SEQUENCE STRATIGRAPHIC DIVISION METHOD OF HYDROTHERMAL SHALE: AN EXAMPLE OF THE LOWER CAMBRIAN SHALE OF YANGTZE REGION IN XIUWU BASIN

2018 ◽  
Author(s):  
Kun Zhang ◽  
◽  
Yan Song ◽  
Chengzao Jia ◽  
Shu Jiang ◽  
...  
2019 ◽  
Vol 11 (1) ◽  
pp. 183-195
Author(s):  
Zhuo Li ◽  
Kun Zhang ◽  
Yan Song ◽  
Zhenxue Jiang ◽  
Xiaoxue Liu ◽  
...  

Abstract It is a common method to use sequence stratigraphic theory to identify favourable intervals in hydrocarbon exploration. The Lower Cambrian shale of Well Jiangye-1 in Yangtze Region in Xiuwu Basin was chosen as the research object. The content of excess silicon of siliceous minerals in shale was calculated quantitatively, and the concentration distribution of Al, Fe, Mn showed that the excess silicon is of hydrothermally origin and the shale deposited in an environment with hydrothermal activity. Using U/Th values in the study, combined with lithology and logging data, in order to divide sequences of the Lower Cambrian shale in Yangtze Region in Xiuwu Basin. The result shows that the shale of the Lower Cambrian shale is recognized as 1 2nd sequence (TST-RST, TST = Transgressive systems tract; RST = Regressive systems tract) and then further subdivided into 5 3rd sequences (SQ1-SQ5). During the deposition of SQ2 and SQ3, hydrothermal activity was active, and their excess silicon content was generally above 20%-30%. Rising sea level and active hydrothermal activity were beneficial for the enrichment of siliceous minerals and organic matter. Based on the comparison of the reservoir parameters, it tells that SQ2 and SQ3 have relatively higher content of TOC, higher content of brittle minerals (such as siliceous minerals, carbonate minerals and so on), larger effective porosity and higher content of gas, which make it as the most favourable intervals of the Lower Cambrian in Xiuwu Basin.


2000 ◽  
Vol 74 (5) ◽  
pp. 858-878 ◽  
Author(s):  
Stephen R. Westrop ◽  
Ed Landing

The Hanford Brook Formation, one of the classic Cambrian units of Avalonian North America, contains at least eight species of endemic trilobites, including Berabichia milleri Westrop n. sp., that are assigned to seven genera. The vertical succession of faunas is far more complex than has been recognized previously, with each member containing a lithofacies-specific assemblage. These are, in ascending order: a bradoriid-linguloid Association without trilobites in the nearshore St. Martin's Member, a Protolenus Association in dysaerobic siltstones and sandstones of the Somerset Street Member, and a Kingaspidoides-Berabichia Association in hummocky cross-stratified sandstones of the Long Island Member that overlie a parasequence boundary at Hanford Brook. Due to the breakdown of biogeographic barriers in the late Early Cambrian, two new species-based zones, the Protolenus elegans and Kingaspidoides cf. obliquoculatus zones, share trilobite genera with the Tissafinian Stage of Morocco. This generic similarity has been the basis for correlation of this upper Lower Cambrian interval on the Avalon continent with the West Gondwanan lowest Middle Cambrian. However, the clear facies control on the occurrence of genera in the Hanford Brook Formation and the presence of an abrupt faunal break and unconformity at the base of the Tissafinian in Morocco makes this correlation questionable. The Hanford Brook Formation may represent a late Early Cambrian interval unknown in Gondwana. Sequence-stratigraphic criteria even raise the possibility that the Protolenus Association is the biofacies equivalent of Callavia broeggeri Zone faunas of the Brigus Formation of Newfoundland, Nova Scotia and Massachusetts.


2001 ◽  
Vol 138 (4) ◽  
pp. 387-396 ◽  
Author(s):  
ARTEM KOUCHINSKY ◽  
STEFAN BENGTSON ◽  
VLADIMIR V. MISSARZHEVSKY ◽  
SHANE PELECHATY ◽  
PETER TORSSANDER ◽  
...  

Carbon isotopic oscillations are useful to elucidate the stratigraphy and biogeochemical events around the Precambrian–Cambrian transition. New isotopic data from the Manykaj and Emyaksin formations of the eastern Anabar Uplift (Siberia) help to correlate the Lower Cambrian and Neoproterozoic–Cambrian transitional beds across the Siberian Platform. The similarity of trends and amplitudes of the carbon isotopic curves, together with biostratigraphic and sequence-stratigraphic markers from the Anabar Uplift, provide a precise correlation with the southern part of the Siberian Platform. Diagenesis of argillaceous limestones of the Emyaksin Formation has apparently not affected the primary isotopic variations. The resulting curve is nearly identical in sections about 100 km apart in the Tommotian–Atdabanian portion of the formation. Relatively frequent and pronounced isotopic oscillations in the lower beds of the Emyaksin Formation fit between features I and II of the southern Siberian isotopic reference scale but are undetected therein owing to the depositional hiatus at the base of the Tommotian Stage in its type section. This confirms the transgressive onlap from the north suggested by previous studies, and makes the appearance of the Cambrian skeletal fossils on the Siberian Platform less abrupt. The hiatus in the south appears to embrace at least two biostratigraphic zones as recognized in the north. The case is strengthened for a pre-Tommotian Cambrian Stage in Siberia, the biostratigraphic framework for which has been elaborated earlier.


2014 ◽  
Vol 1010-1012 ◽  
pp. 1359-1364
Author(s):  
Ang Li ◽  
Lai Xing Cai ◽  
Shuang Liu ◽  
Qi Li

Many scholars in China introduced the theory of sequence stratigraphy,applying to Chinese continental fault depression lake, they have made a lot of achievements in scientific research. However, there are still a lot of controversy according to the establishment in Shahezi group of sequence stratigraphic framework in Xujiaweizi fault depression.Sequence boundary identification method in this paper is based on the “instruction of Vail’s sequence stratigraphy theory, identification of seismic unconformity, verification by using logging methords”. And, following the principle of isochronous ,sequence stratigraphic framework of this region is established clearly. The southern Xujiaweizi fault depression in Shahezi group is divided into 1 second grade sequence, in the interior distributed SQ1-SQ4 4 third grade sequences from the bottom. Developmental stages at the bottom of SQ1 and the top of SQ4, basin is small and water is shallow. However, Developmental stages in SQ2 and SQ3,water enters the lake basin continuously, formed a sedimentary background of “wide basin and deep water”. In addition, each of the three grade sequence has split structure, the lake transgressive domain and lake regression domain two system tracts. Besides, the reversed order para-sequence sets caused by the lake regression and progradation set on the positive para-sequence sets caused by the lake transgression and retrogradation. On the basis of sequence stratigraphic division and correlation, conbined with the regional construction and the supply of provenance ,the sedimentary sequence framework of evolution characteristics are studied.That fan delta,braided river delta, lacustrine are the main facies types in study area. Characteristics of sedimentary evolution there are like this: the characteristics of sedimentation evolution show framework controls sand, succession of evolution, separated-source sedimentary, contiguously distribution.


2013 ◽  
Vol 734-737 ◽  
pp. 362-365
Author(s):  
Yu Sun ◽  
Xiu Li Zhang ◽  
Jin Yan Zhang ◽  
Chen Chen

By using the cores, drilling and logging data, Fuyu oil layer in the northern Honggang is divided into 2 long-term base level cycle, 4 medium-term base level cycles, 20 short-term base level cycles, and monosandbody high-resolution sequence strata framework is established, monosandbody isochronic correlation is achieved in Isochronic strata framework at the same time. Through high--resolution sequence stratigraphic analysis, sedimentary evolution, monosandbody distribution, sand geometry and distribution characteristics of reservoir are controlled by base-level changes in Fuyu oil layer of the northern Honggang. The lower Fuyu oil layer is dereliction prograding sequence stratigraphic modes in fall range of base-level. Space stacked form of the sand body is controlled by A/S ratio or base level changes. The symmetry of cyclic changes with the geographical location and distance from the sedimentary source.


2013 ◽  
Vol 772 ◽  
pp. 823-827 ◽  
Author(s):  
Da Wei Ji ◽  
Ji Li ◽  
Guang Dong Lu

In this paper, the method and effect of logging curves wavelet transform in high-resolution sequence division are discussed, taking the middle oil sequence stratigraphic of DU-432 oil well in north-Songliao basin as an example. Using Wavelet Transform to GR logging curves, the relationship between logging curve signals and depth is transformed to the relationship between the depth and the scale domain, so that the wavelet curves in different scale are obtained. Then the relationship between the periodic oscillation characteristics of the wavelet curves under the best optimal scale factor and the sequence. Comparing the Sequence Stratigraphic Division by wavelet transform with the manual division, Results show that the Division by Sequence Stratigraphic wavelet transform is more objective and more effective and the Division provides a new way to high-resolution sequence stratigraphy.


Author(s):  
Zijie Wu ◽  
Guoren Zhang ◽  
Fuliang Gao ◽  
Haipeng Wang ◽  
Longwei Qiu ◽  
...  

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