The Early Cambrian Yuertusi Formation(Є_(1)y)in the Tarim Basin of China deposits a continuously developed suite of organic-rich black mudstones,which constitute an important source of oil and gas reservoirs in the Pa...The Early Cambrian Yuertusi Formation(Є_(1)y)in the Tarim Basin of China deposits a continuously developed suite of organic-rich black mudstones,which constitute an important source of oil and gas reservoirs in the Paleozoic.However,its hydrocarbon generation and evolution characteristics and resource potential have long been constrained by deeply buried strata and previous research.In this paper,based on the newly obtained ultra-deep well drilling data,the hydrocarbon generation and expulsion model ofЄ_(1)y shale was established by using data-driven Monte Carlo simulation,upon which the hydrocarbon generation,expulsion,and retention amounts were calculated by using the diagenetic method.The research indicates that theЄ_(1)y shale reaches the hydrocarbon generation and expulsion threshold at equivalent vitrinite reflectances of 0.46%and 0.72%,respectively.The cumulative hydrocarbon generation is 68.88×10^(10)t,the cumulative hydrocarbon expulsion is 35.59×10^(10)t,and the cumulative residual hydrocarbon is 33.29×10^(10)t.This paper systematically and quantitatively calculates the hydrocarbon expulsion at various key geological periods for theЄ_(1)y source rocks in the study area for the first time,more precisely confirming that the black shale of theЄ_(1)y is the most significant source rock contributing to the marine oil and gas resources in the Tarim Basin,filling the gap in hydrocarbon expulsion calculation in the study area,and providing an important basis for the formation and distribution of Paleozoic hydrocarbon reservoirs.The prospect of deep ultra-deep oil and gas exploration in the Tarim Basin is promising.Especially,the large area of dolomite reservoirs under the Cambrian salt and source rock interiors are the key breakthrough targets for the next exploration in the Tarim Basin.展开更多
Climate change is significantly impacting cotton production in the Tarim River Basin.The study investigated the climate change characteristics from 2021 to 2100 using climate change datasets simulated per the coupled ...Climate change is significantly impacting cotton production in the Tarim River Basin.The study investigated the climate change characteristics from 2021 to 2100 using climate change datasets simulated per the coupled model inter-comparison project phase six(CMIP6)climatic patterns under the shared socioeconomic pathways SSP2-4.5 and SSP5-8.5.The DSSAT-CROPGROCotton model,along with stepwise multiple regression analyses,was used to simulate changes in the potential yield of seed cotton due to climate change.The results show that while future temperatures in the Tarim River Basin will rise significantly,changes in precipitation and radiation during the cotton-growing season are minimal.Seed cotton yields are more sensitive to low temperatures than to precipitation and radiation.The potential yield of seed cotton under the SSP2-4.5 scenario would increase by 14.8%,23.7%,29.0%,and 29.4%in the 2030S,2050S,2070S,and 2090S,respectively.In contrast,under the SSP5-8.5 scenario,the potential yield of seed cotton would see increases of 17.5%,27.1%,30.1%,and 22.6%,respectively.Except for the 2090s under the SSP5-8.5 scenario,future seed cotton production can withstand a 10%to 20%deficit in irrigation.These findings will help develop climate change adaptation strategies for cotton cultivation.展开更多
Groundwater is the main water supply source in the Tarim Basin in China.Endemic disease caused by high iodine(I)groundwater in the Tarim Basin was reported previously.Therefore,it is crucial to systematically identify...Groundwater is the main water supply source in the Tarim Basin in China.Endemic disease caused by high iodine(I)groundwater in the Tarim Basin was reported previously.Therefore,it is crucial to systematically identify the distribution and genesis of groundwater I.Based on hydrochemical analysis of 717 groundwater samples collected in 2015–2018,spatial distribution and hydrogeochemistry characteristic of high I groundwater in different aquifers were analyzed.Results showed that groundwater I ranged between<10.00 and 4000.00μg/L(mean of 53.71μg/L).High I groundwater(I>100.00μg/L)accounted for 7.25%of the total samples.Horizontally,groundwater I significantly increased from recharge zone(RZ)to transition zone(TZ)and to evaporation zone(EZ).Vertically,groundwater in shallow confined aquifer(SCA)had the greatest I concentration,followed by single-structure phreatic aquifer(SSPA),phreatic aquifer in confined groundwater area(PACGA),while groundwater in deep confined aquifer(DCA)generally had low I concentration.Groundwater I enrichment in SSPA was mainly affected by organic matter(OM)decomposition and that in SCA was mainly affected by evaporite mineral dissolution,OM decomposition under alkaline environment.While I enrichment in groundwater of PACGA was restrained under neutral environment.Lacustrine sedimentary environment was crucial for I enrichment in groundwater.Besides,fine-grained lithology of aquifer,smooth topographic slope,shallow buried depth of groundwater,weak alkaline and reducing environment,reductive dissolution of iron oxide/hydroxide minerals and OM decomposition were advantageous to I enrichment in groundwater.展开更多
The Yingshan Formation of the Lower-Middle Ordovician in the Tarim Basin(NW China)was mainly deposited in a shallow platform,which was intensely bioturbated with burrows filled with both dolomites and calcites.This st...The Yingshan Formation of the Lower-Middle Ordovician in the Tarim Basin(NW China)was mainly deposited in a shallow platform,which was intensely bioturbated with burrows filled with both dolomites and calcites.This study aims to figure out the controls on the dolomitization of burrow infills and the effects on petroleum reservoir quality based on petrographic examination,fluid inclusion microthermometry,and isotopic(C-O-Sr)geochemical analyses.The differentiation of burrow-associated carbonates(dolomites and calcites)was likely controlled by the interactions of sea-level oscillations of variable orders and depositional environments.The burrow-associated dolomites(BADs)were precipitated in a relatively restricted(i.e.,lagoon)depositional environment during the lowstand of long-term sea level.In contrast,the burrow-associated calcites(BACs)were formed in a water circulation-improved lagoonal environment during the transgression of long-term sea level.Isotopic geochemical data indicate that the BADs in the Yingshan Formation were formed from slightly saline(i.e.,mesosaline to penesaline)seawater,whereas the BACs were precipitated from nearly normal seawater.In addition to the anoxic condition,the presence of marine-sourced organic matter and sulfate-reducing bacteria,and a sufficient supply of dolomitizing fluids enriched in magnesium ions(Mg^(2+))and their Mg^(2+)concentration may have played a critical role in the formation of BADs.In the more permeable and disturbed burrow sediments as a result of burrowing,penetrating fluids with higher salinities and higher Mg^(2+)concentration relative to seawater favored dolomite precipitation.The fluids with seawater-like Mg^(2+)concentration,however,would lead to calcite precipitation.The progressive dolomitization of these burrowed sediments could have propagated the dolomitizing fronts and extended into ambient limestones,leading to the development of extensive dolomites.This dolomitization process can improve the petrophysical properties(porosity and permeability)and the potential as hydrocarbon reservoirs during the emplacement of hydrocarbons from underlying source rocks of the Cambrian to Lower Ordovician.展开更多
Deep carbonate reservoirs affected by prominent strike-slip faults represent crucial targets in oil and gas exploration owing to their immense resource potential.However,the complex geological environments and poorly ...Deep carbonate reservoirs affected by prominent strike-slip faults represent crucial targets in oil and gas exploration owing to their immense resource potential.However,the complex geological environments and poorly understood histories of the associated paleo-fluid activity have hindered the development of robust theories regarding pore formation and preservation mechanisms,resulting in suboptimal exploration strategies.Leveraging the extensive well deployment by the China Sinopec Group in the Shunbei area of the Tarim Basin,this study addresses these challenges by establishing a comprehensive framework for the evolution of diagenetic fluids within the Middle-Lower Ordovician carbonate formations.Using core samples,thin-section analysis,and cathodoluminescence observations,this study employs high-resolution geochemical methodologies,including isotopic analyses,rare earth element profiling,fluid inclusion studies,and uranium-lead dating,as primary tools for identifying and interpreting paleo-fluid characteristics across various rock types and calcite cement varieties within this stratigraphic interval.The findings reveal several key insights:(i)both RFC and C1 cements are derived from seawater,with C1 forming under burial conditions;(ii)C2,C3,and VC cements result from distinct tectonic events,specifically during the first and third episodes of the Middle Caledonian movement,with meteoric water infiltrating fault systems independently of orogenic belts or paleo-karst systems;and(iii)previous conclusions are challenged,as the influence of hydrothermal activity in this area is found to be minimal.Furthermore,the model presented here serves as a valuable reference for understanding fluid activity events at distal locations within orogenic belts under compressive stress,while accurately capturing fluid variations over different temporal scales within fault zones plays a decisive role.展开更多
The Cambrian platform margin in the Tarim Basin boasts favorable source-reservoir-cap assemblages,making it a significant target for hydrocarbon exploration in ultra-to extra-deep facies-controlled for-mations.Of the ...The Cambrian platform margin in the Tarim Basin boasts favorable source-reservoir-cap assemblages,making it a significant target for hydrocarbon exploration in ultra-to extra-deep facies-controlled for-mations.Of the three major basins in western China,Tarim is the only basin with large-scale platform margin where no exploration breakthrough has been achieved yet.This study determines the vertical and lateral differential evolution of the platform margin(in the Manxi area hereafter referred to as the Cambrian Manxi platform margin)through fine-scale sequence stratigraphic division and a segmented analysis.The platform margin can be divided into the Yuqi,Tahe,Shunbei,and Gucheng segments,from north to south,based on the development of different ancient landforms and the evolutionary process of the platform.The Yuqi and Shunbei segments exhibit relatively low-elevation ancient landforms.Both segments were in a submarine buildup stage during the Early Cambrian,resulting in overall limited scales of their reservoirs.The Gucheng segment features the highest-elevation ancient landforms and accordingly limited accommodation spaces.As a result,the rapid lateral migration of high-energy facies zones leads to the development of large-scale reservoirs with only limited thicknesses.In contrast,the Tahe segment,exhibiting comparatively high-elevation ancient landforms,is identified as the most favorable segment for the formation of large-scale reservoirs.The cap rocks of the platform margin are dominated by back-reef dolomitic flats and tight carbonate rocks formed in transgressive periods.A comprehensive evaluation of source rocks,reservoirs,and cap rocks indicates that the Tahe segment boasts the optimal hydrocarbon accumulation conditions along the platform margin.In this segment,the Shayilike Formation transgressive deposits and the high-energy mound-shoal complexes along the platform margin of the Wusonggeer Formation constitute the optimal reservoir-cap rock assemblage,establishing this segment as the most promising target for hydrocarbon exploration in the platform margin.展开更多
The reservoired petroleum fluids in the deep Ordovician carbonates in the Tazhong area,Tarim Basin,exhibit diverse and intricate geochemical properties and petroleum phases.However,the study on the causal mechanisms f...The reservoired petroleum fluids in the deep Ordovician carbonates in the Tazhong area,Tarim Basin,exhibit diverse and intricate geochemical properties and petroleum phases.However,the study on the causal mechanisms for the genesis of co-existed complex petroleum phases and their distribution remains relatively limited.The quantitative assessment of changes in molecular compounds in petroleum pools influenced by secondary alteration to different degrees also needs further investigation.In this study,eight samples including condensate,volatile,and black oil from the Tazhong area were analyzed via GC×GC-TOFMS.The results reveal that condensate oil exhibits complete normal alkane distribution,with abundant diamantanes and organic sulfur compounds(OSCs),and features high density(>0.83 g/cm^(3)),elevated wax content(>20%),and remarkable gas washing loss.The condensate gas is characterized by highly mature oil-cracking gas with a heavy carbon isotope.Geological analysis indicates that the current Ordovician reservoir temperatures generally remain below 140℃,which is insufficient to induce in-situ oil cracking.Additionally,black oil pools are formed adjacent to the condensate gas pools,suggesting that the latter is not a result of in-situ oil cracking,but rather represents a secondary condensate gas pool formed through gas invasion of a pre-existed oil pool.Based on the loss of n-alkanes and variations in adamantanes(As)and diamantanes(Ds)content across different oil samples,the degree of gas invasion was assessed.We divided gas invasion intensity into strong(Q≥80%,As≥5000μg/g,Ds≥400μg/g),weak(20%≤Q<80%,3000μg/g≤As<5000μg/g,200μg/g≤Ds<400μg/g)and negligible(0≤Q<20%,As<3000μg/g,Ds<200μg/g).The multistage oil/gas charging events,specifically the sequence of“early oil and late gas”in the Ordovician from the Tazhong area,predominantly drives the phase evolution of reservoired petroleum.Furthermore,differential gas invasion alteration exacerbates the intricacy of petroleum phase distribution.Notably,gas washing processes significantly influence the disparate enrichment of diamondoids homologues in crude oil.Specifically,lower carbon number diamondoids are more abundant in condensate oil,while higher ones exhibit relatively increased abundance in black oil,potentially serving as a valuable quantitative assessment parameter.The findings in this study will provide guiding significance for the analysis and quantitative assessment of deep petroleum phase diversity.Additionally,this research will provide novel insights for comprehensively evaluating basins worldwide with complex petroleum phases distribution.展开更多
Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground frac...Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground fractures within the complex three-dimensional geometry of strike-slip fault zones remains challenging.This study investigates the characteristics of natural fractures controlled by strike-slip faults in the fractured Middle and Lower Ordovician reservoirs of the central and northern Tarim Basin,China.Seismics,cores,and image logs were integrated to quantitatively analyze the intensity and dip angle of natural fractures and findings were verified using published sandbox simulations.The carbonate reservoir contains three main types of natural fractures:tectonic fractures,abnormal high-pressure-related fractures,and stylolites.Strike-slip faults control the distribution and characteristics of tectonic fractures across various scales.Generally,both fracture intensity and porosity exhibit a decreasing trend as the distance from the main fault surface increases.Compared with those in non-stepover zones along a strike-slip fault,natural fractures and faults in stepover zones are more developed along the fault strike,with significantly greater development intensity in central stepover regions than that at its two ends.Furthermore,strike-slip faults influence the dip angles of both natural fractures and secondary faults.The proportion of medium-to-low-dip angle fractures and faults in the stepover zone is greater than that in the non-stepover zone.Additionally,the proportion of medium-to low-dip angle fractures and faults in the middle of the stepover is greater than that at both ends.Therefore,strike-slip fault structures control the dip angle of natural fracture and the heterogeneity of secondary fault and fracture intensity.The linking damage zone in the stepover contains a larger volume of fractured rocks,making it a promising petroleum exploration target.The development of stepovers and the orientation of present-day in-situ stress substantially influence the productivity of fractured reservoirs controlled by strike-slip faults.The analysis in this study reveals that reservoir productivity increases as the angle between the strike-slip fault segment and the maximum horizontal principal stress decreases.This study provides valuable insights for quantitatively evaluating fracture heterogeneity in fractured reservoirs and establishing optimized selection criteria for favorable targets in fault-related fractured reservoirs.展开更多
The Tarim River Basin(TRB)is a vast area with plenty of light and heat and is an important base for grain and cotton production in Northwest China.In the context of climate change,however,the increased frequency of ex...The Tarim River Basin(TRB)is a vast area with plenty of light and heat and is an important base for grain and cotton production in Northwest China.In the context of climate change,however,the increased frequency of extreme weather and climate events is having numerous negative impacts on the region's agricultural production.To better understand how unfavorable climatic conditions affect crop production,we explored the relationship of extreme weather and climate events with crop yields and phenology.In this research,ten indicators of extreme weather and climate events(consecutive dry days(CDD),min Tmax(TXn),max Tmin(TNx),tropical nights(TR),warm days(Tx90p),warm nights(Tn90p),summer days(SU),frost days(FD),very wet days(R95p),and windy days(WD))were selected to analyze the impact of spatial and temporal variations on the yields of major crops(wheat,maize,and cotton)in the TRB from 1990 to 2020.The three key findings of this research were as follows:extreme temperatures in southwestern TRB showed an increasing trend,with higher extreme temperatures at night,while the occurrence of extreme weather and climate events in northeastern TRB was relatively low.The number of FD was on the rise,while WD also increased in recent years.Crop yields were higher in the northeast compared with the southwest,and wheat,maize,and cotton yields generally showed an increasing trend despite an earlier decline.The correlation of extreme weather and climate events on crop yields can be categorized as extreme nighttime temperature indices(TNx,Tn90p,TR,and FD),extreme daytime temperature indices(TXn,Tx90p,and SU),extreme precipitation indices(CDD and R95p),and extreme wind(WD).By using Random Forest(RF)approach to determine the effects of different extreme weather and climate events on the yields of different crops,we found that the importance of extreme precipitation indices(CDD and R95p)to crop yield decreased significantly over time.As well,we found that the importance of the extreme nighttime temperature(TR and TNx)for the yields of the three crops increased during 2005-2020 compared with 1990-2005.The impact of extreme temperature events on wheat,maize,and cotton yields in the TRB is becoming increasingly significant,and this finding can inform policy decisions and agronomic innovations to better cope with current and future climate warming.展开更多
This study investigated the impacts of Tibetan Plateau(TP) snow cover extent(SCE) on the interannual variation in spring precipitation over the Tarim Basin(SPTB) for the period 1980–2019. Significant anomalies in wes...This study investigated the impacts of Tibetan Plateau(TP) snow cover extent(SCE) on the interannual variation in spring precipitation over the Tarim Basin(SPTB) for the period 1980–2019. Significant anomalies in westerly winds,associated with a low-pressure anomaly in the northern Tarim Basin and a high-pressure anomaly in the southwestern basin, enhance moisture conveyance from upstream areas to the inland, thereby promoting increased SPTB. The analysis shows that anomalous snow over the northwestern and central-western TP, persisting from winter to spring, has a close relationship with SPTB variation. A localized energy budget analysis reveals that increased winter TP snow induces a cooling effect on the overlying atmosphere, resulting in an abnormal low-pressure system prevailing over the troposphere above the western TP. This anomalous low-pressure system can persist into the subsequent spring facilitated by the local snow–atmosphere feedback effects and energy conversion from the background flow. This persistence is accompanied by upward motion and moisture convergence, ultimately enhancing the SPTB. Further analysis indicates that anomalous warming in the Indian Ocean sea surface temperature(SST) during winter intensifies the subtropical high, facilitating the uplift and transport of warm moisture from lower latitude oceans to middle latitudes, thereby contributing to the increased TP snow and SPTB. Importantly, the impact of TP snow on SPTB is primarily independent of anomalous Indian Ocean SST in the northern Tarim Basin. This study elucidates a complex mechanism of ocean–land–atmosphere interaction,enhancing our understanding of SPTB variation and highlighting the significant role of TP snow in this process.展开更多
Recent exploration has highlighted the critical role of strike-slip faults in shaping ultra-deep carbonate reservoirs in the Tarim Basin.This study integrates satellite imagery,UAV photogrammetry,outcrop surveys and m...Recent exploration has highlighted the critical role of strike-slip faults in shaping ultra-deep carbonate reservoirs in the Tarim Basin.This study integrates satellite imagery,UAV photogrammetry,outcrop surveys and microscopic analysis to investigate the architecture of these faults and their impact on reservoir petrophysical properties.The strike-slip faults exhibit cores consisting of calcite bands,fault breccias and fractures,while the damage zones are predominantly fractured.Thicker fault cores and fault zones are associated with more extensive reservoir development.Individual strike-slip fault zones are primarily characterized by two sets of fractures intersecting the fault at small angles.When two fault systems interact,the dominant pattern is two sets of fractures intersecting the main fault at small angles and one set at larger angles,facilitating the formation of large-scale reservoirs.We propose a model for the fault core,which primarily consists of a calcite band and fault breccias.These breccias are composed of original host rock,calcite cement and quartz,which exhibit poor physical properties,while fractures and vugs show favorable reservoir characteristics.This model offers valuable insights into the development of fault-controlled reservoirs,particularly in the Tarim Basin.展开更多
The ultra-deep(deeper than 8000 m)petroleum in the platform-basin zones of the Tarim Basin has been found mainly in the Lower Paleozoic reservoirs located to the east of the strike-slip fault F5 in the north depressio...The ultra-deep(deeper than 8000 m)petroleum in the platform-basin zones of the Tarim Basin has been found mainly in the Lower Paleozoic reservoirs located to the east of the strike-slip fault F5 in the north depression.However,the source and exploration potential of the ultra-deep petroleum in the Cambrian on the west of F5 are still unclear.Through the analysis of lithofacies and biomarkers,it is revealed that there are at least three kinds of isochronous source rocks(SRs)in the Cambrian Newfoundland Series in Tarim Basin,which were deposited in three sedimentary environments,i.e.sulfide slope,deep-water shelf and restricted bay.In 2024,Well XT-1 in the western part of northern Tarim Basin has yielded a high production of condensate from the Cambrian.In the produced oil,entire aryl-isoprenoid alkane biomarkers were detected,but triaromatic dinosterane was absent.This finding is well consistent with the geochemical characteristics of the Newfoundland sulfidized slope SRs represented by those in wells LT-1 and QT-1,suggesting that the Newfoundland SRs are the main source of the Cambrian petroleum discovered in Well XT-1.Cambrian crude oil of Well XT-1 also presents the predominance of C29 steranes and is rich in long-chain tricyclic terpanes(up to C39),which can be the indicators for effectively distinguishing lithofacies such as siliceous mudstone and carbonate rock.Combined with the analysis of hydrocarbon accumulation in respect of conduction systems including thrust fault and strike-slip fault,it is found that the area to the west of F5 is possible to receive effective supply of hydrocarbons from the Cambrian Newfoundland SRs in Manxi hydrocarbon-generation center.This finding suggests that the area to the west of F5 will be a new target of exploration in the Cambrian ultra-deep structural-lithologic reservoirs in the Tarim Basin,in addition to the Cambrian ultra-deep platform-margin facies-controlled reservoirs in the eastern part of the basin.展开更多
This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistr...This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistry experiment and production test data,to systematically explore the control mechanisms of structure and fluid on the scale,quality,effectiveness and connectivity of ultra-deep fault-controlled carbonate fractured-vuggy reservoirs in the Tarim Basin.The results show that reservoir scale is influenced by strike-slip fault scale,structural position,and mechanical stratigraphy.Larger faults tend to correspond to larger reservoir scales.The reservoir scale of contractional overlaps is larger than that of extensional overlaps,while pure strike-slip segments are small.The reservoir scale is enhanced at fault intersection,bend,and tip segments.Vertically,the heterogeneity of reservoir development is controlled by mechanical stratigraphy,with strata of higher brittleness indices being more conducive to the development of fractured-vuggy reservoirs.Multiple phases of strike-slip fault activity and fluid alterations contribute to fractured-vuggy reservoir effectiveness evolution and heterogeneity.Meteoric water activity during the Late Caledonian to Early Hercynian period was the primary phase of fractured-vuggy reservoir formation.Hydrothermal activity in the Late Hercynian period further intensified the heterogeneity of effective reservoir space distribution.The study also reveals that fractured-vuggy reservoir connectivity is influenced by strike-slip fault structural position and present in-situ stress field.The reservoir connectivity of extensional overlaps is larger than that of pure strike-slip segments,while contractional overlaps show worse reservoir connectivity.Additionally,fractured-vuggy reservoirs controlled by strike-slip faults that are nearly parallel to the present in-situ stress direction exhibit excellent connectivity.Overall,high-quality reservoirs are distributed at the fault intersection of extensional overlaps,the central zones of contractional overlaps,pinnate fault zones at intersection,bend,and tip segments of pure strike-slip segments.Vertically,they are concentrated in mechanical stratigraphy with high brittleness indices.展开更多
0 INTRODUTION The Kuqa Depression,situated along the northern margin of the Tarim Basin,holds substantial geological significance due to its intricate sedimentary burial history,tectonic history,and the evolution of h...0 INTRODUTION The Kuqa Depression,situated along the northern margin of the Tarim Basin,holds substantial geological significance due to its intricate sedimentary burial history,tectonic history,and the evolution of hydrocarbon source rocks(Jiang et al.,2024;Zhang et al.,2023;Huang et al.,2019;Yang et al.,2017;Jia et al.,2003;Hendrix,2000).展开更多
Desertification poses a significant ecological threat to global sustainability,notably within arid regions such as the Tarim Basin surrounding the extensive Taklimakan Desert in Northwest China.This study used the Goo...Desertification poses a significant ecological threat to global sustainability,notably within arid regions such as the Tarim Basin surrounding the extensive Taklimakan Desert in Northwest China.This study used the Google Earth Engine(GEE)platform and Random Forest(RF)to analyze multi-temporal Landsat images to reveal desertification dynamics in the Tarim Basin spanning from 1990 to 2020.The results showed that land use types of the Tarim Basin were classified into three types:artificial oases,natural oases,and desertified land.To robustly quantify the spatiotemporal dynamics of land use,we introduced the Desertification Change Index(DCI),a novel metric specifically designed to measure the transformation sensitivity of land use types.Our analysis demonstrated that from 1990 to 2020,artificial oases showed a continuous increasing trend,while desertified land decreased significantly.Natural oases decreased during 1990–2000,then continued to grow,and showed a decreasing trend again after 2015.Moreover,natural oases have mainly been converted into desertified land and artificial oases.Artificial oases were mainly converted into natural oases,and most of desertified land was converted into natural oases.Regions with significant oasis expansion(DCI=2)were mostly concentrated within the influence radius of artificial oases.In contrast,regions with significant oasis degradation(DCI=–2)were generally farther from artificial oases.Finally,this study found that the changes in land use types of the Tarim Basin are mainly driven by human activities,which play a dual role—mitigating desertification by controlling oasis expansion and exacerbating desertification through unsustainable resource utilization.Ultimately,this research provides essential insights for policy-makers and land managers aiming to devise adaptive and sustainable desertification control measures in the Tarim Basin and similarly arid regions globally.展开更多
The strike-slip fault system in the central Tarim Craton controls a complex petroleum system with estimated reserves exceeding 1×10^(9)t,the fault-related fractures are important for hydrocarbon accumulation.In t...The strike-slip fault system in the central Tarim Craton controls a complex petroleum system with estimated reserves exceeding 1×10^(9)t,the fault-related fractures are important for hydrocarbon accumulation.In this paper,the basic parameters such as density and width of fractures are counted and classified,and the effects of fractures on reservoirs are analyzed.The results show that:(1)Structural fractures and stylolite were widely developed in Halahatang area and experienced at least three stages of activity based on the infilling materials and crosscutting relationship.(2)Fracture density,width,aperture,and dip angle vary in different wells,but the relationship between the above parameters and the distance to the fault core indicates the fracture differences in the fault damage zone and further provides a method to divide the inner units in the fault damage zone.In addition,oil and gas wells with high production mainly concentrate in the inner unit.(3)The infilling materials and degree of fractures vary.Fractures formed in the early stage are more filled and less open,while the fractures formed in the late stage are relatively less filled and more open.(4)Fractures improve porosity to a certain extent but greatly increase permeability,especially in the inner zone of fault damage zone with large quantity,multiple inclinations,less filling and large width.These features contribute to the formation of a higher-quality reservoir,further improving oil and gas production.This paper provides a quantitative characterization method for the study of strike-slip fault-related fracture-caved reservoirs,and points out that fault damage zone,especially the inner zone of the fault damage zone,is the potential goal for oil and gas exploration.展开更多
Significant exploration progress has been made in ultra-deep clastic rocks in the Kuqa Depression,Tarim Basin,over recent years.A new round of comprehensive geological research has formed four new understandings:(1)Es...Significant exploration progress has been made in ultra-deep clastic rocks in the Kuqa Depression,Tarim Basin,over recent years.A new round of comprehensive geological research has formed four new understandings:(1)Establish structural model consisting of multi-detachment composite,multi-stage structural superposition and multi-layer deformation.Multi-stage structural traps are overlapped vertically,and a series of structural traps are discovered in underlying ultra-deep layers.(2)Five sets of high-quality large-scale source rocks of three types of organic phases are developed in the Triassic and Jurassic systems,and forming a good combination of source-reservoir-cap rocks in ultra-deep layers with three sets of large-scale regional reservoir and cap rocks.(3)The formation of large oil and gas fields is controlled by four factors which are source,reservoir,cap rocks and fault.Based on the spatial configuration relationship of these four factors,a new three-dimensional reservoir formation model for ultra-deep clastic rocks in the Kuqa Depression has been established.(4)The next key exploration fields for ultra-deep clastic rocks in the Kuqa Depression include conventional and unconventional oil and gas.The conventional oil and gas fields include the deep multi-layer oil-gas accumulation zone in Kelasu,tight sandstone gas of Jurassic Ahe Formation in the northern structural zone,multi-target layer lithological oil and gas reservoirs in Zhongqiu–Dina structural zone,lithologic-stratigraphic and buried hill composite reservoirs in south slope and other favorable areas.Unconventional oil and gas fields include deep coal rock gas of Jurassic Kezilenuer and Yangxia formations,Triassic Tariqike Formation and Middle-Lower Jurassic and Upper Triassic continental shale gas.The achievements have important reference significance for enriching the theory of ultra-deep clastic rock oil and gas exploration and guiding the future oil and gas exploration deployment.展开更多
The Well Tashen 5(TS5),drilled and completed at a vertical depth of 9017 m in the Tabei Uplift of the Tarim Basin,NW China,is the deepest well in Asia.It has been producing both oil and gas from the Sinian at a depth ...The Well Tashen 5(TS5),drilled and completed at a vertical depth of 9017 m in the Tabei Uplift of the Tarim Basin,NW China,is the deepest well in Asia.It has been producing both oil and gas from the Sinian at a depth of 8780e8840 m,also the deepest in Asia in terms of oil discovery.In this paper,the geochemical characteristics of Sinian oil and gas from the well were investigated and compared with those of Cambrian oil and gas discovered in the same basin.The oil samples,with Pr/Ph ratio of 0.78 and a whole oil carbon isotopic value of31.6‰,have geochemical characteristics similar to those of Ordovician oils from the No.1 fault in the North Shuntuoguole area(also named Shunbei area)and the Middle Cambrian oil from wells Zhongshen 1(ZS1)and Zhongshen 5(ZS5)of Tazhong Uplift.The maturity of light hydrocarbons,diamondoids and aromatic fractions all suggest an approximate maturity of 1.5%e1.7%Ro for the samples.The(4-+3-)methyldiamantane concentration of the samples is 113.5 mg/g,indicating intense cracking with a cracking degree of about 80%,which is consistent with the high bottom hole temperature(179℃).The Sinian gas samples are dry with a dryness coefficient of 0.97.The gas is a mixture of kerogen-cracking gas and oil-cracking gas and has Ro values ranging between 1.5%and 1.7%,and methane carbon isotopic values of41.6‰.Based on the equivalent vitrinite reflectance(R_(eqv)=1.51%e1.61%)and the thermal evolution of source rocks from the Cambrian Yu'ertusi Formation of the same well,it is proposed that the Sinian oil and gas be mainly sourced from the Cambrian Yu'ertusi Formation during the Himalayan period but probably also be joined by hydrocarbon of higher maturity that migrated from other source rocks in deeper formations.The discovery of Sinian oil and gas from Well TS5 suggests that the ancient ultra-deep strata in the northern Tarim Basin have the potential for finding volatile oil or condensate reservoirs.展开更多
New discovery of the early Silurian fossil fish Changxingaspis(Xiushuiaspidae,Galeaspida),Changxingaspis nianzhongi sp.nov.and C.gui,are described from the Tataertag Formation in Tarim Basin and the Kangshan Formation...New discovery of the early Silurian fossil fish Changxingaspis(Xiushuiaspidae,Galeaspida),Changxingaspis nianzhongi sp.nov.and C.gui,are described from the Tataertag Formation in Tarim Basin and the Kangshan Formation in Zhejiang Province,respectively.C.nianzhongi mainly differs from C.gui in the shape of the median dorsal opening that is transverse elliptic with a width/length ratio of about 3.0,the long lateral transverse canals extending to the lateral margin of the headshield,and the second lateral transverse canal with dichotomous branchings.Discovery of C.nianzhongi from the Tataertag Formation and C.gui from the Kangshan Formation provide direct evidence on the specific level for the correlation between these two formations,which further supports the Silurian fish-bearing red beds in northwest Zhejiang belonging to the Silurian Lower Red Beds(LRBs)rather than the Upper Red Beds(URBs).Additionally,as the first record of the Changxingaspis in Tarim Basin,it extends the paleogeographical distribution of this genus from the South China Block to the Tarim Block,providing new evidence to support faunal exchanges between these two blocks and the hypothesis of a united Tarim-South China Block during the early Silurian.展开更多
According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the p...According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.展开更多
基金supported by the CNPC Science and Technology Major Project of the Fourteenth Five-Year Plan(2021DJ0101)the National Natural Science Foundation of China(U19B600302,41872148)。
文摘The Early Cambrian Yuertusi Formation(Є_(1)y)in the Tarim Basin of China deposits a continuously developed suite of organic-rich black mudstones,which constitute an important source of oil and gas reservoirs in the Paleozoic.However,its hydrocarbon generation and evolution characteristics and resource potential have long been constrained by deeply buried strata and previous research.In this paper,based on the newly obtained ultra-deep well drilling data,the hydrocarbon generation and expulsion model ofЄ_(1)y shale was established by using data-driven Monte Carlo simulation,upon which the hydrocarbon generation,expulsion,and retention amounts were calculated by using the diagenetic method.The research indicates that theЄ_(1)y shale reaches the hydrocarbon generation and expulsion threshold at equivalent vitrinite reflectances of 0.46%and 0.72%,respectively.The cumulative hydrocarbon generation is 68.88×10^(10)t,the cumulative hydrocarbon expulsion is 35.59×10^(10)t,and the cumulative residual hydrocarbon is 33.29×10^(10)t.This paper systematically and quantitatively calculates the hydrocarbon expulsion at various key geological periods for theЄ_(1)y source rocks in the study area for the first time,more precisely confirming that the black shale of theЄ_(1)y is the most significant source rock contributing to the marine oil and gas resources in the Tarim Basin,filling the gap in hydrocarbon expulsion calculation in the study area,and providing an important basis for the formation and distribution of Paleozoic hydrocarbon reservoirs.The prospect of deep ultra-deep oil and gas exploration in the Tarim Basin is promising.Especially,the large area of dolomite reservoirs under the Cambrian salt and source rock interiors are the key breakthrough targets for the next exploration in the Tarim Basin.
基金supported by the Science and Technology Program of Xinjiang Construction Corps(No.2024AB064)the National Natural Science Foundation of China(Nos.41975044,42001314)。
文摘Climate change is significantly impacting cotton production in the Tarim River Basin.The study investigated the climate change characteristics from 2021 to 2100 using climate change datasets simulated per the coupled model inter-comparison project phase six(CMIP6)climatic patterns under the shared socioeconomic pathways SSP2-4.5 and SSP5-8.5.The DSSAT-CROPGROCotton model,along with stepwise multiple regression analyses,was used to simulate changes in the potential yield of seed cotton due to climate change.The results show that while future temperatures in the Tarim River Basin will rise significantly,changes in precipitation and radiation during the cotton-growing season are minimal.Seed cotton yields are more sensitive to low temperatures than to precipitation and radiation.The potential yield of seed cotton under the SSP2-4.5 scenario would increase by 14.8%,23.7%,29.0%,and 29.4%in the 2030S,2050S,2070S,and 2090S,respectively.In contrast,under the SSP5-8.5 scenario,the potential yield of seed cotton would see increases of 17.5%,27.1%,30.1%,and 22.6%,respectively.Except for the 2090s under the SSP5-8.5 scenario,future seed cotton production can withstand a 10%to 20%deficit in irrigation.These findings will help develop climate change adaptation strategies for cotton cultivation.
基金financially supported by the National Natural Science Foundation of China(Nos.42067035 and 42007161)Water Conservancy Engineering Key Discipline Project of Xinjiang Agricultural University(No.SLXK2019-10)the Opening Project of Xinjiang Key Laboratory of Hydraulic Engineering Security and Water Disasters Prevention in 2021(No.ZDSYS-JS-2021-10)。
文摘Groundwater is the main water supply source in the Tarim Basin in China.Endemic disease caused by high iodine(I)groundwater in the Tarim Basin was reported previously.Therefore,it is crucial to systematically identify the distribution and genesis of groundwater I.Based on hydrochemical analysis of 717 groundwater samples collected in 2015–2018,spatial distribution and hydrogeochemistry characteristic of high I groundwater in different aquifers were analyzed.Results showed that groundwater I ranged between<10.00 and 4000.00μg/L(mean of 53.71μg/L).High I groundwater(I>100.00μg/L)accounted for 7.25%of the total samples.Horizontally,groundwater I significantly increased from recharge zone(RZ)to transition zone(TZ)and to evaporation zone(EZ).Vertically,groundwater in shallow confined aquifer(SCA)had the greatest I concentration,followed by single-structure phreatic aquifer(SSPA),phreatic aquifer in confined groundwater area(PACGA),while groundwater in deep confined aquifer(DCA)generally had low I concentration.Groundwater I enrichment in SSPA was mainly affected by organic matter(OM)decomposition and that in SCA was mainly affected by evaporite mineral dissolution,OM decomposition under alkaline environment.While I enrichment in groundwater of PACGA was restrained under neutral environment.Lacustrine sedimentary environment was crucial for I enrichment in groundwater.Besides,fine-grained lithology of aquifer,smooth topographic slope,shallow buried depth of groundwater,weak alkaline and reducing environment,reductive dissolution of iron oxide/hydroxide minerals and OM decomposition were advantageous to I enrichment in groundwater.
基金supported by Guizhou Provincial Science and Technology Projects(No.ZK[2021]ordinary 199)the National Natural Science Foundation of China(Nos.42262019,92062221)the National Key R&D Program of China(No.2017YFC0603103)。
文摘The Yingshan Formation of the Lower-Middle Ordovician in the Tarim Basin(NW China)was mainly deposited in a shallow platform,which was intensely bioturbated with burrows filled with both dolomites and calcites.This study aims to figure out the controls on the dolomitization of burrow infills and the effects on petroleum reservoir quality based on petrographic examination,fluid inclusion microthermometry,and isotopic(C-O-Sr)geochemical analyses.The differentiation of burrow-associated carbonates(dolomites and calcites)was likely controlled by the interactions of sea-level oscillations of variable orders and depositional environments.The burrow-associated dolomites(BADs)were precipitated in a relatively restricted(i.e.,lagoon)depositional environment during the lowstand of long-term sea level.In contrast,the burrow-associated calcites(BACs)were formed in a water circulation-improved lagoonal environment during the transgression of long-term sea level.Isotopic geochemical data indicate that the BADs in the Yingshan Formation were formed from slightly saline(i.e.,mesosaline to penesaline)seawater,whereas the BACs were precipitated from nearly normal seawater.In addition to the anoxic condition,the presence of marine-sourced organic matter and sulfate-reducing bacteria,and a sufficient supply of dolomitizing fluids enriched in magnesium ions(Mg^(2+))and their Mg^(2+)concentration may have played a critical role in the formation of BADs.In the more permeable and disturbed burrow sediments as a result of burrowing,penetrating fluids with higher salinities and higher Mg^(2+)concentration relative to seawater favored dolomite precipitation.The fluids with seawater-like Mg^(2+)concentration,however,would lead to calcite precipitation.The progressive dolomitization of these burrowed sediments could have propagated the dolomitizing fronts and extended into ambient limestones,leading to the development of extensive dolomites.This dolomitization process can improve the petrophysical properties(porosity and permeability)and the potential as hydrocarbon reservoirs during the emplacement of hydrocarbons from underlying source rocks of the Cambrian to Lower Ordovician.
基金supported by the National Natural ScienceFoundation of China(42102191)。
文摘Deep carbonate reservoirs affected by prominent strike-slip faults represent crucial targets in oil and gas exploration owing to their immense resource potential.However,the complex geological environments and poorly understood histories of the associated paleo-fluid activity have hindered the development of robust theories regarding pore formation and preservation mechanisms,resulting in suboptimal exploration strategies.Leveraging the extensive well deployment by the China Sinopec Group in the Shunbei area of the Tarim Basin,this study addresses these challenges by establishing a comprehensive framework for the evolution of diagenetic fluids within the Middle-Lower Ordovician carbonate formations.Using core samples,thin-section analysis,and cathodoluminescence observations,this study employs high-resolution geochemical methodologies,including isotopic analyses,rare earth element profiling,fluid inclusion studies,and uranium-lead dating,as primary tools for identifying and interpreting paleo-fluid characteristics across various rock types and calcite cement varieties within this stratigraphic interval.The findings reveal several key insights:(i)both RFC and C1 cements are derived from seawater,with C1 forming under burial conditions;(ii)C2,C3,and VC cements result from distinct tectonic events,specifically during the first and third episodes of the Middle Caledonian movement,with meteoric water infiltrating fault systems independently of orogenic belts or paleo-karst systems;and(iii)previous conclusions are challenged,as the influence of hydrothermal activity in this area is found to be minimal.Furthermore,the model presented here serves as a valuable reference for understanding fluid activity events at distal locations within orogenic belts under compressive stress,while accurately capturing fluid variations over different temporal scales within fault zones plays a decisive role.
基金funded by SINOPEC Science and Technology Research Program (project Nos:P24226, P24077)Northwest Oil Field Company,SINOPEC.
文摘The Cambrian platform margin in the Tarim Basin boasts favorable source-reservoir-cap assemblages,making it a significant target for hydrocarbon exploration in ultra-to extra-deep facies-controlled for-mations.Of the three major basins in western China,Tarim is the only basin with large-scale platform margin where no exploration breakthrough has been achieved yet.This study determines the vertical and lateral differential evolution of the platform margin(in the Manxi area hereafter referred to as the Cambrian Manxi platform margin)through fine-scale sequence stratigraphic division and a segmented analysis.The platform margin can be divided into the Yuqi,Tahe,Shunbei,and Gucheng segments,from north to south,based on the development of different ancient landforms and the evolutionary process of the platform.The Yuqi and Shunbei segments exhibit relatively low-elevation ancient landforms.Both segments were in a submarine buildup stage during the Early Cambrian,resulting in overall limited scales of their reservoirs.The Gucheng segment features the highest-elevation ancient landforms and accordingly limited accommodation spaces.As a result,the rapid lateral migration of high-energy facies zones leads to the development of large-scale reservoirs with only limited thicknesses.In contrast,the Tahe segment,exhibiting comparatively high-elevation ancient landforms,is identified as the most favorable segment for the formation of large-scale reservoirs.The cap rocks of the platform margin are dominated by back-reef dolomitic flats and tight carbonate rocks formed in transgressive periods.A comprehensive evaluation of source rocks,reservoirs,and cap rocks indicates that the Tahe segment boasts the optimal hydrocarbon accumulation conditions along the platform margin.In this segment,the Shayilike Formation transgressive deposits and the high-energy mound-shoal complexes along the platform margin of the Wusonggeer Formation constitute the optimal reservoir-cap rock assemblage,establishing this segment as the most promising target for hydrocarbon exploration in the platform margin.
基金jointly supported by the National Natural Science Foundation of China(Grant Nos.42002178 and 42472203)“CUG Scholar”Scientific Research Funds at China University of Geosciences(Grant No.2022193)China National Petroleum Corporation(CNPC)Scientific Research and Technology Development Projects(Grant Nos.2019B-04 and 2021DJ05)。
文摘The reservoired petroleum fluids in the deep Ordovician carbonates in the Tazhong area,Tarim Basin,exhibit diverse and intricate geochemical properties and petroleum phases.However,the study on the causal mechanisms for the genesis of co-existed complex petroleum phases and their distribution remains relatively limited.The quantitative assessment of changes in molecular compounds in petroleum pools influenced by secondary alteration to different degrees also needs further investigation.In this study,eight samples including condensate,volatile,and black oil from the Tazhong area were analyzed via GC×GC-TOFMS.The results reveal that condensate oil exhibits complete normal alkane distribution,with abundant diamantanes and organic sulfur compounds(OSCs),and features high density(>0.83 g/cm^(3)),elevated wax content(>20%),and remarkable gas washing loss.The condensate gas is characterized by highly mature oil-cracking gas with a heavy carbon isotope.Geological analysis indicates that the current Ordovician reservoir temperatures generally remain below 140℃,which is insufficient to induce in-situ oil cracking.Additionally,black oil pools are formed adjacent to the condensate gas pools,suggesting that the latter is not a result of in-situ oil cracking,but rather represents a secondary condensate gas pool formed through gas invasion of a pre-existed oil pool.Based on the loss of n-alkanes and variations in adamantanes(As)and diamantanes(Ds)content across different oil samples,the degree of gas invasion was assessed.We divided gas invasion intensity into strong(Q≥80%,As≥5000μg/g,Ds≥400μg/g),weak(20%≤Q<80%,3000μg/g≤As<5000μg/g,200μg/g≤Ds<400μg/g)and negligible(0≤Q<20%,As<3000μg/g,Ds<200μg/g).The multistage oil/gas charging events,specifically the sequence of“early oil and late gas”in the Ordovician from the Tazhong area,predominantly drives the phase evolution of reservoired petroleum.Furthermore,differential gas invasion alteration exacerbates the intricacy of petroleum phase distribution.Notably,gas washing processes significantly influence the disparate enrichment of diamondoids homologues in crude oil.Specifically,lower carbon number diamondoids are more abundant in condensate oil,while higher ones exhibit relatively increased abundance in black oil,potentially serving as a valuable quantitative assessment parameter.The findings in this study will provide guiding significance for the analysis and quantitative assessment of deep petroleum phase diversity.Additionally,this research will provide novel insights for comprehensively evaluating basins worldwide with complex petroleum phases distribution.
基金supported by the National Natural Science Foundation of China(No.U21B2062)funding from the Chinese Scholarship Council(CSC)and the American Association of Petroleum Geologists Foundation Grantsin-Aid Program.
文摘Natural fractures controlled by faults in ultradeep carbonate strata play substantial roles as both fluid migration channels and storage spaces.However,characterizing the heterogeneous distribution of underground fractures within the complex three-dimensional geometry of strike-slip fault zones remains challenging.This study investigates the characteristics of natural fractures controlled by strike-slip faults in the fractured Middle and Lower Ordovician reservoirs of the central and northern Tarim Basin,China.Seismics,cores,and image logs were integrated to quantitatively analyze the intensity and dip angle of natural fractures and findings were verified using published sandbox simulations.The carbonate reservoir contains three main types of natural fractures:tectonic fractures,abnormal high-pressure-related fractures,and stylolites.Strike-slip faults control the distribution and characteristics of tectonic fractures across various scales.Generally,both fracture intensity and porosity exhibit a decreasing trend as the distance from the main fault surface increases.Compared with those in non-stepover zones along a strike-slip fault,natural fractures and faults in stepover zones are more developed along the fault strike,with significantly greater development intensity in central stepover regions than that at its two ends.Furthermore,strike-slip faults influence the dip angles of both natural fractures and secondary faults.The proportion of medium-to-low-dip angle fractures and faults in the stepover zone is greater than that in the non-stepover zone.Additionally,the proportion of medium-to low-dip angle fractures and faults in the middle of the stepover is greater than that at both ends.Therefore,strike-slip fault structures control the dip angle of natural fracture and the heterogeneity of secondary fault and fracture intensity.The linking damage zone in the stepover contains a larger volume of fractured rocks,making it a promising petroleum exploration target.The development of stepovers and the orientation of present-day in-situ stress substantially influence the productivity of fractured reservoirs controlled by strike-slip faults.The analysis in this study reveals that reservoir productivity increases as the angle between the strike-slip fault segment and the maximum horizontal principal stress decreases.This study provides valuable insights for quantitatively evaluating fracture heterogeneity in fractured reservoirs and establishing optimized selection criteria for favorable targets in fault-related fractured reservoirs.
基金funded by the Tianshan Yingcai Program of the Xinjiang Uygur Autonomous Region(2022TSYCCX0038)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(Y2022108)the Postdoctoral Fellowship Program of Chinese Postdoctoral Science Foundation(CPSF)(GZC20232962).
文摘The Tarim River Basin(TRB)is a vast area with plenty of light and heat and is an important base for grain and cotton production in Northwest China.In the context of climate change,however,the increased frequency of extreme weather and climate events is having numerous negative impacts on the region's agricultural production.To better understand how unfavorable climatic conditions affect crop production,we explored the relationship of extreme weather and climate events with crop yields and phenology.In this research,ten indicators of extreme weather and climate events(consecutive dry days(CDD),min Tmax(TXn),max Tmin(TNx),tropical nights(TR),warm days(Tx90p),warm nights(Tn90p),summer days(SU),frost days(FD),very wet days(R95p),and windy days(WD))were selected to analyze the impact of spatial and temporal variations on the yields of major crops(wheat,maize,and cotton)in the TRB from 1990 to 2020.The three key findings of this research were as follows:extreme temperatures in southwestern TRB showed an increasing trend,with higher extreme temperatures at night,while the occurrence of extreme weather and climate events in northeastern TRB was relatively low.The number of FD was on the rise,while WD also increased in recent years.Crop yields were higher in the northeast compared with the southwest,and wheat,maize,and cotton yields generally showed an increasing trend despite an earlier decline.The correlation of extreme weather and climate events on crop yields can be categorized as extreme nighttime temperature indices(TNx,Tn90p,TR,and FD),extreme daytime temperature indices(TXn,Tx90p,and SU),extreme precipitation indices(CDD and R95p),and extreme wind(WD).By using Random Forest(RF)approach to determine the effects of different extreme weather and climate events on the yields of different crops,we found that the importance of extreme precipitation indices(CDD and R95p)to crop yield decreased significantly over time.As well,we found that the importance of the extreme nighttime temperature(TR and TNx)for the yields of the three crops increased during 2005-2020 compared with 1990-2005.The impact of extreme temperature events on wheat,maize,and cotton yields in the TRB is becoming increasingly significant,and this finding can inform policy decisions and agronomic innovations to better cope with current and future climate warming.
基金funded by the National Natural Science Foundation of China (Grant No.42275031)Natural Science Foundation of Yunnan Province (Grant No.202302AN360006)。
文摘This study investigated the impacts of Tibetan Plateau(TP) snow cover extent(SCE) on the interannual variation in spring precipitation over the Tarim Basin(SPTB) for the period 1980–2019. Significant anomalies in westerly winds,associated with a low-pressure anomaly in the northern Tarim Basin and a high-pressure anomaly in the southwestern basin, enhance moisture conveyance from upstream areas to the inland, thereby promoting increased SPTB. The analysis shows that anomalous snow over the northwestern and central-western TP, persisting from winter to spring, has a close relationship with SPTB variation. A localized energy budget analysis reveals that increased winter TP snow induces a cooling effect on the overlying atmosphere, resulting in an abnormal low-pressure system prevailing over the troposphere above the western TP. This anomalous low-pressure system can persist into the subsequent spring facilitated by the local snow–atmosphere feedback effects and energy conversion from the background flow. This persistence is accompanied by upward motion and moisture convergence, ultimately enhancing the SPTB. Further analysis indicates that anomalous warming in the Indian Ocean sea surface temperature(SST) during winter intensifies the subtropical high, facilitating the uplift and transport of warm moisture from lower latitude oceans to middle latitudes, thereby contributing to the increased TP snow and SPTB. Importantly, the impact of TP snow on SPTB is primarily independent of anomalous Indian Ocean SST in the northern Tarim Basin. This study elucidates a complex mechanism of ocean–land–atmosphere interaction,enhancing our understanding of SPTB variation and highlighting the significant role of TP snow in this process.
基金supported by the National Natural Science Foundation of China(Grant No.U21B2062).
文摘Recent exploration has highlighted the critical role of strike-slip faults in shaping ultra-deep carbonate reservoirs in the Tarim Basin.This study integrates satellite imagery,UAV photogrammetry,outcrop surveys and microscopic analysis to investigate the architecture of these faults and their impact on reservoir petrophysical properties.The strike-slip faults exhibit cores consisting of calcite bands,fault breccias and fractures,while the damage zones are predominantly fractured.Thicker fault cores and fault zones are associated with more extensive reservoir development.Individual strike-slip fault zones are primarily characterized by two sets of fractures intersecting the fault at small angles.When two fault systems interact,the dominant pattern is two sets of fractures intersecting the main fault at small angles and one set at larger angles,facilitating the formation of large-scale reservoirs.We propose a model for the fault core,which primarily consists of a calcite band and fault breccias.These breccias are composed of original host rock,calcite cement and quartz,which exhibit poor physical properties,while fractures and vugs show favorable reservoir characteristics.This model offers valuable insights into the development of fault-controlled reservoirs,particularly in the Tarim Basin.
基金Supported by the CNPC Science and Technology Project(2024ZZ0203)。
文摘The ultra-deep(deeper than 8000 m)petroleum in the platform-basin zones of the Tarim Basin has been found mainly in the Lower Paleozoic reservoirs located to the east of the strike-slip fault F5 in the north depression.However,the source and exploration potential of the ultra-deep petroleum in the Cambrian on the west of F5 are still unclear.Through the analysis of lithofacies and biomarkers,it is revealed that there are at least three kinds of isochronous source rocks(SRs)in the Cambrian Newfoundland Series in Tarim Basin,which were deposited in three sedimentary environments,i.e.sulfide slope,deep-water shelf and restricted bay.In 2024,Well XT-1 in the western part of northern Tarim Basin has yielded a high production of condensate from the Cambrian.In the produced oil,entire aryl-isoprenoid alkane biomarkers were detected,but triaromatic dinosterane was absent.This finding is well consistent with the geochemical characteristics of the Newfoundland sulfidized slope SRs represented by those in wells LT-1 and QT-1,suggesting that the Newfoundland SRs are the main source of the Cambrian petroleum discovered in Well XT-1.Cambrian crude oil of Well XT-1 also presents the predominance of C29 steranes and is rich in long-chain tricyclic terpanes(up to C39),which can be the indicators for effectively distinguishing lithofacies such as siliceous mudstone and carbonate rock.Combined with the analysis of hydrocarbon accumulation in respect of conduction systems including thrust fault and strike-slip fault,it is found that the area to the west of F5 is possible to receive effective supply of hydrocarbons from the Cambrian Newfoundland SRs in Manxi hydrocarbon-generation center.This finding suggests that the area to the west of F5 will be a new target of exploration in the Cambrian ultra-deep structural-lithologic reservoirs in the Tarim Basin,in addition to the Cambrian ultra-deep platform-margin facies-controlled reservoirs in the eastern part of the basin.
基金Supported by the National Natural Science Foundation of China(U21B2062).
文摘This study comprehensively uses various methods such as production dynamic analysis,fluid inclusion thermometry and carbon-oxygen isotopic compositions testing,based on outcrop,core,well-logging,3D seismic,geochemistry experiment and production test data,to systematically explore the control mechanisms of structure and fluid on the scale,quality,effectiveness and connectivity of ultra-deep fault-controlled carbonate fractured-vuggy reservoirs in the Tarim Basin.The results show that reservoir scale is influenced by strike-slip fault scale,structural position,and mechanical stratigraphy.Larger faults tend to correspond to larger reservoir scales.The reservoir scale of contractional overlaps is larger than that of extensional overlaps,while pure strike-slip segments are small.The reservoir scale is enhanced at fault intersection,bend,and tip segments.Vertically,the heterogeneity of reservoir development is controlled by mechanical stratigraphy,with strata of higher brittleness indices being more conducive to the development of fractured-vuggy reservoirs.Multiple phases of strike-slip fault activity and fluid alterations contribute to fractured-vuggy reservoir effectiveness evolution and heterogeneity.Meteoric water activity during the Late Caledonian to Early Hercynian period was the primary phase of fractured-vuggy reservoir formation.Hydrothermal activity in the Late Hercynian period further intensified the heterogeneity of effective reservoir space distribution.The study also reveals that fractured-vuggy reservoir connectivity is influenced by strike-slip fault structural position and present in-situ stress field.The reservoir connectivity of extensional overlaps is larger than that of pure strike-slip segments,while contractional overlaps show worse reservoir connectivity.Additionally,fractured-vuggy reservoirs controlled by strike-slip faults that are nearly parallel to the present in-situ stress direction exhibit excellent connectivity.Overall,high-quality reservoirs are distributed at the fault intersection of extensional overlaps,the central zones of contractional overlaps,pinnate fault zones at intersection,bend,and tip segments of pure strike-slip segments.Vertically,they are concentrated in mechanical stratigraphy with high brittleness indices.
基金supported by the National Key Research and Development Project(No.2019YFA0708601)the National Natural Science Foundation of China(No.4231101056)the Chinese Academy of Geological Sciences Basic Research Fund(No.JKYZD202402)。
文摘0 INTRODUTION The Kuqa Depression,situated along the northern margin of the Tarim Basin,holds substantial geological significance due to its intricate sedimentary burial history,tectonic history,and the evolution of hydrocarbon source rocks(Jiang et al.,2024;Zhang et al.,2023;Huang et al.,2019;Yang et al.,2017;Jia et al.,2003;Hendrix,2000).
基金supported by the Third Xinjiang Scientific Expedition and Research Program-Investigation and Risk Assessment of Drought and Aeolian Disasters in Tarim River Basin(2021xjkk0300)the Xinjiang Tianshan Talent Program(2022TSYCLJ0002)the Basic Frontier Project of Xinjiang Institute of Ecology and Geography,Chinese Academy of Sciences(E3500201).
文摘Desertification poses a significant ecological threat to global sustainability,notably within arid regions such as the Tarim Basin surrounding the extensive Taklimakan Desert in Northwest China.This study used the Google Earth Engine(GEE)platform and Random Forest(RF)to analyze multi-temporal Landsat images to reveal desertification dynamics in the Tarim Basin spanning from 1990 to 2020.The results showed that land use types of the Tarim Basin were classified into three types:artificial oases,natural oases,and desertified land.To robustly quantify the spatiotemporal dynamics of land use,we introduced the Desertification Change Index(DCI),a novel metric specifically designed to measure the transformation sensitivity of land use types.Our analysis demonstrated that from 1990 to 2020,artificial oases showed a continuous increasing trend,while desertified land decreased significantly.Natural oases decreased during 1990–2000,then continued to grow,and showed a decreasing trend again after 2015.Moreover,natural oases have mainly been converted into desertified land and artificial oases.Artificial oases were mainly converted into natural oases,and most of desertified land was converted into natural oases.Regions with significant oasis expansion(DCI=2)were mostly concentrated within the influence radius of artificial oases.In contrast,regions with significant oasis degradation(DCI=–2)were generally farther from artificial oases.Finally,this study found that the changes in land use types of the Tarim Basin are mainly driven by human activities,which play a dual role—mitigating desertification by controlling oasis expansion and exacerbating desertification through unsustainable resource utilization.Ultimately,this research provides essential insights for policy-makers and land managers aiming to devise adaptive and sustainable desertification control measures in the Tarim Basin and similarly arid regions globally.
基金supported by the Natural Science Foundation of China-Youth Foundation(42402163)Natural Science Foundation of Sichuan Province of China(2024NSFSC0814)Science and Technology Cooperation Project of the CNPC-SWPU Innovation Alliance(2020CX010101).
文摘The strike-slip fault system in the central Tarim Craton controls a complex petroleum system with estimated reserves exceeding 1×10^(9)t,the fault-related fractures are important for hydrocarbon accumulation.In this paper,the basic parameters such as density and width of fractures are counted and classified,and the effects of fractures on reservoirs are analyzed.The results show that:(1)Structural fractures and stylolite were widely developed in Halahatang area and experienced at least three stages of activity based on the infilling materials and crosscutting relationship.(2)Fracture density,width,aperture,and dip angle vary in different wells,but the relationship between the above parameters and the distance to the fault core indicates the fracture differences in the fault damage zone and further provides a method to divide the inner units in the fault damage zone.In addition,oil and gas wells with high production mainly concentrate in the inner unit.(3)The infilling materials and degree of fractures vary.Fractures formed in the early stage are more filled and less open,while the fractures formed in the late stage are relatively less filled and more open.(4)Fractures improve porosity to a certain extent but greatly increase permeability,especially in the inner zone of fault damage zone with large quantity,multiple inclinations,less filling and large width.These features contribute to the formation of a higher-quality reservoir,further improving oil and gas production.This paper provides a quantitative characterization method for the study of strike-slip fault-related fracture-caved reservoirs,and points out that fault damage zone,especially the inner zone of the fault damage zone,is the potential goal for oil and gas exploration.
基金Supported by the National Natural Science Foundation of China(U22B6002)PetroChina Science and Technology Project(2023ZZ14).
文摘Significant exploration progress has been made in ultra-deep clastic rocks in the Kuqa Depression,Tarim Basin,over recent years.A new round of comprehensive geological research has formed four new understandings:(1)Establish structural model consisting of multi-detachment composite,multi-stage structural superposition and multi-layer deformation.Multi-stage structural traps are overlapped vertically,and a series of structural traps are discovered in underlying ultra-deep layers.(2)Five sets of high-quality large-scale source rocks of three types of organic phases are developed in the Triassic and Jurassic systems,and forming a good combination of source-reservoir-cap rocks in ultra-deep layers with three sets of large-scale regional reservoir and cap rocks.(3)The formation of large oil and gas fields is controlled by four factors which are source,reservoir,cap rocks and fault.Based on the spatial configuration relationship of these four factors,a new three-dimensional reservoir formation model for ultra-deep clastic rocks in the Kuqa Depression has been established.(4)The next key exploration fields for ultra-deep clastic rocks in the Kuqa Depression include conventional and unconventional oil and gas.The conventional oil and gas fields include the deep multi-layer oil-gas accumulation zone in Kelasu,tight sandstone gas of Jurassic Ahe Formation in the northern structural zone,multi-target layer lithological oil and gas reservoirs in Zhongqiu–Dina structural zone,lithologic-stratigraphic and buried hill composite reservoirs in south slope and other favorable areas.Unconventional oil and gas fields include deep coal rock gas of Jurassic Kezilenuer and Yangxia formations,Triassic Tariqike Formation and Middle-Lower Jurassic and Upper Triassic continental shale gas.The achievements have important reference significance for enriching the theory of ultra-deep clastic rock oil and gas exploration and guiding the future oil and gas exploration deployment.
基金funded by projects of the National Natural Science Foundation of China(Nos.:42272167,U19B6003 and 41772153)projects of the Science&Technology Department of Sinopec(Nos.:P22121,P21058-8 and P23167).
文摘The Well Tashen 5(TS5),drilled and completed at a vertical depth of 9017 m in the Tabei Uplift of the Tarim Basin,NW China,is the deepest well in Asia.It has been producing both oil and gas from the Sinian at a depth of 8780e8840 m,also the deepest in Asia in terms of oil discovery.In this paper,the geochemical characteristics of Sinian oil and gas from the well were investigated and compared with those of Cambrian oil and gas discovered in the same basin.The oil samples,with Pr/Ph ratio of 0.78 and a whole oil carbon isotopic value of31.6‰,have geochemical characteristics similar to those of Ordovician oils from the No.1 fault in the North Shuntuoguole area(also named Shunbei area)and the Middle Cambrian oil from wells Zhongshen 1(ZS1)and Zhongshen 5(ZS5)of Tazhong Uplift.The maturity of light hydrocarbons,diamondoids and aromatic fractions all suggest an approximate maturity of 1.5%e1.7%Ro for the samples.The(4-+3-)methyldiamantane concentration of the samples is 113.5 mg/g,indicating intense cracking with a cracking degree of about 80%,which is consistent with the high bottom hole temperature(179℃).The Sinian gas samples are dry with a dryness coefficient of 0.97.The gas is a mixture of kerogen-cracking gas and oil-cracking gas and has Ro values ranging between 1.5%and 1.7%,and methane carbon isotopic values of41.6‰.Based on the equivalent vitrinite reflectance(R_(eqv)=1.51%e1.61%)and the thermal evolution of source rocks from the Cambrian Yu'ertusi Formation of the same well,it is proposed that the Sinian oil and gas be mainly sourced from the Cambrian Yu'ertusi Formation during the Himalayan period but probably also be joined by hydrocarbon of higher maturity that migrated from other source rocks in deeper formations.The discovery of Sinian oil and gas from Well TS5 suggests that the ancient ultra-deep strata in the northern Tarim Basin have the potential for finding volatile oil or condensate reservoirs.
基金supported by the National Natural Science Foundation of China(Grant Nos.92255301,41972006,42072026,42130209)Mee-mann Chang Academician Workstation in Yunnan Province(Grant No.202205AF150002)。
文摘New discovery of the early Silurian fossil fish Changxingaspis(Xiushuiaspidae,Galeaspida),Changxingaspis nianzhongi sp.nov.and C.gui,are described from the Tataertag Formation in Tarim Basin and the Kangshan Formation in Zhejiang Province,respectively.C.nianzhongi mainly differs from C.gui in the shape of the median dorsal opening that is transverse elliptic with a width/length ratio of about 3.0,the long lateral transverse canals extending to the lateral margin of the headshield,and the second lateral transverse canal with dichotomous branchings.Discovery of C.nianzhongi from the Tataertag Formation and C.gui from the Kangshan Formation provide direct evidence on the specific level for the correlation between these two formations,which further supports the Silurian fish-bearing red beds in northwest Zhejiang belonging to the Silurian Lower Red Beds(LRBs)rather than the Upper Red Beds(URBs).Additionally,as the first record of the Changxingaspis in Tarim Basin,it extends the paleogeographical distribution of this genus from the South China Block to the Tarim Block,providing new evidence to support faunal exchanges between these two blocks and the hypothesis of a united Tarim-South China Block during the early Silurian.
基金Supported by the Sichuan Province Regional Innovation Cooperation Project(21QYCX0048)Sinopec Science and Technology Department Project(P21048-3)。
文摘According to the complex differential accumulation history of deep marine oil and gas in superimposed basins,the Lower Paleozoic petroleum system in Tahe Oilfield of Tarim Basin is selected as a typical case,and the process of hydrocarbon generation and expulsion,migration and accumulation,adjustment and transformation of deep oil and gas is restored by means of reservoine-forming dynamics simulation.The thermal evolution history of the Lower Cambrian source rocks in Tahe Oilfield reflects the obvious differences in hydrocarbon generation and expulsion process and intensity in different tectonic zones,which is the main reason controlling the differences in deep oil and gas phases.The complex transport system composed of strike-slip fault and unconformity,etc.controlled early migration and accumulation and late adjustment of deep oil and gas,while the Middle Cambrian gypsum-salt rock in inner carbonate platform prevented vertical migration and accumulation of deep oil and gas,resulting in an obvious"fault-controlled"feature of deep oil and gas,in which the low potential area superimposed by the NE-strike-slip fault zone and deep oil and gas migration was conducive to accumulation,and it is mainly beaded along the strike-slip fault zone in the northeast direction.The dynamic simulation of reservoir formation reveals that the spatio-temporal configuration of"source-fault-fracture-gypsum-preservation"controls the differential accumulation of deep oil and gas in Tahe Oilfield.The Ordovician has experienced the accumulation history of multiple periods of charging,vertical migration and accumulation,and lateral adjustment and transformation,and deep oil and gas have always been in the dynamic equilibrium of migration,accumulation and escape.The statistics of residual oil and gas show that the deep stratum of Tahe Oilfield still has exploration and development potential in the Ordovician Yingshan Formation and Penglaiba Formation,and the Middle and Upper Cambrian ultra-deep stratum has a certain oil and gas resource prospect.This study provides a reference for the dynamic quantitative evaluation of deep oil and gas in the Tarim Basin,and also provides a reference for the study of reservoir formation and evolution in carbonate reservoir of paleo-craton basin.
