scholarly journals Application of Elemental Geochemistry in High-Frequency Sequence—Stratigraphic Analysis of Lacustrine Shale

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 657
Author(s):  
Hongliang Wang ◽  
Zehua Zhang ◽  
Jintong Liang ◽  
Huimin Liu ◽  
Shige Shi
Keyword(s):  
Shale Gas ◽  
High Frequency ◽  
Ph Value ◽  
Sedimentary Environment ◽  
Lake Basin ◽  
Bohai Bay ◽  
Oil Exploration ◽  
Response Characteristics ◽  
Transport Distance ◽  
Frequency Sequence

The successful development of shale gas and oil in North America has created considerable interest in shale. The analysis of genetic types, the sedimentary environment, and the mudstone development mechanism within sequences is critical for evaluating shale gas and oil exploration prospects, exploration favorable zones, and resource potential. This study focused on the shale of Shahejie Formation in Dongying Depression of Bohai Bay Basin. Shale lithofacies division, geochemical analysis, and well-log analysis were performed for a sedimentary environment and its related elemental response characteristics’ identification. Based on the results, we concluded that the sedimentary environment of the lake basin evolved from the saltwater lake to the ambiguous lake and then the open lake to the delta. In response, we observed gradually decreasing Sr/Ba and Ca/Mg ratios and increasing Rb/Ca and Fe/Mn ratios during the whole process during the reduction of the salinity and the decrease in PH value and sediments’ transport distance. The relationship between ratio elements and high-frequency sequences was initially established within the shale strata. Our results show that ratios of Sr/Ba and Ca/Mg ratios near the sequence boundary are relatively low, and ratios of Fe/Mn and Rb/Ca are relatively high, while ratios of Sr/Ba and Ca/Mg near the flooding surface are relatively high, and ratios of Fe/Mn and Rb/Ca are relatively low. Those features can be used as a marker for high-frequency sequence division of shale strata. Our results provided a new theoretical basis and technical method for shale gas and oil exploration and development.

High Resolution Sequence Stratigraphy Characteristics and Distribution of Donghe Sandstone in Qunkuqiake Region in Tarim Basin

2014 ◽  
Vol 1044-1045 ◽  
pp. 570-573
Author(s):  
Mu Wei Cheng
Keyword(s):  
Tarim Basin ◽  
High Frequency ◽  
Oil And Gas ◽  
Sedimentary Environment ◽  
Sedimentary Facies ◽  
Sequence Stratigraphic ◽  
Sedimentary Characteristics ◽  
Sand Body ◽  
Frequency Sequence ◽  
High Resolution Sequence Stratigraphy

Qunkuqiake Region is an important exploration block in Tarim Basin. Donghe Sandstone is the main oil and gas target stratum. In order to reveal the rules of migration of the sand body and predict the favorable reservoir accurately, two high-frequency cycles are identified in Donghe Sandstone each of which consists of rising hemicycle and descending hemicycle, the sedimentary characteristics are analysed within the sequence stratigraphic framework and the barrier bar subfacies are identified beginning with the sedimentary characteristics of glutenite through the study of drilling stratigraphic section using drilling data, well logging data and cores data. This paper has disclosed the transition of the sedimentary environment from barrier-free coast system to barrier coast system during the period from rising hemicycle to descending hemicycle and the planar distribution of sedimentary facies of different high frequency sequence of Donghe Sandstone.

High-frequency sequence stratigraphy of Upper Cenozoic deposits in the central and southeastern North Sea areas

1997 ◽  
Vol 14 (2) ◽  
pp. 99-123 ◽  
Author(s):  
Jan C. Sørensen ◽  
Ulrik Gregersen ◽  
Morten Breiner ◽  
Olaf Michelsen
Keyword(s):  
Sequence Stratigraphy ◽  
North Sea ◽  
High Frequency ◽  
Upper Cenozoic ◽  
Frequency Sequence

Lithology and sedimentary heterogeneity of the Longmaxi Shale in the southern Sichuan Basin, China

2021 ◽  
pp. 1-49
Author(s):  
Boling Pu ◽  
Dazhong Dong ◽  
Ning Xin-jun ◽  
Shufang Wang ◽  
Yuman Wang ◽  
...  
Keyword(s):  
Continental Shelf ◽  
Deep Water ◽  
Shale Gas ◽  
Sichuan Basin ◽  
Sedimentary Environment ◽  
Gas Production ◽  
Carbonaceous Shale ◽  
Gas Wells ◽  
Longmaxi Shale ◽  
Siliceous Shale

Producers have always been eager to know the reasons for the difference in the production of different shale gas wells. The Southern Sichuan Basin in China is one of the main production zones of Longmaxi shale gas, while the shale gas production is quite different in different shale gas wells. The Longmaxi formation was deposited in a deep water shelf that had poor circulation with the open ocean, and is composed of a variety of facies that are dominated by fine-grained (clay- to silt-size) particles with a varied organic matter distribution, causing heterogeneity of the shale gas concentration. According to the different mother debris and sedimentary environment, we recognized three general sedimentary subfacies and seven lithofacies on the basis of mineralogy, sedimentary texture and structures, biota and the logging response: (1) there are graptolite-rich shale facies, siliceous shale facies, calcareous shale facies, and a small amount of argillaceous limestone facies in the deep - water shelf in the Weiyuan area and graptolite-rich shale facies and carbonaceous shale facies in the Changning area; (2) there are argillaceous shale facies and argillaceous limestone facies in the semi - deep - water continental shelf of the Weiyuan area and silty shale facies in the Changning area; (3) argillaceous shale facies are mainly developed in the shallow muddy continental shelf in the Weiyuan area, while silty shale facies mainly developed in the shallow shelf in the Changning area. Judging from the biostratigraphy of graptolite, the sedimentary environment was different in different stages.

Effect of sedimentary environment on shale lithofacies in the lower third member of the Shahejie Formation, Zhanhua Sag, eastern China

2017 ◽  
Vol 5 (4) ◽  
pp. T487-T501 ◽  
Author(s):  
Tingwei Li ◽  
Zhenxue Jiang ◽  
Chenlu Xu ◽  
Yuan Yuan ◽  
Pengfei Wang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Early Stage ◽  
Eastern China ◽  
Sedimentary Environment ◽  
Gas Production ◽  
Bohai Bay ◽  
Calcareous Shale ◽  
Shahejie Formation ◽  
Scanning Electron

Research on shale lithofacies is important for shale oil and gas production. This study focused on the lower third member of the Shahejie Formation ([Formula: see text]) in the Luo-69 well in the Zhanhua Sag, Jiyang Depression, Bohai Bay Basin, eastern China. Several methods, including thin section observations, total organic carbon (TOC) analysis, X-ray diffraction analysis, quantitative evaluations of minerals by scanning electron microscopy, major and trace-element analyses, and field emission-scanning electron microscopy, are used to investigate the effect of sedimentary environment on the type and distribution of shale lithofacies. Our research indicates that 36 types of shale lithofacies can be classified based on the TOC content, mineral composition, and sedimentary structure, of which five types are identified in the study area. The [Formula: see text] shale has a high calcareous mineral content (average of 49.64%), low clay and siliceous minerals contents (averages of 19.54% and 19.02%, respectively), a high TOC content (average of 3.00 wt%), and well-developed horizontal bedding. The sedimentary environment during the deposition of the [Formula: see text] shale in the Zhanhua Sag had a warm and moist climate, limited provenance, saline water, and strong reducibility. The sedimentary environment in the early stage had a drier climate, more limited provenance, higher salinity, and stronger reducibility than that in the later stage. Shale lithofacies can reflect a certain sedimentary environment and depositional process; similarly, a depositional environment controls the type and distribution of shale lithofacies. Due to the characteristics of the [Formula: see text] sedimentary environment, organic-rich massive mixed shale, organic-rich bedded mixed-calcareous shale, organic-rich laminated calcareous shale, and organic-fair laminated calcareous shale are developed in the [Formula: see text] formation from top to bottom.

scholarly journals Well Logging Based Lithology Identification Model Establishment Under Data Drift: A Transfer Learning Method

Sensors ◽  
2020 ◽  
Vol 20 (13) ◽  
pp. 3643
Author(s):  
Haining Liu ◽  
Yuping Wu ◽  
Yingchang Cao ◽  
Wenjun Lv ◽  
Hongwei Han ◽  
...  
Keyword(s):  
Extreme Learning Machine ◽  
Transfer Learning ◽  
Domain Adaptation ◽  
Sedimentary Environment ◽  
Well Logging ◽  
Learning Technologies ◽  
Bohai Bay ◽  
Learning Method ◽  
Lithology Identification ◽  
Learning Machine

Recent years have witnessed the development of the applications of machine learning technologies to well logging-based lithology identification. Most of the existing work assumes that the well loggings gathered from different wells share the same probability distribution; however, the variations in sedimentary environment and well-logging technique might cause the data drift problem; i.e., data of different wells have different probability distributions. Therefore, the model trained on old wells does not perform well in predicting the lithologies in newly-coming wells, which motivates us to propose a transfer learning method named the data drift joint adaptation extreme learning machine (DDJA-ELM) to increase the accuracy of the old model applying to new wells. In such a method, three key points, i.e., the project mean maximum mean discrepancy, joint distribution domain adaptation, and manifold regularization, are incorporated into extreme learning machine. As found experimentally in multiple wells in Jiyang Depression, Bohai Bay Basin, DDJA-ELM could significantly increase the accuracy of an old model when identifying the lithologies in new wells.

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