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Total organic carbon (TOC) content of source rocks is usually determined by geochemical analysis of samples, but this process takes a long time and costs a lot. Using high-resolution and continuous logging information to evaluate the TOC content can solve the above problems. Previous studies have shown that there are certain differences in the response of logging curves such as spontaneous potential (SP), acoustic interval transit time (AC), natural gamma ray (GR), resistivity (Rt) and density (DEN) to TOC. Based on the response characteristics, this article uses the logging data of nine wells in Wenchang A and Wenchang B depressions to predict TOC by multiple regression method, and proves its accuracy by comparing with the density logging method and ΔlogR method. In addition, the influencing factors of logging evaluation are discussed: ① Type difference of parent rock affects the structural evolution and reservoir conditions of upper strata; ② Different clay mineral compositions lead to the difference in the distribution of argillaceous types and content, thus affecting the logging data. Therefore, clarifying the factors affecting logging evaluation and establishing effective prediction models in different blocks have important guiding significance for oil and gas exploration and development in the Zhu III sub-basin. [ABSTRACT FROM AUTHOR]

The paleovegetation and paleoclimate characteristics are studied in the Palaeogene strata of Hetao Basin, Subei Basin and Qaidam Basin in China, and the Cretaceous Guyang Formation (K1g) in the Hetao Basin. These three basins receive high attention, different distribution areas, representative. Pollen evidence shows that: (1) The sporopollen assemblage of Palaeogene Linhe Formation (E3l) in Hetao Basin is characterised by Pinaceae-Ephedripites-Ulmipollenites-Chenopodipollis. It reflects that the ancient vegetation types were mainly coniferous and evergreen woody plants, and the climate was cold temperature. The sporopollen assemblage characteristics of the upper member of the Palaeogene Xiaganchaigou Formation (E32) in the Qaidam Basin are similar to it. (2) The sporopollen characteristics of the K1g in the Hetao Basin reflect that its ancient vegetation was dominated by evergreen woody plants and belongs to a warm and humid subtropical climate. (3) The assemblage of Palaeocene Funing Formation (E1f) in Subei Basin was Pterisisporites undulatus-Ulmipollenites minor-Taxodiaceaepollenites hiatus. The climate type was humid north temperate climate, vegetation was mainly deciduous trees and evergreen woody plants. (4) Leiosphaeridia/Granodiscus, Pediastrum and Botryococcus were also detected in the E1f of Subei Basin. The appearance of these algae indicates the special saline water environment and good hydrocarbon potential. [ABSTRACT FROM AUTHOR]

The alkaline lacustrine source rock developed in Fengcheng Formation is the main source of Mesozoic oil and gas in the Mahu Sag of the Junggar Basin. The study is related to the Total organic carbon (TOC) evaluation of the Fengcheng source rock. Utilizing the improved ΔlogR method and multiple regression of logging data on the SPSS software, the TOC logging calculation model of the Fengcheng source rock has been obtained. Results show that the Fengcheng source rock in the western slope of the Mahu Sag is concentrated in the longitudinal direction. The TOC values are more than 0.6%, and the highest value is greater than 2.0%. TOC gradually decrease from west to east on the plane. [ABSTRACT FROM AUTHOR]

We explore the interaction between estrogen and PCSK9 and their collective impact on lipid metabolism, especially concerning the regulation of low-density lipoprotein receptor levels. Utilizing both animal and cellular models, including ovariectomized mice and HepG2 cell lines, we demonstrate that estrogen deficiency leads to a disruption in lipid metabolism, characterized by elevated levels of total cholesterol and LDL-C. The study commences with mice undergoing ovariectomy, followed by a diet regimen comprising either high-fat diet or normal feed for a four-week duration. Key assessments include analyzing lipid metabolism, measuring PCSK9 levels in the bloodstream, and evaluating hepatic low-density lipoprotein receptor expression. We will also conduct correlation analyses to understand the relationship between PCSK9 and various lipid profiles. Further, a subset of ovariectomized mice on high-fat diet will undergo treatment with either estrogen or PCSK9 inhibitor for two weeks, with a subsequent re-evaluation of the earlier mentioned parameters. Our findings reveal that estrogen inhibits PCSK9-mediated degradation of low-density lipoprotein receptor, a process crucial for maintaining lipid homeostasis. Through a series of experiments, including immunohistochemistry and western blot analysis, we establish that PCSK9 is involved in lipid metabolism disorders caused by estrogen deficiency and that estrogen regulates PCSK9 and low-density lipoprotein receptor at post-transcriptional level. The study provides a mechanism for the involvement of PCSK9 in elucidating the disorders of lipid metabolism caused by estrogen deficiency due to perimenopause and ovarian decline. [ABSTRACT FROM AUTHOR]

The source rocks in the Zhu III sub-basin of the Pearl River Mouth Basin are mainly developed within the Eocene Wenchang Formation (E 2 w) and the Oligocene Enping Formation (E 3 e), which are widely distributed and have great resource potential. The source rocks in the Zhu III sub-basin are mainly type II 1 kerogens to type II 2 kerogens, with high organic matter abundance and in the mature stage. However, the source rocks in this area lack a systematic classification and interpretation, to distinguish the shore-shallow lake facies of the E 2 w and E 3 e, both having similar carbon isotope values and biomarkers. According to organic geochemical data from 67 specimens of source rocks and 45 data of biomarkers in the E 2 w and E 3 e of the Zhu III sub-basin, particularly the biomarker compound indicators, the following three tasks were performed: (1) The paleoenvironmental characteristics of the E 2 w and E 3 e were investigated. (2) The geochemical identification criteria were established, and the E 2 w and E 3 e source rocks were divided into five categories: the E 3 e river swamp facies, the E 3 e shore-shallow lake facies, the E 2 w fan-delta facies, the E 2 w shore-shallow lake facies, and the E 2 w profundal lake facies. (3) Biomarkers indexes for evaluating maturity of source rocks in Zhusan sub-basin are optimized and quantified. The results of this investigation effectively solve the problem of identification of the source rocks with similar geochemical characteristics in the western Pearl River Mouth Basin, laying a good foundation for oil source correlation and hydrocarbon exploration. Moreover, this research can provide reference for the division and evaluation of the source rocks in offshore lacustrine basins worldwide. • The paleoenvironment characteristics of the Wenchang and Enping Formation were analyzed. • A geochemical classification scheme of source rocks were established, based on biomarkers indexes. • Selected biomarkers indicators for evaluating maturity of source rocks in Zhu III sub-basin are quantified. [ABSTRACT FROM AUTHOR]