Marine and Petroleum Geology最新文献

{"title":"Hydraulic and thermal controls on gas production from methane hydrate reservoirs","authors":"Kehua You ,&nbsp;Peter Flemings ,&nbsp;David DiCarlo","doi":"10.1016/j.marpetgeo.2025.107378","DOIUrl":"10.1016/j.marpetgeo.2025.107378","url":null,"abstract":"<div><div>This study explores the controls of fluid flow and heat transport on gas production from methane hydrate reservoirs under depressurization. We find that effective water permeability of hydrate-bearing sediments plays a primary role in determining the reservoir response and gas production. Effective water permeability determines the velocity of water flow and the speed of pressure propagation. These propagation speeds give rise to two distinct behaviors of hydrate dissociation, which in turn lead to two distinct regimes of gas production. In reservoirs with high effective water permeability (&gt; <span><math><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>16</mn></mrow></msup></mrow></math></span> m² or &gt;10⁻¹ mD), the low-pressure wave propagates rapidly, creating a wide, laterally expansive zone of hydrate dissociation. This large dissociation zone leads to a broad region where free methane gas is released, supporting a high-rate gas production at the wellbore. The hydrate-dissociation zone continuously expands with time until it reaches the lateral edge of the reservoir, enhancing both the gas production rate and the cumulative gas-to-water production ratio. Increased heat conduction further accelerates the gas production rate. Conversely, in reservoirs with low effective water permeability (&lt; <span><math><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>18</mn></mrow></msup></mrow></math></span> m² or &lt;10⁻³ mD), pressure propagation is more restricted, which limits the extent of hydrate dissociation to a narrow interface. This confined dissociation zone results in a significantly lower gas production rate, with minimal increase over time and a declining gas-to-water production ratio. These conclusions are based on a multiphase flow, multicomponent reactive transport numerical model applied to hydrate reservoirs with initial effective permeabilities spanning five orders of magnitude. Our findings highlight the importance of accurately characterizing the effective permeability of hydrate-bearing sediments, particularly in the context of methane hydrate presence and sediment compaction, to assess the viability of gas hydrates as an energy resource.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107378"},"PeriodicalIF":3.7,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of the correlation between fracture topology and mechanical properties of rocks in fractured carbonate reservoirs: In Dehram group, Fars arc Zone (Southwest Iran)","authors":"Mohadese Ajami ,&nbsp;Kimia Asgari ,&nbsp;Ali Kadkhodaie","doi":"10.1016/j.marpetgeo.2025.107368","DOIUrl":"10.1016/j.marpetgeo.2025.107368","url":null,"abstract":"<div><div>Fractures play a critical role in fluid transport within brittle rocks, particularly in carbonate reservoirs. This study focuses on understanding the relationship between mechanical stratigraphy and natural fractures in the carbonate reservoirs of the Dehram Group in the Zagros region (Fars Arc), Southwest Iran. Using high-resolution borehole images and various well logs, the spatial distribution of fractures in this group are investigated. The study examines mechanical stratigraphy at two scales: large-scale mechanical stratigraphy, characterized by rock strength variations in units thicker than 1 m, primarily affecting overall fracture intensity; and small-scale mechanical stratigraphy, revealed through borehole images, which significantly influences fracture aperture and continuity. The connectivity of fractures was evaluated using the degree of fracture connectivity (D), with results showing \"good\" connectivity in terms of increased permeability (D = 2.6) in the Kangan formation and \"excellent\" connectivity (D = 3.5) in the Dalan formation. Block intensities (R₂₂) were measured at 0.4 in the Kangan and 0.2 in the Dalan, indicating varying degrees of rock fragmentation. Spatial variations in fracture connectivity across different zones are influenced by lithology, strain distribution, and the presence of weakness zones such as faults. These insights are essential for developing predictive models of reservoir performance in naturally fractured carbonate systems.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107368"},"PeriodicalIF":3.7,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143628810","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":"Structural control on basin architecture and hydrocarbon play types of the Miocene carbonate reservoirs, southern Gulf of Suez rift, Egypt","authors":"S.K. Moawad ,&nbsp;A.R. Baghdady ,&nbsp;A.R. Moustafa ,&nbsp;H.M. Helmy ,&nbsp;S.M. El-Hadidy","doi":"10.1016/j.marpetgeo.2025.107365","DOIUrl":"10.1016/j.marpetgeo.2025.107365","url":null,"abstract":"<div><div>The complex architecture of syn-rift carbonate reservoirs remains challenging in hydrocarbon exploration and development in rift basins such as the Gulf of Suez basin. The analysis of subsurface data of five boreholes, including composite logs, stratigraphy, and core data, was supported by 3D seismic data. Additional surface geological data were obtained from a syn-rift Miocene carbonate exposure in the western onshore area of the rift. Together, these data provided insights into the architecture of syn-rift Miocene carbonate depositional basin and the impact of structural control and diagenetic processes on reservoir quality. Structural reconstruction of the displacement of major normal faults of the rift illustrates the effect of structural geometry on the paleogeography and bathymetry. The study highlights how structural controls significantly influenced syn-rift carbonate deposition and played a critical role in shaping reservoir quality. Facies analysis revealed the presence of four key facies associations (lime mudstone, wackestone, packstone, and boundstone) with varying reservoir qualities based on porosity-permeability relationships. Diagenetic processes, such as dolomitization and dissolution variably impacted the reservoir quality across different structural settings. The Miocene carbonate play models in the southern Gulf of Suez basin have been classified to address the impact of structures on reservoir development and quality. These insights aim to encourage the re-evaluation of undeveloped hydrocarbon discoveries. They also improve hydrocarbon reserve assessment of complex carbonate reservoirs in the southern Gulf of Suez basin with advanced exploration strategies.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107365"},"PeriodicalIF":3.7,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143642755","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":"Internal structure of the Upper Jurassic subsurface carbonate buildups of the northern Tethys shelf in southern Poland – integration of seismic forward modeling and outcrop analogs","authors":"Łukasz Słonka ,&nbsp;Marcin Krajewski ,&nbsp;Piotr Krzywiec","doi":"10.1016/j.marpetgeo.2025.107367","DOIUrl":"10.1016/j.marpetgeo.2025.107367","url":null,"abstract":"<div><div>The Upper Jurassic carbonate buildups are considered to be exploration targets along the northern margin of the Tethys shelf in Central and Eastern Europe due to their prospective reservoir parameters. However, detailed internal structure of the Upper Jurassic subsurface buildups in the majority of the Polish part of the shelf remains largely uncharted. One of such under-documented areas is the Miechów Trough, where these structures are still poorly recognized in terms of their facies/microfacies composition and petrophysical properties. In order to fill these gaps, we have integrated the subsurface well and seismic data with sedimentological data from adjacent surface areas where equivalent reefs were documented based on facies/microfacies analysis. This paper presents the results of interpretation of the internal structure of the subsurface carbonate buildups, using seismic forward modeling supported by outcrop analogs. Eight main seismic intervals corresponding to internal levels of the Upper Jurassic succession were distinguished and integrated with the lithological intervals from the studied outcrops. The internal structure of the reefs is heterogenous and in terms of facies distribution it corresponds to that observed in adjacent areas of the Late Jurassic carbonate platform. The important aspect of the reefs internal structure is the existence of highly porous intervals, as they could be regarded as potential objects for further investigation as CO₂ storage sites. Modeling results proved that their detection using seismic data is primarily constrained by lateral resolution limits.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107367"},"PeriodicalIF":3.7,"publicationDate":"2025-03-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610498","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 sequence stratigraphic controls on reservoir quality in the Upper Jurassic Smackover Formation, southern Arkansas, USA","authors":"Cameron J. Manche ,&nbsp;Jim Markello ,&nbsp;Juan Carlos Laya ,&nbsp;Mike Pope ,&nbsp;Kenneth Fritsche ,&nbsp;Kevin Hill","doi":"10.1016/j.marpetgeo.2025.107363","DOIUrl":"10.1016/j.marpetgeo.2025.107363","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The Upper Jurassic Smackover Formation of the U.S. Gulf Coast Region is a mature hydrocarbon play that, in recent decades, has become a target for producing lithium-rich brines and a potential site for carbon storage. Despite this activity, the sequence stratigraphic framework of the Smackover Formation is widely disputed. One of the most challenging aspects of understanding the spatial and temporal controls on diagenesis is establishing the sequence stratigraphic framework. These uncertainties have resulted in uncertainty in delineating trends in porosity and permeability. Here, we characterize the reservoir quality, establish the sequence stratigraphic framework, and determine the spatio-temporal relationship between depositional and diagenetic processes in the Smackover Formation.&lt;/div&gt;&lt;div&gt;This study utilizes twelve subsurface cores from the Smackover Formation across southern Arkansas, including predominantly the Smackover “B” [Upper Jurassic (UJ) III Sequence] and, to a lesser degree, the Smackover “C” (UJ II Sequence). 215 well logs were correlated to assess the 3-D stratigraphic framework of the Smackover “B” and “C”. From a north-south oriented 2D seismic profile, the Smackover “B” is interpreted to consist of a series of progradational parasequences deposited over the lower-angle Smackover “C” ramp in southern Arkansas. Based on log-correlations, we interpret the Smackover “B” progradational parasequences to have top-set beds with a dip of 0.25° along the inner ramp, foreset beds with a dip of 0.5°–1.0° along the mid ramp, and bottomset beds with a dip of 0.25° along the outer ramp in this area. Based on these geometries, twenty-five parasequences were correlated within the Smackover “B”. The Smackover \"B” and overlying Buckner Formation is characterized by seven different depositional facies interpreted to reflect a depositional profile that extends from coastal interdune salinas or sabkhas to a shallow marine mid-outer ramp setting. The Smackover “B” is interpreted to reflect a shallowing upward trend consisting of peloidal wacke-to-packstone overlain by ooid-oncoid grainstone, capped by silty dolomitic mudstone and shaley nodular anhydrite of the Buckner Formation. The underlying Smackover “C” consists predominantly of peloidal wacke-to-packstone. In general, the Smackover “B” and “C” have undergone varying degrees and styles of diagenesis, including cementation, dissolution, and dolomitization. Based on the classification of diagenetically altered depositional facies, sixteen diagenetic facies were identified. The Smackover “B” consists of alternating beds of thin-rim cemented ooid, tight fully cemented ooid, moldic ooid, and peloidal grainstones. Vertical patterns in the styles and degree of cementation and dissolution in the Smackover “B” is interpreted to reflect oscillations between the meteoric vadose, meteoric phreatic, and marine phreatic zones driven by low amplitude, high-frequency relative sea level changes withi","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107363"},"PeriodicalIF":3.7,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580763","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 preliminary investigation of pore development mechanisms in highly matured solid bitumen: Implications from the Ediacaran Dengying Formation solid bitumen in the central Sichuan Basin, Southwest China","authors":"Lianqiang Zhu ,&nbsp;Hui Tian ,&nbsp;Peng Cheng ,&nbsp;Haifeng Gai ,&nbsp;Tengfei Li ,&nbsp;Qin Zhou ,&nbsp;Wei Wu ,&nbsp;Chao Luo ,&nbsp;Ping'an Peng","doi":"10.1016/j.marpetgeo.2025.107366","DOIUrl":"10.1016/j.marpetgeo.2025.107366","url":null,"abstract":"<div><div>Although pores in solid bitumen are crucial for shale reservoirs, their development mechanisms have not been fully understood partly due to the small size of solid bitumen in shales and the difficulty in its discrimination from residual kerogen. However, solid bitumen in conventional reservoirs generally has a larger size and definite origin, and therefore the examination of their pores can provide some insights into the mechanisms of pore formation in shale solid bitumen. In this study, solid bitumen samples from conventional reservoirs of the Ediacaran Dengying Formation in the central Sichuan Basin were collected for petrographic and geochemical analyses to investigate their pore characteristics and formation mechanisms. The results indicate that pores are commonly identified in solid bitumen grains that are derived from the cracking of tar pads and in solid bitumen grains that have experienced gravity-driven component separation during their formation. The development of pores in solid bitumen is controlled by the combined effect of gas expulsion and the viscosity of solid bitumen during its movable stage. The gas expulsion from movable bitumen creates pores, and they can be preserved or healed depending on the component-controlled viscosity of movable bitumen. The enrichment of sulfur- and oxygen-containing compounds and heavy components such as asphaltenes in movable bitumen can enhance its viscosity and thus inhibit the healing of pores, ultimately facilitating pore development in the present overmature solid bitumen grains.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107366"},"PeriodicalIF":3.7,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143580762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The early Aptian marine stratigraphic record in the interior of Gondwana: New insights from the Araripe Basin, Northeastern Brazil","authors":"Henrique Parisi Kern ,&nbsp;Jorge Villegas-Martín ,&nbsp;Gerson Fauth ,&nbsp;Fernanda Luft-Souza ,&nbsp;Oscar Strohschoen ,&nbsp;Lilian Maia Leandro ,&nbsp;Alessandra Santos ,&nbsp;Mauro Daniel Rodrigues Bruno ,&nbsp;Edna de Jesus Francisco Tungo ,&nbsp;Marcos Antonio Batista dos Santos Filho ,&nbsp;Daiane Ceolin ,&nbsp;Simone Baecker-Fauth ,&nbsp;Amanda Santa Catharina ,&nbsp;Francisco Henrique de Oliveira Lima ,&nbsp;Marcelo Augusto De Lira Mota ,&nbsp;Marcelo de Araújo Carvalho ,&nbsp;Mario Luis Assine","doi":"10.1016/j.marpetgeo.2025.107364","DOIUrl":"10.1016/j.marpetgeo.2025.107364","url":null,"abstract":"<div><div>The lower Cretaceous is marked by several episodes of global extension, such as greenhouse effects, sea level rises, oceanic anoxic events and deposition of important petroleum plays. Regarding the interior Cretaceous basins of NE South America, one of the questions to be answered is when the first marine floods occurred, how they were recorded and what their implications for the stratigraphic evolution of the sedimentary deposits. This work details the stratigraphic and paleoenvironmental evolution of Lower Cretaceous (Aptian) from the Barbalha Formation, located in the eastern portion of the Araripe Basin. For the study, six boreholes were described for obtain sedimentological, and ichnological data, and sampled to carry out petrographic (microbiofacies) and micropaleontological (calcareous and organic microfossils) analyses. Furthermore, four additional boreholes were also used for spot sampling and stratigraphic correlations. The multiproxy results allowed a new interpretation of the depositional environments and stratigraphic evolution of the two depositional sequences that make up the Barbalha Formation. The first depositional sequence comprises fluvial meandering deposits (LST1) overlain by lacustrine-lagoon deposits (TST1/HST1; equivalent to Batateira Beds). The second depositional sequence comprises alluvial plain and tidally-influenced delta deposits (LST2), overlain by bayhead delta deposits (TST2). These new interpretations are supported by microfossils (e.g., foraminifera and calcareous nannofossils) and/or marine to brackish ichnofossils that confirm marine incursions of greater or lesser magnitude throughout the analyzed interval. Finally, the preferential preservation of micropaleontological and ichnological elements in the boreholes located in the extreme east of the area studied (1PS-06-CE and 1PS-07-CE) suggests that the east-southeast region was the most affected by marine influence.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"177 ","pages":"Article 107364"},"PeriodicalIF":3.7,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The methane-sulfate transition interface in offshore sediments serves as a critical boundary for abrupt transitions in sedimentary environments","authors":"Xue Li ,&nbsp;Xiaoyong Duan ,&nbsp;Ping Yin ,&nbsp;Ke Cao ,&nbsp;Xingliang He ,&nbsp;Jianghai Yang ,&nbsp;Bin Chen","doi":"10.1016/j.marpetgeo.2025.107362","DOIUrl":"10.1016/j.marpetgeo.2025.107362","url":null,"abstract":"<div><div>Methane is commonly observed in unconsolidated sediments prevalent coastal areas. It widely acknowledged within the scientific community that the methane-sulfate transition zone (SMTZ) forms due to the upward diffusion of methane and downward diffusion of sulfate within these sedimentary environments. However, this study presents a detailed analysis using a borehole sample from the continental shelf of the East China Sea as a representative case study, revealing distinct findings. The entire borehole was 60 m long and predominantly composed of clay with extremely fine sediment particles, conditions that are inherently unfavorable for diffusion. The SMTZ was identified at a depth of 9 m. Geochemical characteristics of the sediments showed significant differences above and below this interval. The carbon-to-nitrogen (C/N) ratios, the carbon isotopic compositions of total organic carbon (TOC), and nitrogen isotopic compositions of total nitrogen (TN), etc., all showed a peak at this specific depth. Additionally, elements such as thorium (Th), vanadium (V), cobalt (Co), and nickel (Ni), along with redox condition indicators such as the Ni/Co and Th/U ratios, demonstrated abrupt changes around the 8.5 m mark. The findings of this study suggest that the SMTZ functions as a transitional interface within the sedimentary environment, rather than merely representing the boundary where methane and sulfate converge. This insight is crucial for enhancing our comprehension of global carbon cycling in marine sediments, as prevailing estimates of methane release fluxes based on concentration gradient diffusion theory may lead to significant discrepancies between estimated and actual values.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"176 ","pages":"Article 107362"},"PeriodicalIF":3.7,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Do hydrothermal fluids cause a dilution effect on organic matter in the Early Cambrian marine black shales?","authors":"Hezheng Dong ,&nbsp;Dongsheng Zhou ,&nbsp;Xiaowei Huang ,&nbsp;Yufei Liang ,&nbsp;Lei Huang ,&nbsp;Jie Xu","doi":"10.1016/j.marpetgeo.2025.107361","DOIUrl":"10.1016/j.marpetgeo.2025.107361","url":null,"abstract":"<div><div>Hydrothermal fluids play a significant role in the formation of black shales. However, most previous studies have focused on their positive impacts on the formation and enrichment of organic matter (OM), while overlooking potential dilution effects. This study uses organic geochemistry, elemental geochemistry, and field emission scanning electron microscopy (FE-SEM) to examine the marine black shales of the Lower Cambrian Hetang Formation at the Hongtao (HT) section in southern Anhui Province and the contemporaneous Niutitang Formation at the Yangtiao (YT) section in Guizhou Province, China. We systematically analyze the paleo-environmental conditions and the influence of hydrothermal activity during the formation of black shales with varying OM abundances. Our findings show that black shales with different OM abundances in the HT and YT section exhibit similar paleo-productivity, paleo-redox conditions, and sedimentation rates, and all show evidence of hydrothermal sedimentation. Notably, hydrothermal activity significantly affects the content of non-terrestrial silicon (Si_ex), which strongly correlates negatively with total organic carbon (TOC). This suggests that an increased silicon flux due to hydrothermal processes leads to OM dilution. Additionally, we explore the origin of silicon, suggesting that hydrothermal sources are a critical contributor to silicon in shales. We develop a silicon cycling model for black shale formation, which highlights the dual role of hydrothermal activity: promoting OM formation and enrichment yet also causing dilution. This study emphasizes the importance of considering both nutrient transport, enhanced anoxia, and OM dilution when evaluating the influence of hydrothermal activity on black shale formation. Our findings offer new insights into the complex interactions between hydrothermal processes and OM dynamics, providing significant scientific implications for a deeper understanding of black shale formation.</div></div>","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"176 ","pages":"Article 107361"},"PeriodicalIF":3.7,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534593","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 fluid evolution and its implication for hydrocarbon accumulation in Ordovician carbonate of the Tazhong area, Tarim Basin: Constraints from petrology, fluid inclusions, and geochemistry of calcite cements","authors":"Haocheng Liu ,&nbsp;Chengyan Lin ,&nbsp;Chunmei Dong ,&nbsp;Guoqiang Luan ,&nbsp;Lihua Ren ,&nbsp;Guoyin Zhang ,&nbsp;Yintao Zhang ,&nbsp;Baozhu Guan","doi":"10.1016/j.marpetgeo.2025.107360","DOIUrl":"10.1016/j.marpetgeo.2025.107360","url":null,"abstract":"&lt;div&gt;&lt;div&gt;The Ordovician carbonate reservoirs in the Tarim Basin have undergone multiple tectonic events and fluid activities, complicating reservoir quality. Understanding these fluid-rock interaction processes is critical for unraveling reservoir heterogeneity evolution and hydrocarbon migration chronostratigraphy. Multiple generations of carbonate cements in fault-related reservoirs preserve important fluid activity signatures, providing constraints on fault reactivation, vertical hydrocarbon migration pathways, and accumulation preservation mechanisms. This investigation systematically examines fault-zone hosted carbonate cements and fracture-filling vein assemblages obtained from well cores, with particular emphasis on their fluid origins and the evolutionary processes. We utilized an integrated approach incorporating petrographic analysis, fluid inclusion microthermometry, and geochemical techniques to identify two distinct generations of fault-associated carbonate cements and three discrete phases of calcite veins, listed chronologically from oldest to youngest: fibrous calcite cements (C1), blocky calcite cements (C2), fracture-filling fine calcite cements (C3), coarser blocky calcite vein cements with zoned cathodoluminescence (C4), and last fracture-filling coarse calcite cements (C5).&lt;/div&gt;&lt;div&gt;The carbon and oxygen isotopic composition of C1, similar to well-preserved Ordovician carbonate rocks, along with its fibrous texture and near-micritic grain size, suggests formation during the early diagenetic stage under a marine environment. The lighter δ&lt;sup&gt;18&lt;/sup&gt;O (av. = −7.12‰ ± 0.40‰ VPDB) and lower Sr (av. = 183.75 ± 32.30 ppm) content of C2 indicate precipitation during shallow burial diagenesis. Early vein cement (C3) containing single-phase liquid inclusions suggests precipitation in a near-surface environment. The estimated δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;fluid&lt;/sub&gt; and REE&lt;sub&gt;SN&lt;/sub&gt; patterns, which parallel the seawater profile, further support the parent fluid of C3 originated from primary marine water. The slightly depleted δ&lt;sup&gt;13&lt;/sup&gt;C values (av. = −0.97‰ ± 1.02‰) of C4 reflect external organic carbon input. Additionally, the δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;fluid&lt;/sub&gt; and river-like REE&lt;sub&gt;SN&lt;/sub&gt; patterns, reflecting parent fluid of C4 was derived from a mixture of meteoric and marine water. The non-CL vein cement of C5 displays more depleted δ&lt;sup&gt;18&lt;/sup&gt;O (av. = −10.98‰ ± 1.24‰) value and higher Fe (av. = 34 513.66 ± 269.3 ppm) and Mn (av. = 248.86 ± 104.85 ppm) concentrations, indicating its precipitation in an intermediate to deep burial reducing environment. The higher δ&lt;sup&gt;18&lt;/sup&gt;O&lt;sub&gt;fluid&lt;/sub&gt; values, combined with higher temperatures and salinities, are consistent with a burial basin brine origin.&lt;/div&gt;&lt;div&gt;Consequently, we developed a spatial-temporal evolution model of fault-related fluid circulation. The driving mechanism of marine-meteoric mixed fluid circulation is associated with extensive exposure and erosion events ","PeriodicalId":18189,"journal":{"name":"Marine and Petroleum Geology","volume":"176 ","pages":"Article 107360"},"PeriodicalIF":3.7,"publicationDate":"2025-02-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143551908","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}