Discovery of Mass Independent Oxygen Isotopic Compositions in Superscale Nitrate Mineral Deposits from Turpan-Hami Basin,Xinjiang,China and Its Significance

The Turpan-Hami Basin in eastern Xinjiang is one of the driest regions on Earth and a premier environment to form and preserve nitrate.A large nitrate ore field in this basin was found recently.It is estimated there are about 2.5 billion tons of resources of nitrate,and the amount is as much as the Atacama Desert super-scale nitrate deposit in Chile.Nitrate is one of a few minerals with mass-independent fractionation（MIF）,and the oxygen isotope MIF is an effective method to determine the source of nitrate.Theδ^（17）O,δ^（18）O of nitrate were measured by fluorination and thermal decomposition method.The date indicated that this is the first time that oxygen isotope MIF has been located in inland nitrate minerals.The results obtained by two methods are similar,⊿^（17）=δ^（17）O-0.52×δ^（18）O=12‰-17‰.The experiment and observation data proved that oxygen isotope MIF of nitrate are the result of photochemical reactions in the troposphere and stratosphere.Thus, evidence from MIF oxygen isotopic compositions indicate that long term atmospheric deposition of nitrate aerosol particles produced by photochemical reactions is the source of the deposits.

The Characteristics and Genesis of the Massive Nitrate Deposits in the Turpan-Hami Basin of Xinjiang,China

Massive nitrate deposits have been discovered in the Turpan-Hami basin in northwestern China.Previously,large ore grade nitrate minerals were thought only to exist in the Atacama Desert in northern Chile.Estimates of the

Oil accumulation related to migration of source kitchens in the Lukeqin structural belt, Turpan-Hami Basin, China

The Lukeqin structural belt is the main heavy oil accumulation zone in the Turpan-Hami Basin. The recent discovery of light oil in the Triassic indicates that there may be multiple source kitchens contributing to the oil accumulation. According to oil geochemical analysis and oil-source correlation, the oil in deep and shallow reservoirs of the Lukeqin Oilfield presents different physical and saturated hydrocarbon mass spectrum characteristics. The Triassic heavy oil is from the northern Upper Permian lacustrine source rocks, and the light oil represented by the Yudong-9 Well is from the northwestern Lower Jurassic coal-measure source rocks. The timing of oil charging was determined by K/Ar isotope dating, reservoir fluid inclusion analysis and the evolution history of different source rocks. In summary, the accumulation process consists of two stages. From the end of Triassic to early Jurassic, the northern Permian source kitchen generated a considerable amount of oil, which was finally degraded to heavy oil, migrated to the south and then accumulated. The northwestern Jurassic coal-measure source kitchen began to generate oil at the end of Cretaceous, while the northern source kitchen could only generate a little hydrocarbon. The heavy oil and the light oil have different source rock locations, migration directions and accumulation times. The migration of hydrocarbon source kitchens affects the distribution of heavy oil and light oil reservoirs at the present time.

Types of Organic Fades and Source Rock Assessment of the Coal-Measure Mudstone in the Turpan-Hami Basin

This paper discusses the enviromental characteristics of carbonaceous mudstone and mudstone (coal-measure mudstone in short) of the Early and Middle Jurassic in the Turpan-Hami basin, which were formed in swamps. Through the organic facies study of the coal-measure mudstone in this area, the authors clarify that the flowing-water swamp is the most advanced organic facies belt. Furthermore, according to the practical materials of coal-measure mudstone in the area and with the evaluation criteria of lacustrine mudstone in the past, the authors have established the integrated symbol systems from the abundance of organic matter and the type of organic matter, which can be used in the source rock evaluation of the coal-measure mudstone.

The World's Largest Soda-Niter Ore Intensive Region Found in the Turpan–Hami Basin

The Xinjiang Geology and Mineral Resources Exploration and Development Bureau have conducted a detailed investigation project of the Xigobi soda-niter deposit in Hami, Xinjiang Province, which was completed at the end of 2011. The project put much emphasis on research of soda-niter mineralization rules, stratum classification, ore-forming

Provenance Variability of the Triassic Strata in the TurpanHami Basin: Detrital Zircon Record of Indosinian Tectonic Reactivation in the Eastern Tianshan

The Triassic strata in the Turpan-Hami Basin potentially chronicled the missing sedimentary record of Indosinian tectonic evolution in the Eastern Tianshan.In this study,we conducted detrital zircon U-Pb geochronological analyses on subsurface Triassic samples collected from the Turpan-Hami Basin to unravel sedimentary response of Indosinian tectonic reactivation and its geodynamics.The detrital zircon age spectra of the Triassic samples are quite different,reflecting significant provenance variability.The zircon grains in the Lower Triassic sample were mainly from the Central Tianshan,while the Jueluotag acted as a minor provenance.By contrast,the Late Paleozoic rocks in Jueluotag act as the main provenance for the Middle-Upper Triassic samples,while the Central Tianshan acted as a minor provenance.Furthermore,zircon grains in the Middle Triassic sample were mainly from the Permian rocks in Jueluotag,while Indosinian strike-slipdriven rapid exhumation brought deeper Carboniferous rocks of Jueluotag as an important age population for the Upper Triassic sample.The inter-sample variability of age spectra of the Triassic samples provides sedimentary evidence for Indosinian tectonic reactivation in the Eastern Tianshan and its periphery,which could be attributed to differential exhumation of different sources driven by coeval strike-slip tectonics along deep faults.The Indosinian tectonic behavior in the Eastern Tianshan,which is characterized by partial melting of the pre-thickened crust and strike-slip deformation,acted as a far-field respond to the coeval continental accretion occurring along the southern Eurasian margin.Additionally,our new detrital zircon data,together with previously published data in the Turpan-Hami Basin,demonstrate that there are significant changes in source-to-sink system from the Permian to the Triassic,suggesting that the Permian-Triassic unconformity in the Eastern Tianshan and its periphery was generated by Late Permian-Early Triassic tectonic contraction and inversion rather than an increasingly arid climate.

Early and Middle JurassicPalaeogeography of the Turpan-Hami Basin

The Turpan-Hami oil basin is well known for its Jurassic oil-prone coal. The palaeogeograpbical units or the Early and Middle Jurassic coal measures iuclude braided chaunel-alluvial plain, meandering channel-alluvial plain, upper delta plain, lower delta plain, subaqueous delta, inter-deltaic bay,lacustrine bay and sballow lake euvironments. The beneficial environments for coal accumulation were tke inter-delta bay and the lower delta plain where intermediate subsidence was maintaiued and there was little input of coarse graiued ediments.

Sequence Stratigraphy and Paleogeography of the Early and Early Middle Jurassic Coal Measures in the Turpan-Hami Basin,Northwestern China

This paper analyses the sequence stratigraphy and palaeogeography of the Early and early Middle Jurassic coal measures in the Turpan-Hami Basin, northwestern China.The controls of the palaeogeography and sequence stratigraphy on the coal accumulation in this basin have been discussed.The results show that the coal measures were formed in a fluvial-delta-lacustrine sedimentary system,and a total of 4 third-order sequences were developed,

Stable carbon and hydrogen isotopic characteristics of natural gas from Taibei sag, Turpan-Hami Basin, NW China

Turpan-Hami Basin is a major petroliferous basin in China. To date the natural gas exploration is concentrated in the Taibei sag. The origin and source of natural gas in the Taibei sag has long been controversial. To further investigate the origin and source of the natural gas in the Taibei sag, combined with previous studies and the local geological backgrounds, this study collected 23 gas samples from the Baka, Qiuling, Shanshan and Wenmi oil fields in the Taibei sag and analyzed the sample composition, stable carbon and hydrogen isotopes of all the gas samples. The results show that, gases from the four oil fields in the Taibei sag are dominated by hydrocarbon gas and belong to wet gas. Methane accounts for 65.84% to 97.94%, the content of heavy hydrocarbon (C2-5) can be up to 34.98%, while the content of nonhydrocarbon (CO2, N2) is trace. The δ13C1 value is –44.9‰ to –40.4‰,δ13C2 is –28.2‰ to –24.9‰,δ13C3 is –27.1‰ to –18.0‰ and δ13C4 is –26.7‰ to –22.1;while the variation of δD1 is not significant from –272‰ to –252‰,δD2 is –236‰ to –200‰ and δD3 is –222‰ to –174‰. Methane and its homologues (C2-5) are characterized by normal stable carbon and hydrogen isotopic distribution pattern, i.e., with the increase of carbon number, methane and its homologues become more and more enriched in 13C or D (δ13C1<δ13C2<δ13C3<δ13C4<δ13C5,δD1<δD2<δD3), which is consistent with the carbon and hydrogen isotopic features of typical thermogenic gas. All these results show that the natural gases in the four oil fields are coal-derived gas with low maturity (Ro averaged at 0.7%), and are sourced from the Middle-Lower Jurassic coal measure. The hydrogen isotopic data of natural gas are affected by both thermal maturity and the water medium of the environment where source rocks are formed. The hydrogen isotopic data indicate that the source rocks are formed in terrestrial limnetic facies with freshwater. Natural gases from Well Ba23 and Well Ke19 experienced biodegradation in the late stage.

Zircon U-Pb SHRIMP Ages from the Late Paleozoic Turpan-Hami Basin,NW China

Permian volcanic rocks are widely distributed in the Turpan-Hami Basin, which is part of the Central Asian orogenic belt. Here we present SHRIMP zircon data for the rhyolite in Well Baocan 1, one of the deepest wells in the basin. The 283.9±2.7 Ma reported in our study provides the best precise age determination for the Yierxitu Formation, the oldest Permian layer of Hami Depression, one of the three substructural units of the Turpan-Hami Basin, and a potential hydrocarbon reservoir in this basin. Our data refines earlier imprecise 39^Ar-40^Ar ages and shows that the volcanic rocks both inside the Turpan-Hami Basin and along its margin are almost coeval. We delineate a collisional orogenesis, and the new age of 283.9±2.7 Ma may limit the latest time of the collision orogenesis.

Geochemical characteristics of light hydrocarbons in natural gases from the Turpan-Hami Basin and identification of low-mature gas

Theoretical and practical knowledge regarding low-mature gasses is of significant importance to identifying potential natural gas resources.Light hydrocarbon parameters and C and H isotopes are useful tools to identify low-mature gas.Twenty gas samples were collected from the Turpan-Hami Basin for light hydrocarbon analyses.The results showed that the light hydrocarbon components of natural gases contain high methylcycloxane,high isoparaffin and low benzene.This implies that the gas-generating parent materials are of typical humus type and the paleoenvironment is a fresh water sedimentary environment.These features are consistent with the geological setting of the basin.Comparative studies of isoheptane,heptane,and the carbon isotopic compositions of methane in natural gases,and other maturity indices indicated that natural gases in the Turpan-Hami Basin are dominated by low-mature gas formed during the low evolution stage of Jurassic coal seams.The parent materials are of type III,and the maturation degree was in the low evolution stage.These are the fundamental characteristics of low-mature gas.Results of light hydrocarbon research provided further evidence to suggest that the Turpan-Hami Basin is a large-scale gas producer of low-mature gas in China.It is likely that this resource will play an important role in future exploration and development of low-mature gas in China.

Development characteristics of interlayer oxidation zone type of sandstone uranium deposits in the southwestern Turfan-Hami basin

The Turfan-Hami basin is the key area for the exploration of sandstone uranium deposits of the leachable interlayered oxidation zone type. The aim of this study is to shed light on the development characteristics of this type of uranium deposits and provide new clues to further exploration. Detailed study led to the following conclusions: (1) uranium orebodies are hosted mainly in the lower Middle Jurassic Xishanyao Formation and the lower Lower Jurassic Badaowan Formation; (2) the formation of uranium orebodies is closely related to organic matter; (3) the front of the interlayered oxidation zone is snake-shaped in plane and imbricated in the section; the more the interlayered oxidation zone and zonation are developed, the better the uranium mineralization will be; according to lithological and geochemical characteristics, the oxidation zone, the oxidation-reduction transitional zone and the reduction zone can be distin-guished; (4) the development of interlayered oxidation zone is controlled by geological structure, underground water, sandstone permeability and other factors; (5) sandstone uranium orebodies hosted in the interlayered oxidation zone are very complicated in spatial distribution, of which some are rolled and plated in shape and some are highly variable in shape.

Paleogeothermal gradient and geologic thermal history of the Turpan-Hami Basin, Xinjiang

Synthetical research has been done on the geological thermal history of the Turpan-Hami Basin by using vitrinite reflectance, fluid inclusion geothermometry and fission track. The geotcmperature of the Turpan-Hami Basin has the character that suggests higher temperature in the past, in the east and south of the basin, and in the areas of large-fracture, and lower temperature in the present day and in the west and north of the basin. This feature is controlled by the difference of burial depth of basement and heat flow values, which made Permian source rock mature in the late Triassic and Jurassic source rock mature at the end of Jurassic and the early Tertiary.

Analysis on Hydrological Regimes of the Medium and Small Rivers in Hami of Xinjiang——Take Toudaogou Basin as an Example

[ Objective] The research aimed to analyze hydrological regimes of the medium and small rivers in Hami of Xinjiang. [ Method] According to actual observation data at Toudaogou hydrological station during 1956 -2010, climate, runoff, flood, sediment and water quality in the basin were analyzed. [ Result] Runoff in Toudaogou River was mainly from bedrock fissure water and rainfall, and depended on temperature and precipi- tation in the catchment zone. Runoff in Toudaogou River had very big change during the year. Runoff in whole year mainly concentrated during April -June, which occupied 57.9% of annual runoff. Flood in Toudaogou basin was divided into spring and summer flood from time, and snowmelt and rainstorm flood from type. Sediment load was related to terrain, gradient, runoff, precipitation, flood and process. Suspended sediment load at Toudaogou hydrological station had close relationship with the annual maximum flow capacity of flood peak, and related coefficient was 0.917. [ Conclusion] Hydrological regime in Toudaogou basin basically represented corresponding hydrological information of rivers without glacier water supply in Hami even whole western arid zone of China. The research could provide theoretical basis for scientifically using water resources of the medium and small rivers in the zone.

吐哈盆地台北凹陷中侏罗统西山窑组深层煤岩气地质特征与勘探潜力

深层煤岩气是吐哈盆地油气勘探的新领域,但研究程度相对较低。基于煤岩测试与基础资料,系统研究了吐哈盆地台北凹陷中侏罗统西山窑组煤层分布、煤岩煤质、储层物性、宏微观煤岩、煤储层气源及煤岩等温吸附特征,揭示了煤岩储层含气性及其影响因素,提出了深层煤岩气形成富集条件,建立了深层煤岩气富集成藏模式,预测了台北凹陷煤岩气勘探潜力。结果表明:(1)台北凹陷深层侏罗系西山窑组煤层分布广、厚度大,为中低阶、原生结构、割理发育的低灰、低水、富镜质组煤层;(2)煤储层孔渗较高且受埋深影响不明显,煤层段气测异常普遍且储层吸附性能中等—好,具有游离气与吸附气共存、试采快速见气、气组分齐全等特征;(3)台北凹陷煤岩气的油气供给充注,可以形成正向构造带“调整型”和斜坡及洼陷区“自生自储型”两种成藏模式;(4)台北凹陷煤岩气资源丰富,西山窑组主煤层煤岩气资源量近3×10^(12)m^(3)。根据煤岩气资源丰度、煤层厚度、含气量、保存条件等综合评价优选出温吉桑构造带、小草湖南斜坡为深层煤岩气勘探有利目标区。

基于PLUS-InVEST模型吐哈盆地陆地生态系统碳储量时空变化及多情景模拟

土地覆盖变化能够改变区域碳储存能力,从而引起全球气候变化。研究土地覆盖变化对碳储量的影响,预测未来不同土地覆盖情景下的碳储量,对实现区域“碳中和”战略目标具有重要意义,然而目前针对中国西部生态脆弱区的研究仍有待探究。以新疆吐哈盆地为研究区,基于土地覆盖产品数据,结合PLUS模型和InVEST模型,探讨了土地覆盖变化与区域碳储量的时空变化关系,预测和评估了2025、2030年可持续发展情景,维持现状发展情景,经济优先发展情景下土地覆盖和碳储量的时空动态特征。结果表明:(1)近20 a来,吐哈盆地耕地和裸土地面积增加最大,其次是建设用地,而草地表现出最大的减少趋势,草地转为耕地和建设用地是最主要的转移类型。(2)2000、2010年和2020年吐哈盆地平均碳储量分别为26.01 t·hm~(-2)、25.68 t·hm~(-2)、25.73 t·hm~(-2),呈现出先降低后增加的趋势,平均碳储量累计减少了0.28 t·hm~(-2),其中土壤有机质碳储量占比最高,约占总碳储量的94%,裸土地、草地贡献了最多的碳储量。(3)2030年3种情景下,森林、灌木林、湿地几乎无明显变化,裸土地呈现出减少的趋势,而建设用地呈现增加的趋势。(4)到2030年可持续发展情景下吐哈盆地总碳储量较2020年增加了0.18×10~6t,维持现状发展情景和经济优先发展情景下分别减少了0.30×10~6t、1.01×10~6t,经济优先发展情景下碳储量损失最大。研究结果可为吐哈盆地土地利用优化以及制定生态系统可持续发展措施提供依据。

深层煤层气水平井安全钻井技术

针对吐哈盆地深层煤层气的勘探,前期以直井试采为主,水平井的钻井技术仍处于探索阶段。由于该区块属于高陡斜坡区、煤系地层发育,导致直井段井斜易超标、煤系地层的井眼井壁易失稳、水平井井段的轨迹难以控制及固井质量差等问题,文章通过分析高陡斜坡区提速限制因素,引入自动垂钻系统,形成直井段防斜打快技术,解决了高陡斜坡区防斜和大钻压快速钻进的矛盾;分析煤层井壁失稳机理,开展浸泡实验,优选了胺基有机盐钻井液体系,提高抑制性和封堵固结井壁性能,强化了煤系地层井壁稳定;结合深层煤层三压力剖面预测数据优化井身结构及轨迹控制,设计防卡PDC钻头和钻具组合,配套强抑制、强封堵性胺基有机盐钻井液,实现了煤层水平段安全延伸;强化钻井参数,应用岩屑清洁工具和个性化通井钻具组合,提高了井眼清洁效率;优化套管选型、扶正器配置及水泥浆体系,保障了固井质量。该系列技术为实现吐哈盆地深层煤层气水平井安全高效钻探奠定了基础。

吐哈盆地丘东洼陷碱泉子沟断裂描述及致密油气控藏分析

走滑断裂在油气成藏中具有重要的控制作用,其识别、判断和对油气藏控制要素的研究分析是当前勘探的热点。文中首次在吐哈盆地台北凹陷丘东洼陷中部发现碱泉子沟断裂,为了落实其空间展布特征、成因机制及其对油气藏的控制作用,开展了进一步研究。结果表明:碱泉子沟断裂在露头上水平错动、在剖面上断面陡直且发育“花状构造”、在平面上呈“雁列式”展布,并具有“四层构造”特征,走滑特征明显;碱泉子沟断裂是照壁山大断裂的派生次级走滑断裂,沿Sylveser简单剪切模式中的R′剪切面发育,结合流体包裹体均一温度推测其形成于晚印支期,早—中燕山期活动强烈,晚燕山期活动减弱;碱泉子沟断裂具有控圈、控储、控运和控藏作用,其空间结构、活动期次和与成藏期次的匹配关系决定油气运聚的流体相态、油气排替顺序和聚集位置,尤其是断裂中下层结构在中燕山期活动,后续静止封闭,这是导致下侏罗统致密油气藏大面积分布的重要原因。研究成果对吐哈盆地致密油气勘探具有非常重要的指导意义。

吐哈盆地低煤阶煤岩孔隙结构精细表征及吸附性主控因素评价

为研究吐哈盆地低煤阶煤岩孔隙结构及其吸附特性,探讨煤岩吸附性能主控因素,通过高压压汞、低温液氮、核磁共振及等温吸附实验,对该盆地主要含煤地区低煤阶煤的孔隙结构及其甲烷吸附性影响因素进行了精细表征与分析。结果表明:①低煤阶煤岩发育多种吸附—脱附曲线,孔隙类型主要以细颈瓶状的一端封闭型孔为主,连通性较差。②吸附孔比表面积主要由微孔贡献,而吸附孔孔容主要由小孔提供,比表面积等孔隙结构参数差异大。③核磁共振实验表明煤样发育多种孔裂隙系统,但主要以微、小孔为主,中大孔及裂隙相对发育。④煤岩吸附性能受煤岩煤质及吸附孔孔隙结构共同控制,灰分及水分不利于甲烷的吸附。⑤镜质组孔隙发育,与最大吸附气量呈正相关关系;不同尺度吸附孔隙的吸附性能差异明显,小孔孔容及比表面积与最大吸附气量呈正相关关系,是吐哈盆地低煤阶煤岩吸附性能的主要贡献者。

三塘湖-吐哈盆地富油煤赋存特征与资源潜力分析

富油煤是焦油产率≥7%且具备煤、油、气属性的特殊煤炭资源,是煤炭清洁利用的重要资源和开发方向,对缓解国家油气资源紧缺、推动煤化工突破性发展具有重要的科学价值。新疆东部盆地蕴藏着大量富油煤资源,为探明富油煤的赋存特征与分布规律,通过沉积环境分析,结合煤工业分析、元素分析、格金低温干馏测试等手段研究东疆富油煤聚煤规律与赋存特征,采用地质块段法估算富油煤资源量。结果表明:三塘湖盆地富油煤层主要分布于八道湾组上段(J_(1)b^(2))、三工河组(J_(1)s)以及西山窑组下段(J_(2)x^(1))3个层位,焦油产率约13.67%,总体属高油煤;吐哈盆地富油煤发育在西山窑组中段(J_(2)x^(2)),焦油产率约7.6%,总体为含-富油煤。区内富油煤总体特征为特低-中低水分、低-中低灰分、中高-高挥发分,焦油产率高,富含镜质组和壳质组等生油组分,煤化程度低,形成于湖泊-三角洲的沉积环境。研究区富油煤资源潜力大,估算三塘湖盆地2000 m以浅的富油煤资源量约670.83亿t,吐哈盆地2000 m以浅的富油煤资源量约417.55亿t,可采煤层平均厚度达9 m以上。为有效动用富油煤资源,提出煤炭地下干馏的技术设想,即通过石油工程技术在地下煤层建立热量导入和产品产出通道,通过人工加热方式使煤原位发生干馏反应,热解产物包括焦油、煤气(CH_(4)、H_(2)、轻烃C_(2+)等)、水等,煤中的碳元素主要以半焦形式留在地下,产生的二氧化碳可为三塘湖-吐哈盆地的油田提供气驱气源,剩余的二氧化碳可以利用半焦层原位埋存。煤炭地下干馏通过“取氢留碳”实现煤炭资源清洁转化,有望成为富油煤低碳绿色开发的重要技术方向。