Variation of the Distribution of Organic Matter Within a Transgressive System TractKimmeridge Clay (Jurassic), England

1993 ◽  
Author(s):  
Jean Paul Herbin ◽  
Carla Müller ◽  
Jeannine R. Geyssant ◽  
Frédéric Mélières ◽  
Ian E. Penn ◽  
...  
Keyword(s):  
Organic Matter ◽  
Transgressive System Tract ◽  
System Tract

scholarly journals Sedimentary Evolution Characteristics of Fine-Grained Lithofacies under the High-Resolution Isochronous Shelf System: Insights from the Wufeng-Longmaxi Shales in the Sichuan Basin

Lithosphere ◽  
2021 ◽  
Vol 2021 (Special 1) ◽  
Author(s):  
Guanping Wang ◽  
Zhijun Jin ◽  
Zongquan Hu ◽  
Guangxiang Liu ◽  
Tong Zhu ◽  
...  
Keyword(s):  
Organic Matter ◽  
High Resolution ◽  
Shale Gas ◽  
Transgressive System Tract ◽  
Fine Grained ◽  
Sedimentary Sequences ◽  
Evolution Characteristics ◽  
Sedimentary System ◽  
Siliceous Shale ◽  
System Tract

Abstract The deposition and evolution of fine-grained sediments is a hot topic in fine-grained sedimentary rock studies and is important for accurately evaluating shale gas sweet spots. In this paper, the fine-grained deposition and evolution characteristics of the Wufeng-Longmaxi shales, major targets for Chinese shale gas exploration, were studied by using core observations, thin section analyses, scanning electron microscopy, geochemical analysis, and fossil identification. This work accurately identified six typical lithofacies; among them, the organic matter-rich siliceous shale facies (OMRSSF), the high-organic matter siliceous argillaceous shale facies (HOMSASF), and the medium-high organic matter low calcareous siliceous shale facies (M-HOMLCSASF) are favorable facies for shale gas exploration. The high-resolution isochronous unit in the shelf fine-grained sedimentary system was established, and the differential evolution of lithofacies in the system tract was discussed. The lithofacies deposition and differentiation in the transgressive system tract were controlled by the transgressive scale and tectonics under increasingly shallow water conditions. The lithofacies deposition and differentiation in the regressive system tract were controlled by tectonics and the preexisting lithofacies. The lithofacies in the regressive system tract had more frequent facies transitions and greater differentiation than those in the transgressive system tract, and they exhibited significant spatiotemporal inheritance. Sequential differential sedimentary sequences and symmetric differential sedimentary sequences were distinguished in the continental shelf sedimentary system. The lithofacies depocenters and subsidence centers were consistent in the transgressive system tract, while the tectonically active paleocontinent was important in the regression system tract. This study is of great significance for further high-resolution exploration of marine shale and improvement of the theory of shelf fine-grained sedimentary systems.

KAJIAN HUBUNGAN DIAGENESIS DAN SIKUEN STRATIGRAFI FORMASI NANGGULAN BERDASARKAN ANALISIS PETROGRAFI BATUPASIR

KURVATEK ◽  
2018 ◽  
Vol 3 (1) ◽  
pp. 71-82
Author(s):  
Wahyu Sasongko
Keyword(s):  
Transgressive System Tract ◽  
Highstand System Tract ◽  
System Tract

Proses diagenesis yang terjadi pada batuan memiliki hubungan yang erat dengan konsep sikuen stratigrafi. Proses diagenesis awal (eogenesis) yang terbentuk pada suatu batuan dipengaruhi oleh posisi stratigrafi batuan tersebut dalam tataan sikuen stratigrafi. Eogenesis tersebut dapat diteliti dengan menggunakan data petrografi batupasir mengenai proses diagenesis yang terdapat pada batuan, dan juga dengan melihat posisi batuan dalam tataan sikuen stratigrafi. Formasi Nanggulan yang tersingkap di Kulon Progo, Yogyakarta merupakan salah satu formasi yang dengan beberapa interval litologi batupasir. Analisis mengenai sikuen stratigrafi Formasi Nanggulan telah diteliti sebelumnya dengan menggunakan analisis batuan inti. Studi lebih lanjut mengenai Formasi Nanggulan bertujuan untuk mengetahui karakteristik batupasir dan proses diagenesisnya, serta mencari hubungan antara proses diagenesis dan sikuen stratigrafi. Penelitian dilakukan dengan menggunakan analisis petrografi dari data batuan inti dan singkapan permukaan dengan tujuan untuk mengetahui hubungan antara diagenesis dan sikuen stratigrafi pada batupasir Formasi Nanggulan.Berdasarkan analisis petrografi terhadap diagenesis pada Formasi Nanggulan, dapat dikonfirmasi bahwa Formasi Nanggulan terdiri dari 3 system tract yaitu lowstand system tract (LST), transgressive system tract (TST), dan highstand system tract (HST). Tahapan proses diagenesis yaitu eogenesis, mesogenesis dan telogenesis telah mempengaruhi Formasi Nanggulan. Karakteristik diagenesis pada Formasi Nanggulan bervariasi sesuai dengan system tract dan marker batas sikuen pada tataan sikuen stratigrafi. Berdasaran penelitian ini dapat diketahui bahwa sikuen stratigrafi Formasi Nanggulan dapat dikonfirmasi dengan data diagenesis.

scholarly journals Benthonic foraminifera of the northern Monagas area, in the eastern Venezuelan basin: its implications in hydrocarbon exploration

1992 ◽  
Vol 6 ◽  
pp. 52-52
Author(s):  
Marta Carrillo ◽  
S.A. Intevep
Keyword(s):  
New Taxa ◽  
Hydrocarbon Exploration ◽  
Early Miocene ◽  
Late Oligocene ◽  
Oil Sand ◽  
Transgressive System Tract ◽  
Main Species ◽  
System Tract

An association of benthonic foraminifera, Late Oligocene to Early Miocene in age, characteristic of the Monagas area, Eastern Venezuelan Basin, is presented in this paper.The identified assemblage could indicate a sequence boundary between a lowstand wedge and a transgressive system tract; this assemblage overlies the Naricual Formation oil sand reservoirs; therefore it is very important to have it well described.The studied assemblage has been picked out of samples analyzed from ten wells in the El Carito - El Furrial area. A total of one hundred species were identified, including twenty species turned out to be unidentifiable. Four new taxa have been described in this age interval.The fauna exhibits strong dominance, being the main species: Nonionella opima, Nonion atlanticus, Textularia cf. T. grenadana, Textularia sp., Textularia panamensis, Valvulineria sp., Ammonia beccarii, Nonionella sp., and Trochammina sp. All these species correspond to a transitional to inner neritic environment.The detailed identification of this fauna assemblage will contribute to a better understanding of the stratigraphy in the area, and in consequence to optimize hydrocarbon exploration.

scholarly journals Sequence stratigraphic analysis of the Surma Group in X Gas Field, Surma Basin, Bengal Delta

2019 ◽  
Vol 58 ◽  
pp. 39-52
Author(s):  
Afroza Parvin ◽  
A. S. M. Woobaidullah ◽  
Md Jamilur Rahman
Keyword(s):  
Tidal Flat ◽  
Transgressive System Tract ◽  
Gas Field ◽  
Depositional Sequences ◽  
Sequence Stratigraphic ◽  
Bengal Delta ◽  
Stratigraphic Framework ◽  
Facies Associations ◽  
Surma Group ◽  
System Tract

This study builds a high-resolution sequence stratigraphic framework for the Surma Group in the X Gas field. At first, electrofacies and depositional sequences were interpreted from wire line logs. Then, the field wide configurations of these sequences have been identified in seismic using reflection terminations (of flap, onlap, top lap and down lap relationship). Finally, wire line log and seismic interpretations were integrated to establish sequences stratigraphic framework in the Surma Group. Electrofacies analysis has revealed four major facies associations namely: (i) Bell shaped fining upward facies corresponds to retrogradational shoreface to tidal flat deposits, (ii) Funnel shaped coarsening upward facies corresponds to progradational shoreface to tidal flat, (iii) Cylindrical aggradational facies interpreted as stacked channel and (iv) Symmetrical or Bow shaped facies corresponds to heterolithic unit. The succession of Surma group of about 3100+ m has been divided into twelve depositional sequences. With exception of depositional sequence 1, 11 and 12, most of them are composed of three system tracts: sandy lowstand system tract, shaley transgressive system tract and heterolithic to shaley highstand system tract. Repetitive occurrence of incised valley, shoreface sand as well as tidal channel sand separated by transgressive system tract shelfal mud resulted in sand-shale alternation in the Surma Group. The lower depositional sequences (up to sequence-6) are shale dominated and equivalent to the Lower Surma Group. The upper six sequences are sand dominated, have more channel incisions and sequence boundary representing the Upper Surma Group

Sequence Stratigraphic Analysis of Badaowan Formation in Dishuiquan Area, Junggar Basin

2012 ◽  
Vol 616-618 ◽  
pp. 56-59 ◽  
Author(s):  
Zhe Wang ◽  
Zhen Kui Jin ◽  
Gui Zai Li
Keyword(s):  
Lacustrine Sediments ◽  
Junggar Basin ◽  
Sedimentary Facies ◽  
River Delta ◽  
Braided River ◽  
Transgressive System Tract ◽  
Sequence Stratigraphic ◽  
Sedimentary Microfacies ◽  
System Tracts ◽  
System Tract

In the light of the principle and method of sequence stratigraphy, the sequence stratigraphic framework of Badaowan formation in the Dishuiquan area was established. The results show that the sequence of Badaowan formation is one and half, including 5 system tracts. The whole experiences the process of retrogradation, progradation and then retrogradation again. There develop three types of sedimentary facies such as braided river, braided river delta and lakes, five types of sedimentary subfacies and 10 types of sedimentary microfacies. Most of JSQ1 sequence lowstand system tract is braided rivers, the lacustrine transgressive system tract mainly develops shore-shallow lacustrine sediment and most of highstand system tract is braided river delta; lowstand systems tract of JSQ2 sequence mainly develops braided river delta, most of the lacustrine transgressive system tract is shore-shallow lacustrine sediments.

scholarly journals Shale Gas Exploration Potential in Southwestern Shandong Province of Eastern China

2021 ◽  
Vol 9 ◽  
Author(s):  
Li Cuifang ◽  
Huang Xinglong ◽  
Shao Yubao ◽  
Dou Fengke
Keyword(s):  
Organic Matter ◽  
Shale Gas ◽  
Mineral Content ◽  
Eastern China ◽  
Shandong Province ◽  
Reservoir Rock ◽  
Level System ◽  
Geological Characteristics ◽  
Taiyuan Formation ◽  
System Tract

The shale layers of the Permian Shanxi Formation and Taiyuan Formation in the southwestern part of Shandong Province are marine-continental transitional sedimentary facies. When compared with the Ordos Basin, which was a typical breakthrough in marine-continental transitional shale gas exploration, the geological characteristics, exploration, and development prospects of marine-continental transitional shale gas in the southwestern section of Shandong Province are more defined. The shale gas deposits of the Shanxi and Taiyuan Formations in southwestern Shandong Province have the following geological characteristics. The sedimentary environments of Shanxi and Taiyuan Formations are considered to be stable and characterized with widely distributed organic-rich shale, which can be used as composite evaluation layers. The total thickness of the shale range is between 140 and 350 m, with an average of 230 m. The main types of organic matter in the Shanxi Formation are Type Ⅲ and Type Ⅱ2 kerogen, while the main types of organic matter in the Taiyuan Formation are rock types. The abundance and maturity of the organic matter are high, and the gas generating capacity is strong. The reservoir rock mineral composition is complex in the region. The clay mineral content is relatively high and the brittle mineral content is rich. Also, the shale fracturing ability is good. The region has the characteristics of a low porosity and low permeability reservoir, with relatively good reservoir capacity. Three primary points of interest have stably been developed within the region, which are located in the upper high water level system, near the initial flood surface, and the majority of flood surface, including a transgressive system tract and high level system tract. The total gas content is estimated to range between 0.03 and 4.47 m3/t, with an average of 0.30 m3/t. The shale gas resources are rich, including one favorable Class I location with an area of 819.06 km2 and a resource amount of 985.84 × 108 m3; four favorable Class Ⅱ locations with an area of 1,979.68 km2 and a resource amount of 2,278.14 × 108 m3; and five prospective locations with an area of 8,385.52 km2 and a resource amount of 7,299.48 × 108 m3. Therefore, the region was considered to have major exploration potential.

scholarly journals Towards an integrated stratigraphy of the Gramame Formation (Maastrichtian), CIPASA quarry, Pernambuco-Paraíba Basin, NE Brazil

2006 ◽  
Vol 29 (1) ◽  
pp. 81-94
Author(s):  
Francisco Henrique de Oliveira Lima ◽  
Eduardo A. M Koutsoukos
Keyword(s):  
Order Type ◽  
Passive Margin ◽  
Northeastern Brazil ◽  
Calcareous Nannofossils ◽  
Calcareous Nannofossil ◽  
Warm Climate ◽  
Third Order ◽  
Transgressive System Tract ◽  
System Tract ◽  
Integrated Stratigraphy

This study presents the integrated biostratigraphic (calcareous nannofossils and foraminifera), petrographic, geochemical and ichnological analyzes of the Gramame Formation (Maastrichtian) at the CIPASA Quarry section, in the Pernambuco-Paraíba Basin, northeastern Brazil. A high resolution calcareous nannofossil biostratigraphic study has been carried out, allowing to subdivide the studied section into three subzones of Maastrichtian age: CC25A, CC25B, and CC25C. Each biostratigraphic unit was further characterized by petrographic, geochemical and ichnological parameters. During the Maastrichtian the area was characterized by a dry and warm climate with low influx of terrigenous sediments. These conditions were fundamental to the widespread development of a carbonate ramp system in an outer neritic to bathyal setting, with deposition of alternating calcareous mudstones and argillaceous mudstones of the Gramame Formation. The Gramame Formation belongs to the transgressive system tract of second-order type, characteristic of a Passive Margin Sequence. The studied section consists of part of a third order deposicional cycle, which is arranged in a transgressive systems tract and a highstand systems tract. The lowstand systems tract was not characterized.

scholarly journals Lithofacies Types, Assemblage Characteristics, and Sedimentary Evolution Model of Lacustrine Shale in Dongyuemiao Formation of Fuxing Area

2021 ◽  
Vol 9 ◽  
Author(s):  
Yi Shu ◽  
Hanyong Bao ◽  
Youheng Zheng ◽  
Miankun Chen ◽  
Yongchao Lu ◽  
...  
Keyword(s):  
Oil And Gas ◽  
Sedimentary Environment ◽  
Shale Oil ◽  
Transgressive System Tract ◽  
Oil And Gas Exploration ◽  
Sedimentary Evolution ◽  
Lacustrine Shale ◽  
System Tract ◽  
Fossil Shell

The identification and classification of lithofacies’ types are very important activities in shale oil and gas exploration and development evaluation. There have been many studies on the classification of marine shale lithofacies, but research on lacustrine shale lithofacies is still in its infancy. Therefore, in this study, a high-resolution sequence stratigraphic framework is established for the lacustrine shale of the Jurassic Dongyuemiao Formation in the Fuxing area using detailed core observations, thin section identification, XRD analysis, major and trace element analysis, wavelet transform analysis, and detailed identification and characterization of the fossil shell layers in the formation. In addition, the lithofacies’ types and assemblages are identified and characterized, and the lithofacies’ characteristics and sedimentary evolution models in different sequence units are analyzed. The significance of the lithofacies assemblages for shale oil and gas exploration is also discussed. The results show that the shale of the target interval can be divided into 8 parasequence sets; further, 9 types of lithofacies and 6 types of lithofacies assemblages are identified. The 9 lithofacies are massive bioclast-containing limestone shoal facies (LF1), thick-layered fossil shell–containing limestone facies (LF2), layered mud-bearing fossil shell–containing limestone facies (LF3), laminated fossil shell–containing argillaceous shale facies (LF4), laminated fossil shell–bearing argillaceous shale facies (LF5), argillaceous shale facies (LF6), massive storm event–related bioclast-containing facies (LF7), massive argillaceous limestone facies (LF8), and massive mudstone facies (LF9). The sedimentary evolution models of different lithofacies are established as follows: Unit 1 (LF1-LF6) of the Dong-1 Member corresponds to the early stage of a lake transgressive system tract, and Units 2–4 (LF4-LF7) correspond to the middle to late stage of the lake transgressive system tract, which was an anoxic sedimentary environment. The Dong-2 Member (LF7-LF8) and the Dong-3 Member (LF5+LF9) correspond to a lake regressive system tract, which was an oxygen-rich sedimentary environment. Based on the characteristics of the shale lithofacies, sedimentary environment, and the quality of the reservoir, the lithofacies assemblage of LF4–LF7 in Unit 4 is the most favorable type for oil and gas exploration, followed by the lithofacies assemblage in Unit 2; the lithofacies assemblage in the Dong-2 and Dong-3 Members are the worst.

scholarly journals Palaeoenvironmental evolution of formation of Bayanjargalan oil shale: evidence from trace elements and biomarkers

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Youhong Sun ◽  
Demchig Tsolmon ◽  
Xuanlong Shan ◽  
Wentong He ◽  
Wei Guo
Keyword(s):  
Organic Matter ◽  
Oil Shale ◽  
Oil Content ◽  
Higher Plants ◽  
Large Set ◽  
Lake Productivity ◽  
Element Analysis ◽  
Mine Area ◽  
Oil Shales ◽  
System Tract

AbstractThe genetic type of the Bayanerhet Formation oil shale in the Bayanjargalan mine area is an inland lacustrine oil shale deposit. Inorganic element analysis and organic geochemical testing of oil shale samples collected in three boreholes show that the Bayanerhet Formation oil shale has relatively high organic contents, e.g., average TOC values of 6.53, 7.32 and 8.84 (corresponding to oil contents of 5.49%, 6.07% and 7.50%) in boreholes BJ3807, BJ3405 and BJ3005, respectively. Analysis of organic matter sources with biomarkers indicates that lower aquatic organisms such as algae contribute more to the organic matter than higher plants do. According to research on the values of Fe2O3/FeO, Rb/Sr and w (La) n/w (Yb)n in cores from the three boreholes, the Bayanjargalan oil shale is inferred to have formed in a humid paleoclimate with a relatively high sedimentation rate. In research on the evolution of the paleoaquifer in which the oil shale formed, the values of Fe3+/Fe2+, V/V + Ni, Ni/V, Ceanom and δCe are applied as sensitive indicators of the redox conditions in the aqueous medium. These values indicate that the Bayanjargalan oil shale formed in a water body with a weak redox environment. Moreover, the values of Ca/(Ca + Fe) and Sr/Ba and the values of gammacerane/αβC30 hopane in biomarkers show that the oil shale was formed in a saltwater environment. Analysis of Mo and U shows high endogenous lake productivity, corresponding to high TOC, which suggests that the lacustrine productivity played an important role in organic matter enrichment. The Lower Cretaceous Bayanerhet Formation (K1bt) in the Bayanjargalan mine area encompasses a complete sequence and was formed during lowstand, transgression, highstand and regression periods. The dominant oil shale deposits were formed in the transgression system tract and high stand system tract, and these oil shales have a high oil content and stable occurrence. A large set of thick, high-TOC and high-oil-content oil shales in the second member of the Bayanerhet Formation was deposited under such conditions. The abundant terrigenous supply under warm and humid conditions significantly promoted the primitive biological productivity, and the weak redox saltwater environment had relatively high productivity. All the favorable conditions promoted the formation of high-quality oil shale.

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