Authigenic seep-carbonates cementing coarse-grained deposits in a fan-delta depositional system (middle Miocene, Marnoso-arenacea Formation, central Italy)

Sedimentology ◽  
2008 ◽  
Vol 55 (2) ◽  
pp. 471-486 ◽  
Author(s):  
S. CONTI ◽  
D. FONTANA ◽  
C.C. LUCENTE
Keyword(s):  
Middle Miocene ◽  
Central Italy ◽  
Coarse Grained ◽  
Fan Delta ◽  
Depositional System

Characteristics and origins of ridges and troughs on the top of the Middle Miocene strata in the Beijiao sag of the Qiongdongnan basin, northern South China Sea

2020 ◽  
pp. 1-57
Author(s):  
Yufeng Li ◽  
Renhai Pu ◽  
Gongcheng Zhang ◽  
Hongjun Qu
Keyword(s):  
High Resolution ◽  
Seismic Data ◽  
Middle Miocene ◽  
Northern South China Sea ◽  
Qiongdongnan Basin ◽  
Coarse Grained ◽  
Bottom Currents ◽  
Fine Grained ◽  
Sediment Waves ◽  
History Of

Sedimentary structures generated by bottom currents are poorly understood worldwide. Ridges and troughs are imaged for the first time by 3D high-resolution seismic data and drilled by a well, YL19-1-1, in the Beijiao sag of Qiongdongnan basin (QDNB). Combined with 2D high resolution seismic data, they are analyzed in detail. The results show that ridges and troughs occur on the top of the Middle Miocene, dominantly present a wave-shaped structure. Their magnitudes are larger on the middle (regional) slope than on the upper and lower slope. They extend for tens of kilometers, dominantly parallel to one another, evenly spaced and nearly E-W directed distribution, some of which locally merge and bifurcate. They are aligned oblique to the regional slope. Both internal mounded reflections and parallel underlying-strata reflections, occur within ridges. The presence of polygonal faults and weak-to-moderate amplitudes within the ridges and troughs, suggests that they consist of fine-grained mudstones, as confirmed by well YL19-1-1. High amplitudes filled within troughs are probably composed of coarse-grained turbidite sandstones where polygonal faults are inhibited. Truncated reflections and onlaps occur along the thalweg of a trough, and are also clearly observed on the sides of ridges and troughs. We conclude the troughs are a product of erosion of bottom currents, and ridges are remnant underlying (sediment waves) strata as a result of this erosion. Besides, troughs are filled by turbidite sandstones with high amplitudes in the southwestern part of the study area, where ridges and troughs a combined result of early erosion by bottom currents and later reworking by turbidity flows. Conceptual schematic models are proposed to show the evolutionary history of ridges and troughs. This study provides new insights into further understanding of erosion and deposition of bottom currents.

Fan-delta sedimentation in the Silurian Coralliferous Formation of SW Wales: implications for the structure of the southern margin of the Welsh Basin

2007 ◽  
Vol 144 (2) ◽  
pp. 319-331 ◽  
Author(s):  
S. J. VEEVERS ◽  
A. T. THOMAS ◽  
P. TURNER
Keyword(s):  
Transition Zone ◽  
Coarse Grained ◽  
The South ◽  
Fine Grained ◽  
Fan Delta ◽  
Facies Associations ◽  
Storm Wave ◽  
Marine Influence ◽  
Mass Flow Deposits ◽  
Basin Margin

The uppermost Llandovery to lower Wenlock Coralliferous ‘Group’ in SW Pembrokeshire is here redefined as a single formation with two members. The Coralliferous Formation is approximately 150 m thick and comprises a basal unit of granule- to pebble-grade rudite beds, the Renney Slip Member, overlain by interbedded mudstones and fine sandstones of the Deadman's Bay Member. The Renney Slip Member lies unconformably above the Skomer Volcanic Group and includes 12.4 m of coarse grained, granule- and pebble-rich rudites, with beds up to 0.94 m thick. Three lithofacies are recognized within this unit: coarse, granule-rich rudite beds are interpreted as a variety of mass flow deposits, some of which have been reworked in a marine environment; thick sandstones with planar and ripple lamination are shoreface to offshore transition zone deposits; silty mudstones interbedded with very fine grained sandstones represent marine offshore deposits, formed largely below mean storm wave base. These facies associations, and abundant bioturbation, indicate an environment with a strong marine influence, and a proximal source of coarse grained sediment. The Renney Slip Member is reinterpreted in the context of a fan delta depositional model. At least seven cycles of deposition are recognized, each showing an upwards-fining pattern, representing deposition from fan delta, shoreface–transition zone to open marine environments. These patterns of deposition are attributed to localized tectonic movements causing variations in relative sea level. At the time the Renney Slip Member was deposited, the southern Welsh Basin margin is interpreted as a fault-block extensional margin, with the landmass of Pretannia to the south. Though fan-delta deposition took place southwards against the uplifted footwall of the Wenall Fault, the basin margin lay to the south of the Ritec Fault.

Petrophysical data analysis using MATLAB tools for the middle Miocene sediments in the Gulf of Suez, Egypt

2020 ◽  
Author(s):  
Douaa Fathy ◽  
Eun Young Lee
Keyword(s):  
Middle Miocene ◽  
Oil Field ◽  
Coarse Grained ◽  
High Resistivity ◽  
Gulf Of Suez ◽  
High Porosity ◽  
Oil Saturation ◽  
Fluid Saturation ◽  
Important Relationship ◽  
Petrophysical Data

<p>Middle Miocene sediments are the most important productive oil zone in the Sidri Member within Belayim oil field. The Belayim oil field is one of well-known oil fields in Egypt, which is located on the eastern side of the Gulf of Suez. The Sidri Member consists of shales, sandstones and limestone with net pay thickness ranges from 5 to 60 m. The oil saturated sandstone layers are coarse grained and poorly sorted, which are classified into sub-litharenite, lithic arkose and arkose microfacies with several diagenetic features. This study measured and collected petrophysical data from the sandstone core samples and well logging of drilling sites to evaluate oil potentiality and reservoir characteristics of the Sidri Member. The collected petrophysical data are porosity, permeability, water and oil saturation, resistivity and grain and bulk density. MATLAB tools were used to analyze the extensive dataset, quantify the correlation trends and visualize the spatial distribution. The porosity values range from 2% to 30%, which show very good positive correlation with horizontal permeability (0 to 1,300 md). The porosity as well as type and radius of pore throats present important relationship with permeability and fluid saturation. The petrophysical characteristics of the Sidri sandstones are controlled by the depositional texture, clay-rich matrix and diagenetic features. This study distinguished poorly, fairly, good to excellent reservoir intervals in the Sidri Member. The best quality reservoir potentiality is recorded in the well sorted sand layers with little clay matrix in the lower part of the Sidri Member. The petrophysical characteristics are high porosity (20% to 30%), high permeability (140 to 1250 md), high oil saturation (20% to 78%), low water saturation (13% to 36%), moderate to high resistivity and relatively low grain density. The hydrocarbon production rates reported from the Sidri reservoirs are greatly correlated with the petrophysical characteristics described in this study.</p>

scholarly journals Palaeoenvironmental reconstruction of a middle Miocene alluvial fan to cyclic shallow lacustrine depositional system in the Calatayud Basin (NE Spain)

Sedimentology ◽  
2003 ◽  
Vol 50 (2) ◽  
pp. 211-236 ◽  
Author(s):  
Hayfaa Abdul Aziz ◽  
Enrique Sanz-Rubio ◽  
Jose P. Calvo ◽  
Fredirik J. Hilgen ◽  
Wout Krijgsman
Keyword(s):  
Middle Miocene ◽  
Alluvial Fan ◽  
Palaeoenvironmental Reconstruction ◽  
Depositional System ◽  
Ne Spain

scholarly journals Utilizing Integrated Prediction Error Filter Analysis (INPEFA) to divide base-level cycle of fan-deltas: A case study of the Triassic Baikouquan Formation in Mabei Slope Area, Mahu Depression, Junggar Basin, China

2018 ◽  
Vol 10 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Rui Yuan ◽  
Rui Zhu ◽  
Jianhua Qu ◽  
Jun Wu ◽  
Xincai You ◽  
...  
Keyword(s):  
Prediction Error ◽  
Junggar Basin ◽  
Coarse Grained ◽  
Positive Trend ◽  
Medium Term ◽  
Short Term ◽  
Base Level ◽  
Fan Delta ◽  
Depositional Systems ◽  
Filter Analysis

Abstract The Mahu Depression is an important hydrocarbon-bearing foreland sag located at the northwestern margin of the Junggar Basin, China. On the northern slope of the depression, large coarse-grained proximal fan-delta depositional systems developed in the Lower Triassic Baikouquan Formation (T1b). Some lithologic hydrocarbon reservoirs have been found in the conglomerates of the formation since recent years. However, the rapid vertical and horizontal lithology variations make it is difficult to divide the base-level cycle of the formation using the conventional methods. Spectral analysis technologies, such as Integrated Prediction Error Filter Analysis (INPEFA), provide another effective way to overcome this difficultly. In this paper, processed by INPEFA, conventional resistivity logs are utilized to study the base-level cycle of the fan-delta depositional systems. The negative trend of the INPEFA curve indicates the base-level fall semi-cycles, adversely, positive trend suggests the rise semi-cycles. Base-level cycles of Baikouquan Formation are divided in single and correlation wells. One long-term base-level rise semi-cycle, including three medium-term base-level cycles, is identified overall the Baikouquan Formation. The medium-term base-level cycles are characterized as rise semi-cycles mainly in the fan-delta plain, symmetric cycles in the fan-delta front and fall semi-cycles mainly in the pro-fan-delta. The short-term base-level rise semi-cycles most developed in the braided channels, sub-aqueous distributary channels and sheet sands. While, the interdistributary bays and pro-fan-delta mud indicate short-term base-level fall semi-cycles. Finally, based on the method of INPEFA, sequence filling model of Baikouquan formation is established.

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