Multi-spherical interactions and mechanisms of hydrocarbon enrichment in the Southeast Asian archipelagic tectonic system

Global cooling began since 50 Ma,but a warm climate was maintained in the archipelagic tectonic system in Southeast Asia where a wealth of Cenozoic oil and gas resources was formed and preserved.From the perspective of Earth system,this study analyzes Cenozoic tectonic activities,climatic and environmental evolution,and petroleum enrichment in Southeast Asia,and provides the following insights:(1)Subduction of oceanic plates and the extension of overlying continental lithosphere resulted in widespread volcanic eruptions as well as the formation of rift basins and shallow marine shelves,leading to complex interactions between deep tectonic processes and Earth’s surface including mountains,basins,and seas.(2)Microcontinental accretion and prolonged stay in equatorial low-latitude regions have changed trade winds into monsoons,altered ocean current pathways and flow rates,and profoundly affected rainfall and climate.(3)The archipelagic tectonic system,coupled with a hot and rainy climate,fostered tropical rainforests,mangroves,and phytoplankton,providing abundant organic matter and promoting the development of petroleum resources.(4)Combinations of rift basin development and marine transgression and regression led to an effective superposition of source-reservoir-seal combinations from multiplepetroleum systems.Rapid deep burial of organic matter and high geothermal gradients facilitated the generation and large-scale accumulation of oil and gas.(5)Multi-spherical(such as atmosphere,biosphere,hydrosphere and lithosphere)interactions on the Earth,which resulted from the convergence of multiple tectonic plates,are believed as the primary driver for exceptional enrichments of Cenozoic oil and gas resources in Southeast Asia.These understandings are significant for developing theories of oil and gas enrichment under the guidance of Earth System Science.In order to continue making significant oil and gas exploration discoveries in the deep-layers,deep-waters,and unconventional oil and gas fields of Southeast Asia,attention should be paid to the oil and gas resource effects of the collision between Australia and Sunda blocks and the high-temperature and high-rainfall climate environment,and efforts should be made to develop economic development and CO_(2)sequestration technologies for offshore CO_(2)-rich gas fields.

A novel model of the carbon cycle in the Cambrian ocean

The classic model of the carbon cycle suggests that the extensive burial of ^(12)C-enriched organic carbon leads to a positive carbon isotope(δ^(13)C)excursion(CIE),while massive oxidation of organic carbon results in a negative CIE.However,global events such as the BAsal Cambrian Carbon isotope Excursion(BACE)and the Steptoean Positive Carbon Isotope Excursion(SPICE)are global negative and positive δ^(13)C excursions,respectively,and they also exhibit significant organic carbon burial anomalies,displaying decoupling between carbon isotope anomalies and organic carbon burial.Based on the analyses of the Cambrian carbon cycle and paleoceanographic evolution records from well Tadong2 in the Tarim Basin,we propose a novel model of the carbon cycle in the Cambrian ocean that incorporates oceanic dissolved organic carbon(DOC).Our findings are as follows.(1)The Cambrian ocean maintained substantial DOC reservoirs,which were regulated by ocean currents and paleo-redox conditions and exerted significant influence on the oceanic carbon cycle.(2)The oxidation of the oceanic DOC reservoirs during the early Cambrian led to the BACE and the Asian Phenomenon of the Cambrian petroleum systems,while the expansion of the oceanic DOC reservoirs during the SPICE resulted in a global positive δ^(13)C excursion and the absence of significant organic carbon burial.(3)The deep-basin sedimentary environment in the eastern depression of the Tarim Basin may have fostered the development of organic-rich black shales during the Furongian Series,corresponding to organic carbon burial during the SPICE and representing potential prospects for ultra-deep oil and gas exploration.Future research should focus on the formation mechanism,reserve scale,and influencing factors of the oceanic DOC reservoirs,as well as their resource and environmental effects.It is expected that new breakthroughs will be made in the fields of Earth system science and oil and gas exploration.

Multi-spheric interactions driven differential formation and accumulation of hydrocarbon resources in the North Sea Basin

The North Sea Basin is the most important oil and gas producing area in Europe and the birthplace of many classic petroleum geological theories. From the perspective of multi-spheric interactions in the Earth, this study investigated the riftforeland-rift evolution process of the North Sea Basin, which was controlled by the deep dynamic driving forces of the continental collision orogeny, mantle plume uplift, and intraplate deformation. The North Sea Basin was found to have drifted northward since the Carboniferous and passed through the low-latitude Hadley and the mid-latitude Ferrel cells. Two sets of main hydrocarbon source rocks have formed, the coals and coal measures of the Upper Carboniferous Westphalian and the marine shale of the Upper Jurassic Kimmeridge Clay Formation. We propose that the deep processes, tectonic activity, and transgression-climate evolution jointly controlled the types and horizons of the source rocks, reservoirs, and seals in different regions of the North Sea Basin. In the southern North Sea Basin, a Carboniferous-Lower Triassic gas-rich petroleum system was formed,which is characterized by transitional coal measure source rocks, desert aeolian sandstone reservoirs, and evaporite cap rocks. In the northern North Sea Basin, an Upper Triassic-Paleogene oil-rich petroleum system was formed, which is characterized by marine graben-type source rocks, deltaic sandstone and marine limestone reservoirs, and marine tight marl and shale cap rocks.The late tectonic burial and uplift in the North Sea Basin further controlled the processes of oil and gas generation and accumulation, ultimately leading to a differential distribution pattern which is oil rich in the northern part and gas rich in the southern part of the basin. In the future, there is an urgent need to re-examine the mechanisms for the petroleum generation and accumulation in large mature exploration areas(e.g., super basins such as the North Sea) and low exploration areas(e.g., the Okhotsk Sea and Arctic regions) from the perspective of multi-spheric interactions in the Earth in order to provide new theoretical support for increasing the identification of oil and gas reserves globally. The development of artificial intelligence in the petroleum industry should focus on the massive amount of exploration and geological data collected in the North Sea Basin.Through digital geological innovation, carbon neutral comprehensive utilization of oil, gas, and associated resources(e.g.,helium and hydrogen) can be achieved, providing a new paradigm for global oil and gas exploration and development.

Proven and Potential Microbial Contributions to the Gulong Shale Oil

0 INTRODUCTION The Gulong shale oil is a new type of hydrocarbon resource enriched in the clay-rich shale of the Upper Cretaceous Qingshankou Formation in the Songliao Basin.Because it is most typical in the Gulong depression in the northern part of the Songliao Basin and has been commercially developed,it is called Gulong shale oil(Sun et al.,2021).

Lacustrine carbon sink:A hidden driver of the Late Cretaceous Cooling Event

Lacustrine systems since the Mesozoic have sequestered large quantities of organic carbon,which may have important value for global climate cooling,but there is still a lack of geological evidence of this sequestration.Taking the Songliao Basin in China as a case study,we elucidate the important function of lacustrine basins as sinks of a large amount of organic carbon,particularly when the contemporaneous marine sediments were poor sinks of organic carbon.Volcanic activities and orbital forcing were likely key factors influencing the water transportation between the land and oceans,as well as the alternating burial of organic carbon in the oceans and land.Microorganisms related to methane metabolism may have been highly involved in the mineralization and sequestration of lacustrine organic carbon.This study provides new insights into the coupled carbon–water cycle between the land and oceans and the influence of this process on global climate evolution.

最小含氧带和硫化环境控制14亿年前有机质生烃能力

显生宙沉积有机质富集和生烃潜力受控于初级生产力和保存环境,但元古宙以原核生物为主的广泛厌氧环境对烃源岩发育的控制作用并不清楚.中国华北燕辽盆地中元古界下马岭组发育一套厚达250 m的富有机质烃源岩,主要形成于硫化厌氧和最小含氧带(oxygen minimum zone,OMZ)水体环境,沉积时限约为1400~1360 Ma.选择有代表性的两类黑色页岩样品开展了黄金管热模拟实验,结果表明,14亿年前富有机质页岩的生油气潜力与显生宙优质烃源岩相当,且明显受控于沉积时的海洋水体环境;硫化厌氧环境的沉积有机质,虽丰度略低(TOC 5%),但生油能力明显高于OMZ环境下的沉积有机质(TOC达12%);两类沉积环境有机质的生烷烃气能力却相反.这说明,厌氧环境不但有利于有机质富集,同时保存了对生油更加有效的富氢脂肪结构;尽管OMZ海洋初级生产力很高,在底层水有氧环境下也能够沉积高丰度的有机碳,但氧化作用使其生油潜力明显降低.研究证实,中元古代海洋环境的动态演化对沉积有机质的母源构成、生烃潜力和产物组成具有重要影响,为深入了解并探索中新元古界的烃源岩发育机制和油气资源潜力提供了一个重要窗口.

中元古代海洋生物碳泵:有机质来源、降解与富集

碳循环是生命改造地球的最主要途径.海洋是地球上最大的活跃碳库,其储碳-释碳的异常波动对地球表层系统演化具有革命性影响.然而,中元古代无机碳同位素的相对稳定表明,地球碳循环达到了一个相对平衡的状态.因此,研究中元古代海洋中由微生物主导的碳循环对于我们认识地球宜居演化具有重要意义.本文从有机质来源、降解与富集等方面论证了中元古代海洋生物碳泵的主要地球化学过程,提出初始有机质来自以蓝细菌为主的多源生物,有机质降解有反硝化细菌、铁还原菌、硫酸盐还原菌、产甲烷菌等多种微生物参与.以中元古界下马岭组为例,定量分析了受初级生产水平和水体氧化还原程度控制的微生物降解作用及降解程度,估算14亿年前的海洋惰性可溶碳库增储可能达1000×10;~2500×10;t,仅燕辽盆地埋藏的有机碳就达6000×10;t.最后,本文讨论了磷、铁供给对海洋碳循环的重要控制作用,提出未来开展高精度沉积地球化学解析和多元素循环精细建模研究的必要性.

Hydrocarbon generation characteristics and exploration prospects of Proterozoic source rocks in China

A large number of primary oil and gas reservoirs have been discovered in Proterozoic strata all over the globe.Proterozoic sequences are widely distributed in China, and the discovery of large Sinian-aged gas reservoirs in the Sichuan Basin and Mesoproterozoic liquid oil seepages in North China shows that attention should be paid to the exploration potential of Proterozoic strata. In this paper, the main controlling factors of Proterozoic source rocks are discussed. Principally, active atmospheric circulation and astronomical cycles may have driven intense upwelling and runoff to provide nutrients; oxygenated oceanic surface waters could have provided suitable environments for the organisms to thrive; volcanic activity and terrestrial weathering caused by continental break-up would have injected large amounts of nutrients into the ocean, leading to persistent blooms of marine organisms; and extensive anoxic deep waters may have created ideal conditions for the preservation of organic matter. Additionally, the appearance of eukaryotes resulted in diversified hydrocarbon parent material, which effectively improved the generation potential for oil and gas. Through the comparison of Formations across different cratons, seven sets of Proterozoic organic-rich source rocks have been recognized in China, which mainly developed during interglacial periods and are also comparable worldwide. The Hongshuizhuang and Xiamaling Formations in North China have already been identified previously as Mesoproterozoic source rocks. The early Proterozoic Changchengian System is highly promising as a potential source rock in the Ordos Basin. In the Upper Yangtze area, the Neoproterozoic Datangpo and Doushantuo Formations are extensively distributed, and represent the major source rocks for Sinian gas reservoirs in the Sichuan Basin. Moreover, the Nanhuan System may contain abundant shales with high organic matter contents in the Tarim Basin, although this possibility still needs to be verified. Indeed, all three cratons may contain source rocks of Proterozoic strata; thus, these strata represent major exploration targets worthy of great attention.

The Mesoproterozoic Oxygenation Event

The accumulation of oxygen is one of the most important characteristics that distinguish Earth from other planets in the solar system,which is also considered to be the key factor influencing the birth and evolution of complex life forms.The oxygenation process of the Earth surface has long been viewed to be episodic with two critical intervals occurring in the early Paleoproterozoic(2.45-2.10 Ga)and the late Neoproterozoic(0.80-0.54 Ga),with a 1.3-billion-year-long low oxygen period in between.Recently,increasing independent works carried out by different scientific teams in the Yanliao Basin,North China are demonstrating that the atmospheric oxygen concentrations had reached>4%PAL(present atmospheric levels)at least during 1.59-1.56,1.44-1.43,and 1.40-1.36 Ga.These estimated values are higher than the previously recommended values of<0.1-1%PAL.Such a scenario discovered in the Yanliao Basin is consistent with the synchronously deposited strata in Australia and Siberia,pointing to a Mesoproterozoic oxygenation event(1.59-1.36 Ga)between the two major oxygenation intervals during the Proterozoic.This Mesoproterozoic oxygenation event is coupled with the break-up of the Columbia(Nuna)supercontinent,the formation of organic-rich shales and Fe-Mn deposits,and the early innovation of eukaryotic algae,indicating that the geological and biological co-evolutionary processes control the Earth surface system.

What are the Limiting Environmental Factors for the Evolution of Early Eukaryotic Diversity?

Exploring the mysteries of life is an eternal frontier of science. Containing complex and diverse organisms on the surface of the Earth is one of the most crucial characteristics that distinguish the Earth from other planets in the Solar system. Almost all animals, plants, and fungi that can be seen with the naked eye belong to eukaryotes。

A post-synthesis modification method of molecular sieve 13X for enriching hopanoids in petroleum

In this study,alkali/acid treatment and ion exchange post-synthesis modification methods to modify the pore diameter and structure of molecular sieve 13X(MS13X)were applied to obtain products,which could then be implemented to improve the enrichment recovery of hopanoids in petroleum.The modification products were analyzed by SEM with EDS,XRD and nitrogen physisorption.The results indicated that the product which had been prepared in the oxalic acid ethanol solution formed some mesopores,and also retained the initial framework of crystal.It was revealed that this product was able to remarkably increase the recovery rate of hopanoids in petroleum without leading to a significant isotope fractionation phenomenon.It is thus shown that this modification method of non-aqueous oxalic acid solution for MS13X can be used as an effective pretreatment tool in the application of compoundspecific isotope analysis of hopanes with low concentration.