scholarly journals Application of seismic attribute analysis in fluvial seismic geomorphology

2019 ◽  
Vol 10 (3) ◽  
pp. 1009-1019 ◽  
Author(s):  
Shakhawat Hossain

AbstractSeismic attributes can be important predictors, either qualitative or quantitative, of reservoir geometries when they are correctly used in reservoir characterization studies. This paper discusses seismic attribute analyses and their usefulness in seismic geomorphology study of Moragot field of Pattani Basin, Gulf of Thailand. Early to Middle Miocene fluvial channel and overbank sands are the reservoirs in Pattani Basin. Due to their limited horizontal and vertical distribution, it is not always possible to predict the geometry and distribution of these sands based on the conventional seismic interpretation. This study utilized various seismic attributes, e.g., RMS amplitude analysis, spectral decomposition, semblance and dip-steered similarity, RGB blending to image the geometry and the spatial distribution of sand bodies in horizon and stratal slices at different stratigraphic intervals. Attribute analyses reveal, at shallow stratigraphic levels, RMS and semblance can successfully identify channel-shaped sand bodies and mud-filled channels associated with channel belts. On the other hand in deeper stratigraphic intervals, sand distribution can be imaged more effectively by using spectral decomposition and dip-steered similarity volumes. High-frequency spectral decomposition slices can image thin sands, and low-frequency slices can image thick sands quite effectively in deeper intervals. RGB blending of different frequency slices is particularly useful in delineating channel systems of various dimensions at deeper intervals. These images show the distribution of sands and mud-filled channels at various stratigraphic levels. The width of channel belts varies from 200 m to 3 km. These channel belts are N–S or NW–SE oriented. From the channel pattern and their dimensions, depositional environments can be predicted. Mud-filled channels identified in the horizon slices will act as a connectivity barrier between sand bodies at either side of the channel. They can also act as lateral and up-dip seal to form stratigraphic traps. The seismic attribute analyses clearly show the geometry and spatial distribution of sand bodies. Hence, this method for predicting sand body geometry might help in field development planning as well as in reducing exploration risk.

2013 ◽  
Vol 807-809 ◽  
pp. 2639-2642
Author(s):  
Yu Ze Ren ◽  
Ning Ning Song ◽  
Shi Qiang Xia

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.


Geophysics ◽  
2020 ◽  
Vol 85 (4) ◽  
pp. O59-O70
Author(s):  
Sergius Dell ◽  
Jan Walda ◽  
Andreas Hoelker ◽  
Dirk Gajewski

Seismic attributes play a crucial role in fault interpretation and mapping fracture density. Conventionally, seismic attributes derived from migrated reflections are used for this purpose. The attributes derived from the other counterparts of the recorded wavefield are often ignored and excluded from the categorization. We have performed categorization of the attributes derived from the diffracted part of the wavefield and combine them into a new seismic attribute class, which we call diffractivity attributes. The extraction of diffractivity attributes is based on the 3D Kirchhoff time migration operator that includes a dynamic muting. We distinguish three major classes in the diffractivity attributes, which describe geometric and amplitude properties of the seismic diffractions. We assign point and edge diffraction focusing as well as the azimuth to the geometric class. The amplitudes of the isolated seismic diffractions are used to extract the instantaneous attributes based on the complex-trace approach. The instantaneous amplitudes, phase, frequency, and sweetness build up the instantaneous attribute class. We perform a spectral decomposition of the isolated diffractions into the isofrequencies using the wavelet approach. The isofrequencies compose the spectral-decomposition class. We also link the new diffractivity class to the conventional seismic reflection attributes. We use a deep learning approach based on convolutional neural networks for classifying and correlating the diffractivity attributes.


2010 ◽  
Vol 29 (6) ◽  
pp. 95-102
Author(s):  
Jian GONG ◽  
Shumei XU ◽  
Yun MA ◽  
Jianguo YU ◽  
Jinduo WANG

2020 ◽  
Vol 11 (1) ◽  
pp. 219
Author(s):  
Jing Zeng ◽  
Alexey Stovas ◽  
Handong Huang ◽  
Lixia Ren ◽  
Tianlei Tang

Paleozoic marine shale gas resources in Southern China present broad prospects for exploration and development. However, previous research has mostly focused on the shale in the Sichuan Basin. The research target of this study is expanded to the Lower Silurian Longmaxi shale outside the Sichuan Basin. A prediction scheme of shale gas reservoirs through the frequency-dependent seismic attribute technology is developed to reduce drilling risks of shale gas related to complex geological structure and low exploration level. Extracting frequency-dependent seismic attribute is inseparable from spectral decomposition technology, whereby the matching pursuit algorithm is commonly used. However, frequency interference in MP results in an erroneous time-frequency (TF) spectrum and affects the accuracy of seismic attribute. Firstly, a novel spectral decomposition technology is proposed to minimize the effect of frequency interference by integrating the MP and the ensemble empirical mode decomposition (EEMD). Synthetic and real data tests indicate that the proposed spectral decomposition technology provides a TF spectrum with higher accuracy and resolution than traditional MP. Then, a seismic fluid mobility attribute, extracted from the post-stack seismic data through the proposed spectral decomposition technology, is applied to characterize the shale reservoirs. The application result indicates that the seismic fluid mobility attribute can describe the spatial distribution of shale gas reservoirs well without well control. Based on the seismic fluid mobility attribute section, we have learned that the shale gas enrich areas are located near the bottom of the Longmaxi Formation. The inverted velocity data are also introduced to further verify the reliability of seismic fluid mobility. Finally, the thickness map of gas-bearing shale reservoirs in the Longmaxi Formation is obtained by combining the seismic fluid mobility attribute with the inverted velocity data, and two favorable exploration areas are suggested by analyzing the thickness, structure, and burial depth. The present work can not only be used to evaluate shale gas resources in the early stage of exploration, but also help to design the landing point and trajectory of directional drilling in the development stage.


Author(s):  
Atheer Dheyauldeen ◽  
Omar Al-Fatlawi ◽  
Md Mofazzal Hossain

AbstractThe main role of infill drilling is either adding incremental reserves to the already existing one by intersecting newly undrained (virgin) regions or accelerating the production from currently depleted areas. Accelerating reserves from increasing drainage in tight formations can be beneficial considering the time value of money and the cost of additional wells. However, the maximum benefit can be realized when infill wells produce mostly incremental recoveries (recoveries from virgin formations). Therefore, the prediction of incremental and accelerated recovery is crucial in field development planning as it helps in the optimization of infill wells with the assurance of long-term economic sustainability of the project. Several approaches are presented in literatures to determine incremental and acceleration recovery and areas for infill drilling. However, the majority of these methods require huge and expensive data; and very time-consuming simulation studies. In this study, two qualitative techniques are proposed for the estimation of incremental and accelerated recovery based upon readily available production data. In the first technique, acceleration and incremental recovery, and thus infill drilling, are predicted from the trend of the cumulative production (Gp) versus square root time function. This approach is more applicable for tight formations considering the long period of transient linear flow. The second technique is based on multi-well Blasingame type curves analysis. This technique appears to best be applied when the production of parent wells reaches the boundary dominated flow (BDF) region before the production start of the successive infill wells. These techniques are important in field development planning as the flow regimes in tight formations change gradually from transient flow (early times) to BDF (late times) as the production continues. Despite different approaches/methods, the field case studies demonstrate that the accurate framework for strategic well planning including prediction of optimum well location is very critical, especially for the realization of the commercial benefit (i.e., increasing and accelerating of reserve or assets) from infilled drilling campaign. Also, the proposed framework and findings of this study provide new insight into infilled drilling campaigns including the importance of better evaluation of infill drilling performance in tight formations, which eventually assist on informed decisions process regarding future development plans.


2015 ◽  
Vol 3 (1) ◽  
pp. SB5-SB15 ◽  
Author(s):  
Kurt J. Marfurt ◽  
Tiago M. Alves

Seismic attributes are routinely used to accelerate and quantify the interpretation of tectonic features in 3D seismic data. Coherence (or variance) cubes delineate the edges of megablocks and faulted strata, curvature delineates folds and flexures, while spectral components delineate lateral changes in thickness and lithology. Seismic attributes are at their best in extracting subtle and easy to overlook features on high-quality seismic data. However, seismic attributes can also exacerbate otherwise subtle effects such as acquisition footprint and velocity pull-up/push-down, as well as small processing and velocity errors in seismic imaging. As a result, the chance that an interpreter will suffer a pitfall is inversely proportional to his or her experience. Interpreters with a history of making conventional maps from vertical seismic sections will have previously encountered problems associated with acquisition, processing, and imaging. Because they know that attributes are a direct measure of the seismic amplitude data, they are not surprised that such attributes “accurately” represent these familiar errors. Less experienced interpreters may encounter these errors for the first time. Regardless of their level of experience, all interpreters are faced with increasingly larger seismic data volumes in which seismic attributes become valuable tools that aid in mapping and communicating geologic features of interest to their colleagues. In terms of attributes, structural pitfalls fall into two general categories: false structures due to seismic noise and processing errors including velocity pull-up/push-down due to lateral variations in the overburden and errors made in attribute computation by not accounting for structural dip. We evaluate these errors using 3D data volumes and find areas where present-day attributes do not provide the images we want.


1984 ◽  
Vol 21 (6) ◽  
pp. 698-714 ◽  
Author(s):  
David R. Taylor ◽  
Roger G. Walker

The marine Moosebar Formation (Albian) has a currently accepted southerly limit at Fall Creek (Ram River area). It consists of marine mudstones with some hummocky and swaley cross-stratified sandstones indicating a storm-dominated Moosebar (Clearwater) sea. We have traced a tongue of the Moosebar southward to the Elbow River area (150 km southeast of Fall Creek), where there is a brackish-water ostracod fauna. Paleoflow directions are essentially northwestward (vector mean 318°), roughly agreeing with turbidite sole marks (329°) in the Moosebar of northeastern British Columbia.The Moosebar sea transgressed southward over fluvial deposits of the Gladstone Formation. In the Gladstone, thick channel sands (4–8 m) are commonly multistorey (up to about 15 m), with well developed lateral accretion surfaces. The strike of the lateral accretion surfaces and the orientation of the walls of channels and scours indicate northwestward flow (various vector means in the range 307–339°). The Moosebar transgression was terminated by construction of the Beaver Mines floodplain, with thick, multistorey sand bodies up to about 35 m thick. Flow directions are variable, but various vector means roughly cluster in the north to northeast segment. This indicates a major change in dispersal direction from the Gladstone and Moosebar formations.A review of many Late Jurassic and Cretaceous units shows a dominant dispersal of sand parallel to regional strike. This flow is mostly north-northwestward (Passage beds, Cadomin, Gladstone, Moosebar, Gates, Chungo), with the southeasterly dispersal of the Cardium being the major exception. Only at times of maximum thickness of clastic input (Belly River and higher units, and possibly Kootenay but there are no published paleocurrent data) does the sediment disperse directly eastward or northeastward from the Cordillera toward the Plains.


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