Gilbert-type deltas recording short-term base-level changes: Delta-brink morphodynamics and related foreset facies

Sedimentology ◽  
2015 ◽  
Vol 62 (7) ◽  
pp. 1923-1949 ◽  
Author(s):  
Katarina Gobo ◽  
Massimiliano Ghinassi ◽  
Wojciech Nemec
Keyword(s):  
2013 ◽  
Vol 339 ◽  
pp. 728-731 ◽  
Author(s):  
Cun Lei Li ◽  
Lei Qin ◽  
Xue Li ◽  
Xi Long Zhang

With the instruction of the high resolution sequence stratigraphy and sedimentology theory, and the comprehensive application of 11 wells core, more than 800 mud logging and log data, high resolution sequence stratigraphic characteristics research in the XII Group of the Member III of Qing Shankou Formation in the Qianan oilfield has been finished. The results show that the study area can be divided into one middle-term base level cycle and five short-term base level cycles. The only sequence structure of middle term cycle is (B type) and the short term cycle mainly consists of B types meanwhile there are small mounts of upward deepening structures (A type) and symmetric structures (C type). Based on the classification of base-level cycles, fine stratigraphic correlation is conducted by using isochronous cycle correlations. In addition, 15 high resolution sequence stratigraphic frameworks are established which unify the study area and provide the solid geological basis for the sandstone distribution, the identification of mainly oil-bearing sand bodies and potential oil reservoirs.


2020 ◽  
Vol 10 (21) ◽  
pp. 7697
Author(s):  
Dario Gioia ◽  
Marcello Schiattarella

Simulation scenarios of sediment flux variation and topographic changes due to dam removal have been investigated in a reservoir catchment of the axial zone of southern Italy through the application of a landscape evolution model (i.e.,: the Caesar–Lisflood landscape evolution models, LEM). LEM simulation highlights that the abrupt change in base level due to dam removal induces a significant increase in erosion ability of main channels and a strong incision of the reservoir infill. Analysis of the sediment dynamics resulting from the dam removal highlights a significant increase of the total eroded volumes in the post dam scenario of a factor higher than 4. Model results also predict a strong modification of the longitudinal profile of main channels, which promoted fluvial incision upstream and downstream of the former reservoir area. Such a geomorphic response is in agreement with previous analysis of the fluvial system short-term response induced by base-level lowering, thus demonstrating the reliability of LEM-based analysis for solving open problems in applied geomorphology such as perturbations and short-term landscape modification natural processes or human impact.


2011 ◽  
Vol 347-353 ◽  
pp. 56-59
Author(s):  
Rui Zhang ◽  
You Liang Ji

Based on the depositional model and characteristics of fan delta, the short-term base-level cycle of the third submember of the third member of Shahejie Formation (Es33)in North region major oil layer of Liuzan Oilfield of Nanpu Sag is divided into three basic categories applying high-resolution sequence stratigraphy with the reference to core and logging data, namely, deepening-upward asymmetrical type, shallowing-upward asymmetrical type and symmetrical type. Different variation models for macroscopic heterogeneity of reservoir belonging to different categories of short-term base-level cycle were established in this paper; it was further pointed out that the changes of base-level and the ancient landform were major factors controlling the characteristic discrepancy of macroscopic heterogeneity of reservoir. In fan delta plain area, the ancient landform is smooth. Deepening-upward asymmetrical cycle is mainly composed of braided river sand body, and the changes of base-level exert little control on porosity with significant control on permeability. At the delta front slope, the landform becomes steep. Deepening-upward asymmetrical cycle is mainly composed of underwater distributary channel with genetic mechanism of gravity flow. The vertical variations of porosity and permeability inside the cycle are rather complicated. Since the physical properties are mainly manifested as the control on autogenic cycle, they do not directly influence the changes of base level.


2018 ◽  
Vol 10 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Rui Yuan ◽  
Rui Zhu ◽  
Jianhua Qu ◽  
Jun Wu ◽  
Xincai You ◽  
...  

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.


2013 ◽  
Vol 339 ◽  
pp. 732-736
Author(s):  
Lei Qin ◽  
Cun Lei Li ◽  
Yan Li ◽  
Jing Zhe Li

With the method of the high resolution sequence stratigraphy and sedimentology theory, oil-bearing sand bodies have been accurately recognized and descripted which could provide precisely geological data for 3-D modeling and numerical simulation. It has the vital significance for the development of oilfield during the late stage of high water cut. According to the drilling, logging, seismic and analytical experiments data, the results show that the study area can be divided into one long-term base level cycle, four middle-term base level cycles, sixteen short-term base level cycles and twenty-eight super short-term base level cycles. Based on the classification of base-level cycles, control functions of cycles which have effects on the sediment environment have been discussed. And with the application of the chronostratigraphic correlation fine stratigraphic correlation, 10 high resolution sequence stratigraphic frameworks are established in the direction that is parallel and perpendicular to the source.


2013 ◽  
Vol 868 ◽  
pp. 177-180 ◽  
Author(s):  
Zheng Li ◽  
Shi Zhong Ma ◽  
Yu Sun ◽  
Jin Yan Zhang

Using high-resolution sequence stratigraphy theory and its technology, based on 22 well cores and 4 256 logging data, interface types and characteristics of different grades the base-level cycle in Putaohua oil layer of Sanzhao Sag was systematically analyzed, and Putaohua oil layer is divided into 1 medium-term base level cycle, 4 short-term base level cycles, 8 super-short-term base level cycles, established high-resolution sequence strata framework, and proposed sequence stratigraphy model of middle super-short-term base level cycles meridionally grado-thin and up to vanish with syndepositional structure lifting control in the south of Putaohua oil layer. Sandstone is offlap Pinch-out in the upper of Putaohua oil layer, and Sandstone is onflap Pinch-out in the under of Putaohua oil layer from north to south.


2016 ◽  
Vol 39 ◽  
Author(s):  
Mary C. Potter

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.


Author(s):  
M. O. Magnusson ◽  
D. G. Osborne ◽  
T. Shimoji ◽  
W. S. Kiser ◽  
W. A. Hawk

Short term experimental and clinical preservation of kidneys is presently best accomplished by hypothermic continuous pulsatile perfusion with cryoprecipitated and millipore filtered plasma. This study was undertaken to observe ultrastructural changes occurring during 24-hour preservation using the above mentioned method.A kidney was removed through a midline incision from healthy mongrel dogs under pentobarbital anesthesia. The kidneys were flushed immediately after removal with chilled electrolyte solution and placed on a LI-400 preservation system and perfused at 8-10°C. Serial kidney biopsies were obtained at 0-½-1-2-4-8-16 and 24 hours of preservation. All biopsies were prepared for electron microscopy. At the end of the preservation period the kidneys were autografted.


Author(s):  
E. Rau ◽  
N. Karelin ◽  
V. Dukov ◽  
M. Kolomeytsev ◽  
S. Gavrikov ◽  
...  

There are different methods and devices for the increase of the videosignal information in SEM. For example, with the help of special pure electronic [1] and opto-electronic [2] systems equipotential areas on the specimen surface in SEM were obtained. This report generalizes quantitative universal method for space distribution representation of research specimen parameter by contour equal signal lines. The method is based on principle of comparison of information signal value with the fixed levels.Transformation image system for obtaining equal signal lines maps was developed in two versions:1)In pure electronic system [3] it is necessary to compare signal U (see Fig.1-a), which gives potential distribution on specimen surface along each scanning line with fixed base level signals εifor obtaining quantitative equipotential information on solid state surface. The amplitude analyzer-comparator gives flare sport videopulses at any fixed coordinate and any instant time when initial signal U is equal to one of the base level signals ε.


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