Marine and Petroleum Geology最新文献

{"title":"Trace and rare earth element signatures in microcrystalline aragonite as indicators of oil vs. methane seepage","authors":"Yuedong Sun ,&nbsp;Shanggui Gong ,&nbsp;Jörn Peckmann ,&nbsp;Fang Chen ,&nbsp;Yao Guan ,&nbsp;Dong Feng","doi":"10.1016/j.marpetgeo.2025.107534","DOIUrl":"10.1016/j.marpetgeo.2025.107534","url":null,"abstract":"<div><div>Oil seeps are important hydrocarbon sources to the ocean and sustain diverse chemosynthesis-based ecosystems. Distinguishing oil- from methane-dominated seeps in the geological record is crucial for reconstructing the evolution of chemosynthetic communities, yet remains challenging. Authigenic carbonates precipitating at seeps offer a valuable archive of the composition of seep fluid. While previous work has focused on fibrous aragonite cement, the geochemical potential of volumetrically dominant microcrystalline analog remains underexplored. Here, we present a comprehensive study of the petrography and stable isotope as well as element composition of oil-derived seep carbonates from the northern Gulf of Mexico (sites GC232, GC185), compared to methane-derived seep carbonates from the northern Gulf of Mexico (site AT340) and the South China Sea (site GMGS2-08). All studied samples are dominated by microcrystalline aragonite. Carbon isotope data (average δ¹³C = −20.9 ± 4.5 ‰; VPDB) and the presence of oil residues agree with crude oil degradation as the main carbon source of the oil-seep carbonate. Compared to methane-seep carbonates, oil-seep carbonates exhibit higher rare earth elements (REE) contents, slight light-REE enrichment, and elevated contents of uranium (U), molybdenum (Mo), zinc (Zn), and cobalt (Co), signatures linked to microbial oil oxidation. These element patterns preserved in microcrystalline aragonite offer a novel proxy for identifying oil seepage in the rock record, particularly in cases where fibrous cement is absent.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107534"},"PeriodicalIF":3.7,"publicationDate":"2025-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144579701","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":"Inter-strata oil migration and its implications of hydrocarbon accumulation in the lacustrine shale system of the Lucaogou Formation, Jimusaer Sag, Junggar Basin","authors":"Enze Wang ,&nbsp;Maowen Li ,&nbsp;Xiaoxiao Ma ,&nbsp;Menhui Qian ,&nbsp;Tingting Cao ,&nbsp;Zhiming Li ,&nbsp;Zhijun Jin","doi":"10.1016/j.marpetgeo.2025.107533","DOIUrl":"10.1016/j.marpetgeo.2025.107533","url":null,"abstract":"<div><div>Traditionally, shale petroleum systems are considered to possess self-generating and self-storing characteristics. However, with the advancement in understanding of these systems, researchers have discovered that hydrocarbon migration is a common phenomenon within them. Given that the scale of hydrocarbon migration in shale petroleum systems is significantly smaller compared to conventional systems, identifying such migration within shales remains a challenging endeavor. Moreover, few studies have systematically discussed the impact of hydrocarbon migration on petroleum accumulation in shale systems. This study focuses on the Lucaogou Formation in the Jimusar Sag of the Junggar Basin. Building upon geochemical data reported by previous research, we have reinterpreted and further explored geochemical data, presenting a novel approach for quantitatively identifying various types of hydrocarbon migration within shale using pyrolysis and molecular geochemical parameters, which are commonly generated in the petroleum industry. Additionally, it explores the influence of hydrocarbon migration on oil enrichment. The findings reveal that various forms of hydrocarbon migration have contributed to the paradoxes in the pyrolysis (the mismatch between TOC and S₁ contents) and molecular geochemical features (anomalies of the C₂₉ αββ/(αββ+ααα) and C₂₉ ααα 20S/(20S + 20R) ratios) of the Lucaogou Formation. Based on the hydrocarbon migration status, four distinct types of reservoirs are identified within the Lucaogou Formation shale: lateral migration, carrier bed, inter-layer migration, and in situ retention. According to exploration practices, the Lucaogou shale can be divided into different sections (upper section sweet spot, middle section mudstone, and lower section sweet spot), each exhibiting distinct differences in hydrocarbon migration types. Lateral migration is commonly observed in the upper section sweet spot, whereas in the middle-section mudstone and the lower section sweet spot, the occurrence of lateral migration is limited, with inter-layer migration and in situ retention being more prevalent. In shale systems, extensive lateral hydrocarbon migration facilitates the formation of localized, high-quality exploration sweet spots, although these sweet spots bear more resemblance to conventional structural-lithologic reservoirs. Future exploration and development strategies for shale petroleum systems should consider the patterns of hydrocarbon migration when formulating plans. This study offers a framework for the detailed characterization of hydrocarbon migration types within shale petroleum systems and highlights the impact of hydrocarbon migration on shale oil enrichment.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107533"},"PeriodicalIF":3.7,"publicationDate":"2025-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556798","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":"Onset of the Messinian Salinity Crisis: Insights from molecular organic geochemistry","authors":"A. Permanyer ,&nbsp;M.A. Kruge ,&nbsp;L. Gibert","doi":"10.1016/j.marpetgeo.2025.107532","DOIUrl":"10.1016/j.marpetgeo.2025.107532","url":null,"abstract":"<div><div>The Messinian Salinity Crisis (MSC) generated extensive anoxic sediments under the evaporitic deposits in marginal Mediterranean basins. In an interdisciplinary approach combining field work with multiple laboratory techniques, the oil source rock potential and biomarkers of pre-evaporitic Messinian sediments from the Caltanissetta Basin (Sicily) were evaluated using Rock-Eval pyrolysis, gas chromatography-mass spectrometry, isotopic analysis and optical and electron microscopy. Organic-rich samples from the 45 m Serra Pirciata section consist of cycles of diatomaceous and carbonate layers alternating with organic shales of variable TOC. The organic matter is mostly optically amorphous, increasing in content upwards in the section. Of the 43 samples analyzed within the section, an especially organic- and sulfur-rich interval shows TOC values up to 10 %, and oil generation potential (Rock-Eval S2) up to 75 mg HC/g rock. Samples show Rock-Eval Hydrogen Indices (HI) up to ca. 800 mg HC/g TOC, but most fall in the range of 300–600 mg HC/g TOC, indicating type II kerogen. Within this section, a specific interval is especially remarkable for its unusual biomarker assemblage, having abundant sulfur compounds including isoprenoid, steroid, and hopanoid thiophenes and thiolanes, as well as microscopic sponge fossils. We propose that this organic-rich interval with its distinctive biomarkers represents an initial episode of basin restriction and, based on cyclostratigraphic interpretations, constitutes a non-evaporitic record of the onset of the MSC in the deeper part of the Caltanissetta Basin, where gypsum deposits were initially absent. If the depocenter of the Caltanissetta Basin is an analog for the deep Mediterranean basin, these results suggest that a large volume of organic matter of bacterial origin accumulated in the deep Mediterranean prior to evaporitic deposition.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107532"},"PeriodicalIF":3.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144556799","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":"Genesis of differential cementation by authigenic kaolinite in deep-buried tight sandstone reservoirs for the upper Triassic Xujiahe Formation, western Sichuan foreland basin, China","authors":"Mengfei Zhang ,&nbsp;Mingjie Liu ,&nbsp;Bo Cao ,&nbsp;Peng Huang ,&nbsp;Zilong Wang","doi":"10.1016/j.marpetgeo.2025.107526","DOIUrl":"10.1016/j.marpetgeo.2025.107526","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The tight sandstone reservoirs of the Xu3 Member in the Depression Zone of the Western Sichuan Foreland Basin (WSFB-DZ) are characterized by the widespread development of kaolinite cement, with notable cementation variations observed between the northern and southern regions of the depression zone. Utilizing an integrated methodology that encompasses cast thin section petrography, SEM, XRD, CL, fluid inclusion homogenization temperatures, in-situ micro-area carbon and oxygen isotopes, and trace element analysis, this study compared the differential cementation traits and genetic mechanisms of authigenic kaolinite within the Xu3 Member tight sandstone reservoirs, distinguishing between the northern and southern regions of WSFB-DZ. The study indicates that the northern Xu3 Member tight sandstone reservoirs are predominantly litharenite. The authigenic kaolinite crystals exhibit well-defined structures, predominantly, manifesting as pseudo-hexagonal platy single crystals and vermicular-to-booklet-like aggregates. These crystals fill predominantly intragranular dissolution pores and intergranular pores, and coexist mainly with quartz cement and carbonate cement. In contrast, the southern region is primarily litharenite and sublitharenite. The crystal morphology of authigenic kaolinite in this area is less well-developed compared to that in the northern region, with rare vermicular aggregates. Additionally, kaolinite cement in this region underwent substantial transformation into illite and chlorite through late diagenetic alteration. The Xu3 Member tight sandstone reservoirs in the WSFB-DZ exhibit two stages of kaolinite cementation, early and late. These cements originated from the dissolution of easily soluble grains such as feldspar and rock fragments by humic acids derived from early coal-bearing strata and organic acids generated during organic matter maturation and decarboxylation in the late stage. The southern Xu3 Member sandstone reservoirs exhibit a relatively high content of K-feldspar grains, and the dissolution of K-feldspar by organic acids released a significant amount of K&lt;sup&gt;+&lt;/sup&gt; ions. Additionally, the late-stage carbonate cementation consumed only a small amount of Fe&lt;sup&gt;2+&lt;/sup&gt; and Mg&lt;sup&gt;2+&lt;/sup&gt; ions, resulting in late diagenetic fluids that were rich in K&lt;sup&gt;+&lt;/sup&gt;, Fe&lt;sup&gt;2+&lt;/sup&gt;, and Mg&lt;sup&gt;2+&lt;/sup&gt; ions. These geochemical conditions favor the widespread transformation of authigenic kaolinite into illite and chlorite in the southern Xu3 Member sandstone reservoirs. Consequently, the southern sandstones are characterized by a low content of kaolinite cement and a relatively high content of illite and chlorite cement. In contrast, the northern Xu3 Member sandstone reservoirs have a lower content of K-feldspar grains, resulting in reduced K&lt;sup&gt;+&lt;/sup&gt; ions release from organic acid dissolution. Simultaneously, the late-stage carbonate cementation sequestered substantial Fe&lt;sup&gt;2+&lt;/sup&gt; and Mg&lt;sup&gt;2+&lt;/sup&gt; ion","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107526"},"PeriodicalIF":3.7,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523363","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":"Multiple observations to delineate the characteristics of cold seep system in the Qiongdongnan Basin","authors":"Xiujuan Wang ,&nbsp;Wenlu Wang ,&nbsp;Jiapeng Jin ,&nbsp;Guangxu Zhang ,&nbsp;Zhendong Luan ,&nbsp;Chaolun Li ,&nbsp;Minxiao Wang ,&nbsp;Zhengyi Zhang ,&nbsp;Bo Liu ,&nbsp;Wei Li ,&nbsp;Sanzhong Li","doi":"10.1016/j.marpetgeo.2025.107522","DOIUrl":"10.1016/j.marpetgeo.2025.107522","url":null,"abstract":"<div><div>Cold seeps in the Qiongdongnan Basin have been identified from three-dimensional (3D) seismic data, geophysical attributes, and in situ observations. Amplitude, dip, coherence and acoustic impedance attributes are employed to delineate the spatial variations of cold seeps across different layers by identifying faults, fractures and reservoir properties. These variations arise from the differences inside and outside of cold seeps due to the occurrence of gas hydrate, where mass transport deposits (MTDs) are widely distributed. The primary objective is to characterize the diverse features of cold seep systems, including seafloor features, plumbing systems, and their potential relationships with gas hydrates and shallow gas. Moreover, new remotely operated vehicle (ROV) dives have been utilized to distinguish two distinct chemosynthetic biological communities associated with methane bubble plumes. One community represents an active cold seep, characterized by abundant mussels and clams on or around carbonates, while the other is a paleo-cold seep that has been reactivated by gas hydrate drilling due to the leakage of trapped gas near the base of gas hydrate stability zone. All identified cold seeps exhibit weak amplitude anomalies, pull-up reflections, and chimney-like structures, which are located within high amplitude zones above local uplift in different sags of the Qiongdongnan Basin. Logging-while-drilling and coring data within these chimney-like structures have confirmed moderate to high gas hydrate saturations with diverse morphologies, as well as methane-related carbonates, indicating the presence of buried or active cold seeps. These findings suggest that cold seep activity is influenced by MTDs and that the upward fluid migration is closely linked to deep gas or shallow gas below the BGHSZ, which penetrate through MTDs along fault and fracture systems, suggesting pressure-controlled gas seepage.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107522"},"PeriodicalIF":3.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523394","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":"Paleolandscapes recorded by the Top Basement surface in the Norwegian North Sea","authors":"M.S. Bauck ,&nbsp;J.I. Faleide ,&nbsp;H. Fossen ,&nbsp;R.L. Gawthorpe","doi":"10.1016/j.marpetgeo.2025.107527","DOIUrl":"10.1016/j.marpetgeo.2025.107527","url":null,"abstract":"<div><div>Mapping the diachronous Top Basement in the North Sea reveals a complex amalgamation of paleolandscapes and provides valuable insights into the Late Paleozoic and Mesozoic geologic history. To illuminate the temporal geologic and geomorphic evolution, we document and analyze geomorphic characteristics and relate these to the regional tectonostratigraphic events. The paleolandscapes represented by the Top Basement surface generally fall into the following categories: rough, irregular terrains; rough, confined drainage networks; and smooth, planar landscapes. Notably, the irregular landscape found at the base of the deep basins is covered by Upper Paleozoic sediments and represents a potential late stage of the Devonian denudation of the Caledonian mountain chain. A distinct drainage network on the Top Basement of the Patch Bank Ridge represents two exposure phases: one related to extension during Devonian exhumation and the other associated with Carboniferous exhumation. Two regional tectonic events are candidates for such Carboniferous exhumation, one is Variscan contraction, the other is the Pennsylvanian event dated onshore Greenland and Fenoscandia. Preserved drainage networks observed on various basement highs correspond to local Late Permian to Early Triassic fault block uplift. In tilted fault blocks, these features are significant, while in horst block structures, smooth, planar landscape expression occurs. This is linked to repeated uplift of horst block structures, while tilted fault blocks get buried sooner. A distinct terrain observed in a confined area on the western Måløy Slope exhibits geomorphic characteristics comparable to those found on the tilted Vette and Tusse fault blocks overlain by sediment of Triassic or older origin. Thus, we suggest that this is a strong indication that Late Permian to Early Triassic rifting impacted the Måløy Slope. Tectonic and climatic processes controlled the relief and spatial extent of these landscapes. Our findings correlate with onshore exhumation and landscape development documented from other studies onshore East Greenland and Fennoscandia. These insights highlight the potential for identifying further paleolandscape features across the wider North Sea region and beyond.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107527"},"PeriodicalIF":3.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144548665","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":"Tectono-stratigraphic evolution of the Late Cretaceous-Eocene of Jordan and implications for the Arabian Plate convergent margin phase","authors":"Amir Kalifi ,&nbsp;Jihede Haj Messaoud ,&nbsp;Guillaume Baby ,&nbsp;Khalil Ibrahim ,&nbsp;John H. Powell ,&nbsp;Frans van Buchem","doi":"10.1016/j.marpetgeo.2025.107525","DOIUrl":"10.1016/j.marpetgeo.2025.107525","url":null,"abstract":"<div><div>The Late Cretaceous-Eocene geodynamic evolution of Jordan is presented, combining, for the first-time, outcrop and subsurface data in this poorly known, yet important part of the Arabian Plate. A new age model developed for outcrop sections, integrating biostratigraphy, C/O and Sr isotopes, together with seismic and well log data significantly improves the timing of the structural events in Jordan and shows their potential relationship to Arabian Plate scale deformation events.</div><div>The late Albian-early Turonian displays a gradual north-northwestward thickening trend across Jordan during a phase of tectonic quiescence, whereas in the overlying late Turonian-early Campanian there is ample evidence for extensional/transtensional tectonic activity, with an acme during the early Campanian, expressed in the development of the northwest-trending Azraq-Hamza Graben in central-east Jordan. This graben, with an offset of c. 1800 m, extends southeastwards to the Wadi Sirhan Graben in Saudi Arabia and northwestwards to the Levant Basin. The subsequent late Campanian-Eocene succession records reduced tectonic subsidence within the graben during a sag phase and marks a return to regional stability.</div><div>The Azraq-Hamza Graben is proven to be time-equivalent to the similarly oriented extensional events in Syria (Euphrates Graben) and Iraq (Sinjar Graben) and is coeval with the compressional structures of the foreland basins in Oman and Iran. This study contributes, to the large-scale tectonic evaluation of the African-Arabian plate deformation and evolution during the Late Cretaceous obduction and subduction phases, which played a critical role in the shaping of the petroleum systems and phosphorite sedimentation of the region.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107525"},"PeriodicalIF":3.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563090","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":"Submarine morphology offshore Crotone (Calabrian accretionary prism, Central Mediterranean): Pockmark fields and mud extrusion in a mobile shale domain","authors":"Andrea Argnani,&nbsp;Marzia Rovere","doi":"10.1016/j.marpetgeo.2025.107530","DOIUrl":"10.1016/j.marpetgeo.2025.107530","url":null,"abstract":"<div><div>The narrow Calabrian Arc accretionary prism, in the Mediterranean Sea, is known to be populated by mud volcanoes, although only a few of them have been extensively documented. The Ionian Sea offshore the Crotone Promontory offers examples where the expressions of fluid expulsion and sediment mobilization are visible both in the subsurface and at the seafloor. The analysis of a proprietary 3D seismic data cube allows characterization of pockmark patterns and identification of a mud diapir, which appears at the seafloor as a large mud pool, ca. 1200 m in diameter. The high resolution 3D seismic profiles allow differences to be inferred about the mechanisms of fluid focusing at very shallow sub-seafloor depths. Fluid focusing and pockmark formation are aided by normal faults arising from both outer arc extension and dilation in shallow unconsolidated sediments influenced by sharp increases in slope gradient. In some instances, it can be shown that fluid venting also contributed to destabilizing the uppermost sedimentary strata, triggering small landslides along the slope. The mud diapir has apparently been mobilized along an extensional fault, which tapped into a mobile shale domain. A fossil mud pool has also been recognized in the study area. This fossil mud pool is sealed by undeformed sedimentary strata which constrains a minimum age for fluid and sediment mobilization in the accretionary prism. Seismic reflection amplitudes suggest that the fossil conduit still acts as a preferential fluid seepage pathway, contributing to destabilization of the overlying slope sediments.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107530"},"PeriodicalIF":3.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518186","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 stratigraphic analysis of the Pre-salt of Berbigão, Sururu, and Atapu fields, Santos Basin, Brazil","authors":"Victor Haas Pizarro ,&nbsp;Fábio André Perosi ,&nbsp;Leonardo Borghi ,&nbsp;Marcos Fetter","doi":"10.1016/j.marpetgeo.2025.107529","DOIUrl":"10.1016/j.marpetgeo.2025.107529","url":null,"abstract":"<div><div>The Pre-salt section of Santos Basin, formed during the Lower Cretaceous, hosts one of the world's most significant hydrocarbon provinces, yet its complex carbonate reservoirs are yet to be fully understood. This study consists of a seismic analysis and interpretation of the Pre-salt interval of Berbigão, Sururu, and Atapu fields, focusing on the Upper Barra Velha Formation. A 3D seismic volume and sixteen wells were analyzed. At the Pre-salt level, five seismic units were defined. Distinct seismic facies were described and mapped throughout the Sag unit. These seismic facies were analyzed for occurrence patterns and incorporated with data from lithofacies and electrofacies. It was concluded that seismic facies Parallel corresponds to carbonate platforms principally composed of spherulitestone and mudstone variations and developed in both high- and low-energy sublittoral lake zones. Seismic facies Divergent Wedge and Fill represent profundal sediments deposited in deeper portions of the lake, where a higher concentration of organic-rich shales and mudstones would occur. This element is often associated with syndepositional faulting in the Sag unit. Seismic facies Mound represents carbonate mounds predominantly composed of shrubstone variations and shrubby spherulitestones. They occur along deep-seated faults and contain conspicuous amounts of silica and uranium. Mounds likely formed in intermediate to shallow sublittoral zones, being occasionally subjected to subaerial exposure. The formation and enrichment of these carbonate mounds are likely associated with hydrothermal processes, where faults would have acted as conduits for the percolation of hydrothermal fluids. Significant concentrations of shrubs in the Upper Barra Velha Formation are probably related to carbonate precipitation from hydrothermal fluids. The interpretations derived from this integrated study provide new insights into reservoir heterogeneity in the Upper Barra Velha, with direct implications for reservoir prediction, well placement, and production optimization in similar Pre-salt settings.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"182 ","pages":"Article 107529"},"PeriodicalIF":3.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144654700","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":"Diagenetic and depositional controls on reservoir quality in a Middle Miocene carbonate buildup, Central Luconia, offshore Malaysia","authors":"Puntira Henglai ,&nbsp;Rattanaporn Fongngern ,&nbsp;Arthur Saller ,&nbsp;Rapheephan Laochamroonvorapongse ,&nbsp;Phalaphoom Thamniyom ,&nbsp;Sorasak Lendam","doi":"10.1016/j.marpetgeo.2025.107528","DOIUrl":"10.1016/j.marpetgeo.2025.107528","url":null,"abstract":"<div><div>Middle Miocene carbonate buildups in Central Luconia, offshore Malaysia, are major contributors to hydrocarbon production in Southeast Asia; however, the interaction between depositional facies and diagenetic processes in controlling porosity development remains poorly understood. This study utilized petrographic analysis, seismic interpretation, and isotopic measurements to provide new insights into the diagenesis that enhances reservoir quality of a deeply buried dominantly limestone buildup (3600–4400 m). The studied platform has a thick reservoir section and a gas column exceeding 600 m that was divided by low-permeability flooding layers into five zones (from top to bottom): 1, 2 Upper, 2 Lower, 3 Upper, and 3 Lower. Freshwater dissolution below subaerial exposure surfaces created high porosity intervals with variations in reservoir properties due to depositional facies. Coral boundstones at the reef margin have moderate to high porosity (4–32 %) and high permeability (1–988 mD). Bioclastic packstones deposited in backreef environments have high porosity (2–32 %) and moderate permeability (0.1–193 mD). Bioclastic wacke-packstones deposited in platform interior environments have moderate porosity (2–19 %) and low permeability (0.01–9 mD). Seismic coherency attributes revealed small dendritic features, suggesting brief subaerial exposure events. A thick gas column and overpressure in the platform carbonate and overlying shale are the key mechanisms for porosity preservation in the upper part of this deep-buried platform. Early replacive dolomitization preserved porosity of 23 % in the lower platform where adjacent limestones have &lt;5 %. In contrast to other Luconia platforms, this aquifer is small and has minimal impact on gas recovery, allowing efficient recovery through gas expansion when reservoir pressure is lowered.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"181 ","pages":"Article 107528"},"PeriodicalIF":3.7,"publicationDate":"2025-06-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144563091","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}