The strike-slip fault system in the eastern Yuqi area of the Caohu Sag, distinct from the conjugate strike-slip fault systems in the Halahatang Sag, provides a valuable case study for understanding the genetic variations among strike-slip faults across different locations within the Tabei Uplift. This system in the eastern Yuqi area comprises ENE-, NE-, N-S-, and E-W-oriented strike-slip faults. The development of the ENE- and NE-oriented faults was primarily influenced by the paleostructure, specifically the structural slope-break zone. The evolution of these fault sets can be divided into three main stages: (1) In the Late Ordovician, initial uplift occurred in the Akekule Uplift and the northern Caohu Sag, leading to the development of the western Akekule Uplift as a paleostructural high. Conjugate faults formed in the western Akekule Uplift, constrained by the rigid Yakela Fault-convex. (2) During the Silurian to Early Devonian, northward compression and subsequent extrusion along the Akekumu Fault resulted in the formation of a series of ENE- and NE-oriented sinistral strike-slip faults in the western Yuqi area, at the leading edge of the Akekumu Fault. Simultaneously, the structural slope-break zone began to develop in the eastern Yuqi area, controlling the formation and orientation of the NE- and ENE-oriented faults. (3) In the Permian, increased N-S-trending regional compression, driven by the closure of the South Tianshan Ocean, led to the formation of the reverse fault RF-ENE1 and an upward-steepening interlayer reverse fault (RF-CAO2). NEoriented strike-slip faults, such as Fault YQ13, were reactivated, and NS-oriented strike-slip faults, including Fault YQD and Fault Lungudong, potentially experienced sinistral strike-slip movement.

The Tarim Basin, with its relatively low level of exploration, is one of China's largest superimposed petroliferous basins. Recent exploration advancements in the Shunbei-Shunnan area highlight the significant potential for ultra-deep marine natural gas. However, uncertainties surrounding the origin, alteration, and accumulation models of ultra-deep marine natural gas have greatly hindered future hydrocarbon exploration. This study systematically analyzes the geochemical characteristics and genesis of ultra-deep marine natural gas in the Shunbei-Shunnan area. Results indicate that the natural gas in this region comprises both primary and oil-cracking gases. Specifically, the Shunbei area's natural gas is primarily oil-associated, dominated by primary cracking gas with minor contributions from oil-cracking gas, whereas the Shunnan area's natural gas is predominantly oil-cracking gas. The maturity of marine natural gas varies, being higher near the Manjiaer Depression and relatively lower farther away. A sequential distribution of highly mature dry gas, condensate oil and gas, volatile oil, and light oil, accompanied by a gradual decrease in gas-oil ratio, is observed with increasing distance from the Manjiaer Depression. The marine natural gas in the Shunbei-Shunnan area has undergone various alterations, including cracking, thermochemical sulfate reduction, and hydrothermal fluid alteration. Hydrocarbon alteration is more pronounced in the Shunnan area than in the Shunbei area. The active period of strike-slip faults in the Shunbei-Shunnan area coincides with the major hydrocarbon generation and expulsion phases of the source rock. These strike-slip faults serve as critical conduits for hydrocarbon migration, enabling oil and gas to migrate vertically into the middle and upper Ordovician reservoirs, where they form the primary reservoir spaces for accumulation.

Typical condensate reservoirs have been developed in the No.4 fault zone of the Shunbei area in the Tarim Basin. However, exploration expansion is restricted due to the unclear genetic mechanisms and main controlling factors of condensate accumulation. Through a comprehensive analysis of organic geochemical characteristics and the regional geological background, the genetic mechanisms and main controlling factors of condensate accumulation in the No.4 fault zone of the Shunbei area have been identified, and the following understandings are mainly obtained: (1) the condensate oil and gas reservoirs in the No.4 fault zone of the Shunbei area are mainly primary condensate reservoirs, and their formation is mainly affected by differential maturation of organic matter, multi-phase accumulation, and secondary alteration; (2) the overall secondary effects on the condensate oil and gas reservoirs in the Shunbei No.4 fault zone are relatively weak, however, the secondary effect experienced by the middle and southern sections is relatively stronger compared to the northern section; these secondary processes include oil cracking, gas invasion, and thermochemical sulfate reduction (TSR); and (3) the enrichment degree of condensate oil and gas reservoirs in the northern section of the Shunbei No.4 fault zone is significantly higher than in the middle and southern sections; the enrichment and high production of condensate oil and gas are mainly controlled by transport conditions and reservoir scale. Stronger fault activity, better transport conditions, larger reservoir size, and thinner gypsum-salt rock layers facilitate the upward migration of oil and gas along strike-slip faults, leading to higher production and enrichment of condensate.

The Tarim Basin is the largest superimposed and oil-bearing basin in China, presented as an episodic tectonic superposition in the Central uplift. Understanding hydrocarbon differential accumulation in the Central uplift requires a proper view of the evolution of the early Paleozoic carbonate platform. Through detailed twodimensional seismic interpretation, paleogeographic and paleotectonic reconstructions of the carbonate platform are performed. Tying hydrocarbon accumulation elements to the dynamic evolutionary process of the carbonate platform, this paper provides new insights into hydrocarbon differential accumulation in the Tazhong and Bachu uplifts. Due to ongoing compression from the south, the Hetian paleohigh and the Tazhong uplift initially formed in the Cambrian -Middle Ordovician carbonate platform interior in the latest Middle Ordovician. The climax of uplifting and northward tilting of preexisting paleohighs occurred in the latest Ordovician and latest Middle Devonian, respectively. The carbonate platform suffered polyphase exposures in these paleohighs and strike -slip faulting in the northern slope of the Tazhong uplift, forming favorable karst reservoirs and strike -slip fault -controlled reservoirs. Following the latest Permian uplifting of the northwestern Hetian paleohigh, the Bachu uplift nucleated in the northern Hetian paleohigh in the Cenozoic. The southwestern Hetian paleohigh was inverted into a southwest -dipping monocline. In the Bachu uplift, the allochthonous hydrocarbons from the southwestern Hetian paleohigh underwent episodic migration, accumulation, adjustment, and destruction during the evolution of these uninherited paleohighs. The hydrocarbons mainly remain in structuralstratigraphic traps in the southern margin of the Bachu uplift. Multiple periods of gentle tilting have occurred in the Tazhong uplift since the Late Devonian. Episodic migrating hydrocarbons from autochthonous and neighboring source rocks in the north are enriched in the northern flank of the inherited Tazhong uplift.

The Shunbei oil-and-gas field in the Tarim Basin features a typical strike-slip fault-controlled fractured-vuggy reservoir. The formation of these reservoirs is primarily influenced by fracturing related to structural stress during periods of fault activity. This contrasts with reservoir types such as matrix vugs controlled by original sedimentary facies and caves modified by karst. To study the development mechanism and distribution patterns of strike-slip fault-controlled reservoirs under the influence of multi-stage structural stress, comprehensive analysis of field observations, core samples, well logging data, seismic surveys, and drilling dynamic data was conducted to characterize the development characteristics of fault-controlled reservoirs. This included different strike-slip faults, different parts along a single strike-slip fault, and different stratigraphic levels vertically. Combined with stress field numerical modeling, multi-stage structural stress recovery was carried out to predict the main development periods and distribution patterns of fault-controlled reservoirs. Significant variations in internal stress states were observed across different segments during periods of strike-slip fault activity. Tensile stress predominated in pull-apart segments, resulting in predominantly tensile fractures, whereas compressional stress state in push-up segments led to a variety of fracture types. The fault-controlled fractures in the top of the Yijianfang Formation in the Shunbei area were mainly developed during episode Ⅲ of the Middle Caledonian period and the Late Caledonian-Early Hercynian period. Few fractures were developed during the Middle to Late Hercynian period and thereafter. Compared to the Shunbei No.1 fault, the Shunbei No.18 fault exhibited higher fracture opening degree and density with a large displacement. Strike-slip fault-controlled reservoirs exhibit a cluster-like structure. Structural differences of the reservoirs are influenced by internal stress states in different segments during fault activity. Pull-apart segments typically feature a large fault core-damage zone with more cavities and 'double-cluster' structures, whereas push-up segments display more diverse fault core-damage zones with greater separability and 'multi-cluster' structures. The stress intensity during the strike-slip fault activity controls the types and scale of reservoir spaces, with smaller fault zones dominated by fractures and larger fault zones developing extensive fault core-damage zone architectures. The scale of fault-controlled reservoirs is positively correlated with fault activity intensity. Early fault activity promotes significant fracture development, while later stages, characterized by increased burial depths, result in few newly derived fractures due to reduced rock susceptibility to fracturing.

There are abundant hydrocarbon resources in the strike-slip fault-controlled ultra-deep carbonate reservoirs in the Shunbei area, Tarim Basin. Large strike-slip faults and natural fractures are the main storage space and flow channel of hydrocarbon resources. It is of great significance to study the natural fracture development characteristics in such reservoirs. 39 limestone samples and 7 dolomite samples from 5 wells in Shunbei area are taken as research objects. Through the analysis of thin section of lithofacies, fine description of natural fractures and brittleness test evaluation of core samples, the main controlling factors and influence laws of natural fracture development in Shunbei reservoir are studied. It is found that the reservoir lithology of Middle and Lower Ordovician Yingshan Formation and Yijianfang Formation in Shunbei area is dolomite and limestone, and the lithofacies include grainstone, wackestone, packstone, boundstone, muddy limestone, silicified limestone, silty-fine crystal dolomite and medium-coarse crystal dolomite. In limestone samples, muddy limestone has the highest brittleness index and natural fracture development density, while boundstone has the lowest brittleness index and natural fracture development density. In dolomite samples, the brittleness index of medium-coarse crystalline dolomite is higher than that of silty-fine crystal dolomite, and the coarser the grains are, the more developed the natural fractures are. There is a positive correlation between the natural fracture development density and the brittleness index of rock samples. The porosity, permeability and brittleness index of dolomite are higher than those of limestone. Under the same brittleness index, the fracture development ability of limestone is stronger. Therefore, the highly brittle section of limestone stratum is more likely to be the geological sweet spot in Shunbei area.

随着高精度连片三维地震资料的采集,塔里木盆地克拉通内部发育的中小滑移距走滑断裂呈现出复杂的空间结构与构造样式.为此,以顺北12号断裂为研究对象,开展了顺北12号断裂及派生构造的三维空间结构、活动特征和活动期次的精细解析与成因机制分析.结果表明:(1)顺北地区主干走滑断裂自西向东挤压变形逐渐增强,其中顺北12号断裂处于NE向走滑断裂体系的过渡位置,构造样式上既发育西侧弱挤压断裂体系的"拉分-平移-压隆"三段式分段结构,也发育东侧强挤压断裂体系的"压脊构造".(2)顺北12号断裂碳酸盐岩顶面北部发育NE20°走向派生分支断裂,浅层发育沿下伏主干断裂走向展布的雁列正断层,上部雁列正断层活动强烈,连接形成扇形雁列带,下部主干断裂线性发育,从而形成了一种上部连片发育雁列正断层、下部发育高陡直立断裂的新的分层变形样式.(3)在盆缘动力背景影响下,顺北12号断裂及其派生分支经历了3期左行走滑活动:在加里东中期Ⅲ幕顺北12号断裂及其派生分支断裂初始活动;加里东晚期,深部断裂活化并相互影响,拖曳上覆地层形成第一期雁列正断层;海西中期,形成第二期雁列正断层.

塔里木盆地顺北5号走滑断裂是顺北及邻区一条克拉通内小尺度走滑断裂带,整体分为3段:北段、中段和南段.选取顺北5号断层北段为研究对象,结合断层几何学和运动学解析,应用构造物理模拟实验,明确了走滑断层的变形特征与形成机制.结果表明:顺北5号断层北段主体表现为多段式特征,发育平直型、压隆型和拉分型3种类型构造样式.北段主要活动时期为加里东中期Ⅲ幕与加里东晚期,表现为两期异向叠加变形作用,早期(T74 界面)表现为多种组合样式分段生长特征,晚期(T70界面)表现为雁列式正断层分布特征.基于顺北5号断层北段砂箱物理模拟证实,早期走滑作用控制断层分段变形特征,晚期张扭作用控制着雁列式断层的分布规律.因此,"分期-异向"叠加变形控制了顺北5号断层北段走滑断层的变形过程和形成机制.

Fracture system plays an essential role in controlling the migration and accumulation of hydrocarbon. Previous study indicated that strike-slip fault is composed of several geometric segments. Each geometric segment is a set of independent reservoir units. Through the study of high-quality 3D seismic volume and drilling data on the north slope of Tazhong Uplift, as well as the analysis results of pressure build-up curves and logging data of typical wells, the structural style and hydrocarbon accumulation mechanism of the strike-slip fault on the north slope of Tazhong Uplift are described. The results show that the internal structure of S-1 fault on the north slope of Tazhong Uplift can be divided into five types of fracture cave structures, which are (1) linear main sliding surface; (2) isolated slit holes; (3) breakthrough fracture belt; (4) composite breakthrough fracture belt; (5) fracture zone with strong continuity along fault strike. The production data show that the drilling fluid production capacity of the breakthrough fracture belt and fracture zone with strong continuity along fault strike is the strongest, indicating that the breakthrough fracture belt is the main contribution unit of the reservoir. The above five structural units are consistent with the structure of the fault outcrop of the Hochwab Block in the Austrian Alps. The difference of structural type is caused by the differential fragmentation during the active period of strike-slip faults. The most serious fragmentation is in the pull-apart segment and uplift segment, which is easy to form breakthrough fracture belt. While relatively weak linear structures are developed in the translation segment, which also indicates that the pull-apart segment or uplift segment is the favorable position for reservoir development. This study provides a scientific basis for oil and gas exploration and development in the field of deep and ultra-deep carbonate rocks.

The No. 5 fault zone in Shunbei area, a main strike-slip fault zone running through two paleo-uplifts and being devided into north, middle, south and uplifted segments, has always been the focus of research on the formation and evolution of the strike-slip fault system in Shunbei area and its surroundings. In this study, the latest high-precision 3D seismic data newly acquired and processed are applied to carry out the fine analysis of the uplifted segment of the No. 5 fault zone in Shunbei area, determining its geometric and kinematic characteristics and revealing its formation and evolution process. According to the change of strike angle and segmented deformation pattern, the uplifted segment of the study area can be divided into three sections: the north translational section (NE16°) (uplifted segement Ⅰ), the middle pull-apart section (NE19°) (uplifted segment Ⅱ), and the south compressional-uplifted section (NE25°) (uplifted segment Ⅲ). The uplifted segment in the study area develops a layered deformation pattern composed of high and steep strike-slip faults and multiple suites of en echelon normal faults from bottom to top, while undergoing multistage strike-slip activities during the Middle Caledonian, Late Caledonian, Middle-to-Late Hercynian and Indosinian-Early Himalayan periods. In the study area, the strike-slip activities feature “strong in the segments Ⅱ and Ⅲ, weak in the segment I”. Under the influence of stress transmission from south to north, the south and uplifted segments present sinistral strike-slip from south to north with No. 1 fault zone in Tazhong area as the boundary at the initial stage of development, while the north and middle segments present dextral strike-slip from north to south, with the maximum principal stress deflecting from NW to NE. After the Late Caledonian period, the No. 5 fault zone in Shunbei area presented sinistral strike-slip as a whole, while during the Indosinian-Early Himalayan periods, the uplifted segment reversed to dextral strike-slip, with the maximum principal stress reversing from NW to NE.

Based on the relative content and isotopic composition characteristics of helium in natural gas of multiple structural units in Tarim Basin, combined with geological background and typical helium rich gas reservoirs, the geochemical characteristics and favorable exploration areas of helium in the basin are analyzed. The results show that helium rich natural gas in the Tarim Basin is well displayed, and the helium rich natural gas in platform area is better than that in foreland area. The helium in the Tarim Basin is mainly of crust origin. There is a positive correlation between the relative content of helium and nitrogen in the natural gas of the Tarim Basin, to a certain extent. When the relative content of nitrogen in the gas reservoir is high, the relative content of helium is also high. The general survey of helium exploration in Tarim Basin can focus on the gas reservoirs with high relative content of nitrogen. Helium may migrate mainly in the form of water-soluble in geological bodies, and its accumulation, possibly, are closely related to formation water. Influenced by the difference of partial pressure of different substances in formation water, combined with the Henry’s law analysis, formation water can play the role of “helium pump” in the process of helium-rich natural gas accumulation. Good transport system and high-quality helium source are the basis for the formation of helium rich gas reservoirs. Many blocks in Tarim Basin have good helium rich natural gas display, especially in structural units such as the Shaya Uplift, Katake Uplift, Maigaiti slope and Bachu Uplift. This series of structural units has good helium source and natural gas accumulation conditions, which is conducive to the accumulation of helium rich natural gas. This series of structural units is the preferred block for helium exploration in the Tarim Basin. The Shunbei area has a good prospect for natural gas exploration, and this structural unit is a key block for marine natural gas exploration during the “14th Five-Year Plan”. Therefore, helium exploration and general survey in this area should be strengthened.

氦气是一种重要的战略稀缺资源, 通常与天然气伴生. 中国目前仅发现塔里木盆地和田河气田一例特大型富氦气田. 本文报道了鄂尔多斯盆地东胜气田新的实例, 该气田为首例致密砂岩型特大富氦气田. 鄂尔多斯盆地东胜气田92个天然气样品中氦气相对含量数据统计分析表明, 该气田天然气中氦气平均含量为0.133%, 其中有65个样品氦气含量不小于0.1%, 占比70.7%. 按照东胜气田探明天然气储量折算, 探明氦气地质储量约1.96×108m3, 为我国首个特大致密砂岩型富氦天然气藏. 结合东胜气田5个天然气样品中氦气同位素组成分布区间为3.03×10−8~3.44×10−8, 认为该气田氦气为典型壳源成因, 氦气源为基底富含铀、钍的花岗质基岩. 富氦天然气成藏受到区域构造活动控制, 沟通基底的断裂开启使得源岩中氦气释放, 沿断裂进入上覆地层与常规烃类气体混合聚集成藏. 结合鄂尔多斯盆地构造背景以及氦源岩分布特征, 该盆地北部与中部深层可能是氦气富集主要区域, 具勘探潜力.

为加深对塔里木盆地顺北地区岩浆侵入作用的研究,运用研究区丰富的三维地震资料,在详细刻画火成岩侵入体及相关构造发育特征和展布规律的基础上,建立了岩浆的垂向侵入模式,确立了岩浆的侧向流动方向,探讨了其石油地质意义.结果 表明,顺北地区的碟形火成岩侵入体一般沿中、下奥陶统顶界面及以上界面层状叠置分布,碟形岩床之上发育逆断层和高陡裂隙两类构造,由此自下而上形成了"岩浆通道、叠置岩床、高陡构造"的岩浆垂向侵入模式.碟形岩床及相关构造的展布特征表明,该区岩浆自深部侵入到中、下奥陶统顶界面之后自北向南呈放射状侧向流动.研究火成岩侵入体对储层的改造作用和相关逆断层对油气的运聚作用有利于开拓顺北地区乃至整个塔里木盆地的油气勘探新领域.

在走渭断裂精细解析的基础上,综合利用成像测开、试开和生广动念资科,探讨了顺北油气田顺北1亏、顺北5亏、顺北4亏走滑断裂带的分段差异变形对规模储集体发育和油藏分布的控制作用.顺北地区主干走滑断裂带在几何学、运动学及活动特征方面差异显著,具有"一带一世界"的特点.其中,顺北1号断裂带在三维工区内发育9个左阶斜列展布的几何分段,分段间均发育叠接拉分段;顺北5号断裂带北段以发育压隆段—平移段为主,中段以发育平移段和分支断裂为主,南段发育"两侧地堑断面+中部主走滑断面"复合构造样式;顺北4号断裂带在三维工区内呈"S"形展布,根据走向变化可划分北段、中段和南段,具有"南北挤压、中部拉张"的分段结构特征.顺北地区走滑断裂的内部结构受断裂活动强度控制,随着活动强度增大,碳酸盐岩断裂带内部结构由发育程度较低的裂缝带逐步演化为发育程度较高的破碎角砾带-裂缝带,储集体规模也逐渐增大.顺北1号断裂带的断控规模储集体分段发育,不同分段的储集体内部结构差异明显且多不连通,同一分段的储集体相互连通,具有"一段一油藏"的特征.走滑断裂的差异变形控制了油气差异成藏,其中,受控于晚期活动"北强南弱"的差异,顺北1号断裂带北部分段井组的气油比普遍大于南部井组;顺北5号断裂带南段的中部主走滑断面直接沟通烃源岩层,具有"控储、控藏、控富"特征,而地堑断面未直接沟通烃源岩层,其钻揭的储集体与油气藏规模远小于中部主走滑断面.走滑断裂的断面具有垂向非均质性,受断面活动强度和地层能干性的控制,同一断面不同深度的靶点钻遇储集体的规模差异显著,具有"一点一规模"的特征.研究结果深化了对塔里木盆地内部走滑断裂差异变形特征的认识,可为走滑断裂断控缝洞型油气藏的勘探评价提供重要借鉴.

In this review on the exploration and development process of the Shunbei ultra-deep carbonate oil and gas field in the Tarim Basin, the progress of exploration and development technologies during the National 13th Five-Year Plan of China has been summarized systematically, giving important guidance for the exploration and development of ultra-deep marine carbonate reservoirs in China and abroad. Through analyzing the primary geological factors of "hydrocarbon generation-reservoir formation-hydrocarbon accumulation" of ancient and superposed basin comprehensively and dynamically, we point out that because the Lower Cambrian Yuertusi Formation high-quality source rocks have been located in a low-temperature environment for a long time, they were capable of generating hydrocarbon continuously in late stage, providing ideal geological conditions for massive liquid hydrocarbon accumulation in ultra-deep layers. In addition, strike-slip faults developed in tectonically stable areas have strong control on reservoir formation and hydrocarbon accumulation in this region. With these understandings, the exploration focus shifted from the two paleo-uplifts located in the north and the south to the Shuntuoguole lower uplift located in between and achieved major hydrocarbon discoveries. Through continuing improvement of seismic exploration technologies for ultra-deep carbonates in desert, integrated technologies including seismic acquisition in ultra-deep carbonates, seismic imaging of strike-slip faults and the associated cavity-fracture systems, detailed structural interpretation of strike-slip faults, characterization and quantitative description of fault-controlled cavities and fractures, description of fault-controlled traps and target optimization have been established. Geology-engineering integration including well trajectory optimization, high efficiency drilling, completion and reservoir reformation technologies has provided important support for exploration and development of the Shunbei oil and gas field.

板内中小滑移距走滑断裂因产状高陡、变形微弱,其地震识别与地质解析一直以来是构造领域研究的难点和重点.为加深对此类走滑断裂发育特征的认识,以塔里木克拉通盆地内部顺北4号走滑断裂为例,利用最新采集处理的高精度三维地震资料,对其空间结构及演化过程进行了精细解析,认为顺北4号断裂具有"平面分段多样性、纵向变形差异性、构造演化多期性"的特点,石油地质条件优越.研究结果表明:顺北4号断裂横跨塔北隆起、顺托果勒低隆起、塔中隆起3大构造单元,全长超过280 km,基于走向变化可将三维研究区内的顺北4号断裂划分为南段(NE48°)、中段(NE28°)、北段(NE42°),各段之间叠接面积超2 km2,南段和北段以叠接压隆构造发育为主,中段以叠接拉分构造发育为主;顺北4号断裂纵向自下而上发育"寒武系—中奥陶统高陡走滑断层"+"上奥陶统—石炭系雁列正断层"的分层变形样式,下部高陡断面在3个刚性—塑性岩性地层分界面普遍呈现走滑分段性,其中中—下奥陶统碳酸盐岩顶部可识别出13个断面,平均长度为8 km,上覆雁列正断层的活动强度与下部高陡走滑断层的应变分段性质有关;顺北4号断裂共经历了3期左行走滑活动,加里东中期Ⅲ幕在塔北—塔中体系对接过程中多段拼贴发育,加里东晚期和海西中—晚期均为雁列正断层活动,在三维研究区内呈现"南北弱、中部强"的活动特征.

The connection between source rock and reservoir separated by salt strata is a global problem. Taking Tarim Basin as a typical case, this paper studies how the No. 5 strike-slip fault passes through the salt layers. The No. 5 strike-slip fault system in the Shuntuoguole Low Uplift in the Tarim Basin, China, interacts with Cambrian salt layers at depth. In the present study, a part of this fault system was investigated to assess structural characteristics of the Yijianfang (Ordovician carbonate layer) and the Wusonggeer (Cambrian salt layer) formations. Seismic data reveal three structural styles in the salt layer including transpression, transtension, and pure strike-slip. In transpressional segments, the salt layer is thinned accross the fault plane; transtensional segments involve minor reactive salt diapirs, and pure strike-slip segments display no noticeable variation in the salt thickness. The impact of the deep strike-slip salt tectonics on petroleum exploration in the area is discussed using data from seven wells. Wells in transpressional segments, where the salt is thin, are characterized by good production, whereas those in transtensional segments, where the salt is thick, exhibit poor production. The salt prevents the migration of oil and gas along the strike-slip fault. Strike-slip salt structures examined in the present study improve the understanding of the associated tectonics in the central Tarim Basin and provide insights on hydrocarbon migration and accumulation in the basin.

氦气是一种重要的战略稀缺资源,通常与天然气伴生.中国目前仅发现塔里木盆地和田河气田一例特大型富氦气田.本文报道了鄂尔多斯盆地东胜气田新的实例,该气田为首例致密砂岩型特大富氦气田.鄂尔多斯盆地东胜气田92个天然气样品中氦气相对含量数据统计分析表明,该气田天然气中氦气平均含量为0.133%,其中有65个样品氦气含量不小于0.1%,占比70.7%.按照东胜气田探明天然气储量折算,探明氦气地质储量约1.96×108m3,为我国首个特大致密砂岩型富氦天然气藏.结合东胜气田5个天然气样品中氦气同位素组成分布区间为3.03×10-8～3.44×10-8,认为该气田氦气为典型壳源成因,氦气源为基底富含铀、钍的花岗质基岩.富氦天然气成藏受到区域构造活动控制,沟通基底的断裂开启使得源岩中氦气释放,沿断裂进入上覆地层与常规烃类气体混合聚集成藏.结合鄂尔多斯盆地构造背景以及氦源岩分布特征,该盆地北部与中部深层可能是氦气富集主要区域,具勘探潜力.