Marine and Petroleum Geology最新文献

{"title":"Pore to core plug scale characterization of porosity and permeability heterogeneities in a Cretaceous carbonate reservoir using laboratory measurements and digital rock physics, Abu Dhabi, United Arab Emirates","authors":"Abdulquadri O. Alabere ,&nbsp;Mohamed Soufiane Jouini ,&nbsp;Mohammad Alsuwaidi ,&nbsp;Daniel Morad ,&nbsp;Fadi H. Nader ,&nbsp;Fateh Bouchalaa ,&nbsp;Emad W. Al-Shalabi ,&nbsp;Osama Al Jallad","doi":"10.1016/j.marpetgeo.2024.107214","DOIUrl":"10.1016/j.marpetgeo.2024.107214","url":null,"abstract":"<div><div>Laboratory and digital rock physics study of a Cretaceous limestone reservoir in Abu Dhabi, United Arab Emirates, provides insights into pore connectivity, pore-throat size, and permeability distributions. The procedure involves core analysis at different scales using micro-computed tomography, scanning electron microscopy, and nano-computed tomography; porosity quantification using segmentation techniques; numerical simulation of permeability using lattice Boltzmann method; and upscaling simulation results to core-plug scale using Darcy's Law. The greater proportion of connected versus poorly interconnected pores is attributed to (i) the formation of early diagenetic grain-rimming calcite cement, which reduced the degree of mechanical compaction and pore-throat size reduction, (ii) limited introduction of carbonate mud by bioturbation due to rapid sediment burial, and (iii) dissolution of allochems and partial dolomitization of micrite matrix. Microbial micritization of allochems at the seafloor led to the transformation of grain-supported limestones, dominated by unimodal macropores, into reservoirs with multimodal porosity. Conversely, the mud–supported limestones have depositional unimodal micropore distribution, which is reduced by mechanical compaction and cementation by calcite micro-overgrowths around micrite particles. Good agreement between laboratory and simulated values suggests that lateral facies and related textural variation across different depositional environments have limited implications for digital rock physics techniques in predicting the petrophysical properties of limestone reservoirs. Nevertheless, careful selection of representative elementary volume within a geologic context for a complex, anisotropic limestone reservoir is the key to achieving reliable results.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107214"},"PeriodicalIF":3.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722566","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 56 ka eruptive history of Sartori mud volcano in the Calabrian accretionary prism, Mediterranean Sea","authors":"Mechthild Doll ,&nbsp;Thomas Pape ,&nbsp;Miriam Römer ,&nbsp;Andreas Klügel ,&nbsp;Gerhard Bohrmann","doi":"10.1016/j.marpetgeo.2024.107218","DOIUrl":"10.1016/j.marpetgeo.2024.107218","url":null,"abstract":"<div><div>Mud volcanoes (MVs) are geological structures that episodically eject mud breccias composed of fluids and solids from the Earth's interior. MVs are predominantly associated to converging plate boundaries such as the African-European collision zone in the Mediterranean Sea. Although many investigations have been conducted on the global distribution, morphology and current activity of MVs, studies on the eruptive history and episodic activity of MVs are limited. This study presents a comprehensive analysis of the chronology of mud eruptions from the submarine Sartori MV located in the Calabrian Accretionary Prism in the central Mediterranean Sea at a water depth of about 1900 m. Seafloor bathymetry and backscatter mapping combined with multi-proxy sediment analysis of 16 sediment cores collected in the area of the MV indicate mud breccia deposits from six distinct eruptive phases. Radiocarbon ages of planktonic foraminifera, ages of interbedded tephra layers, identification of the Holocene sapropel marker horizon S1, and correlation with calculated sedimentation rates of hemipelagic sediments revealed that these six phases occurred during the last ∼56 ka. The mudflow deposits of the individual mud eruption phases differ slightly in their bulk organic carbon and nitrogen content, suggesting that the mud breccia composition varied between each eruptive phase. The duration of the quiescent phases between each eruption varied from ∼1.4 ka to ∼12.2 ka. The backscatter data from the seafloor indicate that only the mudflows that were mobilized between ∼56 and 22 ka cover the surroundings of Sartori MV over a wide area. Mudflows generated during more recent eruptive phases remained confined to the central area and the immediate vicinity of the MV, suggesting that MV activity was attenuated during the post-glacial sea level rise and Holocene sea level highstand. Eruptive phases of Sartori MV did not coincide with the eruptions of magmatic volcanoes in the region, and a correlation with earthquake events is also not evident due to the sparse documentation of (pre-)historical events. Internal processes such as pressure release from over-pressured mud chambers are believed to be important drivers of the episodic activity of Sartori MV. This study documents the episodic activity of a MV, and shows the interplay between internal driving processes and external influencing factors over geological time.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107218"},"PeriodicalIF":3.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Differential enrichment of middle-low maturity lacustrine shale oil in the late Eocene Shahejie Formation, Bohai Bay Basin","authors":"Yuan Li ,&nbsp;Di Chen ,&nbsp;Fujie Jiang ,&nbsp;Zhengjun Wang ,&nbsp;Liu Cao ,&nbsp;Renjie Zhao ,&nbsp;Tingwei Guo ,&nbsp;Zhou Fang ,&nbsp;Xiaohao Wang","doi":"10.1016/j.marpetgeo.2024.107217","DOIUrl":"10.1016/j.marpetgeo.2024.107217","url":null,"abstract":"<div><div>The Tertiary lacustrine shales in China display middle-low maturity but have significant resources potential for shale oil compared to North American marine shales. The accumulation mechanism of hydrocarbons in shales of middle-low maturity is of importance for the evaluation of shale oil resources and exploration. This study employs a comprehensive range of geological and geochemical methods to analyze the aggregation characteristics of hydrocarbons in the middle-low maturity lacustrine shales of the late Eocene first member of the Shahejie Formation (EOS shales) in the Bohai Bay Basin. Based on this analysis, the study proposes an aggregation pattern for hydrocarbons specifically in middle-low maturity lacustrine shales. The EOS shales are dominated by felsic minerals followed by clay and carbonate, and enriched Type II₁ and Type II₂ organic matter with an average TOC content of 2.03%. The presence of halite exhibits a positive correlation with the organic matter content, suggesting its important role in the preservation and concentration of organic material. The content of ankerite is negatively correlated with ΔS₁ and positively correlated with OSI, indicating that ankerite promotes hydrocarbon enrichment. The free hydrocarbon index（ΔS₁）was used to evaluate the hydrocarbon migration in EOS shales, and show differential enrichment in vertical profile as verified by multiple indicators. The mineral, lithology and lithofacies affect the enrichment of hydrocarbons. In the differential enrichment model, the hydrocarbons of Group Ⅰ enriched from outside, and the hydrocarbons of Group II were self-generated, while the hydrocarbons of Group Ⅲ expelled outward. This study clarifies the differential enrichment characteristics of hydrocarbons in middle-low maturity lacustrine shales, and proposed the enrichment model, which provides powerful support for the in-depth exploration and effective development of lacustrine shale oil.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107217"},"PeriodicalIF":3.7,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Evolution of rimmed carbonate platform architecture controlled by sea-level change: Insights from the Lower-Middle Cambrian of the Northern Tarim Basin, China","authors":"Qing He ,&nbsp;Kaibo Shi ,&nbsp;Yongsheng Ma ,&nbsp;Bo Liu ,&nbsp;Jun Han ,&nbsp;Jun Li ,&nbsp;Xiangyu Bai ,&nbsp;Chun Wu ,&nbsp;Adam D. McArthur ,&nbsp;Nigel P. Mountney","doi":"10.1016/j.marpetgeo.2024.107215","DOIUrl":"10.1016/j.marpetgeo.2024.107215","url":null,"abstract":"<div><div>The sedimentary architecture of carbonate platforms is determined by distinct paleobiological, tectonics, climatic, oceanic and environmental conditions. During the Cambrian period, a rimmed carbonate platform system developed over an area of ∼28 × 10⁴ km² in the Tarim Basin. However, the evolution mechanism and its predominant controlling factors remain poorly understood. The investigation utilized integrated analysis of cores, thin sections, 3-D seismic, well logging and geochemical data to explain the sequence stratigraphic framework, depositional architecture and main controlling factors. Sixteen distinct microfacies (MF1–MF16) are identified based on thin-section analysis of the five lithofacies, which could be further grouped into fourteen microfacies associations (MA1-MA14). These fourteen microfacies associations respectively represent fourteen facies belts of the five facies of the shelf, outer ramp, middle ramp, platform margin and restricted platform. Microfacies and seismic characteristics have provided the basis for establishing a sequence-stratigraphic framework. Two regionally extensive second-order sequences (CS1-CS2) are developed in the Lower-Middle Cambrian succession; CS1 incorporates five third-order sequences (Sq1-Sq5); CS2 incorporates three third-order sequences (Sq6-Sq8). The lateral migration and vertical arrangement of depositional facies resulted in a unique depositional architecture. The overall carbonate platform architecture is interpreted from 3D seismic data, integrated with the depositional facies interpretations to document the evolution of the depositional setting over time from a broad shelf (Sq1-Sq2), to a distally steepening ramp (Sq3-Sq4), to a weekly rimmed platform (Sq5), and finally to a strongly rimmed platform (Sq6-Sq8). Relative sea-level (RSL) curves were reconstructed through an integrated analysis of Fischer plots from three wells. The determined RSL curve matches closely with reconstructed paleo-water depths indicated by the distribution of microfacies types. The inferred paleo-water depths changes comprise two long-term shallow–deep–shallow trends, upon which eight intermediate-term cycles are superimposed. Microfacies also have been applied to explain the evolution of the platform in response to RSL change and other environmental factors. A major transgression occurred in the lower parts of CS1. Results demonstrate that RSL and paleo-water depth changes in the Lower-Middle Cambrian are consistent with known global sea-level changes indicated by geochemical elements. The architectural and sequence-stratigraphic evolution of the progradational rimmed carbonate platform was controlled principally by eustasy. This study is important due to the limited information on Cambrian rimmed platforms.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"171 ","pages":"Article 107215"},"PeriodicalIF":3.7,"publicationDate":"2024-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703234","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inner architecture of fan delta front deposits: An outcrop example from Xiguayuan formation, Luanping Basin, northeast China","authors":"Zhuo Wen ,&nbsp;Guangqing Yao ,&nbsp;Xiaobo Zhao ,&nbsp;Xiao Lei ,&nbsp;Xinguang Wang ,&nbsp;Haodong Tang ,&nbsp;Xinyang Wu ,&nbsp;Zhongming Huang","doi":"10.1016/j.marpetgeo.2024.107212","DOIUrl":"10.1016/j.marpetgeo.2024.107212","url":null,"abstract":"<div><div>The fan delta front deposit is a notable reservoir type in the basin margin and typically exhibits high heterogeneity in reservoir architecture. With the deepening of exploration and development of oil and gas fields, the study of lower-order depositional architectures is relatively weak, and their implication on remaining oil distribution and enrichment are poorly understood. Field outcrops of the fan delta front deposit exhibit first-hand data of lithofacies, association, and depositional architectures, effectively providing insights for underground reservoir research to guide the development of oil fields, such as high water–cut oil fields in the late development period. Herein, we considered the fan delta front outcrops of the Sangyuan section as an object to reveal the depositional architectures located in the Luanping Basin, northeast China. Using meticulous artificial fieldwork and unmanned aerial vehicle observation, we focused on the 4th-order (single sandbody) and 3rd-order (composite laminaset groups) architectural units. Based on field observations, quantitative statistics, and model matching and guidance, architectural models of the fan delta front in the Sangyuan section were established in response to the high-frequency lake-level. In addition, genetic types of remaining oil controlled by architectural features in Wenchang B oil field during the high water–cut stage were further discussed, and suitable strategies and measures are proposed to produce different types of remaining oil. Results indicate that there are twelve basic types of lithofacies and three types of a single sandbody developed in the Sangyuan section, and evidently, the dimensions and spatial stacking patterns of 4th-order architectural units are closely related to high-frequency lake-level fluctuation, that is, with the rise of lake-level, the thickness and width of a single sandbody gradually decrease, whereas the width–thickness ratio gradually increases. Meanwhile, the spatial stacking patterns of sandbody gradually evolution from the downcut type to the superposition or butted type and finally to the isolated type. A single sandbody is divided into one or more composite laminate groups by the interfaces of 3rd-order architectural elements, which are identified according to the flow regime and sedimentary structures. Different orders of architectural units have different controlling effects over remaining oil distribution and enrichment, and the corresponding technical measures are proposed to enhance the remaining oil recovery. The above mentioned analyses can provide a valuable reference for oil and gas production in the late stage of an oil field with a similar depositional environment.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107212"},"PeriodicalIF":3.7,"publicationDate":"2024-11-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Upscaling characterizing pore connectivity, morphology and orientation of shale from nano-scale to micro-scale","authors":"He Zheng ,&nbsp;Feng Yang ,&nbsp;Qiulei Guo ,&nbsp;Kangfei Liu","doi":"10.1016/j.marpetgeo.2024.107213","DOIUrl":"10.1016/j.marpetgeo.2024.107213","url":null,"abstract":"<div><div>The fluid transport in tight rocks are dominantly controlled by the preferential migration pathways. In this paper, the geometric and topological characteristics of multiscale pore systems of shale were delicately characterized by X-ray computed tomography (CT) and focused ion beam-scanning electron microscope (FIB-SEM). The preferential migration pathways of the three-dimensional pore network of shale were recognized at the micro-to nano-scales. According to the constructed pore network model based on the maximum sphere algorithm, the pore geometric parameters such as pore size, pore coordination number, pore throat size and length were calculated using Micro-CT, Nano-CT and FIB-SEM. Besides, sphericity, azimuthal angle and polar angle of pores were counted to characterize pore morphology and pore orientation. Different from the commonly reported results at the macroscopic scale, this paper proposed to use pore orientation to represent the preferential migration orientation at the pore scale. Results show that the general pore size range of shale is 0.054–50 μm, and the dominant pore size ranges observed using Micro-CT, Nano-CT and FIB-SEM are 2.759∼5 μm, 200∼500 nm and 54∼200 nm, respectively. Pore connectivity is best at FIB-SEM observation scale, middle at Nano-CT observation scale and worst at Micro-CT observation scale. The connected pore volume percentage using Micro-CT, Nano-CT and FIB-SEM is 10.2%, 50.8%, and 90.5%, respectively. Pores are divided into blade pores with the sphericity of being &lt;0.5, rod pores with the sphericity of being 0.5–0.8, and spherical pores with the sphericity of being &gt;0.8. Though the spherical pores and rod pores are dominant in number, the blade pores have larger pore volumes, larger pore diameters and better pore connectivity, and are conducive to fluid transportation. The blade pores are corresponding to the slit-shaped pores and microfractures. The statistics of pore polar angle show that the preferred pore orientations are close to the parallel bedding plane, which is the dominant channel directions of fluid migration.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107213"},"PeriodicalIF":3.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722596","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Controls of paleogeomorphology on organic matter accumulation as recorded in Ordovician–Silurian marine black shales in the western South China Block","authors":"Feng Liang ,&nbsp;Qun Zhao ,&nbsp;Qin Zhang ,&nbsp;Yuman Wang ,&nbsp;Shangwen Zhou ,&nbsp;Zhen Qiu ,&nbsp;Wen Liu ,&nbsp;Bo Ran ,&nbsp;Tong Sun","doi":"10.1016/j.marpetgeo.2024.107206","DOIUrl":"10.1016/j.marpetgeo.2024.107206","url":null,"abstract":"<div><div>The Ordovician–Silurian transition represents a critical period marked by the formation of marine shale gas horizons within the South China Block. However, the mechanism for organic matter enrichment of Paleozoic marine shales in the western South China Block remain contentious, primarily due to insufficient understanding of paleogeomorphological evolution. In this paper, we describe the sedimentology of the Ordovician-Silurian succession composed of the Wufeng-Longmaxi Formation in the western South China Block and report new paleontological, and geochemical data for this succession to explore the relationship between basin paleogeomorphology and water mass environment. Nine graptolite zones are identified, spanning from the WF1 (Linxiang Formation) through WF2–WF4 (Wufeng Formation) to LM1–LM5 (Longmaxi Formation) in this well. Based on sedimentological and geochemical analyse results, three distinct stages of redox and paleoproductivity conditions in the water mass have been identified: (1) suboxic environments and low paleoproductivity in WF2–WF4; (2) euxinic and stagnant water conditions in LM1–LM3 accompanying with high paleoproductivity; and (3) anoxic water and low paleoproductivity in LM4–LM5. By integrating marine redox fluctuation, paleoproductivity conditions and regional hiatus (LM1-LM3) observed across multiple successions, we interpret thatthe western margin of the South China Block have been significantly affected by a collision between the South China Block and Yanbian terrane. The results of this study indicate that the accumulation of organic matter in the western margin of the South China Block was predominantly controlled by paleogeomorphology being caused by this collision event.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107206"},"PeriodicalIF":3.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The role of the Andaman Nicobar fault (ANF) in shaping Narcondam offshore: Insights from high-resolution reflection seismic data","authors":"H.K. Srivastav ,&nbsp;D. Ghosal ,&nbsp;J. Jacob","doi":"10.1016/j.marpetgeo.2024.107211","DOIUrl":"10.1016/j.marpetgeo.2024.107211","url":null,"abstract":"<div><div>The study investigates the Andaman Nicobar Fault (ANF) and its role in the evolution of a volcano-supported basin adjacent to Narcondam Island, using three high-resolution 2D seismic reflection profiles. Migrated images show a fluid zone, determined through velocity and polarity analyses, with mean 1/Q values ranging from 0.0165 to 0.0096 for Lines 1 to 3. Additionally, polygonal faults are imaged, with varying thicknesses (0.1–0.4 km) of Miocene age, positioned above the fluid saturated zone. The migrated sections further show the branches of the ANF to be conduits for fluid migration and accumulation within the basinal deposits. The study finally highlights a shift in depocenter during the Neogene period, indicating fluctuations in sediment supply from the Irrawaddy River and the evolution of the ANF branch.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107211"},"PeriodicalIF":3.7,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Combined use of petroleum inclusion analysis, PVT simulation, and basin modeling for reconstruction of deep fluid phase evolution in condensate gas reservoirs","authors":"Wenzhi Lei ,&nbsp;Dongxia Chen ,&nbsp;Ming Cheng ,&nbsp;Chenyang Cai ,&nbsp;Qiaochu Wang","doi":"10.1016/j.marpetgeo.2024.107210","DOIUrl":"10.1016/j.marpetgeo.2024.107210","url":null,"abstract":"<div><div>The reconstruction of the fluid phase evolution in deep condensate gas reservoirs can reveal the mechanism of condensate gas formation, facilitating the early formulation of drilling strategies. However, the complexity of petroleum fluid phase evolution during hydrocarbon generation, migration, and accumulation poses numerous challenges for the reconstruction process. Therefore, petroleum fluid inclusion analysis, PVT phase simulation, and basin modeling were used to achieve the reconstruction of phase states during key geological periods, elucidating the phase evolution of the deep condensate reservoirs in the Dongying Depression during the whole process. The modeled results show that the mature source rocks contributed to the charging and accumulation of liquid oils (38–14 Ma). Next, a low oil cracking conversion rate limited the increase of gaseous hydrocarbon fraction, so the accumulated hydrocarbons remained in a liquid phase (14–0 Ma). The late external gas inputs significantly increased the gas-oil ratio in the reservoirs, leading to the transition from the liquid oil phase to the condensate phase (5–0 Ma). The fluid compositions obtained from hydrocarbon inclusions and the physical properties of present-day condensates can effectively constrain basin modeling, leading to reliable simulation results. This work revealed that the hydrocarbon generation controls the initial hydrocarbon components in the traps for the phase evolution. Furthermore, the secondary alterations including oil cracking and gas inputs influence the proportion of methane of petroleum in the deep reservoirs, which dominates the phase evolution. Deep petroleum fluid phase changes mainly require the molar ratio of the input gas more than 50%. A model was proposed to explain the formation of deep condensate reservoirs. A series of gas inputs and escape in the successive lithological traps controls an orderly phase change of deep petroleum, and the amount of deeper gas determines the range of the existence of condensate gas reservoirs. This study not only guides the exploration of deep condensate in the Dongying Depression but also offers a workflow for the research on the formation and evolution of condensate reservoirs in other global regions.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"171 ","pages":"Article 107210"},"PeriodicalIF":3.7,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142703472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Assessing the geochemical correlation between petroleum source rocks in the Brazilian Equatorial margin basins and global oceanic anoxic events","authors":"Ediane B. da Silva,&nbsp;Helio J.P. Severiano Ribeiro,&nbsp;Eliane Soares de Souza","doi":"10.1016/j.marpetgeo.2024.107205","DOIUrl":"10.1016/j.marpetgeo.2024.107205","url":null,"abstract":"<div><div>This research aims to investigate the correlation between the Cretaceous Oceanic Anoxic Events (OAEs) and the source rocks of the Brazilian Equatorial Margin (BEM) basins. These source rocks, particularly from the Cenomanian-Turonian interval, are known to contain high levels of Total Organic Carbon (TOC) and exhibit significant hydrocarbon potential. The principal focus is on how global anoxic events, such as OAE-1b, OAE-1d, and OAE-2, influenced the depositional environments and organic matter types across the BEM basins, which include Foz do Amazonas, Pará-Maranhão, Barreirinhas, Ceará, and Potiguar. Key results indicate a strong correlation between periods of anoxia and the accumulation of organic-rich sediments in these basins. The Foz do Amazonas Basin features predominantly terrestrial-derived kerogen (Type III), while the Ceará and Potiguar basins show marine-derived kerogen (Type I and II), aligning with global productivity patterns during anoxic events. These variations in kerogen type reflect differences in depositional environments influenced by sea-level changes and nutrient influx. The research concludes that the OAEs significantly impacted organic matter preservation and hydrocarbon generation in the BEM basins. The study's findings contribute to the broader understanding of how Cretaceous OAEs shaped the geochemical and sedimentary processes in equatorial Atlantic margins, highlighting the potential for further oil and gas exploration in these regions.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107205"},"PeriodicalIF":3.7,"publicationDate":"2024-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}