Marine and Petroleum Geology最新文献

{"title":"Linking provenance and diagenesis to reservoir quality evolution of sandstones: The Paleocene-Eocene Kerri-Kerri Formation, northeastern Nigeria","authors":"Abdulwahab M. Bello , Musa B. Usman , Abduljamiu O. Amao , Anas M. Salisu , Khalid Al-Ramadan , Usman Abubakar , Shehu Mukkafa , Ibrahim A. Kwami , Lukman U. Chiroma , Murtada Al-Hashem , Abubakar Yusuf , Abubakar S. Maigari , Aliyuda Kachalla , Oluwafemi E. Aro , Muhammad A. Ismai'l , Umar S. Umar , Olumuyiwa T. Akinsanpe","doi":"10.1016/j.marpetgeo.2024.107227","DOIUrl":"10.1016/j.marpetgeo.2024.107227","url":null,"abstract":"<div><div>A comprehensive understanding of the controls on sandstone reservoir quality requires the integration of provenance, detrital mineralogy, and diagenesis to effectively optimize their utilization for groundwater and hydrocarbon explorations or CO<sub>2</sub> storage. However, studies on the roles of sedimentary provenance and diagenesis in reservoir quality evolution of sandstones are often conducted separately, even though combining both is crucial for a comprehensive understanding of how these processes jointly influence reservoir quality evolution in sandstones. The Paleocene-Eocene Kerri-Kerri Formation in the Gongola Sub-basin, Upper Benue Trough (NE Nigeria), has yet to be assessed for how the interplay between sedimentary provenance and diagenesis influences its reservoir quality evolution. Therefore, this study aims to investigate the provenance of the Kerri-Kerri Formation and its influence on diagenetic alterations and reservoir quality through thin section petrography, scanning electron microscopy, X-ray diffraction, and X-ray fluorescence analyses. The findings of the study reveal that the sediments were primarily sourced from a quartzose sedimentary provenance and were deposited under warm, humid climatic conditions, influencing diagenesis and reservoir quality by resulting in a chemically stable, quartz-rich mineralogy characterized by near-complete dissolution and alteration of labile feldspar and mica grains. The provenance of the sandstones has significantly contributed to an unusual accumulation of kaolinite (2–46%; average 12.9%) due to intense rainfall, which released previously authigenic kaolinite from the source sandstones and incorporated it into the Kerri-Kerri sediments as detrital clay. The stable quartz-rich mineralogy limited the effects of mechanical compaction in the sandstones, aided by the absence of ductile grains. Minor authigenic kaolinite was formed as eogenetic clay due to the very low reactive feldspar content in the sandstones, while illite and authigenic quartz overgrowths developed as deep-burial cements. However, their effects are largely insignificant due to the scarcity of K-feldspar needed to supply K⁺ for illitization and the presence of well-developed clay coatings that significantly inhibited quartz cementation. Illitization of kaolinite preferentially occurred where discrete kaolinite crystals arranged themselves in a chain-like fashion near K-feldspar, providing the surface area for kaolinite dissolution and K⁺ adsorption in the formation of authigenic illite. Additionally, while grain size and sorting had minimal control over reservoir quality due to the similarities in grain size and sorting classes among the sandstones, detrital matrix content was the primary factor influencing reservoir quality. Channel fill sandstones exhibited the best reservoir quality owing to their low clay matrix, whereas occasional ripple-laminated sandstones from floodplain settings demonstrated the poorest r","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107227"},"PeriodicalIF":3.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756936","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":"Orbital pacing of the early Eocene source rock deposition in Tunisia (Bou Dabbous Formation): Astrobiochronological insights into cyclicities through surface-subsurface integration","authors":"Jihede Haj Messaoud ,&nbsp;Hela Fakhfakh Ben Jemai ,&nbsp;Chokri Yaich","doi":"10.1016/j.marpetgeo.2024.107225","DOIUrl":"10.1016/j.marpetgeo.2024.107225","url":null,"abstract":"<div><div>The Early Eocene Bou Dabbous Formation (BDF) source rock is an economically important source rock in the SW Neo-Tethys covering most of the Ypresian outer ramp to basin deposits in Tunisia. The main rock types of the BDF in central Tunisia include globigerinids-rich grey to black laminated marl and limestone, which occur with an obvious cyclicity at astronomical timescales. This study examines two high-resolution borehole records from northern and eastern Tunisia and an outcrop analog in central Tunisia. The datasets examined were total organic carbon (TOC), magnetic susceptibility, CaCO₃, δ¹³C, δ¹⁸O, and Gamma-Ray (GR). We aim to investigate the relationship between the rhythmic patterns observed at the BDF outcrop and the Milankovitch cycles and contextualize the findings within the Ypresian Astrochronological Time Scale (YATS). Additionally, we will discuss the impact of astronomical forcing on sea-level variations and the upwelling system during a greenhouse world. Field measurements and power spectra of the untuned data reveal a hierarchy of cycles throughout the BDF with ∼11.1 m, 4.1, 2.4 m, 1.1 m, and 0.6 m wavelengths. Tuning the 11.1 m cycles to the 405 kyr eccentricity cycle, the astronomical parameters—eccentricity, obliquity, and the precession index—become apparent. The 405 kyr eccentricity cycle is linked to relative sea-level changes inferred from sequence stratigraphy analysis and sedimentary noise modeling. Periods with increased TOC are associated with strong obliquity forcing inferred from the power decomposition analysis and the strong 173-kyr obliquity modulation cycles. The Ypresian record from Tunisia demonstrates the orbital pacing on the strength of the upwelling system, by affecting both the sea level and the climatic belt (wind regime). From 53.89 Ma to 53.2 Ma (TOC &gt;2 wt %), our model demonstrates that obliquity-driven changes in water stratification led to episodes of varying oxygen levels at the bottom of the basin, affecting organic matter decay and preservation. During the Early Eocene Climatic Optimum, changes in climatic belts and wind patterns, along with rising sea levels, led to a shift in the high organic matter accumulation zone. This resulted in a weakened upwelling system in central Tunisia and reduced organic matter accumulation (TOC &lt;0.5 wt%).</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107225"},"PeriodicalIF":3.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746815","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":"Diverse dolomitization models in the Aptian Dariyan (Shu'aiba) Formation in the Persian Gulf, Iran: Evidence from petrography, geochemistry and impact on reservoir quality","authors":"Hamzeh Mehrabi ,&nbsp;Zahra Pouyafard ,&nbsp;Mohammad Bahrehvar ,&nbsp;Ihsan S. Al-Aasm","doi":"10.1016/j.marpetgeo.2024.107229","DOIUrl":"10.1016/j.marpetgeo.2024.107229","url":null,"abstract":"<div><div>This study investigates dolomitization as one of the key diagenetic processes influencing the reservoir quality of the Dariyan Formation (Aptian) in three oil/gas fields in the Persian Gulf. To achieve this goal, petrographic studies of core samples and thin-sections are integrated with cathodoluminescence microscopy, carbon and oxygen isotopic analyses, and fluid inclusion studies. The formation exhibits two main dolomitization models, including hydrothermal-related saddle dolomites and stylolite-associated dolomites, as well as two minor models including bacterial activity-related dolomites and mixed meteoric and marine waters. Hydrothermal dolomitization, associated with deep burial diagenesis, results in saddle dolomites filling fractures and voids, characterized by high-temperature and salinity formation conditions. Stylolite-related dolomitization occurs in mud-dominated facies, as fine to medium crystals with a cloudy center and a clear rim, concentrated along the solution seams and stylolites. Bacterial activity-related dolomitization is distinguished in Lithocodium–algal facies, highlighting the role of microbial mediation in dolomite formation at low temperatures. Mixed-water dolomitization is observed in grain-dominated shoal and lagoonal facies, where the interaction of meteoric and marine waters leads dolomite cementation. Geochemical (δ¹³C and δ¹⁸O) and cathodoluminescence data support the diagenetic model, indicating varying stages and conditions of dolomite formation. Fluid inclusion analyses of saddle and stylolite-related dolomites reveal salinity (9.5 wt% NaCl equiv.) and temperature (105 °C) conditions consistent with burial diagenesis. The paragenetic sequence shows a diagenetic history encompassing marine, meteoric, and burial environments. Marine diagenesis includes early (microbial and mixing type) dolomitization, bioturbation, micritization and isopachous cementation, while meteoric diagenesis comprises dissolution, cementation and recrystallization during prolonged (&gt;1 Myr) exposure at the end of Aptian. Burial diagenesis involves compaction, hydrothermal and stylolite-related dolomitization, cementation, and recrystallization, critically controlling reservoir quality. This study demonstrates that dolomitization significantly enhances permeability, with the highest reservoir quality found in dolomitized facies of the lower carbonate unit of the Dariyan Formation. This study highlights the complexity of diagenetic processes in the Dariyan Formation, providing valuable insights into the factors controlling its reservoir quality. The findings emphasize the importance of integrated geological and geochemical approaches for accurate reservoir evaluation and prediction in dolomitized carbonate formations.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107229"},"PeriodicalIF":3.7,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746817","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":"Tectonically deformed coal: Focus on microstructures & implications for basin evolution","authors":"Manish Kumar Srivastava ,&nbsp;Kaushal Kishor ,&nbsp;Alok K. Singh ,&nbsp;Soumyajit Mukherjee ,&nbsp;Shivranjan Kumar Bharti","doi":"10.1016/j.marpetgeo.2024.107223","DOIUrl":"10.1016/j.marpetgeo.2024.107223","url":null,"abstract":"<div><div>Traditionally, the Gondwana basins of India were believed to have formed primarily through extensional tectonics that created rift basins. However, recent models propose that strike-slip movements along deep-seated crustal fractures also contributed to their development. This article investigates this theory through a comprehensive structural analysis of the Bokaro Basin, located in the Damodar Valley of eastern India. This study deciphers tectonic history and evolutionary mechanisms of the Bokaro Basin by analyzing its coal samples, especially their structures—a relatively unexplored aspect in Indian coal research. We investigate maceral types, deformation manifestations, and fracture patterns at various scales. This led us to refine the structural classification of (Indian) coals. Deformation imprints were identified using remote sensing for regional features, geological fieldwork for megascopic observations, and petrographic analysis for micro-scale studies. The study utilized ArcGIS for lithology and fault mapping in conjunction with fieldwork in the highly deformed southwestern Bokaro Basin. Petrographic analysis revealed coal macerals and deformation signs. This research confirms that the Bokaro Basin's tectonic evolution involved uneven fault distribution, with significant rift and pull-apart mechanism. Coal seams show diverse deformation patterns, from ductile in fusinite to brittle in collotelinite, indicating multiple deformation stages under varying stress regimes. The East Bokaro Basin, with deeper seams, shows stronger deformation than the West. Shear stress, alongside extension, played a role in shaping the basin, with sigmoidal tension gashes from the coals of Barakar Formation, confirming active shearing through or afterwards coalification during or/and after the Early Permian time. The structural classification aids in coal bed methane (CBM) reservoir characterization, highlighting promising potential in cataclastic/tectonically deformed coal reservoirs. Tectonic deformation has affected the coals from the Bokaro Basin, resulting in structures that range from blocky to cataclastic, with some instances of granulation.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107223"},"PeriodicalIF":3.7,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142756935","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":"Compartmentalization of submarine channel splays controlled by growth faults and mud diapir","authors":"Massine Bouchakour ,&nbsp;Xiaoming Zhao ,&nbsp;Crina Miclăuș ,&nbsp;Liu Fei ,&nbsp;Davide Gamboa ,&nbsp;Baoquan Yang","doi":"10.1016/j.marpetgeo.2024.107221","DOIUrl":"10.1016/j.marpetgeo.2024.107221","url":null,"abstract":"<div><div>Submarine channels and their associated overbank deposits can demonstrate vast array of geomorphological expressions and extremely complex depositional architectures. Defining their distribution around seabed deformation is crucial to better understand the dynamics of sediment routing, networking, and deep-sea fan compartmentalization. Here, we investigate the interactions between the geomorphological evolution of submarine channel splays and the structural deformation induced by growth faults. The well-imaged seismic records of the Amaku Channel Levee System (ACLS), from the offshore Niger Delta Agbada Formation, offers a key location to delineate the responses of splays to structures. An integrated interpretation of seismic reflection and well log data allowed us to define a new type of composite splay – named here the “Fork Splay Complex” (FSC). The FSC were introduced by a fault-diverted channel segment, distributing a set of branched individual splays (Sp1-Sp4). They develop particular zones of connectivity across low fault throws and compartmentalized elements between high fault throws. Downstream, two fan-shaped splays (Splay A and B) emerged from deflected channel segments, the Splay B is particularly rotated and elongated distally where a fault interfered its spatial distribution. Based on this study, we provide evidence that the digitated splays, while less expanded than the lobate splays, potentially maintain a stable distribution of coarse-sediment thicknesses, which is implied to be the major control on channel to lobe transition (CLTZ) –i.e., in the confluence zone between FSC and Channel J. The resolved patterns of the investigated splays serve as prototypes for understanding how structural deformation controls slope sedimentary system architectures, with the aim of assisting subsurface interpretation and characterizing sand connectivity or compartmentalization.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107221"},"PeriodicalIF":3.7,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746816","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":"Establishment of a high-resolution astronomical time scale and high-frequency sequence framework of Paleogene lacustrine fine-grained sediments using logging data: A case study from the Bohai Bay Basin, East China","authors":"Yang Li ,&nbsp;Renchao Yang ,&nbsp;Aiping Fan ,&nbsp;Jie Chen ,&nbsp;Ahmer Bilal ,&nbsp;Zhaoguo Wang","doi":"10.1016/j.marpetgeo.2024.107220","DOIUrl":"10.1016/j.marpetgeo.2024.107220","url":null,"abstract":"<div><div>Integrating geochronological and sequence stratigraphic analyses in a basin can significantly enhance the understanding of its evolution. The Paleogene Middle Sha 3 Member (Es₃^m) in the Dongying Sag is characterized by a lake-delta sedimentary system and is of particular interest due to its abundant hydrocarbon resources. However, the Es₃^m currently lacks a robust chronostratigraphic framework, and the existing sequence stratigraphic framework, primarily based on seismic data from the delta zone, exhibits relatively low resolution. In this study, a cyclostratigraphic analysis was conducted on fine-grained lacustrine sediments of the Es₃^m in the Dongying Sag, utilizing natural gamma (GR) data from three wells. The objective was to establish a high-resolution astronomical time scale (ATS) and a high-frequency sequence framework. Lake-level changes were reconstructed using lag-1 autocorrelation coefficient (ρ₁) analysis and dynamic noise after orbital tuning (DYNOT) analysis. The findings suggest that the Es₃^m spans a duration of approximately 34.7–39.2 Ma. Sedimentary accumulation rates (SARs) of lake sediments within the study area range from approximately 11 to 25 cm/kyr. Furthermore, the lake-level exhibits significant periodic variations, and 11 fourth-order sequences and 3 systems tracts (transgressive systems tract, early highstand systems tract, and late highstand systems tract) were successfully identified in the Es₃^m. This research serves as a typical case study for delineating high-frequency sequences in lacustrine fine-grained sediments and refining the geochronological framework.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107220"},"PeriodicalIF":3.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722612","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":"Seismic geomorphology and reservoir conditions of a Middle Miocene submarine channel system in the Taranaki basin, New Zealand","authors":"Guangxu Wang ,&nbsp;Wei Wu ,&nbsp;Quan Li ,&nbsp;Weiqing Liu ,&nbsp;Yongsheng Zhou ,&nbsp;Shiqin Liang ,&nbsp;Yaping Sui","doi":"10.1016/j.marpetgeo.2024.107219","DOIUrl":"10.1016/j.marpetgeo.2024.107219","url":null,"abstract":"<div><div>Deepwater channels function as vital deep-sea hydrocarbon reservoirs and as major routes for moving terrestrial clastic sediment to deepwater environments. A high-resolution sequence stratigraphic framework was built for the deepwater area of the Taranaki Basin using high-resolution three-dimensional (3D) seismic data, and various seismic interpretation techniques, including seismic attribute analysis, were applied. The principal controlling factors and petroleum development potential of the Middle-Miocene channel system were investigated with sequence stratigraphy and seismic geomorphology. Four understandings were primarily attained in this study: (1) depending on the different levels of the channel surfaces, the channel system can be divided into five sedimentary units (SU1-SU5), which correspond to the five stages of channel system evolution. These surfaces include one primary draping surface (PDS), five secondary channel erosion surfaces (SCES), and several tertiary channel erosion surfaces (TCES). (2) with the use of seismic facies analysis, six sedimentary elements were identified in the channel system: pelagic deposits (PDs), mass transport deposits (MTDs), outer levee complex (OLC), inner levee and terrace complex (ILTC), and turbidite channel complexes (TCCs). (3) The sedimentary evolution of the channel system was jointly influenced by multiple factors. The sediment supply and submarine geomorphology can directly affect the internal stacking and migration patterns of the channel. In contrast, tectonic activity and relative sea level fluctuations can indirectly affect the sedimentary characteristics of the channel by regulating the components and scale of clastic sediment. (4) SU1, SU2, and SU3 are primarily filled with coarse-grained sediments, which can serve as high-quality hydrocarbon reservoirs. In contrast, SU4 and SU5 can serve as regional cap rocks because they are filled with fine-grained sediments, and the overall channel system can represent a potential hydrocarbon reservoir-cap combination, which can be viewed as a significant research target for upcoming deepwater exploration. Clarifying the sedimentary properties and primary controlling factors at the various evolutionary stages of deepwater channels is vital for predicting the hydrocarbon development potential of the basin and reducing the drilling risk. This also helps with the development of deepwater basins with similar sedimentary environments in New Zealand and elsewhere in the world.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"172 ","pages":"Article 107219"},"PeriodicalIF":3.7,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142722563","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":"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}