最新刊期
- 摘要：Ophiolite belts are emerging as important targets for natural hydrogen exploration. Serpentinization is one of the major mechanisms responsible for natural hydrogen generation in the subsurface. Although ophiolite belts are widely distributed across China with numerous high-concentration hydrogen anomalies documented， the accumulation mechanisms and resource potential of natural hydrogen remain unclear. Preliminary progress has been made in geological surveys of natural hydrogen in the ophiolite belts of central Inner Mongolia and the southern Qilian region through the integrated application of technical methods， including the identification of fairy circles， measurements of soil hydrogen concentrations， and deep geophysical exploration. As indicated by the research results， （1） two zones characterized by high-magnetic and high-gravity anomalies associated with concealed ultramafic rocks were preliminarily identified in the Hegenshan ophiolite belt in central Inner Mongolia. A set of fairy circles and occurrences of natural hydrogen trapped in inclusions were also discovered. Together with the associated soil hydrogen seepage anomalies， these findings enabled the delineation of favorable zones for natural hydrogen generation and enrichment. （2） In the Lajishan ophiolite belt in the southern Qilian region， two large ultramafic bodies were recognized， characterized by high magnetization， high gravity and high electrical resistivity. The exposed peridotites show intense serpentinization with high Fe2+ and Fe3+ contents， as well as high Fe3+/Fe2+ ratios， indicating significant hydrogen generation through serpentinization and the presence of potential hydrogen sources. Several high-concentration soil hydrogen anomalies were detected， with a maximum value of 1 000 × 10-6， demonstrating promising exploration potential. （3） The preliminary survey results confirmed the existence of active natural hydrogen sources in the study areas， while revealing the key factors controlling the generation and enrichment of serpentinization-type natural hydrogen. These factors include the coupled effects of ultramafic rocks and an adequate water supply； the scale of ultramafic bodies and their coverage by sedimentary sequences， which serve to determine whether large-scale accumulation can occur； the residence time of hydrogen generation and trapping， which determines hydrogen retention time； and the persistent vs. transient accumulation behavior of hydrogen. （4） The findings also suggest favorable exploration targets： iron-rich rocks in the basement of early sedimentary basins and late-stage ultramafic intrusions rocks within sedimentary basins. The integrated exploration and development of natural hydrogen and geothermal resources have broad prospects. Geological surveys and research on natural hydrogen in China is still in its early stage， with both considerable potential and significant challenges. The progress and insights presented above are expected to help reduce the risks associated with natural hydrogen exploration and facilitate an early breakthrough in natural hydrogen resource discovery.关键词：geological survey;favorable zone;serpentinization;ultramafic rock;ophiolite belt;natural hydrogen2|0|0更新时间：2026-08-21
- 摘要：The source rocks of the Permian Fengcheng Formation in the Junggar Basin possess considerable hydrocarbon exploration potential. However， the hydrocarbon sources and main factors controlling hydrocarbon enrichment in volcanic rock reservoirs along the northwestern margin of the basin have long remained unclear， resulting in a low success rate of sweet-spot drilling and limited reserve expansion， thereby constraining further exploration in the region. This study investigated the dynamic mechanisms of hydrocarbon accumulation and conducted quantitative evaluation of the volcanic rock reservoirs in the Jinlong 2 well block on the northwestern margin of the Junggar Basin， with the aim of precisely addressing key exploration challenges and identifying favorable exploration targets and their productivity potential. The investigation was based on the dynamic field-controlled accumulation theory of the whole petroleum system and incorporated 47 sets of geochemical data from the study area and well-test data from multiple high-yield wells. As indicated by the research results， （1） the critical thresholds defining the lower limit of buoyancy-driven hydrocarbon accumulation for local volcanic rocks stand at porosity of 9% and permeability of 1 × 10⁻³ μm². These two core parameters enable reliable classification of two major hydrocarbon accumulation domains—the free dynamic field and the confined dynamic field. （2） Quantitative characterization of four functional elements for primary accumulation （i.e.， source， facies， potential energy， and cap rock） confirms buoyancy as the dominant migration force within the free dynamic field， and a hydrocarbon-rich accumulation model was constructed based on the spatiotemporal configuration of these functional elements. （3） The dynamic field threshold of the facies-potential-source index （FPSI） served as a benchmark to quantitatively map hydrocarbon-rich sweet spots and precisely delineate potential exploration zones in the study area. （4） A quantitative dynamic-field model delivered calibrated productivity estimates for proposed drilling prospects. One new wildcat well location was prioritized and re-evaluation schemes covering eight prospective intervals across five existing wells were formulated. These findings clarify the hydrocarbon accumulation patterns and enrichment mechanisms of volcanic rock reservoirs in the study area. Its theoretical framework lays a solid foundation for refined exploration， efficient development， and reserve upgrading of volcanic hydrocarbon resources in the study area.关键词：whole petroleum system;sweet-spot prediction and evaluation;dynamic field-controlled accumulation;volcanic rock;Junggar Basin5|2|0更新时间：2026-08-19
- 摘要：The Ledong 8-1 diapir in the Yinggehai Basin is a multi-phase collapsed diapir controlled by strike-slip faulting， which is closely related to hydrocarbon accumulation. Newly acquired ocean bottom node （OBN） seismic data in the Ledong 8-1 diapir zone have resolved long-standing imaging challenges in the diapir core， where previous datasets often yielded poor or no resolution. Based on the interpretation results of the OBN seismic data， the fault deformation characteristics and activity in the Ledong 8-1 diapir zone were systematically analyzed， and the fault formation mechanism was discussed in combination with regional tectonic stress regimes and the causes of diapir collapse. As indicated by the research results， （1） seven types of faults are identified in the Ledong 8-1 diapir zone， exhibiting a distinctive pattern of “plan-view classification， vertical stratification， and multi-phase evolution.” Sub-vertical ridge-like strike-slip faults are developed in the deep section of the diapir zone， whereas master strike-slip faults and their derived R-shears， R'-shears， P-shears， and T-shears， as well as ring faults formed under collapse effects， are developed in the shallow section. （2） Intense fault activity primarily occurred during three major phases： the late Middle Miocene to early Late Miocene （early stage）， the middle Pleistocene to early Holocene （middle stage）， and the late Holocene （late stage）. Kinematic indicators show that the early-stage faults are sinistral strike-slip， while the middle- and late-stage faults are dextral strike-slip. （3） Faults in the Ledong 8-1 diapir zone are controlled by the regional stress field generated by the activity of the No. 1 Fault at the basin margin. During the early phase， the diapir zone was controlled by the sinistral strike-slip of the No. 1 Fault， developing NNE-trending sinistral strike-slip faults and forming structural ridges， whereas at the middle and late stages， the continuous dextral strike-slip of the No. 1 Fault led to the development of extensional fracturing and deep-seated fault reactivation.关键词：collapsed type;formation mechanism;strike-slip fault;Ledong 8-1 diapir;Yinggehai Basin8|0|0更新时间：2026-08-13
- 摘要：The conventional “Golden Zone” theory restricts the stable preservation of liquid hydrocarbons to shallow-to-moderate burial depths and a limited temperature range. However， major discoveries of ultra-deep ancient carbonate oil reservoirs in recent years have challenged this classical understanding. The preservation mechanisms over ultralong timescales have become a critical scientific issue constraining the evaluation of deep petroleum exploration potential. The intrinsic controls on the ultralong-term preservation of ancient oil reservoirs in the northern Tarim Basin were revealed by systematically analyzing their petroleum geological characteristics， hydrocarbon accumulation stages， and post-accumulation alteration mechanisms. As indicated by the research results， （1） the favorable configuration of static geological elements provides the material foundation for preservation. High-quality source rocks of the Lower Cambrian Yuertusi Formation supplied a sustained oil charge； multi-stage karstification coupled with faulting created large-scale fracture-cavity reservoirs； and extremely thick Upper Ordovician mudstones formed a multi-level regional sealing system with high breakthrough pressure. The perfect spatiotemporal matching of these three elements laid the inherent foundation for the formation of giant oil reservoirs. （2） The coupling of a “cold basin” thermal regime with “late-stage rapid deep burial” is the dynamic key to preservation. The basin in this area has maintained a low geothermal gradient over a long geological period and is characterized by a burial history of sustained shallow burial in the early stage followed by rapid deep burial in the late stage. Although the reservoirs were ultimately buried to a depth of more than 7 000 m after the main accumulation period at approximately 250 Ma， they were exposed to high-temperature conditions （>160 ℃） for an extremely short duration （< 5 Ma）， resulting in a markedly insufficient time-temperature compensation effect and fundamentally suppressing the thermal cracking of crude oil. In addition， the coupled effect of high-pressure and overpressure conditions further reduced the risk of crude oil cracking. （3） Weak post-accumulation secondary alteration is the key guarantee for maintaining the liquid hydrocarbon phase state and geochemical stability of the reservoirs. The reservoirs experienced only weak late-stage alteration， including thermochemical sulfate reduction （TSR）， biodegradation， and gas washing. As a result， the geochemical properties of the crude oil remained stable， showing the typical characteristics of “early accumulation and late-stage deep-burial preservation.” In summary， this study establishes a preservation model for ultra-deep ancient oil reservoirs over ultralong timescales and reveals the core mechanism of time-temperature-pressure coupled inhibition. These findings break through the limitations of the traditional “Golden Zone” theory and provide new theoretical guidance for evaluating the exploration potential of ultra-deep liquid hydrocarbons in ancient cratonic basins and selecting favorable zones.关键词：time-temperature compensation effect;reservoir preservation mechanism;ancient carbonate oil reservoir;ultra-deep reservoir;Tarim Basin15|10|0更新时间：2026-07-29
- 摘要：Significant breakthroughs have recently been achieved in deep coal-rock gas exploration in the Ordos Basin， opening up a new frontier for unconventional gas development. However， considerable discrepancies still exist regarding the enrichment mechanisms and favorable exploration targets of deep coal-rock gas， indicating that further research is needed. This study focuses on the No. 8 coal seam of the Benxi Formation， Upper Paleozoic， in the central-eastern Ordos Basin. Geological analysis， statistical analysis， and hydrocarbon dynamic field theory were comprehensively employed to investigate the enrichment conditions and favorable area distributions of deep coal-rock gas. As indicated by the research results， during the critical thermal evolution stage with vitrinite reflectance （Ro） ranging from approximately 1.5% to 2.5%， the hydrocarbon generation， reservoir development， migration， and preservation conditions of coal-rock gas exhibit significant spatiotemporal coupling characteristics， which exert a dominant control on the formation and distribution of gas-rich sweet spots. Specifically， these characteristics are reflected in the following four aspects： （1） coal rocks at this stage are characterized by high gas generation rates and strong hydrocarbon generation intensity， thereby providing a substantial material basis for gas enrichment； （2） coal rocks exhibit abnormally high porosity， with a secondary peak occurring at Ro ≈ 2.0%， while the pore volumes of both micropores and macropores increase synchronously， providing favorable reservoir space for coal-rock gas accumulation； （3） the cleat system of coal rocks is highly developed， and cleat density reaches its maximum at Ro ≈ 1.9%， forming efficient migration pathways for coal-rock gas accumulation； （4） the surrounding strata adjacent to coal seams are characterized by confined dynamic fields， thereby creating favorable preservation conditions for gas-rich sweet spots. On this basis， a comprehensive evaluation model for favorable deep coal-rock gas areas was established based on the quantitative characterization of the four key elements of “generation， reservoir， migration， and preservation.” A multi-parameter superposition method was further adopted to predict and grade favorable areas within the study area. The prediction results divided the study area into Class Ⅰ， Class Ⅱ， and Class Ⅲ favorable areas. Drilling results indicate that high-gas-content wells （gas content ≥ 18 m³/t） account for 90% of wells in Class Ⅰ favorable areas， with an average gas content of 24.04 m³/t. The prediction results are highly consistent with actual exploration performance. The research results provide a reliable theoretical basis and technical support for play fairway delineation and further exploration deployment of deep coal-rock gas in the Ordos Basin， and are of great significance for improving resource development efficiency and safeguarding national energy security.关键词：pore structure;whole petroleum system;favorable area prediction;oil and gas enrichment;coal-rock gas;Ordos Basin21|16|0更新时间：2026-07-17
- 摘要：The Ordovician sub-salt mound-shoal dolomite reservoirs in the central-eastern Ordos Basin are important targets for natural gas exploration. However， systematic research on such reservoirs is limited， and unclear understanding of their development characteristics and distribution patterns have constrained exploration progress. To address these issues， a systematic investigation was conducted based on integrated core， thin-section， well log， petrophysical， and geochemical data. As indicated by the research results， （1） the reservoir lithology is mainly of the algal-laminated dolomite， intraclastic grainstone （very fine-crystalline） dolomite， oolitic dolomite， and recrystallized granular dolomite types. The reservoir spaces include dissolution vugs， intercrystalline （dissolution） pores， intergranular （dissolution） pores， intragranular dissolution pores， and microfractures， with an average porosity of 5.79%. （2） The development of mound-shoal dolomite reservoirs is jointly controlled by sedimentary microfacies， dissolution， and bioturbation. Microbial mounds and grain-shoal deposits serve as the material basis for reservoir development. Dissolution acts as the key process responsible for the formation of dissolution vugs， and burrows formed by bioturbation further improve their physical properties. （3） The reservoir distribution exhibits distinct stratigraphic and geographic controls. Vertically， the reservoirs are layered within the middle-to-upper part of high-frequency shallowing-upward cycles in transgressive hemicycles of third-order sequences， exhibiting a layered distribution. Laterally， they are predominantly distributed in paleohigh crests， paleohigh flanks， and on depression margins. The conclusion is that the Shenmu-Wuqi area is characterized by relatively high paleotopography and strong hydrodynamic conditions during deposition of the 2nd and 4th member， as well as the 9th and 7th sub-members of the 5th member of the Ordovician Majiagou Formation. Microbial mounds and grain shoals are distributed in belts and prone to penecontemporaneous dissolution， providing favorable geological conditions for the large-scale development of multi-layer mound-shoal dolomite reservoirs. Therefore， this area represents a favorable zone for reservoir development.关键词：dissolution;bioturbation;sedimentary microfacies;mound-shoal dolomite reservoir;Ordovician;Ordos Basin10|24|0更新时间：2026-07-17
- 摘要：Coal-rock gas in the Ordos Basin represents an abundant， strategically vital resource for enhancing China’s natural gas supply capacity. However， these deep coal reservoirs exhibit extremely low permeability under in-situ conditions. Although current commercial production breakthroughs primarily rely on large-scale propped hydraulic fracturing， this method is constrained by high operational costs and marginal economic returns. Focusing on the No. 8 coal seam of the Benxi Formation in the eastern Ordos Basin， this study integrates reservoir characterization， rock mechanical testing， water-coal interaction experiments， and post-fracturing conductivity evaluations with field practices for comprehensive analysis. As indicated by the research results， the coal reservoirs are characterized by highly developed natural cleats and pronounced plastic deformation. Under the mechanical boundary conditions of “rigid support” provided by the roof and floor strata， a unique configuration similar to a “stress compartment” is established. The injection of high-pressure fluids induces coupled tensile-shear failure and structural slip within the coal matrix， promoting matrix fragmentation and activation of natural cleats， which ultimately generates a complex fracture network. The resulting fragmented coal significantly expands the available seepage space under in-situ conditions， allowing the unpropped fractures to maintain high conductivity even after fracturing fluid flowback. Based on these insights， the concept of “fracture-network activation and proppant-free stimulation” for coal-rock gas development was proposed， marking a technological paradigm shift from “controlled proppant transport with fluid rate stabilization” to “maximum proppant concentration，” and ultimately to “proppant-free fracturing.” Field pilot tests demonstrate that， under conditions of no proppant and similar fluid volumes， the single-well production is on par with that of conventional fracturing， indicating that fluid volume is a primary factor controlling well productivity. Specifically， a horizontal well with a 1 500 m lateral and subjected to proppant-free fracturing with 24 500 m³ of fluid， achieved a stable daily gas production exceeding 40 × 103 m³. This study concludes that proppant-free fracturing technology successfully capitalizes on the unique geological-engineering attributes of coal-rock reservoirs. While ensuring stable production， it offers substantial cost reduction and environmental advantages， holding profound implications for the commercial， large-scale development of deep coal-rock gas.关键词：field test;water-coal interaction;physical simulation;permeability enhancement mechanism;stress compartment;fracture-network activation and proppant-free fracturing;coal-rock gas;Ordos Basin30|21|0更新时间：2026-06-16
- 摘要：To overcome the high subjectivity of manual identification in traditional sandstone petrographic analysis and the limitations of conventional image analysis methods， which typically focus on isolated tasks and lack systematic quantitative characterization capabilities， this study proposes an integrated intelligent analysis scheme for thin-section images that covers both workflows and techniques. A sandstone petrographic analysis framework encompassing three major domains （i.e.， composition， texture， and porosity） was established. This framework defines a standardized analytical pathway from raw thin-section images to geological parameters. The deep learning and image processing technologies were integrated into this scheme. Specifically， the Mask R-CNN model was employed for the precise segmentation of detrital grains， and the MobileNet model was utilized for compositional classification； meanwhile， tailored image processing algorithms were integrated to systematically extract three categories of parameters： composition， texture （including grain size， sorting， roundness， and grain contacts）， and porosity （areal porosity and pore diameter）. Validation using sandstone samples from multiple basins was performed. As indicated by the research results， （1） the results of the integrated analysis were highly consistent with those of manual identification regarding key parameters， while demonstrating superior objectivity and precision in geologically complex scenarios such as quartz overgrowths； （2） the constructed sandstone analysis framework systematically generated “petrographic datasets”， successfully achieving a paradigm shift from qualitative description to quantitative analysis.关键词：image processing;Mask R-CNN;MobileNet;deep learning;sandstone petrography;intelligent quantitative analysis22|7|0更新时间：2026-06-02
- 摘要：The Kebai fault zone is a critical area for the Late Paleozoic tecto-stratigraphic evolution and hydrocarbon exploration along the northwestern margin of the Junggar Basin. The stratigraphic assignment of the Carboniferous volcanic rocks in the fault zone has long been a controversial issue. The volcanic rock sequence encountered in well Baiwu 21 within the Kebai fault zone， previously assigned to the Early Permian Jiamuhe Formation， was selected as the research object. Integrated lithologicalassociation analysis， LA-ICP-MS zircon U-Pb dating， and seismic profile interpretation were conducted on this sequence to redefine its stratigraphic assignment. As indicated by the research results， （1） the volcaniclastic zircon U-Pb ages obtained from two tuffaceous sandy conglomerate samples of the volcanic rock sequence in well Baiwu 21 are （311.9 ± 2.2） Ma and （311.6 ± 2.2） Ma， respectively， indicating a formation age of the late stage of Late Carboniferous and reassigning the sequence to the Chengjisihanshan Formation （C2c）. （2） The rock suite is dominated by amygdaloidal andesite and basaltic andesite， exhibiting subalkaline， sodium-rich， and potassium-poor geochemical characteristics that are regionally consistent with those of the C2c， but markedly distinct from those of the Jiamuhe Formation （P1 jm）. （3） Seismic profile interpretation confirms that this stratigraphic unit has an angular unconformity contact with the underlying Lower Carboniferous Baogutu Formation （C1b）， mirroring the basal structural boundaries of the regional C2c rather than the sequence stacking pattern of P1 jm. Consequently， these multiple lines of evidence justify the redefinition of this volcanic rock sequence as part of the Chengjisihanshan Formation. This new insight resolves the long-standing controversy over stratigraphic division in the area， refines the Late Paleozoic stratigraphic framework along the northwestern margin of the Junggar Basin， and provides fresh chronological constraints on the closure timing and tectonic evolution of the western Paleo-Asian Ocean. Furthermore， it opens up new strata and horizons for deep Carboniferous hydrocarbon exploration in the northwestern margin of the Junggar Basin.关键词：LA-ICP-MS zircon U-Pb dating;geochronology;stratigraphic redefinition;Chengjisihanshan Formation;Kebai fault zone;northwestern margin of the Junggar Basin18|4|0更新时间：2026-06-02
- 摘要：To achieve the dual goals of efficient shale gas development and geological CO2 sequestration， supercritical CO2 （Sc-CO2） displacement technology shows promising application potential. However， the microscopic mechanisms by which Sc-CO2 displaces CH4 in shale porous media remain insufficiently understood. In particular， the mass-transfer mechanisms at the pore scale are yet to be clarified. Based on the nanopore-matrix structure of shale， a two-dimensional pore-scale model was constructed in this study. The microscopic process and controlling factors of shale gas displacement by Sc-CO2 at 40 ℃ and 8 MPa were， thereby， systematically investigated under convection-diffusion-adsorption effects. As indicated by the research results， （1） in the pore space， Sc-CO2 forms a propagating concentration front through convection-diffusion， enabling efficient displacement of free CH4. In the matrix space， Sc-CO2 gradually replaces adsorbed CH4 owing to its stronger adsorption affinity. Its adsorption amount shows a three-stage evolution of zero adsorption， increase， and saturation， whereas the adsorbed CH4 amount undergoes a corresponding process of saturation maintenance， desorption， and depletion. （2） With increasing diffusion coefficient （Ds）， Sc-CO2 adsorption in the matrix is enhanced， but its convection-diffusion in the pores is weakened. This leads to a decrease in the Sc-CO2 concentration and an increase in the CH4 concentration in the pores. （3） As transport selectivity （sel） increases， Sc-CO2 adsorption in the matrix is enhanced， whereas pore-scale convection-diffusion is suppressed. As a resut， the Sc-CO2 concentration decreases and the equilibration time is prolonged， while the migration behavior of CH4 is less affected by sel. （4） An increase in the desorption rate constant （kd） significantly promotes CH4 desorption and increases its pore concentration. In contrast， Sc-CO2 is insensitive to changes in kd because of its strong adsorption， and both its adsorption amount and concentration remain stable.关键词：convection-diffusion-adsorption;mass transfer;pore-scale simulation;nanoscale;supercritical carbon dioxide （Sc-CO2）;shale gas14|4|0更新时间：2026-06-02
- 摘要：With the extensive development of shallow unconsolidated sandstone heavy oil resources， conventional sealed coring methods have struggled to address the issue of getting intact cores from unconsolidated sandstone reservoirs. Consequently， improvements in coring techniques have been made， resulting in the development and application of sealed cryogenic pressure-maintaining coring technology. However， field practice has shown that cryogenic coring may introduce deviations in the determination of reservoir oil saturation and petrophysical parameters. In this study， comparative experiments on artificial cores were systematically conducted at different freezing temperatures， and correspondingly the variation patterns of core oil saturation and petrophysical parameters， together with the impact mechanism， were analyzed in depth. The experimental results show that oil saturation exhibits significant nonlinear variation with freezing temperature： it generally decreases between -10 and -20 °C， slightly increases again at -40 °C， and rises markedly under cryogenic conditions at -60°C. Porosity， by contrast， shows an overall decreasing trend under low-temperature conditions. Based on the experimental observation and mechanism analysis， this study delves into the coupled influence of multiple factors， including phase transitions of crude oil components， ice-crystal plugging， microfracture development， and rock-fluid interactions， on oil saturation and porosity. A temperature-interval-based linear correction model for oil saturation was established using the experimental data. This model can， to a certain extent， correct measurement deviations introduced by freezing treatment， and provides experimental evidence and reference for restoring the original fluid occurrence state of cores and improving the accuracy of reserve evaluation for shallow unconsolidated sandstone reservoirs.关键词：cryogenic coring;unconsolidated sandstone;oil saturation;porosity;correction model11|5|0更新时间：2026-06-02
- 摘要：To elucidate the heterogeneity and its origins in deep to ultra-deep clastic reservoirs， typical reservoirs of the 2nd member of the Xujiahe Formation （Xu 2 Member） in the western Sichuan Basin were selected as a case study. Integrated petrophysical testing， petrographic analyses， and diagenetic-fracture characterization were employed to systematically investigate the reservoir characteristics， heterogeneity patterns， and genetic features of Xu 2 Member in the western Sichuan Depression. As indicated by the research results， （1） the deep to ultra-deep reservoirs of Xu 2 Member exhibit an average porosity of 3.5% and an average permeability of 0.077 × 10⁻³ µm²， representing typical tight reservoirs. Diagenetic processes are complex and characterized by intense compaction， strong cementation， and weak dissolution. Multi-scale fractures are widely developed， with multi-stage fracturing and mineral infilling， resulting in extremely strong reservoir heterogeneity. （2） Reservoir heterogeneity is primarily manifested in physical-property variations. Sedimentary heterogeneity includes two aspects： material composition and sedimentary structure. Sedimentary architecture and lithofacies associations control the migration and precipitation of diagenetic materials at different scales， leading to significant variations in diagenetic type and intensity. The development of small-scale fractures is closely related to local stress magnitudes， sedimentary architecture interfaces， and lithofacies association types. （3） The variability of sedimentary environments and depositional processes， diagenetic environments and material migration， and stress regimes and fracture responses constitutes the key controlling factors underlying the origins of heterogeneity at different forms and scales in deep to ultra-deep reservoirs. （4） Detailed characterization of depositional processes， reconstruction of diagenetic evolution， and quantitative constraint of fracture responses are considered the main approaches for understanding the heterogeneity of deep to ultra-deep reservoirs.关键词：heterogeneity;origin;clastic reservoir;deep to ultra-deep reservoir;Xu 2 Member;Sichuan Basin13|11|0更新时间：2026-06-02
- 摘要：The Cenozoic continental rift basins are extensively developed in China. Under the influence of episodic extensional faulting， the constituent “source-conduit-sink” elements frequently undergo significant modification or reorganization， making deep-time Source-to-Sink （S2S） coupling a challenging issue in contemporary basin analysis. Recently， major exploration breakthroughs in the syn-rift successions of the southwestern Huizhou Sag， Pearl River Mouth Basin （PRMB）， have yielded a wealth of well， seismic， and analytical data， providing a robust foundation for addressing these complexities. By integrating prototype basin restoration with quantitative analysis of sediment provenance and catchment units， this study clarifies the differential evolution and response mechanisms of the S2S system of the Wenchang Formation， southwestern Huizhou Sag. The research results shows that denudation during the Early Wenchang Formation deposition was primarily concentrated on intra-basinal uplifts controlled by syn-sedimentary faults or basement upheaval， with a relatively restricted denudational extent and thicknesses ranging from 40 to 300 m， whereas the denudational area expanded significantly during the Late Wenchang period， reaching a maximum thickness of 500 m. Three major S2S systems were identified within and around the study area： the Southern （Huixi low uplift and Dongsha uplift）， Northern （northern uplift）， and Eastern （Huizhong uplift to the Huibei area） S2S systems. Specifically， the Southern system， controlled by pre-existing faults， exhibits well-defined watersheds and drainage divides and is subdivided into four first-order and eighteen second-order catchment units， with transport conduits dominated by structural transfer zones and fault-related valleys， exhibiting a width-to-depth ratio less than 10）； the Northern system’s drainage divides are jointly constrained by NE- and NW-trending faults， with 4 first-order catchment units identified for the early Wenchang period， which evolved into 5 during the late Wenchang period， and the transport pathways are characterized by lateral denudation， exhibiting a width-to-depth ratio greater than 20； the Eastern system lacks stable drainage divides， with sediment primarily sourced from fault-bounded steep slopes. The Huizhou Movement （ca. 43 Ma） caused a northwestward migration of the rifting center， accompanied by extensive basement uplift. This movement reshaped the paleogeomorphic framework from the early to late Wenchang periods， driving drainage divide retreat in the Southern system and reorganization in the Northern system， which profoundly impacted basin-filling patterns and reservoir sand-body distribution. This study elucidates the dynamic coupling of S2S systems and sand-body dispersal patterns driven by tectonic migration， providing insights for the analysis of similar complex rift basins.关键词：Source-to-Sink system;dynamic coupling;controlling factors;tectonic-sedimentary evolution;rift basin;Wenchang Formation;Pearl River Mouth Basin15|3|0更新时间：2026-06-02
- 摘要：Exploration breakthroughs have been achieved across multiple sags and stratigraphic intervals in the Paleogene of the Jiyang Depression， Bohai Bay Basin， with cumulative shale oil production exceeding 1.0 × 106 t. This area has become a viable replacement play for increasing reserves and production at Shengli oilfield. Based on geochemical analyses and production data from shale oil wells in the lower sub-member of the third member and the upper sub-member of the fourth member of the Paleogene Shahejie Formation （Es3L-Es4U）， this study systematically examines production behavior， geological control factors on enrichment and high productivity， and distribution patterns using statistical analysis， laboratory tests and typical case studies. As indicated by the research results， shale oil production in the Jiyang Depression is characterized by early oil discovery， high initial productivity， and a three-stage decline trend throughout the full lifecycle production. Shale oil enrichment and high productivity are jointly controlled by oil-bearing properties， reservoir quality， sealing capacity， and oil mobility. Favorable oil-bearing content and reservoir quality constitute the fundamental basis for oil enrichment and high productivity. In particular， carbonate-rich lithofacies with free hydrocarbon content （S1） greater than 2 mg/g and well-developed pore-fracture networks are more conducive to enrichment and high productivity. Effective sealing conditions provide a critical guarantee for shale oil preservation and productivity. Seal rocks of laminated shale facies enclosed by layered or massive lithofacies of poor physical properties， not only facilitate hydrocarbon retention but also promote the development of abnormally high pressure， thereby enhancing oil output. Favorable mobility conditions are the key to achieving high productivity. Well-connected pore-fracture networks in laminated carbonate-rich shales provide efficient seepage channels. Elevated formation temperatures and preferential water-wet conditions enhance imbibition-driven displacement， improving oil mobility and sustaining production. Abnormally high pressure further supplies the driving force for elastic oil production. Shale oil in the Jiyang Depression exhibits a facies-controlled， laterally contiguous distribution， with differential enrichment governed by fault systems. These findings provide a scientific basis for integrated deployment and efficient exploration， contributing to strategic breakthroughs and the development of national-level Jiyang Shale Oil Demonstration Zone.关键词：reservoir capability;oil-bearing property;mobility;sealing capacity;distribution pattern;shale oil;Jiyang Depression;Bohai Bay Basin17|10|0更新时间：2026-06-02
- 摘要：Research on shale pore structure and its heterogeneity plays a pivotal role in the study of unconventional oil and gas reservoirs.Fractal dimension is a key parameter for characterizing the complexity of shale pore systems.However， existing fractal dimension calculation methods are typically computationally demanding and require substantial data.Moreover， the quantitative control law and mechanism of total organic carbon （TOC） content over the surface fractal dimension of highly evolved shale pores remain unclear.Shale samples were collected from wells Y201 and Y211 of the Silurian Longmaxi Formation in the Tiangongtang block in southern Sichuan Basin and Weiyuan County.TOC measurements， X-ray diffraction （XRD） mineral composition analysis， and nitrogen gas adsorption （N2-GA） experiments were conducted.On this basis， an empirical formula for calculating the fractal dimension （D1） based on TOC was established， yielding results with excellent equivalence to those obtained from the Frenkel-Halsey-Hill （FHH） model.Preliminary application results confirm that， compared with the D1 values calculated from measured data in the Changning area using the FHH model， the TOC-based D1 values have an average error of ± 0.012， an error range of no more than ± 2%， and a relative error within ± 2%.Compared with published fractal dimension data for the Wufeng Formation-Longmaxi Formation shale from parts of southern Sichuan Basin and the Jingmen exploration area in Hubei Province， the error narrowed to ± 0.027， with an error range of no more than ± 5% and a relative error within ± 10%.The TOC-based D1 can effectively characterize the roughness of pore surfaces in marine， highly evolved shale samples and has broad geological applicability.It can accurately characterize the pore structures of shales from highly mature shale formations and provide important theoretical and technical support for shale gas reservoir evaluation.关键词：gas adsorption;pore structure;fractal dimension;marine shale;Longmaxi Formation;Sichuan Basin11|6|0更新时间：2026-06-02
- 摘要：The Liangjiashan Formation is widely developed in the Ordovician on the North China Platform， and its type section is located in the Liangjiashan area of Shimenzhai， Qinhuangdao， Hebei Province. Previous studies suggested that the Liangjiashan Formation mainly consists of argillaceous banded limestone， bioclastic limestone， and leopard-spotted limestone. It is characterized by abundant stromatolites and archaeocyathids， together with abundant biogenic dolomites. Recent studies indicate that substantial microbial carbonates are developed in the lower part of the Liangjiashan Formation， forming a microbial reef complex. To reveal the characteristics of the microbial reef in the Lower Ordovician Liangjiashan Formation in the Liangjiashan area of Shimenzhai， Qinhuangdao， a combination of fine outcrop description with microscopic identification of systematically collected samples was applied to characterize the microbial types， lithology， sedimentary structures， and vertical succession of the Shihuiyao section in the Liangjiashan area. As indicated by the research results， the microbial carbonates are rich in calcified cyanobacteria fossils， commonly including filamentous cyanobacteria， and net-like cyanobacteria and girvanella. Based on the mesoscopic characteristics of the carbonate bodies in the study area， four microbialite types were identified， namely thrombolite， stromatolite， leiolite， and laminite. Six types of microbial carbonate bodies were also recognized， namely bedded， wedge-shaped， mound-shaped， lenticular， mushroom-shaped， and columnar bodies. These rock bodies form rigid biogenic reef-building frameworks， building reef cores capable of resisting erosion caused by intense waves， tides， and storms， while also exerting binding and baffling effects， thereby forming the reef framework subfacies. This reef framework subfacies， together with the tempestite subfacies and storm-tidal delta subfacies， constitutes the microbial reef complex.关键词：cyanobacteria;stromatolite;storm deposit;microbial carbonate;microbial reef complex;Liangjiashan Formation;Shimenzhai area;Liujiang Basin8|4|0更新时间：2026-06-02
- 摘要：Commercial breakthroughs were achieved in both organic-rich shale and organic-poor silty shale gas reservoirs within the Lower Cambrian Qiongzhusi Formation of the Sichuan Basin. However， the pronounced differences in petrophysical properties between these two shale types and their underlying diagenetic controls remain poorly understood， thereby impeding reservoir-specific exploration strategies and targeted development. By integrating total organic carbon （TOC） analysis， X-ray diffraction （XRD）， and high-pressure mercury intrusion （HPMI） for geochemical and mineralogical characterization， low-temperature N₂ adsorption （LTNA）， low-pressure CO₂ adsorption （LPCA）， and spontaneous imbibition for pore structure assessment， and large-area imaging in scanning electron microscopy （MAPS-SEM）， energy-dispersive spectroscopy （EDS）， and quantitative evaluation of minerals by scanning electron microscopy （QEMSCAN） for microstructural imaging， we characterized the organic geochemical， mineralogical， petrophysical and microscopic pore structure characteristics of layer ⑤ organic-rich shale and layer ⑥ organic-poor silty shale of the Qiongzhusi Formation in the central Sichuan Basin. Meanwhile， the intensities of compaction， dissolution， and cementation were quantitatively assessed. The research results are as follows. （1） The two shale types exhibited similar mineral compositions； however， the organic-rich shale of layer ⑤ was superior to the organic-poor silty shale of layer ⑥ in terms of TOC content （avg. 2.03%）， porosity （avg. 3.80%）， and pore connectivity. Although the latter had relatively well-developed macropores， its total pore volume and specific surface area were lower. （2） The initial porosity of the organic-poor silty shale of layer ⑥ （avg. 65.40%） was slightly higher than that of the organic-rich shale of layer ⑤ （63.70%）； however， owing to its poorly sorted mineral grains and consequently lower compaction resistance， its porosity loss due to compaction （avg. 40.32%） was significantly higher than that of the organic-rich shale of layer ⑤ （avg. 33.06%）. （3） The high TOC content in the organic-rich shale of layer ⑤ promoted stronger acid-driven dissolution. The porosity increments derived from feldspar and carbonate mineral dissolution （avg. 0.43%） and from organic matter thermal evolution （avg. 0.12%） were both greater than that in the organic-poor silty shale of layer ⑥ （avg. 0.28% and 0.06%， respectively）. On the other hand， the abundant ions derived from intense dissolution in the sublayer also exacerbated cementation， resulting in a higher porosity loss due to cementation （avg. 19.76%） compared to the organic-poor silty shale of layer ⑥ （avg. 16.72%）. Taken together， these findings indicate that differences in compaction resistance arising from contrasting mineral grain sorting represent the primary control on the divergence in petrophysical properties between the two reservoir types. Furthermore， differences in the coupled intensity of dissolution-cementation， driven by TOC contrasts between the two shale types， further enhanced the discrepancy in reservoir quality.关键词：petrophysical properties;diagenesis;organic-poor silty shale;organic-rich shale;Qiongzhusi Formation;Sichuan Basin13|5|0更新时间：2026-06-02
- 摘要：Although marine sequences in the southern Sichuan are generally gas-bearing， hydrocarbon exploration discoveries remain disproportionate to the region’s resource potential compared with other zones in the basin. The key constraints are the poorly understood primary controlling factors governing reservoir formation and the unclear distribution patterns of large-scale reservoirs. Based on the latest exploration progress and integrating extensive field outcrop analyses， core testing data， and seismic interpretation， this study systematically evaluated the reservoir formation models and exploration potential of key marine sequences in the southern Sichuan Basin from the perspective of tectono-sedimentary differentiation. As indicated by the research results， although the southern Sichuan Basin shared the same evolutionary stages and cycles as the entire Sichuan Basin， it was relatively weakly affected by marginal tectonic stresses of the basin owing to its distal position relative to the Longmenshan tectonic belt and the Dabashan-Micangshan tectonic belt. Consequently， its sedimentary infill and evolution were governed by a dynamic regime of weak extension and weak compression. The differentiation features of the region are summarized as follows： rift-controlled differentiation during the Sinian （Ediacaran）-Early Cambrian， uplift-depression differentiation during the Middle-Late Cambrian to Silurian， reactivation-induced differentiation during the Early-Middle Permian， and paleogeomorphic differentiation during the Late Permian-Middle Triassic； since the Late Triassic， the region has been dominated by tectonic overprinting. Governed by this weak-differentiation dynamic background， three reservoir formation models were identified. First， the “dual-facies and pressure-field” relay reservoir formation model involves three key elements： sedimentary facies， diagenetic facies， and pressure field. In terms of reservoir-space architecture and evolution， sedimentary facies create the environment conducive to enrichment of dissolution-prone minerals， and sufficient mineral transformation provides the basis for porosity enhancement； diagenetic facies furnishes conditions favorable for diagenetic porosity modification， which in combination with widespread penecontemporaneous dissolution improve reservoir space； the pressure field sustains reservoir effectiveness with a stable overpressure system ensuring long-term capacity. The “facies-dissolution-fault” composite reservoir formation model includes three essential elements： favorable facies belts， dissolution-driven porosity enhancement， and interlayer faults. Favorable facies belts provide the fundamental framework that controls accumulation units at the macroscopic scale； dissolution-driven porosity enhancement is the key shaping reservoir architecture at the regional scale； interlayer faults spatially govern hydrocarbon enrichment， with platform margins or platform slope-break zones being optimal locations. While the “depositional-diagenetic” dual-phase superimposed reservoir formation model consists of sedimentary facies and diagenetic facies. Original high-energy facies belts underpin the development of large-scale high-quality reservoirs； tectonic uplifting-induced zoned karstification during the penecontemporaneous stage， is critical for the quality grading and spatial localization of large-scale， high-quality reservoirs； the superposition of early favorable sedimentary facies belts and penecontemporaneous diagenetic facies belts formed a dual-phase superimposed zone that ultimately controls the distribution of large-scale， high-quality reservoirs. Under the combined control of the four types of sedimentary differentiation and the three reservoir formation models， four types of hydrocarbon reservoirs were identified in the study area： near-source shoal-facies， laterally juxtaposed dolomite， facies-dissolution-fault composite， and marlstone oil and gas reservoirs. These reservoir types are systematically distributed across multiple stratigraphic horizons， defining a vertically stacked， multi-target exploration framework for the marine successions in the southern Sichuan Basin. In addition， the principal stratigraphic intervals associated with each reservoir formation and accumulation type were analyzed， and favorable exploration zones were identified.关键词：genetic mechanism;reservoir type;sedimentary differentiation;reservoir formation model;marine strata;southern Sichuan Basin12|8|0更新时间：2026-06-02
- 摘要：Natural hydrogen， characterized by its zero-carbon emission， low price， and sustainable supply， has emerged as a pivotal frontier in the development of hydrogen energy. Its enrichment process is fundamental to the formation and efficient utilization of natural hydrogen reservoirs. Based on a systematic review of relevant studies from both domestic and international sources， this study investigated the types of material foundations for natural hydrogen generation （hydrogen source rocks） and their differences in hydrogen-generation capacity， the dissipation mechanisms （including diffusion， dissolution， and adsorption） of natural hydrogen， the methodological similarities and differences between natural hydrogen and conventional oil and gas resource assessment， and the value of numerical simulation in advancing natural hydrogen research. As indicated by the research results， the distribution of natural hydrogen varies significantly due to diverse geotectonic structures； specifically， deep-seated faults serve both as pathways for deep-sourced hydrogen upwelling and as primary constraints on the distribution of effective hydrogen source rocks. However， current genetic identification using hydrogen and helium isotopes remains challenged by uncertainties regarding the co-genetic nature of hydrogen and helium， as well as the ambiguous evolutionary pathways of hydrogen isotopes. Furthermore， natural hydrogen faces complex preservation conditions. Diffusion， aqueous dissolution， and adsorption were identified as the primary drivers of hydrogen loss， which represent the most critical factors affecting the accuracy of resource assessment. In terms of resource evaluation， adapting conventional oil and gas assessment methods to natural hydrogen resources poses three major challenges， that is， differing evaluation logic， distinct evaluation criteria， and fundamental disparities in core parameters and quantification methods. Therefore， numerical simulation represents a key approach for quantifying natural hydrogen resource volumes and， following further development， can be more widely applied to studies of the migration and enrichment mechanisms of natural hydrogen.关键词：numerical simulation;enrichment process;resource evaluation;hydrogen source rock;hydrogen generation;natural hydrogen15|11|0更新时间：2026-06-02
- 摘要：The Early Cambrian represents a critical period marked by the Rodinia supercontinent breakup and global marine transgressions. However， the sedimentary responses associated with the syn-rift to post-rift-depression transition along passive continental margins during this period， as well as their geological significance， remain poorly understood. In this study， we investigate the sedimentary facies model of the Maidiping-Qiongzhusi formations and its evolution within the Upper Yangtze region by fully utilizing data from 17 wells and 2 outcrop sections. The results indicate the presence of 5 sedimentary facies types in the study area， i.e.， tidal flat， deltaic， rift trough， neritic shelf， and turbidite facies， whose spatiotemporal evolution was governed by the rifting-to-depression tectonic sequence. During the rifting stage （i.e.， the deposition of the Maidiping Formation to the 6th sub-member of the Qiongzhusi Formation）， sedimentation was primarily confined within the Deyang-Anyue rift trough， characterized by the technically controlled basin architecture. During the depression stage （i.e.， the deposition of the 7th and 8th sub-members of the Qiongzhusi Formation）， sedimentation expanded laterally， transitioning into the widespread deposition of tidal flat and shelf facies， which is characterized by sea-level change-controlled sedimentary facies. On this basis， the origins of several critical paleooceanographic events are effectively constrained by sedimentological evidence. Specifically， the coupling relationship between phosphorites at the base of the Maidiping Formation and the Basal Cambrian Carbon Isotope Excursion （BACE） supports the integrated model involving volcanic/hydrothermal activity， nutrient salt inputs， increased productivity， and the formation of an anoxic environment. Furthermore， the high-frequency redox fluctuations recorded within the Qiongzhusi Formation provide direct evidence supporting the turbulent ocean hypothesis. Overall， this study provides an Early Paleozoic sedimentological example for the classical rifting-to-depression transition model while also supplementing sedimentological evidence for the dynamic changes in the oceanic redox interface during the Early Cambrian. Besides， the results of this study offer a critical geological basis for the prediction of ultra-deep shale gas sweet spots.关键词：sea-level change;sedimentary facies model;shale gas exploration;Early Cambrian;Upper Yangtze region24|16|0更新时间：2026-06-02
- Postal code：102206
- Tel：010-56607717，56608306
- Technical support is provided by Beijing Founder electronics co., LTD 京ICP备09064830号-19
京公网安备11010802024621 - It is recommended to read the content of this site in Chrome&IE9+. Please switch to extreme mode in browser 360.
- Cookies We use cookies to help provide and enhance our service and tailor content. By continuing, you agree to the use of cookies.
0