the method of fuzzy clustering analysis are applied to get the seismic attributes from the 3D data volume of oilfield C. The seismic attributes are then quantified and the ones which are good for depicting the reservoir are found and fine depict, thus the application of the seismic attributes is more specifically. It provides good idea and method for the optimization and application of seismic attributes.

Study and Application of Seismic Attributes on Coal Seam Thickness Prediction

Seismic wave contain more information about the sediments. The seismic attributes has some relationship with the coal seam thickness. Through analysis of the wedge-shaped coal seam’s seismic attributes, when the seam thickness is less than the tuning thickness, there is proportional relationship between the amplitude value and seam thickness; while the apparent time difference between the wave peak and trough is not sensitive. When the coal seam thickness is above the tuning thickness, the conclusion is opposite. As a result, it’s difficult to predict the coal seam thickness only by using one single attribute. Therefore, we use the nonlinear-regression method to analyze the relationship between the seam thickness and both attributes, and get a method to predict the coal seam thickness. With the method we predict the coal seam thickness in a coal mine and get a perfect result.

Application of seismic attributes and neural network for sand probability prediction — A case study in the North Malay Basin

Application of seismic attributes and neural network for sand probability prediction — A case study in the North Malay Basin

ABSTRACT: Reservoir Characterization using 3D AVO and 3D Net Sand Prediction

Abstract The major issues that face us today revolve around economics. Finding hydrocarbons has been made easier with 3D data, but the proper delineation and quality of the deposit still often elude us. Application of a series of amplitude attributes indicates that applying one technology, such as Amplitude Strength, is not enough. The issues that impact the economics of a reservoir are varied and complex, therefore multiple techniques must be used to address them. Application of seismic attributes to three areas of the Gulf of Mexico, in a consistent manner, demonstrates how effective technology can be when applied properly. The three areas examined all had similar Amplitude Strength, but drilling results in the area produced varied results. The Mississippi Canyon 486 field was first examined because of the strong variation in reservoir thickness. The sixteen wells drilled in the field have a gross thickness variation of 160 feet, and net thickness variation of 105 feet. Amplitude maps over the field do not indicate this complexity, and agree very poorly with the drill results. Advances in technology, mainly in the areas of AVO, Thickness, and Rock Property estimation, offer a much clearer picture of the reservoir size. Similar technology applied to a second area correctly predicted the poor outcome of an initial well and indicated the presence of cleaner and thicker reservoir in the immediate area. A sidetrack was drilled and an economic discovery was announced. The third location also has a strong amplitude anomaly similar to the other two. The AVO signature suggests the presence of hydrocarbons, but thickness predictions indicate very low net/gross sand ratios in the reservoir. The well drilled into the anomaly was plugged and abandoned. End_of_Record - Last_Page 474-------

Seismic attributes for reservoir monitoring: A feasibility study using forward modeling

The application of seismic attributes to 3-D monitoring surveys is the logical extension of their use in reservoir characterization. This study examines attributes used to map reservoir characteristics to determine if they can efficiently and accurately map fluid displacement during production.