最新刊期
卷 47 ， 期 1 ， 2026
- 摘要：In the central Shunbei area of the Tarim Basin， low-order strike-slip faults situated between major faults are identified as the destination of hydrocarbon migration and enrichment， exhibiting favorable conditions for hydrocarbon accumulation. However， hydrocarbon exploration targeting these faults faces both geological and engineering challenges. Geologically， the developmental mechanisms of the low-order faults remain poorly understood， complicating their effective identification and fine characterization. Regarding engineering， well drilling and completion operations proves prolonged and costly. To address these challenges， we implement all-round exploration practice that integrates research and deployment， geology and geophysics， exploration and exploitation， geology and engineering， and technology and economy. These integrated practices have effectively enhanced the efficiency and benefits of exploration targeting low-order faults in the central Shunbei area. The geology-geophysics integration facilitates the establishment of an interpretation mode of low-order faults. This mode improves the integrity of the diffraction wave-based sampling of small faults using small-bin and wide-azimuth （WAZ） acquisition techniques. Furthermore， it enhances the energy and signal-to-noise ratios of signals from ultra-deep strata in deserts through high-fold coverage. Consequently， a breakthrough is achieved in the seismic identification of low-order faults， transforming them from previously undetectable to clearly identifiable. The exploration-exploitation integration allows three-dimensional analysis of drilled wells and iterative optimization of reservoir models. In combination with detailed characterization， a well trajectory design technique is developed. This technique is distinguished by its ability to control faults using a single well， select optimal anomalous targets in the central portions of fault planes horizontally， select optimal cave reservoirs vertically， and identify multiple barrier-shaped hydrocarbon reservoirs along fault zones. The exploration-exploitation integration provides robust support for efficient oilfield development with fewer wells， high single-well production， and direct transformation of exploratory wells to production wells through holistic planning. The geology-engineering integration enhances the accuracy of geostress prediction and drilling-related geological risks， while also enabling the optimization of integrated wellhead and casing programs. As a result， this integration facilitates the safe， precise， and quick landing of wells in the pay zones of the low-order faults. The technology-economy integration drives the optimization and cost reduction at source for the entire chain comprising seismic acquisition， well drilling， logging， and acid fracturing， thereby enhancing exploration quality and economic benefits. These exploration practices demonstrate that low-order fault zones represent significant targets in ultra-deep hydrocarbon exploration. Despite their relatively low activity intensities， low-order strike-slip fault zones exhibit dense fracture networks， which can induce extensive reservoir fracturing， conducive to hydrocarbon storage and migration. Beyond major fault zones， we quickly identify low-order faults with the potential for a reserve growth of up to 100 million tonnes. This facilitates breakthroughs made in new-type hydrocarbon exploration， expanding horizons for hydrocarbon exploration.关键词：ultra-deep reservoir;fault-controlled hydrocarbon reservoir;integrated exploration;low-order fault;Shunbei area;Tarim Basin365|72|0更新时间：2026-01-29
- 摘要：The ultra-deep， strike-slip fault-controlled condensate gas reservoirs in the Shunbei area of the Tarim Basin exhibit extremely strong heterogeneity， posing significant challenges to both the characterization precision for fractured-vuggy reservoirs and the advancement of exploration technologies. In this study， we investigate the characteristics of such reservoirs in the No. 4 strike-slip fault zone in the Shunbei area. The reservoir geological models are constructed for segments with pull-apart， compressive， translational， and oblique weak compression properties in the fault zone. Moreover， key exploration techniques are developed， focusing on three-dimensional quantitative characterization of fault-controlled fractured-vuggy reservoirs， along with optimal landing zone selection and trajectory design for high-yield wells. The results indicate that the ultra-deep， strike-slip fault-controlled reservoirs exhibit grid-like structures， corresponding to an integrated reservoir model with multiple grid-like structures. These reservoirs exhibit high hydrocarbon enrichment and production due to multiple factors： supply from the Cambrian source rocks， hydrocarbon transport along fault slopes， hydrocarbon enrichment governed by fault-controlled grid-like structures， multi-stage hydrocarbon charging， and dynamic hydrocarbon accumulation. The mechanisms underlying the differential hydrocarbon enrichment of the condensate gas reservoirs include early-stage oil charging， multi-episodic differential gas charging during the late stage， and weak secondary modifications. Two key exploration technologies are developed， that is， a three-dimensional quantitative characterization technology for fault-controlled fractured-vuggy reservoirs， which is centered on compressed sensing-based frequency expansion， phase-controlled wave impedance inversion， and three-dimensional analysis， and a spatial positioning technology for landing target zones based on three parameters： source rock-connecting major fault planes， strong beadlike wave troughs， and stress field direction. These technologies provide technical support for the landing zone selection and trajectory design of high-yield wells. The theoretical achievements and technology application in this study have enabled maximum productivity with a minimum number of wells in the No. 4 fault zone within the Shunbei area， providing a typical case for the exploration and exploitation of ultra-deep carbonate condensate gas reservoirs.关键词：key exploration technology;fault-controlled fractured-vuggy reservoir;condensate gas reservoir;ultra-deep reservoir in Shunbei area;Tarim Basin221|56|0更新时间：2026-01-29
- 摘要：In complex geological settings， seismic data often suffer from limited imaging accuracy and a strong multiplicity of possible interpretations， making it difficult to conduct effective hydrocarbon detection and fluid identification. By investigating the southern Keping area， Tarim Basin， we assess the applicability of the microbial oil survey technique （MOST） to complex piedmont zones， aiming to develop a novel， integrated multi-technique approach to hydrocarbon exploration. By analyzing the content and distribution of surface microorganisms， we predict the subsurface hydrocarbon enrichment zones and identify the fluid properties. A comprehensive assessment is conducted by combining microbial data with seismic data. The results indicate the presence of five stable microbial anomaly zones within the study area. The comprehensive assessment based on microbial and geochemical indicators reveals that the study area can be divided into three categories of play fairway， i.e.， classes Ⅰ， Ⅱ， and Ⅲ anomaly zones. Class Ⅰ anomaly zones， among others， are characterized by high microbial values （MVs）， optimal hydrocarbon preservation conditions， and favorable structural trap conditions. Class Ⅱ anomaly zones exhibit high MVs and favorable preservation conditions but moderate structural trap conditions. In contrast， microbial anomaly zones with poor structural trap conditions are classified as class Ⅲ. The distribution of the anomaly zones has been confirmed by subsequent drilling， exhibiting a high degree of consistency. The microbial geochemical technique has yielded encouraging application results in the complex piedmont zone. The MOST， which directly reflects the present-day hydrocarbon leakage activity based on the abundance of hydrocarbon-oxidizing bacteria （HOB）， is highly sensitive to dynamic hydrocarbon preservation conditions， making it suitable for the rapid delineation of play fairways. In contrast， the geochemical technique， i.e.， sorbed soil gas （SSG）， captures long-term hydrocarbon leakage by detecting historically adsorbed hydrocarbons. MOST and SSG thus complement each other， forming a dual-indicator model that considers both dynamic charging and historical preservation. This model allows for the assessment and classification of play fairways in cases where no reliable direct hydrocarbon indicators （DHIs） are available. Overall， a novel seismic-microbial-geochemical integrated model has been established for the southern Keping area， in which the tectonic framework is defined using seismic data， optimal exploration targets are primarily selected using MOST， and the evolution of hydrocarbon preservation conditions is validated using SSG. This integrated model can provide new ideas for hydrocarbon exploration in the complex piedmont zone.关键词：microbial oil survey technique （MOST）;hydrocarbon-oxidizing bacteria （HOB）;acid-extracted hydrocarbon;microbial anomaly;geochemisty;complex piedmont zone;southern Keping area;Tarim Basin274|42|0更新时间：2026-01-29
- 摘要：To support ongoing hydrocarbon exploration of the marine Mesozoic strata in the Qiangtang Basin， we conduct surveys and reassessments of the regional petroleum geology. Accordingly， several benchmark sections of the basin’s source rocks and reservoirs are established. The results indicate that the Qiangtang Basin contains three dominant source rock sequences （the Bolila， Bagong， and Quse formations）， two suites of carbonate reservoirs （the limestone karst of the Bolila Formation and the dolomites of the Buqu Formation）， three suites of sandstone reservoirs （the Bagong， Quemocuo， and Xiali formations） dominated by tight-sand reservoirs， and three suites of well-developed regional evaporite cap rocks （the Quemocuo/Quse and Xiali formations）. Analysis of oil and gas shows reveals that the marine Mesozoic strata in the Qiangtang Basin experienced the hydrocarbon generation， migration， and accumulation processes. In this basin， oil-generating strata， reservoirs， and cap rocks are well-matched both temporally and spatially， forming two petroleum systems： the Upper Triassic-Lower Jurassic pre-salt system and the Lower-Middle Jurassic intrasalt system. Three hydrocarbon plays are identified in the basin. The first play consists of the source rocks of the Bolila Formation， the karst reservoirs of the Bolila Formation， and the mudstone cap rocks of the lower Bagong Formation. The second one is composed of the mudstone source rocks of the Bolila-Bagong formations， the sandstone reservoirs of the Quemocuo-Bagong formations， and the evaporite cap rocks of the middle-upper Quemocuo Formation. The third one comprises the source rocks of the Quse Formation， the dolomite reservoirs of the Buqu Formation， the sandstone reservoirs of the Xiali Formation， and the evaporite/mudstone cap rocks of the Xiali Formation. Three types of hydrocarbon resources occur in the Qiangtang Basin： conventional， shale， and tight hydrocarbons. In the Maqu area， play fairways cover an area of about 5 × 103 km2. An assessment of the hydrocarbon generation intensity and hydrocarbon accumulation coefficients （HACs） of source rocks in the Bolila-Bagong formations reveals that the Maqu area has conventional hydrocarbon resources of about 0.5 × 109 t when estimated using a minimum resource abundance of 100 × 103 t/km2. Meanwhile， the Bagong Formation contains shale oil resources of approximately 1 × 109 t. In the Biluocuo-Esima area， play fairways with an area of about 8 × 103 km2 are identified. An assessment of the hydrocarbon generation intensity and HACs of source rocks in the Quse and Bagong formations reveals that this area contains conventional hydrocarbon resources estimated at 0.8 × 109 t based on a minimum resource abundance of 100 × 103 t/km2. In this area， the Bagong and Quse formations are identified as play fairways for shale oil exploration， with shale oil resources of approximately 1.6 × 109 t and about 0.8 × 109 t， respectively. In the Shenglihe area， play fairways span an area of 5 × 103 km2， where the Quse Formation holds shale oil resources of about 1 × 109 t.关键词：source rock-reservoir-cap rock assemblage;hydrocarbon play;petroleum system;exploration potential assessment;marine facies;Mesozoic;Qiangtang Basin262|53|0更新时间：2026-01-29
- 摘要：The carbonate-evaporite system in the sub-salt sequence has been a key area for increasing oil and gas reserves and production. Its source rock-reservoir combination styles and distribution have become the key constraints on oil and gas exploration. Analyzing the development and distribution pattern of hydrocarbon source rock-reservoir in the sub-salt carbonate-evaporite system in the Ordos Basin， we explore the controlling factors. The results show that： the hierarchical “uplift-depression” structural pattern determines the sedimentary substrate variability， and the dry and wet paleoclimate changes alter the oceanic conditions， leading to sedimentary differentiation， which results in the formation of different carbonate-evaporite depositional sequences， and the development of various hydrocarbon source rocks and reservoirs. Paleo-uplifts and subordinate uplifts control the distribution of hydrocarbon source rocks for arid-climate argillaceous dolomites， and the paleo-depressions are favorable for the growth of hydrocarbon source rocks for wet-climate micrites； grainstone deposits are prone to developing in paleo-uplift and subordinate uplift zones， which are also a favourable habitat for benthic organisms. These zones are the dominant zones for the reflux of high-salinity brine in the process of the climate shifting from wet to arid， where the occurrence of dolomitization is widely seen， controlling the distribution of crystalline dolostone， grain dolostone， microbial dolostones and porphyritic dolostone reservoirs. Tectonic-sedimentary differentiation governs the distribution pattern of hydrocarbon source rocks and reservoirs in the carbonate-evaporite system. The slope zone around the Central paleo-uplift and the Wushenqi uplift and Shenmu-Mizhi low uplift zone adjacent to the paleo-depression have effective hydrocarbon source rock- reservoir combinations developed， favourable zones for oil and gas exploration in the sub-salt sequence.关键词：paleoclimate;Tectonic-sedimentary differentiation;Carbonate-evaporite system;dolostone;deep to ultra-deep reservoirs;Majiagou Formation;Ordovician;Ordos Basin248|58|0更新时间：2026-01-29
- 摘要：In the Ordos Basin， a significant breakthrough was recently achieved in the hydrocarbon exploration of tight limestones in the Permian Taiyuan Formation. The Carboniferous Benxi Formation， underlying the Taiyuan Formation， also contains limestones. However， these limestones remain poorly understood in terms of lithology， the spatiotemporal distribution of sedimentary facies， and the existence of reservoirs. This has restricted the emplacement of hydrocarbon exploratory wells. Using the latest drilling and outcrop data， we systematically analyze the lithology of limestones in the Benxi Formation in the east-central Ordos Basin， as well as the types and spatiotemporal distributions of their sedimentary facies. Furthermore， we explore the primary factors controlling the occurrence of limestone reservoirs in the formation. The results indicate that the Benxi Formation exhibits diverse types of limestones， including sparry bioclastic limestones， micritic bioclastic limestones， bioclast-bearing micrites， and micrites， all of which occur primarily in the 2nd member of the Benxi Formation （also referred to as the Ben 2 Member）. These limestones mainly feature tidal flat and bioherm subfacies， with the latter being discovered in this member for the first time. The sedimentary facies generally show a C-shaped distribution pattern with an eastward opening. Bioherms are present in the coastal area and gradually transition to low-energy limestone or marl flats eastward. The limestones in the Benxi Formation primarily contain dissolution pores and microfractures， and the reservoirs are significantly governed by sedimentary facies and lithology. Specifically， reservoirs of bioclastic limestones and micritic bioclastic limestones are identified in the bioherm and bioclastic shoal facies zones， with dissolution and fracturing acting as core diagenesis that plays a constructive role in reservoir development. In sum， the Ben 2 Member is considered a favorable interval for the occurrence of tight limestone reservoirs. This provides a valuable reference for hydrocarbon exploration of tight limestones in the Benxi Formation within the Ordos Basin.关键词：limestone;bioherm;sedimentary facies;reservoir;Benxi Formation;Ordos Basin223|55|0更新时间：2026-01-29
- 摘要：The Carboniferous reservoirs in the eastern Sichuan Basin are generally thin， rendering the exploration of stratigraphic-lithologic hydrocarbon accumulations therein more challenging. Therefore， there is an urgent need to determine the coupling relationship between the distribution of detachment layers and regional structural styles， aiming to provide a novel philosophy for the structural trap exploration. Using seismic reflection data， drilling and log data， and the research results of regional geology， we analyze the controlling effects of detachment layers on structural styles in the eastern Sichuan Basin from the perspective of structural geometry. Furthermore， the formation process of the Carboniferous traps under the layered structural deformation pattern is investigated in depth. The research results reveal that the Dachigan-Datianchi area in the eastern Sichuan Basin exhibits thin Triassic but thick Silurian and Cambrian detachment layers. The deformation exhibits distinct stratification bounded by the Silurian： below it， east-dipping reverse faults and folds occur， while fault-propagation folds dominate above. Under this layered deformation system， fault-propagation folds overlying the Silurian strata exhibit steeply dipping faults at the base of their forelimbs， while their gently dipping faults extend forward along detachment layers. These faults jointly control the formation of the Carboniferous faulted anticline traps. Across the eastern Sichuan Basin， the differential distribution of detachment layers is coupled with structural styles. Notably， the Carboniferous traps associated with fault-propagation folds within the layered deformation system of the Dachigan-Datianchi tectonic zone serve as key potential targets for hydrocarbon exploration in the region.关键词：fault-related fold;detachment layer;structural style;Carboniferous;eastern Sichuan Basin58|50|0更新时间：2026-01-29
- 摘要：This study aims to thoroughly assess the prospects for natural gas exploration and exploitation in littoral-shallow lacustrine beach bars within the Tainan area， Qaidam Basin. To this end， we systematically investigate the sedimentary environments， spatial distribution， evolutionary development， and controlling factors of beach bars in sequence Ⅱ of the Quaternary Qigequan Formation in the area using core observations and drilling （log） data analysis， as well as observations of rock thin sections， whole-rock mineral mineralogy via X-ray diffraction， grain-size cumulative probability curves， clay mineral assemblages， chloride content in mudstone cuttings， and net-to-gross （NTG） ratios of limestones （limestones）. The results indicate that the Tainan area primarily exhibits clastic beach bars， with carbonate beach bars occasionally visible. The clastic beach bars consist primarily of lithic-feldspathic fine-grained sandstones and siltstones， with grain-size cumulative probability curves predominantly showing a saltation-suspension dual-segment mode （64.4%）， followed by multi-segment modes （11.9%）. Furthermore， the clastic beach bars exhibit horizontal， wavy， and low-angle cross bedding structures. The carbonate beach bars， on the other hand， are composed mainly of argillaceous and silty micrites with aphanocrystalline to very fine crystalline textures. Clastic beach bars are well developed in sequence Ⅱ of the Qigequan Formation， with an average single-layer thickness of 2.13 m， an average NTG ratio of 0.34， and relatively small sand bodies in individual bars. These clastic beach bars are mainly distributed in a banded pattern in the core of the Tainan anticline. Among these， bars on the east flank of the anticline have a NE-SW strike， while those on the west flank strike NW-SE. The carbonate beach bars in sequence Ⅱ are limited in scale， with an average NTG of 0.37， and are distributed in a ring-like pattern in the anticline core. The lacustrine basin within the Tainan area is dominated by brackish to saline water， with localized occurrences of brine water. During the deposition of the Qigequan Formation， the Tainan area experienced an arid， cold climate with frequent fluctuations. The clay minerals in the area are primarily composed of illite （44.2%）， followed by mixed-layered illite-montmorillonite （22.9%） and chlorite （19.6%）. Therefore， beach bars are well developed in the Tainan area and show noticeable migration and swing， with significant evolutionary differences between the east and west flanks of the Tainan anticline. Factors controlling the beach bar development in the area mainly include the arid climate conditions and the low-amplitude， synsedimentary Tainan anticline.关键词：sedimentary environment;depositional characteristics;Beach-bar sand bodies;Qigequan Formation;Tainan area;Qaidam Basin48|38|0更新时间：2026-01-29
- 摘要：The Bogda Mountains demarcate the Junggar Basin and the Turpan-Hami Basin， yet controversies persist regarding their basin-range relationship and the tectonic attributes of Permian strata on both flanks. Investigating the Permian sedimentary filling characteristics and tectono-sedimentary evolutionary processes in adjacent basins proves crucial for determining their tectonic attributes and elucidating basin-range coupling mechanisms. Building upon previous research and utilizing comprehensive datasets including borehole logs， well cores， and outcrop observations from both basins， this study employs sedimentary filling analysis and facies identification to clarify the Permian tectonic attributes， sedimentary filling patterns， and evolutionary trajectories of the Bogda Mountains and their adjacent basins. Key findings include that during the Early Permian， the study area experienced rift sedimentation under the regional extension， characterized by the formation of the sedimentary system consisting of alluvial fans， braided rivers， and fan deltas. During the Middle Permian， the study area underwent rift-sag sedimentation. In the early stage of the Middle Permian， rift sedimentation continued under regional extensional stress， accompanied by the formation of the Middle Permian bimodal volcanic rocks in the Turpan-Hami Basin. In the late stage of the Middle Permian， the sag-type deposition of littoral-shallow lacustrine and semi-deep lacustrine facies occurred as the extensional stress waned. While the end of the Middle Permian witnessed tectonic inversion with regional stress transitioning from extension to compression. During the Late Permian， continued regional extensional stress led to the large-scale rift inversion and initial uplift， transforming Bogda into a provenance area. Concurrent base-level rise facilitated the deltaic and littoral-shallow lacustrine deposition therein， marking the onset of foreland depression evolution in both basins. The tectono-sedimentary evolution indicates that the Permian basin development in Bogda area is principally driven by regional extension， with subsequent stress transformation and base-level changes serving as primary factors governing prototype basin architecture and paleogeographic configuration.关键词：sedimentary filling;tectonic evolution;Permian;Bogda area;Junggar Basin;Turpan-Hami Basin65|52|0更新时间：2026-01-29
- 摘要：In recent years， continuous breakthroughs have been achieved in exploring the Carboniferous volcanic hydrocarbon reservoirs in the periphery of the Western Well Pen-1 Sag within the central Junggar Basin. However， challenges such as the strong heterogeneity of volcanic reservoirs， complex genesis of high-quality reservoirs， and the unclear reservoir distribution patterns have significantly increased the costs of hydrocarbon exploration and development. To address these issues， we systematically characterize the lithology and lithofacies of volcanic rocks， as well as reservoir space types and their distribution patterns， using multiple techniques including petrology， geochemistry， micro-computed tomography （micro-CT）， well logging， and seismic surveys. Through paleogeomorphic reconstruction and tectonic evolution analysis， we determine the durations of weathering and denudation and explore how tectonic movements， together with the intensities of weathering and leaching， control reservoir occurrence. In combination with differences in lithology， structure， and the intensity of weathering and leaching across various areas， we establish a developmental model for large-scale， high-quality volcanic reservoirs. The results indicate that the volcanic rocks in the study area are dominated by effusive phase （that is， basaltic， andesitic， dacitic， and rhyolitic types） and the pyroclastic flow sub-phase of explosive phase （i.e.， resulting in volcanic breccia lavas and welded tuffs）. The spatiotemporal distribution of the lithology and lithofacies is governed by multi-stage eruption events. The reservoir spaces are dominated by secondary pores and fracture systems， with tectonic fractures and intergranular dissolution pores representing high proportions. The reservoirs exhibit significant differences in vertical zoning. For instance， the Mobei Uplift， located on a structural slope， preserves a complete four-layered structure consisting of clay zone， leaching zone， disintegration zone， and parent rock zone. In contrast， the Shixi Uplift， located at a structural high during the uplifting and denudation stage， experienced the denudation and transport of the clay zone. Weathering and leaching are key geological processes in the formation of weathered crustal reservoirs. A duration of sustained weathering and denudation of approximately 40 Ma is identified as the critical threshold for significant improvement in reservoir physical properties. Pronounced improvements in physical properties are observed in volcanic breccias， basalts， and andesites as these lithologies are more sensitive to weathering and dissolution. The Hercynian to Indosinian tectonic movements significantly improve the storage capacity of interior reservoirs through fracture reactivation， leading to the formation of a dual-layered reservoir structure comprising weathered crustal and interior reservoirs. Preferential lithologies for this reservoir type include dacites， rhyolites， and volcanic breccias. Accordingly， a volcanic reservoir developmental model proposed is characterized by a material basis comprising favorable lithologies and lithofacies， along with the dual control of supergene weathering and tectonic evolution. The superimposed zones of the Hercynian-Indosinian tectonically active areas and areas subjected to long-term weathering （> 40 Ma） are identified as key targets for future exploration of high-quality volcanic reservoirs.关键词：genetic mechanism;reservoir characteristics;volcanic reservoir;Carboniferous;Western Well Pen-1 Sag;Junggar Basin65|42|0更新时间：2026-01-29
- 摘要：The Shahejie Formation in the Huanghua Depression boasts abundant mixed-source hydrocarbons. Determining the charging ratio for mixed-source oil reservoirs is critical to the prediction of hydrocarbon reservoir distribution in the depression. Through the analysis and tests of total organic carbon （TOC） content， rock pyrolysis， and gas chromatography-mass spectrometry （GC-MS） experiments on saturated hydrocarbons， we systematically examine the geochemical characteristics of source rocks and crude oil in the formation. A multi-parameter quantitative model for determining the charging ratio for mixed-source oil reservoirs is established by combining hierarchical cluster analysis （HCA） and principal component analysis （PCA）. With this model， we quantify the contributions of different source rocks to the formation of mixed-source oil reservoirs therein. The results indicate that the source rocks in the 3rd member （Es3； the Sha 3 Member） and the 1st member （Es1； the Sha 1 Member） of the Shahejie Formation show moderate to high organic matter abundance and mixed kerogen types of Ⅱ2 and Ⅱ1， respectively， suggesting the presence of mature source rocks. Oil-source rock correlation reveals that Class A crude oil is derived from source rocks in the Es1 and formed in high-salinity， reducing environments， with organic matter originating primarily from lower-class aquatic organisms. Class B crude oil originates solely from source rocks in the Es3 and is formed in medium-salinity， weakly oxidizing to weakly reducing environments， with organic matter sourced mainly from terrestrial plants. Class C crude oil represents mixed oil derived from source rocks in both Es1 and Es3. Calculations using the quantitative model indicate that the contribution rates of source rocks in the Es1 and Es3 to the mixed-source oil reservoirs range from 22.73 % to 59.11 % and from 40.89 % to 77.27 %， respectively. Model validation using laboratory artificial oil mixing experiments shows prediction errors ranging from 0.44 % to 9.94 % （average： 5.26 %）， indicating high predictive accuracy.关键词：geochemistry;oil-source rock correlation;charging ratio;mixed-source oil reservoir;source rock;1st member of the Shahejie Formation （Es1）;Huanghua Depression;Bohai Bay Basin61|35|0更新时间：2026-01-29
- 摘要：This study aims to systematically compare the hydrocarbon generation and expulsion characteristics of various types of lamellar lacustrine shales. Using semi-closed formation porosity thermocompression simulation experiments on hydrocarbon generation and expulsion， as well as associated geochemical analyses and tests， we conduct a systematic comparative study on the hydrocarbon generation， expulsion， and retention processes of three types of lamellar shales in the 2nd member of the Kongdian Formation （also referred to as the Kong 2 Member） in the Cangdong Sag. Accordingly， we explore the mechanisms underlying the differential evolution of hydrocarbon generation， expulsion， and retention of these lamellar shales. The results indicate that the threshold for retained oil enrichment in lamellar shales corresponds to vitrinite reflectance （Ro） values of 0.4% ~ 1.4%， with the oil retention efficiency （ORE） varying across different types of lamellar shales. In contrast， the “golden window” for retained oil enrichment corresponds to Ro values of 0.8% ~ 1.3%. Compared to the lamellar mixed shales and lamellar carbonate shales， the lamellar feldspathic shales exhibit higher total hydrocarbon yield， total oil yield， and total gas yield. The laminar carbonate shales reach the threshold for the retained oil enrichment earlier （Ro = 0.4%）， exhibiting the characteristics of early generation and early expulsion. The three types of lamellar shales show varying retained hydrocarbon compositions and diverse gas/oil ratios （GORs） across different thermal evolution stages. Notably， the lamellar feldspathic shales show the highest GOR during the highly mature stage. The differences in the paleolake environment govern the organic matter composition and hydrocarbon-generation activation capacity of the three types of lamellar shales， further affecting the differences in their ORE and hydrocarbon generation， expulsion， and retention processes.关键词：differential mechanism;oil retention efficiency （ORE）;hydrocarbon generation and expulsion simulation;lamellar shale;Kongdian Formation;Cangdong Sag;Bohai Bay Basin61|45|0更新时间：2026-01-29
- 摘要：The Pearl River Mouth Basin （PRMB）， located in the deep-water super-extensional region along the northern continental margin of the South China Sea， exhibits complex and diverse tectonic evolution in the rifting stage. Focusing on the Eocene Wenchang and Enping formations in the Baiyun Sag within the PRMB， northern South China Sea， we reconstruct the prototype basin of the entire Baiyun Sag on the scale of third-order sequences. This approach overcomes the limitations of previous analyses on the sag scale and under a second-order sequence stratigraphic framework while also leading to new insights into the tectono-sedimentary evolutionary mechanisms of the Baiyun Sag during rifting. Based on seismic stratigraphic trend analysis， we reconstruct the denuded thickness of the Baiyun Sag during the deposition of the Wenchang and Enping formations. Furthermore， based on an analysis of the regional tectonic setting and previous research results on sedimentary systems， we characterize the dynamic evolutionary process of the prototype basin of the Baiyun Sag. The results indicate that during the deposition of the Wenchang and Enping formations， the prototype basin evolved from small-scale narrow lake basin under strong extension to a wide， shallow-water lacustrine basin under weak extension， ultimately developing into a shallow-water， extensive basin under a stable subsidence setting. The denudation center migrated gradually from the initial axial intra-basin provenance area during the deposition of the lower member of the Wenchang Formation to the northern gentle slope during the deposition of the upper member of the Wenchang Formation and then to the northwestern area outside the basin during the deposition of the Enping Formation. The study area experienced a dynamic evolution of basin-source sedimentary and filling， shifting from proximal to distal provenance. Correspondingly， the basin-source system of the Baiyun Sag transitioned from a proximal provenance-steep slope type to a proximal provenance-gentle slope type and then to a distal provenance-gentle slope type. Specifically， the intra-basin axial supply of the proximal provenance-steep slope type dominant from the 6th to 4th sub-members of the Wenchang Formation during intense rifting changed to the supply of the proximal provenance-gentle slope type in the northern gentle slope zone predominating from the 3rd to 1st sub-members of the Wenchang Formation during weak rifting. Finally， it transitioned to the long-axis supply of the distal provenance-gentle slope type spanning from the 4th sub-member of the Enping Formation to the 1st and 2nd sub-members of the Enping Formation during the rifting-depression transition period. Both the migration of the denudation center and the transformation of the basin-source system are governed by a clockwise variation in the stress field in the northern South China Sea， shifting from NW to NNW and then to nearly NS.关键词：denuded thickness;prototype basin;basin-source evolution;Eocene;Baiyun Sag;Pearl River Mouth Basin （PRMB）63|45|0更新时间：2026-01-29
Petroleum Geology
- 摘要：Underground gas storage （UGS） facilities are recognized as important infrastructures for ensuring the peak shaving， emergency supply， and strategic reserves of natural gas. SINOPEC commenced constructing UGC facilities during the 12th Five-Year Plan and accelerated the construction during the 14th Five-Year Plan. To date， 10 UGS facilities for complex hydrocarbon reservoirs have been built successively. Through technological innovation and integration， SINOPEC has developed a series of key technologies for the construction and operation of complex hydrocarbon reservoir-based UGS facilities. The study results demonstrate that a range of technologies have provided comprehensive technical support for the high-quality construction and safe operation of SINOPEC’s UGS facilities. These technologies include the pressure-bearing capacity assessment of UGS facilities for fault-block reservoirs， injection-production capacity prediction of UGS facilities for ultra-high-pressure fractured reservoirs， enhanced recovery synergistic with gas storage construction in active gas reservoirs with high gas condensate content， construction of UGS facilities for fully waterflooded gas reservoirs， and the operation optimization of UGS facilities for water-drive gas reservoirs. In the future， it is advisable to enhance the capabilities for peak shaving and supply assurance of natural gas by optimizing the gas storage and peak-shaving structures and continuously constructing UGS facilities for both hydrocarbon reservoirs and salt caverns. It is essential to further exploring the peak-shaving potential of existing UGS facilities to improve economic benefits. Additionally， the development of intelligent UGS systems will pioneer diversified carbon-reduction pathways and renewable energy integration， fostering sustainable and green development of gas storage operations.关键词：sealing capacity;inventory assessment;capacity expansion via pressurization;multi-cycle injection and production;injection-production capacity;storage capacity;underground gas storage （UGS） facility;oil & gas storage and transportation69|31|0更新时间：2026-01-29
- 摘要：The Puguang gas field， the first sour gas field developed in China， has maintained efficient and stable production for 15 years. As it enters the mid-to-late stage of development， however， three major challenges threaten its long-term production stability. First， elemental sulfur deposition， unique to sour gas fields， combined with strong edge water incursion， makes it extremely difficult to maintain stable production over an extended period. Second， the effective and economic development of low-permeability gas reservoirs is critical to the stable production of the gas field. However， these reservoirs cannot be accurately identified using conventional methods. Third， wellbore pressure boosting is recognized as an important method to reduce the abandonment pressure of gas reservoirs and enhance the gas recovery of a gas field in the mid-to-late stage of development. However， there has been no precedent for the application of wet gas pressure boosting to a sour gas field， and the technical scheme for such wellbore pressure boosting remains unclear. To achieve long-term stable production and enhanced gas recovery of the Puguang gas field， we identify the patterns of water invasion， sulfur deposition， and differential seepage in the gas field through experiments on their mechanisms. Accordingly， four key techniques are developed： geological and engineering integrated synergistic water control， whole-process sulfur deposition prediction and treatment， fine-scale characterization and effective production of low-permeability reservoirs， and wet gas compression tailored for high-acid gas fields. The application of these techniques has yielded significant results in developing the Puguang gas field， enabling stable production for 15 years， five years longer than the original design. Furthermore， the gas recovery is projected to exceed 70% by 2025. These advances have reinforced the leading position of sour gas fields operated by SINOPEC among their global counterparts in terms of development indices.关键词：water control and management;wet gas pressure boosting;sulfur deposition;low-permeability reservoir;enhanced gas recovery;sour gas field;Puguang gas field80|30|0更新时间：2026-01-29
- 摘要：In high-dip-angle reservoirs， the strong intra- and inter-layer heterogeneity combined with pressure propagation between injection and production wells renders top gas injection-assisted gravity drainage prone to trigger instability of the gas-liquid interface. Maintaining the stability of the gas-liquid interface is crucial to enhancing oil recovery from these reservoirs. Focusing on the X oil reservoir， we construct a 2D profile-based physical model with high dip angles. By combining saturation monitoring techniques， we systematically simulate the displacement process of water-to-gas flooding. Based on the analysis of the dimensionless gravity number and capillary number， as well as the visualized gas saturation profiles from 2D physical simulation， we explore the microscopic mechanical mechanisms behind top gas injection-assisted gravity drainage and elucidate the stability mechanisms of the gas-liquid interface. Based on the residual oil distribution after water and gas flooding， we determine the conditions required for stable gas flooding. The results indicate that increasing the formation dip and the injection-production ratio （IPR） can enhance gravitational differentiation and compress the pressure drop funnel， thereby extending the stability period of the gas-liquid interface. The gas flooding process can be divided into three stages： the initial， effective， and gas breakthrough stages. The first two stages are primarily subjected to gravitational differentiation， which drives the upward migration of the gas phase and helps maintain the interface stability. In contrast， the breakthrough stage is governed by viscous forces， which accelerate the fingering expansion and promote the formation of preferential seepage pathways.关键词：gas-liquid interface stability;2-D physical simulation experiment;secondary gas cap;residual oil distribution;water-to-gas drive;oil reservoir development;high dip reservoir34|26|0更新时间：2026-01-29
- 摘要：Fault-controlled karst reservoirs， recognized as important deep carbonate reservoirs in the Tarim Basin， exhibit diverse morphologies， complex architectures， and extremely strong heterogeneity under the influence of strike-slip faults and karstification. The study investigates the Ordovician fault-controlled karst reservoirs in typical units including S80， S65， T705， and S99 within the main production area of the Tahe oilfield， Tarim Basin， and examine the characteristics， primary controlling factors， architectural types， and spatial distribution of these reservoirs， using data from outcrop and core observations， drilling， logging， and seismic surveys， and guided by theories and methodologies including karstology， structural geology， geophysics， geostatistics， and production dynamic analysis. Accordingly， we develop methods for the seismic prediction and geological modeling of these reservoirs. The results indicate that the Ordovician fault-controlled karst reservoirs are fracture-cave systems with varying spatial architectures that are formed by the dissolution of fracture zones within and surrounding the zones of fracturing and faulting. The scales， morphologies， and architectures of these reservoirs are governed by the properties， styles， grades， and dissolution intensity of faults. An analysis of the geometry， mechanical properties， and associated structures of strike-slip faults reveals that the strike-slip faults within the Ordovician fault-controlled karst reservoirs primarily exhibit three morphologic types on profiles （i.e.， vertical， positive flower， and negative flower structures） and six planar architectural patterns （i.e.， linear， en echelon， X-shaped， oblique， horsetail， and parallel patterns）. The reservoirs are better developed at the intersections， inflection points， overlapping parts， and ends of faults， with the karst scale positively correlated with the fault grade. Along the same strike-slip fault， fault-controlled karst reservoirs exhibit varying characteristics in fault segments with different properties. By employing attributes from spectral decomposition and seismic inversion combined with the developmental patterns of the fault-controlled karst reservoirs， we develop a comprehensive constrained probability volume （CPV）， and training images of these reservoirs are generated through simulations with a target-based approach. In addition， a geological modeling method integrating multi-point statistics and multiple constraints is established， allowing for the fine-scale characterization of the morphologies， scales， and architectural characteristics of fault-controlled karst reservoirs. Geological modeling results effectively reveal that the reservoirs mainly occur along faults and are better developed in parts closer to faults. Validation against the reservoir thickness encountered by sparse wells indicates that the model established using the proposed method increases the drilling coincidence rate from 71.6% to 85.8%.关键词：architectural pattern;characterization method;fault-controlled karst reservoir;fractured-vuggy reservoir;deep carbonate reservoir;Tahe oilfield;Tarim Basin67|39|0更新时间：2026-01-29
- 摘要：Fault-controlled fractured-vuggy reservoirs are extensively developed in ultradeep carbonate strata， and their formation and distribution are closely related to the in situ stress state. Since fractured-vuggy carbonate reservoirs exhibit the characteristics of both discrete and continuous media， conventional methods for geomechanical modeling often struggle to accurately predict stress fields in these complex reservoirs. Using seismic attribute-based inversion， we establish a model to characterize the distribution of rock mechanical parameters of fractured-vuggy reservoirs. Then， a geomechanical heterogeneity model for these reservoirs is developed， achieving both geometric and mechanical similarities between the geological and geomechanical models of fractured-vuggy rock masses （i.e.， twin modeling）. Accordingly， the in situ stress field distribution and activity of complex fractured-vuggy reservoirs are predicted. The geomechanical twin modeling technique enables the reproduction of actual geometric morphologies of subsurface fractured-vuggy rock masses using finite element software. The results indicate that different fractured-vuggy rock mass types exhibit distinct stress field characteristics. Among these， uplifted fractured-vuggy rock masses show strong stress heterogeneity in the compressional segments of major faults， resulting in distinct stress segmentation. Similarly， embedded fractured-vuggy rock masses exhibit significant differences in vertical stress， also suggesting strong stress heterogeneity. In contrast， combined fractured-vuggy rock masses display moderate stress heterogeneity， while chaotic and isolated fractured-vuggy rock masses show uniform stress distribution. Fractured-vuggy rock masses exert significant impacts on rock mechanical strength and stress magnitude. Specifically， karst caves show the highest decreased magnitude of stress at their periphery， followed by fractured-vuggy rock masses， with the periphery of fractures exhibiting the lowest decreased magnitude. Additionally， different types of fractured-vuggy rock masses exhibit varying activity. The domed and down-dipping types exhibit the strongest activity， succeeded by the combined type， while the chaotic and isolated types prove the least active.关键词：geomechanical modeling;twin modeling;in situ stress;ultradeep reservoir;fractured-vuggy reservoir;carbonate rock;Fuman oilfield;Tarim Basin100|32|0更新时间：2026-01-29
- 摘要：Recent exploration practices in the Sichuan Basin reveal the extensive occurrence of bitumen in deep to ultradeep carbonate reservoirs. The existence of asphalt reduces the reservoir capacity， changes the pore-throat structure of the reservoir which leads to the complexity of the conductivity rule of the reservoir. This further affects the difficulty of reservoir logging evaluation of effectiveness and fluid property discrimination. To quantitatively characterize the impacts of bitumen infill on the pore structures and electrical resistivity of carbonate reservoirs， we investigate the Sinian Dengying Formation in the Penglai gas area， Sichuan Basin. Specifically， high-resolution computed tomography （CT） scanning experiments are conducted on full-diameter cores. Based on pore-throat network models， we examine the changes in the reservoir space and pore throats within the cores before and after bitumen infill. Finite element method （FEM） numerical simulations are conducted to assess rock conductivity under varying bitumen infill rates. Accordingly， the variation patterns of the pore structures and resistivity of asphaltic carbonate reservoirs are determined. The results indicate that the grayscale values of bitumen fall between those of pores and rock matrix as seen on CT images. Applying deep learning to the analysis of the infill characteristics and distribution patterns of bitumen in cores and thin sections can significantly enhance the accuracy of CT scanning-based bitumen identification and quantification. Bitumen infill reduces the volume of large pores and the quantity of long， large pore throats. As a result， the quantity of pores with high coordination numbers trends downward. Rock resistivity is positively correlated with the bitumen infill rate， showing a distinct two-stage increase. Notably， the increase in the first stage is attributed primarily to bitumen infill in fractures， while that in the second stage is predominantly due to bitumen infill in pore throats. In both stages， the increasing rate of the resistivity diminishes.关键词：bitumen;pore structure;electrical resistivity;3D digital core;carbonate reservoir;Penglai gas area;Sichuan Basin54|40|0更新时间：2026-01-29
- 摘要：High-porosity sandstones are highly susceptible to the development of deformation bands under tectonic stress. However， limited studies have been conducted on factors controlling the structures and physical properties of these bands. By combining a systematic literature review and experimental analysis， we investigate the macro- and micro-structural characteristics and deformation mechanisms of these bands in high-porosity sandstones. Furthermore， we analyze the primary and secondary factors governing the structural and physical property evolution of these deformation bands， as well as the mechanisms by which these factors operate. The results indicate that effective normal stress and shear displacement serve as the primary factors controlling the structural and permeability evolution of the deformation bands. Specifically， the effective normal stress significantly reduces the permeability by intensifying grain breakage and modifying the boundary morphologies of shear zones. In contrast， shear displacement predominantly governs the thickening and structural stratification of the deformation bands. Notably， such controlling effect exhibits a pronounced nonlinear evolutionary trend， with a critical displacement threshold observed. The secondary controlling factors include the mineral composition， initial porosity， grain size， sorting degree， clay content， and strain rate of surrounding rocks. Under certain geological conditions， these factors modulate the structural morphology and physical property parameters of the deformation bands. The evolution of the deformation bands consists of five stages： non-deformation， initial deformation， initial stratification， stratification transition， and stable formation. Each stage exhibits regular variations in the microstructural parameters of the deformation bands， including band thickness， grain-size distribution， grain roundness， and grain orientation. With increasing stress level and displacement， the deformation bands experience significantly intensified grain breakage and pronounced enrichment of fine-grained matrix. This leads to porosity reduction of up to a maximum of 70% and permeability decreases of two to three orders of magnitude. The evolutionary patterns of the structures and physical properties of the deformation bands derived from laboratory tests are highly consistent with data from field outcrops. Future research on the of deformation bands should focus on computed tomography （CT）-based three-dimensional structural modeling， thermal-hydrological-mechanical-chemical （THMC） multi-field coupling simulations， and machine learning-based modeling for predicting structures and permeability.关键词：permeability;deformation mechanism;fault internal structure;fault seal;deformation band;fault zone;sandstone72|33|0更新时间：2026-01-29
- 摘要：Mesophase spherules are widely distributed in solid bitumen as intermediate products formed during the thermal evolution of crude oil. As a significant bridge linking gas and oil with their source rocks， solid bitumen provides critical geological information for tracing the origin and evolution of petroleum systems， thereby playing an important role in revealing the evolution of deep and ultra-deep reservoirs. To investigate the thermal evolution characteristics of mesophase spherules and their primary controlling factors， we conduct high-temperature and high-pressure gold tube pyrolysis experiments on five oil samples with varying group component contents， that is， four crude oil samples， as well as a crude oil sample in extracted saturated hydrocarbons， aromatic hydrocarbons， saturated + aromatic hydrocarbons， and nonhydrocarbons + asphaltenes. The comparison of the optical characteristics of solid bitumen generated under four temperatures （i.e.， 450 ℃， 500 ℃， 550 ℃， and 600 ℃）， along with the areal proportions and diameters of mesophase spherules in the solid bitumen， reveals that during thermal evolution， the mesophase spherules undergo generation， growth， collision， and coalescence， ultimately evolving into solid bitumen with crystalline-domain mosaic textures. The optical characteristics and evolutionary patterns of the mesophase spherules generated during thermal pyrolysis of group component indicate that the polar compounds （i.e.， resins + asphaltenes） in crude oils act as the dominant factors controlling the formation and thermal evolution of mesophase spherules. Understanding the mesophase spherules in solid bitumen is crucial to revealing the geochemical properties and origin of paleo-oil reservoirs.关键词：mesophase spherule;solid bitumen;optical structure;gold tube pyrolysis experiment;group component;geochemistry;crude oil86|23|0更新时间：2026-01-29
- 摘要：The efficient and high-precision quantitative characterization of laminae is critical to shale reservoir assessment. However， research on shale laminae faces some challenges， including the low accuracy and cumbersome nature of lamina identification methods， as well as the failure to establish the relationship between macroscale and microscale laminae. In this study， we investigate laminae at varying scales in the Qiongzhusi Formation within the southern Sichuan Basin based on thin section and core observations， imaging logs， as well as analytical and test data. Using image and signal processing， Light Gradient Boosting Machine （LightGBM）， convolutional neural networks （CNNs）， Long Short-Term Memory （LSTM） network， and Kolmogorov-Arnold Networks （KANs）， we develop methods to identify the laminae of varying scales and establish a laminaset identification and prediction model （Laminae-Net）. Furthermore， we develop a method for the unified characterization of laminae at varying scales and explore the impacts of lamina characteristics on shale reservoirs. The results indicate that the proposed thin section-based lamina identification method using image and signal processing allows for the accurate discrimination of bright and dark laminae， contributing to the precise characterization of lamina thickness and density. In contrast， the proposed lamina identification method based on FMI images can efficiently characterize the lamina number and thickness with high precision. Eight types of laminasets primarily occur in the Qiongzhusi Formation in the southern Sichuan Basin. Using the Laminae-Net model， these laminasets can be identified with an accuracy of up to 95.4% on the test set. These laminae preferentially occur in the 1st， 3rd， 5th， 6th， 7th， and 8th sublayers of the formation. Scale invariance of lamina development frequency is verified through integrated thin section and image logging analysis.. A first-of-its-kind cross-scale lamina calculation method is built for lamina characterization， achieving a goodness of fit （R2） of up to 0.813. The TOC content shows a negative correlation with the lamina density， while the porosity and horizontal permeability exhibit positive correlations with the lamina density. This study provides methods for identifying and analyzing laminae at varying scales， expanding the scope of lamina research while also serving as a reference for advancing the research.关键词：lamina identification;laminaset identification;deep learning;lamina density;reservoir characterization;shale;Qiongzhusi Formation;southern Sichuan Basin103|45|0更新时间：2026-01-29
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