The Research on the Depositional Systems Types and Characteristics of Sublacustrine Fan Deposits in the Second Member of Dongying Formation, Liaodong Bay

2013 ◽  
Vol 868 ◽  
pp. 46-50
Author(s):  
Zhen Hu ◽  
Jing Yan Liu ◽  
Shi Qiang Xia ◽  
Yan Yan Chang

Integrated employment of wireline logging and seismic data, turbidite fan types and distribution characteristics were analyzed in the Paleogene strata of the second Member of Dongying Formaiton. The results showed that: the study area developed many types of turbidite fan, including the slump turbidite fans, deepwater turbidite fan, steep nearshore turbidite fan, far shore slope turbidite fan, etc. There are significant differences in the developmental environment, sedimentary characteristics, the main factors and so on. The differences in delta size, provenance, ancient terrain and triggering mechanism affect the development of different turbidite fan deposits. By identifying wireline logs stacking patterns, the external geometry and internal reflection structure of seismic events, the types of lacustrine fan identification modes were determined. And also with three-dimensional seismic attribute analysis techniques for predicting sublacustrine fan and determining the plane distribution, it provide basic geological evidence for lacustrine fan hydrocarbon reservoir exploration.

2021 ◽  
Vol 40 (7) ◽  
pp. 484-493
Author(s):  
Doha Monier ◽  
Azza El Rawy ◽  
Abdullah Mahmoud

The Nile Delta Basin is a major gas province. Commercial gas discoveries there have been proven mainly in Pleistocene to Oligocene sediments, and most discoveries are within sandstone reservoirs. Three-dimensional seismic data acquired over the basin have helped greatly in imaging and visualization of stratigraphy and structure, leading to robust understanding of the subsurface. Channel fairways serve as potential reservoir units; hence, mapping channel surfaces and identifying and defining infill lithology is important. Predicting sand distribution and reservoir presence is one of the key tasks as well as one of the key uncertainties in exploration. Integrating state-of-the-art technologies, such as including 3D seismic reflection surveys, seismic attributes, and geobody extractions, can reduce this uncertainty through recognition and accurate mapping of channel features. In this study, seismic attribute analysis, frequency analysis through spectral decomposition (SD), geobodies, and seismic sections have been used to delineate shallow Plio-Pleistocene El Wastani Formation channel fairways within the Saffron Field, offshore Nile Delta, Egypt. This has led to providing more reliable inputs for calculation of volumetrics. Interpretation of the stacked-channels complex through different seismic attributes helped to discriminate between sand-filled and shale-filled channels and in understanding their geometries. Results include more confident delineation of four distinct low-sinuosity channelized features. Petrophysical evaluation conducted on five wells penetrating Saffron reservoirs included electric logs and modular dynamic test data interpretation. The calculated average reservoir properties were used in different volumetric calculation cases. Different approaches were applied to delineate channel geometries that were later used in performing different volumetric cases. These approaches included defining channels from root-mean-square amplitude extractions, SD color-blended frequencies, and geobodies, all calculated from prestack seismic data. The different volumetric cases performed were compared against the latest field volume estimates proven after several years of production in which an area-versus-depth input showed the closest calculated hydrocarbon volumes to the actual proven field volumes.


2020 ◽  
Author(s):  
Naiara Fernandez ◽  
Oliver Duffy ◽  
Frank Peel ◽  
Michael Hudec ◽  
Gillian Apps ◽  
...  

<p>In salt-detached gravity-gliding/spreading systems the detachment geometry is a key control on the downslope mobility of the supra-canopy (supra-salt) sequence. As supra-canopy minibasins translate downslope, they also subside into salt. If the base of salt has high relief, minibasins may weld and stop from further free translation downslope. The degree of minibasin obstruction controls both the kinematics of the individual basins, and the more regional pattern of supra-canopy strain. Here, we use regional 3D seismic data to examine a salt-stock canopy in the northern Gulf of Mexico slope, in an area where supra-canopy minibasins subsided vertically and translated downslope above a complex base-of-salt with high relief.</p><p>At a regional scale, we distinguish two structural domains in the study area: a highly obstructed or locked domain and a highly mobile domain. Large-scale translation of the supra-canopy sequence is recorded in the mobile domain by two different structures (a far-travelled minibasin and a ramp syncline basin). Although identifying the deformation area between the two regional domains is challenging due to its diffusive nature, characterizing domains according to base-of-salt geometry and supra-canopy minibasin configuration is helpful in identifying structural domains that may share similar subsidence and downslope translation histories.</p><p>At minibasin scale, minibasins that become obstructed modify the local strain field, typically developing a zone of shortening immediately updip of it and an extensional breakaway zone immediately downdip. Seismic attribute analysis performed in a cluster of minibasins in the study area illustrates a long-lived sediment transport system affected by the complex strain patterns associated with minibasin obstruction. At an early stage, a submarine channel system is captured and subsequently rerouted in response to the updip shortening associated with minibasin obstruction. At a later stage, a mass-transport complex (MTC) is steered by the topographic barrier created by the downdip extensional breakaway associated with minibasin obstruction.</p><p>Our work illustrates how salt-tectonic processes related to minibasin obstruction can affect the canopy dynamics at both regional and minibasin scale. Furthermore, we show that minibasin obstruction processes can modify the seafloor and subsequently control deepwater sediment dispersal, which, ultimately can affect hydrocarbon reservoir distribution on salt-influenced slopes</p>


2020 ◽  
Vol 4 (1) ◽  
pp. 12-22
Author(s):  
C. C. Okpoli ◽  
D. I Arogunyo

AbstractIntegrated well dataset and seismics delineated the PGS field onshore Niger Delta for reservoir identification. Gamma ray, resistivity, Neutron and density Logs identified four lithologies: sandstone, shaly sandstone, shaly sand and shale. They consist of sand-shale intercalation with the traces of shale sometimes found within the sand Formation. Petrophysical parameters of the reservoirs showed varying degree of lower density, low gamma ray, high porosity and resistivity response with prolific hydrocarbon reservoir G due to its shale volume and the clean sand mapped as a probable hydrocarbon reservoir. 3D seismic data located both seismic scale and sub-seismic scale structural and stratigraphic elements. Risk reduction in dry hole drilling due fault missing in conventional seismic attribute analysis and interpretation, have to be integrated into the Oil companies standard practice.


2016 ◽  
Vol 4 (4) ◽  
pp. SR1-SR18 ◽  
Author(s):  
Cédric Schmelzbach ◽  
Stewart Greenhalgh ◽  
Fabienne Reiser ◽  
Jean-François Girard ◽  
François Bretaudeau ◽  
...  

Seismic reflection imaging is a geophysical method that provides greater resolution at depth than other methods and is, therefore, the method of choice for hydrocarbon-reservoir exploration. However, seismic imaging has only sparingly been used to explore and monitor geothermal reservoirs. Yet, detailed images of reservoirs are an essential prerequisite to assess the feasibility of geothermal projects and to reduce the risk associated with expensive drilling programs. The vast experience of hydrocarbon seismic imaging has much to offer in illuminating the route toward improved seismic exploration of geothermal reservoirs — but adaptations to the geothermal problem are required. Specialized seismic acquisition and processing techniques with significant potential for the geothermal case are the use of 3D arrays and multicomponent sensors, coupled with sophisticated processing, including seismic attribute analysis, polarization filtering/migration, converted-wave processing, and the analysis of the diffracted wavefield. Furthermore, full-waveform inversion and S-wave splitting investigations potentially provide quantitative estimates of elastic parameters, from which it may be possible to infer critical geothermal properties, such as porosity and temperature.


2007 ◽  
Author(s):  
Srinivasa Rao Narhari ◽  
Nikhil Banik ◽  
Sunil Kumar Singh ◽  
Talal Fahad Al-Adwani

2013 ◽  
Vol 734-737 ◽  
pp. 404-407 ◽  
Author(s):  
Yu Shuang Hu ◽  
Si Miao Zhu

A big tendency in oil industry is underestimating the heterogeneity of the reservoir and overestimating the connectivity, which results in overly optimistic estimates of the capacity. With the development of seismic attributes, we could pick up hidden reservoir lithology and physical property information from the actual seismic data, strengthen seismic data application in actual work, to ensure the objectivity of the results. In this paper, the channel sand body distribution in south eighth district of oilfield Saertu is predicted through seismic data root-mean-square amplitude and frequency division to identify sand body boundaries, predict the distribution area channel sand body characteristics successfully, which consistent with the sedimentary facies distribution. The result proves that seismic attribute analysis has good practicability in channel sand body prediction and sedimentary facies description.


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