Marine and Petroleum Geology最新文献

{"title":"Preservation of compound delta in the rapidly subsiding Pliocene Orinoco Delta: Insights from quantitative fluvial, tidal and storm-wave signals","authors":"Yang Peng ,&nbsp;Ronald J. Steel ,&nbsp;Cornel Olariu ,&nbsp;Shunli Li","doi":"10.1016/j.marpetgeo.2025.107456","DOIUrl":"10.1016/j.marpetgeo.2025.107456","url":null,"abstract":"<div><div>Despite the documentation of compound clinoform morphology in modern deltas over the past two decades, there is still a scarce recognition of these in the stratigraphic record. Among the ancient cases that have been recognized, tide- and wave-dominated compound clinoforms have been documented. Here we present a fluvial- and wave-dominated compound clinoform delta in the Pliocene Orinoco Moruga Delta on Trinidad. The outcrops exhibit lateral variation with wave-dominated and mixed-influence deltaic clinothems preserved in the proximal (i.e., upstream) part (SSW) of the compound system and wave-dominated deltaic clinothems in the distal (i.e., downstream) part (NNE). The shoreline clinothems are 5–15 m thick, sandy coarsening-upward units, and they commonly comprise HCS/SCS and wave-rippled sandstones generated by storm wave processes in both upstream and downstream parts. In the upstream part where the deposition location was close to main sediment supply, the shoreline clinothems comprise an upper unit of fluvial-dominated mouth bar and channel deposits overlying a lower unit of mixed-influence mouth bars and wave-to tide-influenced channel deposits. The subaqueous clinothems are 30–50 m thick and are characterized by coarsening-upward units changing from thick, bioturbated siltstones and mudstones at lower levels, through interbedded siltstones/mudstones and thin hummocky/swaley cross-stratified (HCS/SCS) sets, to occasional amalgamated HCS/SCS beds. The subaqueous clinothems in these proximal and upstream parts are somewhat sandy and notably influenced by wave processes. In contrast, the distal parts of the subaqueous clinothems are muddy with repetitive, frequent thin beds of both HCS or wave-rippled beds and especially wave-enhanced sediment gravity flow deposits. The compound clinoform delta in the Moruga Formation thus exhibits a spectrum of fluvial, tidal, and storm-wave signals, along with diverse channel types. This variability provides a valuable opportunity to document the interactions among river, tidal, and storm-wave processes as well as delta building processes driven by the various types of channels within the compound clinoform delta.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107456"},"PeriodicalIF":3.7,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107223","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":"Tectonic controls on the submarine Scoglio d’Affrica mud volcanoes (Northern Apennines hinterland)","authors":"Marco Bonini ,&nbsp;Chiara Del Ventisette ,&nbsp;Riccardo Lanari ,&nbsp;Matteo Lupi ,&nbsp;Daniele Maestrelli ,&nbsp;Giuseppe Nirta ,&nbsp;Samuele Papeschi ,&nbsp;Domenico Montanari","doi":"10.1016/j.marpetgeo.2025.107467","DOIUrl":"10.1016/j.marpetgeo.2025.107467","url":null,"abstract":"<div><div>Four submarine mud volcanoes were discovered in the northernmost Tyrrhenian Basin, Italy, following the eruption of one of them in 2017 near the Scoglio d’Affrica Islet. The eruption occurred a few months after a seismic sequence that hit central Italy (Mwmax 6.5–6.6). Although the peak dynamic stresses estimated at the eruption site are not high enough to confidently substantiate a cause-effect link, they possibly contributed to triggering a delayed response of the mud volcano. These mud volcanoes, along with several pockmarks, lie on top and at the margins of a morpho-structural high known as the Elba-Pianosa Ridge (EPR). The structural setting of the EPR plays an important role in the storage and subsequent upward migration of deep-sourced fluids. However, there is no consensus on the tectonic setting of this feature, and different models have been proposed. We have undertaken a structural-geological study integrating data from (1) wellbores drilled in proximity of the mud volcanoes, (2) the CROPM12A seismic reflection profile, which crosses the EPR near the mud volcanoes, and (3) structural data collected on the Island of Pianosa, an emerged portion of the EPR. The results support the hypothesis that the EPR corresponds to an antiformal stack structure bounded by high-angle normal faults at its margins. Wellbore data indicate the presence of significant overpressures associated with an increase in hydrocarbon gases in the core of the antiform, which suggest the existence of a deep-seated fluid reservoir. The pressurised fluids leak from the reservoir and move upwell capitalizing on a complex network of interconnected brittle planar features (i.e., thrust and normal faults, fractures), reaching both the culmination and the margins of the EPR. The lesson from this study is that mud volcanoes can also form in the innermost part of a thrust belt, where compressional stresses have long since faded. Inactive anticlines still have the capacity to collect and pressurise deep-sourced fluids, which can accumulate into the fold core and ultimately generate mud volcanoes.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107467"},"PeriodicalIF":3.7,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107367","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":"Petroleum system analysis of the Ras Ghara oil Field: Geochemical evaluation and 2D basin modelling of pre-rift and syn-rift formations in the southern Gulf of Suez, Egypt","authors":"Mohamed Reda ,&nbsp;Tamer Salem ,&nbsp;Mohamed I. Abdel-Fattah ,&nbsp;Mohamed Fathy ,&nbsp;Sherif Farouk ,&nbsp;Khaled Al-Kahtany ,&nbsp;Thomas Gentzis","doi":"10.1016/j.marpetgeo.2025.107464","DOIUrl":"10.1016/j.marpetgeo.2025.107464","url":null,"abstract":"<div><div>The southern Gulf of Suez is a prolific hydrocarbon province with considerable exploration potential. This study presents an integrated geochemical and 2D basin modeling evaluation of the petroleum system in the Ras Ghara oil field, with the aim of constraining source rock characteristics, thermal maturity, and hydrocarbon generation and migration processes. Geochemical analyses of cutting samples from the Ghara Land-1 well, spanning the Nukhul to Lower Senonian formations (1995–2223 m), reveal two main source rock types: an oil-prone marine shale with TOC values up to 4.43 wt% and HI values up to 554 mg HC/g TOC, and a mixed oil/gas-prone type with moderate TOC and HI values. Biomarker data and extract composition indicate deposition under anoxic, carbonate-rich marine conditions. Pyrolysis Tmax (416–430 °C), vitrinite reflectance (0.48–0.62 % Ro), and biomarker maturity parameters confirm immature to early oil window conditions in the sampled interval. The 2D basin model, constructed using structural and stratigraphic data from multiple wells and calibrated with measured maturity parameters, simulates the burial and thermal evolution of the source rocks. Modeling results show that the deeper Nukhul and Matulla formations reached peak maturity during the Mid-Cretaceous, with a critical hydrocarbon generation and migration moment around 80 Ma. Vertical migration, enhanced by Miocene fault reactivation, led to the redistribution of hydrocarbons into overlying reservoirs. Structural features, including NW-trending faults and accommodation zones, played a key role in directing fluid flow and trap development. This integrated analysis provides a comprehensive understanding of the petroleum system in Ras Ghara and offers a valuable framework for guiding future exploration strategies in the structurally complex southern Gulf of Suez.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107464"},"PeriodicalIF":3.7,"publicationDate":"2025-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107295","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":"Reservoir modeling of heterogeneities, structures, and petrophysical properties of the Berenice Oil Field: Implications for sustainable management and CO2 storage in the North Western Desert, Egypt","authors":"Amr M. Eid,&nbsp;Walid M. Mabrouk,&nbsp;Mohammed Amer,&nbsp;Ahmed Metwally","doi":"10.1016/j.marpetgeo.2025.107466","DOIUrl":"10.1016/j.marpetgeo.2025.107466","url":null,"abstract":"<div><div>This study evaluates the CO₂ storage potential of the Berenice Oil Field in Egypt's Western Desert using integrated 3D geological and petrophysical modeling. The analysis focuses on the Alam El Bueib AEB-3E formation, a high-quality reservoir with porosity values of 14–16 %, permeability between 10 and 500 mD, and a thick Alamein Dolomite caprock (&gt;100 m), ensuring robust sealing. Seismic interpretation identified structural traps, including tilted fault blocks and horsts, with ENE-WSW and ESE-WNW fault trends forming secure containment structures. Reservoir thickness increases toward the central field, enhancing CO₂ storage capacity. The novelty of this study lies in its application of integrated 3D geological and petrophysical modeling to assess CO₂ sequestration in a previously underexplored region of Egypt's Western Desert. Petrophysical modeling integrated well log data to evaluate porosity, permeability, shale volume, and water saturation. Spatial analyses using Petrel software identified the central and northwestern regions as optimal storage zones, offering a novel framework for selecting CO₂ storage sites based on a combination of structural and petrophysical factors. CO₂ storage capacity estimates range from 12.4 million tons (P10) to 146.5 million tons (P90), with a mean of 45.3 million tons. Structural and petrophysical evidence confirms the reservoir's suitability for CCS, addressing key challenges such as caprock integrity and fault stability. By integrating advanced 3D modeling, this study provides a comprehensive, region-specific assessment of the field's storage potential, contributing to Egypt's climate mitigation strategies. These findings validate the use of depleted oil and gas reservoirs (DOGR) for CO₂ sequestration and offer a replicable framework for assessing similar reservoirs globally.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107466"},"PeriodicalIF":3.7,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070343","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":"From salt carapace to secondary minibasin encasement—The Bolon Secondary Minibasin, Eastern External Betics, SE Iberia","authors":"David Paul Canova ,&nbsp;Eduard Roca ,&nbsp;Oriol Ferrer ,&nbsp;Carles Ferràndez-Cañadell ,&nbsp;Frederic O. Escosa ,&nbsp;Jawad Afzal","doi":"10.1016/j.marpetgeo.2025.107418","DOIUrl":"10.1016/j.marpetgeo.2025.107418","url":null,"abstract":"<div><div>The Bolon Secondary Minibasin (BSM) evolved on the now eroded Elda Salt Sheet, which contains fragments of the diapiric roof and syn-contractional sediments. Our detailed analysis of the BSM reveals how diapir rejuvenation and salt sheet evolution can affect the structural and stratigraphic architecture of secondary minibasins. We present a comprehensive analysis of the BSM integrating detailed cartography with stratigraphic, paleontological, and structural data. The field data show that the BSM contains a carapace of latest Cretaceous marlstones overlain by an up to 800 m thick roof of terrigenous and outer platform deposits. These suprasalt deposits are characterized by tabular beds without diapir derived detritus and are cut by a series of extensional growth faults that sole into the salt. In the Oligocene, diapir rejuvenation due to contractional deformation resulted in the breaching and dismemberment of this diapiric roof and extrusion of allochthonous salt. Roof dismemberment is recorded as an unconformity truncating the roof strata and diapir derived detritus in the Oligocene-lower Miocene units. Throughout the middle Miocene composite halokinetic sequences, rapidly shifting depocenters, episodic unconformities, and stratigraphic onlaps record the rapid sinking and progressive northward rotation of the BSM. Debrite wedges, diapir derived detritus, and ramp-flat geometries along the upper salt-sediment contact show that in the middle Miocene the BSM was fully encased in allochthonous salt. Continued shortening and further extrusion of allochthonous salt rotated the BSM an additional 60° to the NW before its eventual grounding on subsalt strata.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107418"},"PeriodicalIF":3.7,"publicationDate":"2025-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107296","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":"Cyclostratigraphy of the Cenomanian-Turonian boundary in Jordan","authors":"Sherif Farouk ,&nbsp;Ahmed Abdeldaim ,&nbsp;Fayez Ahmad ,&nbsp;Wolfgang Ruebsam ,&nbsp;Mohammad Alsuwaidi ,&nbsp;Khaled Al-Kahtany","doi":"10.1016/j.marpetgeo.2025.107463","DOIUrl":"10.1016/j.marpetgeo.2025.107463","url":null,"abstract":"<div><div>The timescale of the Cenomanian-Turonian interval (Late Cretaceous, ∼94 million years ago) and associated environmental changes remain debated. In particular, the duration of the positive carbon isotope excursion (CIE), marking Oceanic Anoxic Event 2 (OAE2), is subject to controversies. This study presents an astronomical timescale for the Cenomanian-Turonian boundary in the Zarqa section of northern Jordan. Cyclostratigraphic analysis of magnetic susceptibility data and stable carbon isotope data (δ¹³Ccarbonate) reveals an averaged optimal sediment accumulation rate of 1.82 cm per thousand years. The high-resolution astronomical timescale suggests that the positive CIE, marked by positive δ¹³C spikes a-d, lasted about 0.88 Myr and can be correlated to eccentricity cycles E231 and E233. A hiatus of about 240 kyr occurs at the top of the δ¹³C spike d. The data indicate that the C/T transition correlates to an eccentricity minima node (2.4 myr g4-g3) of the La10c astronomical solution, as supported by amplitude and frequency modulation that are evident in the data. The expression of distinct orbital parameters in the analytical data suggest that during the Cenomanian-Turonian transition changes in Earth solar orbit directly impacted carbon cycling and environmental conditions.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107463"},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144070342","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":"Simulation of early karstification by synergistic mixing corrosion and retrograde solubility in carbonate reservoirs","authors":"Xing Gong,&nbsp;Zhuobin Lin,&nbsp;Wenjuan Hou,&nbsp;Sige Peng,&nbsp;Zhenkun Hou","doi":"10.1016/j.marpetgeo.2025.107465","DOIUrl":"10.1016/j.marpetgeo.2025.107465","url":null,"abstract":"<div><div>The mixing of groundwater with varying carbon dioxide content and temperature plays a crucial role in karst evolution in carbonate reservoirs, driving both mixing corrosion and retrograde solubility. Research on karst evolution has primarily focused on independent mixing corrosion (MC), while the synergistic effect of mixing corrosion and retrograde solubility (MR) has received limited attention. This study employs a previously developed hydro-thermal-chemical coupled model to analyze the early karstification of a limestone basin system recharged by meteoric and cross-formational waters, varying in <span><math><mrow><mi>P</mi><mrow><mo>(</mo><msub><mtext>CO</mtext><mn>2</mn></msub><mo>)</mo></mrow></mrow></math></span>, Ca²⁺ concentrations, and temperatures. The model incorporates structural heterogeneity and inflow aggressiveness to simulate two scenarios: MC and MR, for comparison. The results show that MC is more likely to occur in shallow aquifers, promoting preferential pathways along the water table. In contrast, MR not only accelerates dissolution at the water table but also increases flow fluxes and the extent of karstification at greater depths. As the decreasing aggressiveness of meteoric water weakens the nonlinear kinetics of dissolution, the duration of early karstification by MC is significantly longer than that of MR. In the shorter karst evolution process driven by MR, increased flow fluxes and conduit diameters at greater depths facilitate the development of longer vertical permeable tunnels along the faults, while hindering conduits enlargement at the water table. These findings reveal distinct modes of karstification for MC and MR, highlighting the significant role of heat and chemistry heterogeneity in karst evolution. This study provides deeper insights into carbonate reservoirs and offers practical implications for improving the efficiency of hydrothermal resource exploitation and geological CO₂ storage.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107465"},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144107364","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":"Sedimentology and diagenetic evolution of the Upper Permian Khuff Formation in Saudi Arabia. New perspectives from biostratigraphy, U/Pb geochronology and fluid inclusions","authors":"M. Deville de Periere ,&nbsp;X. Mangenot ,&nbsp;V. Dyja-Person ,&nbsp;A. Aldhubaib","doi":"10.1016/j.marpetgeo.2025.107462","DOIUrl":"10.1016/j.marpetgeo.2025.107462","url":null,"abstract":"<div><div>The Upper Permian section of the Khuff Formation is characterized by mud-dominated facies interpreted as lagoonal to peritidal sediments, interbedded with coated grain, grain-rich deposits suggesting lagoonal to high-energy shoal environments. The diagenetic overprint encompasses early dolomitization, dissolution, and burial diagenetic products such as dolomite cements and at least one phase of anhydrite. For the first time in the Khuff Formation of the Arabian Platform, <em>in-situ</em> LA-ICP-MS chronometry using U/Pb age dating has been performed in one well of the Rub al Khali Basin in order to refine the absolute timing of the various cement phases. The early dolomitization is interpreted as a very early replacive event resulting from hypersaline fluids, but is affected by recrystallization during the Middle Triassic (average 244.3 ± 7 Ma). Dolomite cements include a Guadalupian to base Lopingian phase (D1 – 265.5 ± 8 Ma) and a saddle dolomite (D2) dated from the Lower Jurassic (193.5 ± 15.7Ma). Fluid inclusion measurements in the latter indicate minimal precipitation temperatures of around 150 °C from rather medium salinity fluids, probably related to Lower Jurassic faulting. This study also shows the absence of calcite cements and of thermochemical sulfate reduction (TSR), usually present in the Khuff Formation at the platform-scale. The combined biostratigraphy assessment and U/Pb chronometry performed in this study suggest the section directly overlying the Middle Anhydrite to be slightly older than initially thought, and the transgression on top of the Middle Anhydrite marker extending into the Capitanian. Results also suggest that faults might have been active during the burial history allowing hydrothermal brines to percolate through studied interval.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"179 ","pages":"Article 107462"},"PeriodicalIF":3.7,"publicationDate":"2025-05-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942886","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":"Causal-Graph Lithology Classifier: Synergizing causal inference with graph neural networks for high-accuracy rock classification in well logging","authors":"Youzhuang Sun ,&nbsp;Shanchen Pang ,&nbsp;Zhihan Qiu ,&nbsp;Hengxiao Li ,&nbsp;Sibo Qiao","doi":"10.1016/j.marpetgeo.2025.107452","DOIUrl":"10.1016/j.marpetgeo.2025.107452","url":null,"abstract":"<div><div>Lithology classification is a vital task in geological exploration and plays a crucial role in the exploration and development of oil and gas resources. Traditional lithology classification methods often rely on empirical models or statistical approaches. While these methods have achieved some success, they frequently encounter issues such as low classification accuracy and poor model generalization when dealing with complex geological data. With advancements in deep learning technology, machine learning-based lithology classification methods have gradually been adopted. However, these methods often overlook the causal relationships between different lithologies and their impact on classification results. This paper proposes an innovative lithology classification method—the Causal-Graph Lithology Classifier (CG-Litho), which combines Graph Neural Networks (GNNs) and causal inference to effectively enhance classification accuracy and interpretability. Initially, the geological data is represented as a graph structure, where the data from each well is treated as a node, and the geological similarity or geographical relationship between wells is represented as edges. Utilizing GNNs, the model can propagate information across nodes to capture the spatial and geological feature interrelationships between different well locations. To further improve the model's performance, this paper introduces causal inference. By analyzing the causal impact of various geological features on lithology classification results through causal intervention, the model avoids correlation issues that cannot be explained by traditional methods. This GNN-based model, integrated with causal inference, not only identifies the complex interrelationships between lithologies but also effectively reduces the impact of data noise on classification results. Experimental results demonstrate that the proposed Causal-Graph Lithology Classifier excels in multiple practical application scenarios, significantly improving classification accuracy compared to traditional machine learning and deep learning models. Particularly, when handling well data with complex geological backgrounds, the model provides more stable and reliable prediction results. Additionally, the model's causal intervention mechanism offers geologists enhanced interpretability, helping them understand the causal relationships between variables and optimize exploration decisions. This study provides a new approach to lithology classification by integrating spatial information and causal inference through causal graph neural networks, enabling more efficient and interpretable lithology predictions. This method not only holds broad application prospects in geological exploration but also offers valuable insights for causal inference and graph learning problems in other fields.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"180 ","pages":"Article 107452"},"PeriodicalIF":3.7,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144146701","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":"Noble gas constraint of CO2 source and connectivity in a CO2-rich gas reservoir, offshore Angola","authors":"Stuart M.V. Gilfillan ,&nbsp;James A. Scott ,&nbsp;Honggang Zhou ,&nbsp;Magali Pujol","doi":"10.1016/j.marpetgeo.2025.107460","DOIUrl":"10.1016/j.marpetgeo.2025.107460","url":null,"abstract":"<div><div>Subsalt prospects in the South Atlantic margin contain potential hydrocarbon plays as exemplified by significant discoveries on the Brazilian margin. On the conjugate east side of the South Atlantic Ocean, pre-salt sections of the offshore Kwanza Basin, Angola also contain potentially economic reservoirs. Here we report the results of an exploration well which encountered gas containing high portions of CO₂ (82–84 mol%) and CH₄ (14.2–16.6 mol%) from offshore Angola. Using bulk gas, stable carbon isotopes and noble gas compositions of gas samples collected via downhole sampling of the exploration well, we constrain the source and connectivity of the CO₂-rich gas reservoir. Measured CO₂/³He ratios indicate that the CO₂ is primarily mantle-derived, with the samples from the deepest portion of the reservoir exhibiting evidence of CO₂ loss, most probably due to CO₂ dissolution into the groundwater. Using neon isotopes, we show that noble gas measurements constrain that the CO₂ has a Mid-Ocean Ridge Basalt (MORB) source, related to the rifting of the Atlantic margin at approximately 110 Ma. We additionally identify that a recently outlined methodology utilising noble gases can be applied to show a disconnection between the two upper and lower sections of the reservoir encountered in the well. This corroborates the evidence of disconnection provided from the δ¹³C gas fraction (C1 to C5) and provides further verification of the use of noble gases to determine static vertical connectivity within a hydrocarbon prospect.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"179 ","pages":"Article 107460"},"PeriodicalIF":3.7,"publicationDate":"2025-05-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143942887","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}