Characteristics of igneous rocks and their significance in hydrocarbon accumulation in Block C of Santos Basin, SE Brazil

Santos Basin is characterized by multiple phases of magmatic events and widespread distribution of igneous rocks, which have significant affect of hydrocarbon accumulation. Taking Block C of Santos Basin as a typical and representative example, this paper focused on the characteristics of igneous rocks and their roles in hydrocarbon accumulation through the analysis of igneous rock petrology, geochronology, petrogeochemistry, and gas isotopes. In Block C, at least two main stages of magma events were developed: Aptian magma (122.8±0.6-110.8±0.6 Ma) and Santonian-Campanian magma (84.2±0.7-77.4±0.4). The Aptian magma is dominated by eruptive rocks and has experienced dozens of eruptions, accompanied by several layers of subvolcanic rocks. In comparison, Santonian-Campanian magma is distributed in a relatively random pattern. The multipulse eruption of Aptian magma formed an igneous rock-coquinas complex of more than 600 meters in thickness, inducing a local paleohigh in Itapema Formation. This directly caused the trap crest to shift and contributed to the development of high-quality carbonate deposition in Barra Velha Formation. Before the eruption of Aptian magma, the north flank of Block C was paleohigh, where a particular scale of microbial carbonate reservoirs was anticipated to develop in the Barra Velha Formation as well. These carbonate reservoirs were favorable for hydrocarbon accumulation. The later Santonian-Campanian intrusions also impact carbonate reservoirs through hydrothermal fluid circulation and contact metamorphism. Meanwhile, a large amount of associated CO2 accumulated in the trap led to a high GOR (gas oil ratio) and high CO2 content and changed the fluid composition through the extraction process.A CO2 gas reservoir with condensed oil was eventually formed in the current crest in Block C, as proven by drilled well A.Another pool with high CO2 content is also expected in its north flank, to be demonstrated in the future

Fluoride Adsorption Comparison from Aqueous Solutions Using Al- and La-Modified Adsorbent Prepared from <i>Polygonum orientale</i> Linn.

Al- and La-modified adsorbent materials (PO–Al, PO–La) were prepared by impregnating Polygonum orientale Linn. straw with Al2(SO4)3 and La(NO3)3·6H2O solutions. The potential of removing fluoride using these modified adsorbents was examined. In the PO, PO–Al and PO–La adsorption systems, the fluoride adsorption process followed pseudo-second-order kinetics, and the kinetic constants for k2 and R2 were 0.0276 and 0.9609; 0.2070 and 0.9994; 0.1266 and 0.9933, respectively. The adsorption equilibrium results showed the best match with Langmuir isotherms. Moreover, the maximum monolayer adsorption capacity of PO, PO–Al and PO–La are 0.0923, 3.3190 and 1.2514 mg/g, respectively, in 30 °C. The regeneration results show that the effectively regenerating ability of modified adsorbents. Al-modified adsorbent showed the best results in terms of cost-effectiveness and adsorption efficiency for fluoride adsorption

Fluoride Adsorption Comparison from Aqueous Solutions Using Al- and La-Modified Adsorbent Prepared from Polygonum orientale Linn.

Al- and La-modified adsorbent materials (PO&ndash;Al, PO&ndash;La) were prepared by impregnating Polygonum orientale Linn. straw with Al2(SO4)3 and La(NO3)3&middot;6H2O solutions. The potential of removing fluoride using these modified adsorbents was examined. In the PO, PO&ndash;Al and PO&ndash;La adsorption systems, the fluoride adsorption process followed pseudo-second-order kinetics, and the kinetic constants for k2 and R2 were 0.0276 and 0.9609; 0.2070 and 0.9994; 0.1266 and 0.9933, respectively. The adsorption equilibrium results showed the best match with Langmuir isotherms. Moreover, the maximum monolayer adsorption capacity of PO, PO&ndash;Al and PO&ndash;La are 0.0923, 3.3190 and 1.2514 mg/g, respectively, in 30 &deg;C. The regeneration results show that the effectively regenerating ability of modified adsorbents. Al-modified adsorbent showed the best results in terms of cost-effectiveness and adsorption efficiency for fluoride adsorption

Structural Characteristics of Periphytic Algal Community and Its Relationship with Environmental Factors in the Taiyuan Region of the Fenhe River

In order to explore the characteristics of the periphytic algae community structure and its relationship with environmental factors in the Taiyuan region of the Fenhe River, a total of six sampling sites were investigated in July and December 2021. The effects of water quality status and environmental factors at each sampling point on the community structure of epiphytes were detected. The results showed that a total of 7 phyla and 54 genera of periphytic algae were identified in the Taiyuan region of the Fenhe River, and the species composition was mainly Bacillariophyta, Cyanophyta, and Chlorophyta. According to the analysis results of the biodiversity index, the water body of the Taiyuan region of the Fenhe River is in a state of moderate pollution. The correlation analysis between the epiphytic algae and environmental factors showed that the cell density of algae was significantly correlated with dissolved oxygen (DO), phosphate (PO43&minus;-P), chemical oxygen demand (COD), total phosphorus (TP), and transparency (SD) in the wet season. The algal cell density in the dry season was significantly correlated with water temperature (WT), TP, PO43&minus;-P, and COD. According to the redundancy analysis, the community distribution of the epiphytic algae in the Taiyuan region of the Fenhe River was closely related to physical and chemical factors such as COD, nitrate nitrogen (NO&minus;3&nbsp;-N), WT, dissolved organic carbon (DOC), total nitrogen (TN), and TP, and COD is the main environmental factor driving the change in the community distribution of the periphytic algae in the wet season. TN is the main control factor driving the change in the biological community distribution of periphytic algae in the dry season