THE EVOLUTION OF THE LANKAO-LIAOCHENG FRACTURAL ZONE AND ITS OIL-GAS ACCUMULATION

The Lankao-Liaocheng Fractural Zone is a large-seade NNE-trending struetural zone in the North China Crustoblock. Dated from the Late Arehean-Early Proterozoie, it is stil1 active now. Its nature varied with time in its developing process. It has became a tensile ultralithospherie fraetural zone at present or in diwa residual-mobility period. Some cenozoic oil-gas-bearing basins are distributed along the fraetural zone which fomed an important oil-gas accumulating belt in the North China Ctustoblock.

Bedrock outcropping in the accumulation zone of the largest glacier in Mexico(Glaciar Norte of Citlaltépetl),as evidence of a possible accelerated extinction

The highest volcano in Mexico,at the same time the third largest mountain in North America(Citlaltépetl,5610 m a.s.l.),is home to the largest glacier in the country.Because of the extinction of the Popocatépetl glacier(5500 m a.s.l.)caused by eruptive activity,and the almost disappearance of the Iztaccíhuatl glaciers(5220 m a.s.l.)due to the lower elevation of the mountain,the Glaciar Norte of Citlatépetl has been the only glacier that has shown a certain degree of stability as a response to the altitude in which it is located.However,as occurs in almost all glaciers on the planet,the retreat of its glacier terminus has been continuous.Furthermore,during the last years the thickness of its upper part began to decrease rapidly until its bedrock was exposed for the first time in 2019.Due to its ecosystem importance and because it is the main glacier in Mexico,as well as the only one in the world located at latitude 19°N,in this work its current dimensions are updated,as well as the local climatology that governs the current state of the glacier is pointed out.The study was based on the analysis of high-resolution Sentinel-2 optical images,as well as through Sentinel-1 SAR images,with the support of climatological information from the study area.Therefore,the outcropping of the bedrock in the accumulation zone and the consequent horizontal retreat of the upper part of the glacier are documented;at the same time,the decrease in the thickness of the ice along it is noted.The rocky outcrop in the accumulation zone suggests that the flow dynamics of the ice towards the ablation zone will be considerably less,accelerating the retreat of the glacier terminus.Finally,the ascent of the glacial front to 5102 m a.s.l.and the modelled altitude of the equilibrium line to 5276 m a.s.l.are reported as a warning signal in terms of snow catchment and mass balance;likewise,the decrease of 23%of its surface is also indicated regarding the surface reduction monitoring that has been done until 2017.These findings may indicate that the future of this glacier is related to its possible extinction sooner than previously thought,with severe environmental consequences,especially in terms of the provision of drinking water for thousands of inhabitants of the slopes of the volcano.This research is expected to help reflect on the impacts of current climate variability and at the same time serve as a reference for the tropical glaciers on the planet.

Research advances on transfer zones in rift basins and their influence on hydrocarbon accumulation

Transfer zones are structural areas of faults interactions where fault motion or displacement can be transferred from one fault to another, regional strain maintains laterally constant. Transfer zones are widely developed in rift basins and have significance on hydrocarbon accumulation. In this review article, we attempt to summarize recent advances on the types, distance-displacement curves, evolutionary stages and controlling factors of transfer zones in rift basins and their effects on sedimentary systems, reservoir properties, trap formation and hydrocarbon migration. The formation of transfer zones is genetically related to the segmented growth of normal faults. Depending on the degree of interaction between these normal faults, transfer zones in rift basins could be divided into two types: soft-linked and hard-linked, which are further subdivided into transfer slope, oblique anticline, horst and transfer fault based on the combination patterns of normal faults. In general, the development of transfer zones experiences several stages including isolated normal faulting, transfer slope forming, complicating and breaking. During the interaction and growth of segmented normal faults, stress-strain and spatial array of faults, pre-existing basement structures, and mechanical conditions of rocks have a great influence on the location and development processes of transfer zones. A transfer zone is commonly considered as a pathway for conveying sediments from provenance to basin, and it hence exerts an essential control on the distribution of sandbodies. In addition, transfer zone is the area where stresses are concentrated, which facilitates the formation of various types of structural traps, and it is also a favorable conduit for hydrocarbon migration. Consequently, there exists great hydrocarbon potentials in transfer zones to which more attention should be given.

Geochronological Records of Oil-Gas Accumulations in the Permian Reservoirs of the Northeastern Ordos Basin

Geochronology of oil-gas accumulation （OGA） is a challenging subject of petroleum geology in multi-cycle superimposed basins.By K-Ar dating of authigenic illite （AI） and fluid inclusion （FI） analysis combined with apatite fission track （AFT） thermal modeling,a case study of constraining the OGA times of the Permian reservoirs in northeast Ordos basin （NOB） has been conducted in this paper.AI dating of the Permian oil-gas-bearing sandstone core-samples shows a wide time domain of 178-108 Ma.The distribution of the AI ages presents 2-stage primary OGA processes in the Permian reservoirs,which developed in the time domains of 175-155 Ma and 145-115 Ma with 2-peak ages of 165 Ma and 130 Ma,respectively.The FI temperature peaks of the samples and their projected ages on the AFT thermal path not only present two groups with a low and a high peak temperatures in ranges of 90-78℃ and 125-118℃,respectively corresponding to 2-stage primary OGA processes of 162-153 Ma and 140-128 Ma in the Permian reservoirs,but also appear a medium temperature group with the peak of 98℃ in agreement with a secondary OGA process of c.～30 Ma in the Upper Permian reservoirs.The integrated analysis of the AI and FI ages and the tectono-thermal evolution reveals that the Permian reservoirs in the NOB experienced at least 2-stage primary OGA processes of 165-153 Ma and 140-128 Ma in agreement with the subsidence thermal process of the Mid-Early Jurassic and the tectono-thermal event of the Early Cretaceous.Then,the Upper Permian reservoirs further experienced at least 1-stage secondary OGA process of c.～30 Ma in coincidence with a critical tectonic conversion between the slow and the rapid uplift processes from the Late Cretaceous to Neogene.

Origin, hydrocarbon accumulation and oil-gas enrichment of fault-karst carbonate reservoirs: A case study of Ordovician carbonate reservoirs in South Tahe area of Halahatang oilfield, Tarim Basin

Based on comprehensive analysis of tectonic and fault evolution, core, well logging, seismic, drilling, and production data, the reservoir space characteristic, distribution, origin of fault-karst carbonate reservoir in Yueman block of South Tahe area, Halahatang oilfield, Tarim Basin, were studied systematically. And the regular pattern of hydrocarbon accumulation and enrichment was analyzed systematically based on development practice of the reservoirs. The results show that fault-karst carbonate reservoirs are distributed in the form of "body by body" discontinuously, heterogeneously and irregularly, which are controlled by the development of faults. Three formation models of fault-karst carbonate reservoirs, namely, the models controlled by the main deep-large fault, the secondary fault and the secondary internal fault, are built. The hydrocarbon accumulation and enrichment of fault-karst carbonate reservoirs is controlled by the spatiotemporal matching relation between hydrocarbon generation period and fault activity, and the size and segmentation of fault. The study results can effectively guide the well deployment and help the efficient development of fault-karst carbonate reservoirs of South Tahe area, Halahatang oilfield.

Petroleum geology and sub-source hydrocarbon accumulation of Permian reservoirs in Jinan Sag,eastern Junggar Basin,NW China

According to the latest drilling and the analysis of the burial history,source rock evolution history and hydrocarbon accumulation history,the sub-source hydrocarbon accumulation characteristics of the Permian reservoirs in the Jinan Sag,eastern Junggar Basin,are clarified,and the hydrocarbon accumulation model of these reservoirs is established.The results are obtained in four aspects.First,the main body of the thick salified lake basin source rocks in the Lucaogou Formation has reached the mature stage with abundant resource base.Large-scale reservoirs are developed in the Jingjingzigou,Wutonggou and Lucaogou formations.Vertically,there are multiple sets of good regional seals,the source-reservoir-caprock assemblage is good,and there are three reservoir-forming assemblages:sub-source,intra-source and above-source.Second,dissolution,hydrocarbon charging and pore-preserving effect,and presence of chlorite film effectively increase the sub-source pore space.Oil charging is earlier than the time when the reservoir becomes densified,which improves the efficiency of hydrocarbon accumulation.Third,buoyancy and source-reservoir pressure difference together constitute the driving force of oil charging,and the micro-faults within the formation give the advantage of"source-reservoir lateral docking"under the source rock.Microfractures can be critical channels for efficient seepage and continuous charging of oil in different periods.Fourth,the Jingjingzigou Formation experienced three periods of oil accumulation in the Middle-Late Permian,Middle-Late Jurassic and Late Neogene,with the characteristics of long-distance migration and accumulation in early stage,mixed charging and accumulation in middle stage and short-distance migration and high-position accumulation in late stage.The discovery and theoretical understanding of the Permian reservoirs in the Jinan Sag reveal that the thrust belt has good conditions for forming large reservoirs,and it is promising for exploration.The study results are of guidance and reference significance for oil and gas exploration in the Jinan Sag and other geologically similar areas.

Hydrocarbon migration and accumulation along the fault intersection zone-a case study on the reef-flat systems of the No.1 slope break zone in the Tazhong area, Tarim Basin

Understanding hydrocarbon migration and accumulation mechanisms is one of the key scientif ic problems that should be solved for effective hydrocarbon exploration in the superimposed basins developed in northwest China. The northwest striking No.1 slope break zone, which is a representative of superimposed basins in the Tarim Basin, can be divided into five parts due to the intersection of the northeast strike-slip faults. Controlled by the tectonic framework, the types and properties of reservoirs and the hydrocarbon compositions can also be divided into five parts from east to west. Anomalies of all the parameters were found on the fault intersection zone and weakened up-dip along the structural ridge away from it. Thus, it can be inferred that the intersection zone is the hydrocarbon charging position. This new conclusion differs greatly from the traditional viewpoint, which believes that the hydrocarbon migrates and accumulates along the whole plane of the No.1 slope break zone. The viewpoint is further supported by the evidence from the theory of main pathway systems, obvious improvement of the reservoir quality （2-3 orders of magnitude at the intersection zone） and the formation mechanisms of the fault intersection zone. Differential hydrocarbon migration and entrapment exists in and around the strike- slip faults. This is controlled by the internal structure of faults. It is concluded that the more complicated the fault structure is, the more significant the effects will be. If there is a deformation band, it will hinder the cross fault migration due to the common feature of two to four orders of magnitude reduction in permeability. Otherwise, hydrocarbons tend to accumulate in the up-dip structure under the control of buoyancy. Further research on the internal fault structure should be emphasized.

Fault characteristics and control on hydrocarbon accumulation of middle-shallow layers in the slope zone of Mahu sag, Junggar Basin, NW China

The development, evolution and formation mechanism of faults and their control on the migration and accumulation of Mesozoic oil and gas in the middle-shallow layers of the slope zone of Mahu sag were studied by the interpretation of seismic and drilling data. Two types of faults, normal and strike-slip, are developed in the middle-shallow layers of the slope zone of the Mahu sag and they are mostly active in the Yanshanian period. They are divided into four grade faults: The grade I strike-slip faults with NWW to near EW direction are related to the left-lateral transpressive fault zones in the northwest of Junggar Basin since the end of the Triassic. The grade II faults with NE to NNE direction are the normal faults located at the junction of the fault zone and the slope zone, and their formation is related to the extension at the top of the nose-like structures in the fault zone. The grade III faults, which are also the normal faults, are the result of the extension at the top of the lower uplifts in the slope zone and differential compaction. The grade IV faults with NE direction are normal faults, which may be related to the extension environment at the tip of the lower uplifts. Faults not only are the channel for the vertical migration of oil and gas, but also control the oil-gas accumulation. There are two types of oil-gas reservoirs in the middle-shallow layers of slope zone of Mahu sag: fault block reservoirs and fault-lithologic reservoirs. They have large traps and promising exploration potential.

Migration and accumulation characteristics of natural gas hydrates in the uplifts and their slope zones in the Qiongdongnan Basin,China

Various factors controlling the accumulation of natural gas hydrates(NGHs)form various enrichment and accumulation modes through organic combination.This study mainly analyzes the geological and geophysical characteristics of the NGHs occurrence in the uplifts and their slope zones within the deep-water area in the Qiongdongnan(QDN)Basin(also referred to as the study area).Furthermore,it investigates the dominant governing factors and models of NGHs migration and accumulation in the study area.The results are as follows.(1)The uplifts and their slope zones in the study area lie in the dominant pressure-relief direction of fluids in central hydrocarbon-rich sags in the area,which provide sufficient gas sources for the NGHs accumulation and enrichment through pathways such as gas chimneys and faults.(2)The top and flanks of gas chimneys below the bottom simulating reflectors(BSRs)show high-amplitude seismic reflections and pronounced transverse charging of free gas,indicating the occurrence of a large amount of gas accumulation at the heights of the uplifts.(3)Chimneys,faults,and high-porosity and high-permeability strata,which connect the gas hydrate temperature-pressure stability zones(GHSZs)with thermogenic gas and biogenic gas,form the main hydrate migration system.(4)The reservoir system in the study area comprises sedimentary interlayers consisting of mass transport deposits(MTDs)and turbidites.In addition,the reservoir system has developed fissure-and pore-filling types of hydrates in the pathways.The above well-matched controlling factors of hydrate accumulation enable the uplifts and their slope zones in the study area to become the favorable targets of NGHs exploration.

New understandings on gas accumulation and major exploration breakthroughs in subsalt Ma 4 Member of Ordovician Majiagou Formation,Ordos Basin,NW China

Geological conditions and main controlling factors of gas accumulation in subsalt Ma 4 Member of Ordovician Majiagou Formation are examined based on large amounts of drilling,logging and seismic data.The new understandings on the control of paleo-uplift over facies,reservoirs and accumulations are reached:(1)During the sedimentary period of Majiagou Formation,the central paleo-uplift divided the North China Sea in central-eastern of the basin from the Qinqi Sea at southwest margin of the basin,and controlled the deposition of the thick hummocky grain beach facies dolomite on platform margin of Ma 4 Member.Under the influence of the evolution of the central paleo-uplift,the frame of two uplifts alternate with two sags was formed in the central-eastern part of the basin,dolomite of inner-platform beach facies developed in the underwater low-uplift zones,and marl developed in the low-lying areas between uplifts.(2)From the central paleo-uplift to the east margin of the basin,the dolomite in the Ma 4 Member gradually becomes thinner and turns into limestone.The lateral sealing of the limestone sedimentary facies transition zone gives rise to a large dolomite lithological trap.(3)During the late Caledonian,the basin was uplifted as a whole,and the central paleo-uplift was exposed and denuded to various degrees;high-quality Upper Paleozoic Carboniferous-Permian coal measures source rocks deposited on the paleo-uplift in an area of 60000 km^(2),providing large-scale hydrocarbon for the dolomite lithological traps in the underlying Ma 4 Member.(4)During the Indosinian-Yanshanian stage,the basin tilted westwards,and central paleo-uplift depressed into an efficient hydrocarbon supply window.The gas from the Upper Paleozoic source rock migrated through the high porosity and permeability dolomite in the central paleo-uplift to and accumulated in the updip high part;meanwhile,the subsalt marine source rock supplied gas through the Caledonian faults and micro-fractures as a significant supplementary.Under the guidance of the above new understandings,two favorable exploration areas in the Ma 4 Member in the central-eastern basin were sorted out.Two risk exploration wells were deployed,both revealed thick gas-bearing layer in Ma 4 Member,and one of them tapped high production gas flow.The study has brought a historic breakthrough in the gas exploration of subsalt Ma 4 Member of Ordovician,and opened up a new frontier of gas exploration in the Ordos Basin.

Evolution of a hydrodynamic field and its effect on hydrocarbon accumulation in the Biyang depression, Henan province

The hydro-geologic stages in the Biyang Depression, Henan Province, were defined and factors controlling the evolution of the hydrodynamic field in this area were analyzed. The evolution of the paleo-hydrodynamic field was studied by using the method of sedimentary-water-head and the changing patterns of the present hydrodynamic field as determined from measured pressure data. The results show that the evolution of the hydrodynamic field is one of inheritance and that it controls hydrocarbon accumulation. The deposition center in the southeast of the depression is always a high-value zone for water-head and a dynamic- source zone of the hydrodynamic field. The slope zone in the northwest of the depression is always a low-value zone for water-head and is the main discharge area for groundwater; this is the hydrocarbon accumulation zone. Hydrocarbon accumulation is controlled by the hydrodynamic field. The reservoir shows a ring-shaped horizontal pattern. Accumulation occurs in a pressure equilibrium zone at the frontal surface between sedimentary water and infiltrating water. The hydrocarbon accumulations occur in two vertically different discharge units, Eh31 and Eh32, under the action of overpressure.

Differences and controlling factors of composite hydrocarbon accumulations in the Tazhong uplift, Tarim Basin, NW China

Based on three-dimensional seismic interpretation, structural and sedimentary feature analysis, and examination of fluid properties and production dynamics, the regularity and main controlling factors of hydrocarbon accumulation in the Tazhong uplift, Tarim Basin are investigated. The results show that the oil and gas in the Tazhong uplift has the characteristics of complex accumulation mainly controlled by faults, and more than 80% of the oil and gas reserves are enriched along fault zones. There are large thrust and strike-slip faults in the Tazhong uplift, and the coupling relationship between the formation and evolution of the faults and accumulation determine the difference in complex oil and gas accumulations. The active scale and stage of faults determine the fullness of the traps and the balance of the phase, that is, the blocking of the transport system, the insufficient filling of oil and gas, and the unsteady state of fluid accumulation are dependent on the faults. The multi-period tectonic sedimentary evolution controls the differences of trap conditions in the fault zones, and the multi-phase hydrocarbon migration and accumulation causes the differences of fluid distribution in the fault zones. The theory of differential oil and gas accumulation controlled by fault is the key to the overall evaluation, three-dimensional development and discovery of new reserves in the Tazhong uplift.

氦气地质理论认识、资源勘查评价与全产业链一体化评价关键技术

鉴于我国氦气产业链理论技术需求,针对国内外尚无系统的氦气地质理论认识,缺乏针对性的氦气资源评价方法、参数取值标准,缺乏氦气含量综合准确检测、有利富集区优选方法,无成本指标优化体系及全产业链一体化评价方法等卡点和难点,本文运用地质、地球化学、重磁电震、投资经济等多学科方法及实验技术,集中力量攻克氦气成藏机理、资源评价及资产评价的关键技术瓶颈。研发形成1项地质理论认识和3项关键技术:基于典型富氦气藏解剖、地下流体中“氦-气-水”相平衡及相-势耦合分析,研究提出氦气“水溶相、气容相、游离相”3种主要赋存状态、“集流、渗流、扩散”3种运移机理、“近氦源、邻断裂、低压区、高部位”4项分布富集控制因素,初步建立了基于“优质氦源、高效输导、适宜载体”的氦气“生-运-聚”地质理论认识。针对国内氦气含量检测技术参差不齐、部分准确度差、与国外数据差别大、无针对性的氦气资源评价方法等系列难题,以氦气源及氦气含量为核心,研发氦气含量综合准确检测技术,构建4类10种氦气资源评价方法,解决了氦气资源分级分类评价的技术瓶颈。针对基底氦源分布、岩性识别、通源断裂刻画及含氦储层评价难题,创建了归一化重磁下延方案,研发了基于深度学习的多尺度断裂智能识别技术和不同氦气含量下的气藏声学性质模拟方法,为氦源岩分布预测、通源断裂刻画、含氦储层测井解释评价及预测奠定了基础。通过建立多元控氦的富氦区带与目标优选技术,解决了富氦区带与目标优选难题。针对国内贫氦实际情况,以提氦装置投资和操作成本最小化为目标,采用响应面法建立优化目标与各主要工艺参数的非线性回归模型,建立了氦气全产业链一体化评价技术,初步解决了天然气低成本提氦工艺流程优化的技术需求。研究成果为我国长期、安全、规模利用氦气资源资产提供了有效支撑。

中西非裂谷系富油凹陷石油地质特征与勘探方向

基于地震、钻井、烃源岩测试分析等资料,对中西非裂谷系主要盆地富油凹陷石油地质特征进行研究,并探讨未来油气勘探方向。研究表明:中非裂谷系发育下白垩统湖相优质烃源岩,西非裂谷系发育上白垩统陆源海相优质烃源岩,两类烃源岩为中西非裂谷系油气富集提供了物质基础。中西非裂谷系发育包括基岩在内的多套储集层,并存在下白垩统、上白垩统和古近系3套区域盖层。晚中生代以来,受中非剪切带右旋走滑作用等地球动力学因素的影响,中西非裂谷系不同方向的盆地在裂谷作用期次、区域盖层发育层段、圈闭类型及成藏模式等方面存在差异。其中,北东—南西向盆地主要保存了早白垩世一期裂谷层序,区域盖层位于下白垩统裂陷期地层内,形成反转背斜、花状构造及基岩潜山等圈闭类型,发育“源储一体、源内成藏”及“源上储下、源下成藏”两种成藏模式;北西—南东向盆地具有多期裂谷叠置特征,发育上白垩统和古近系区域盖层,形成披覆背斜、断背斜、反向断块等圈闭类型,以“源下储上、源上成藏”为主要成藏模式。多期叠置裂谷盆地的源内成藏组合、强反转盆地的源内岩性油藏及页岩油是中西非裂谷系盆地未来勘探的重要领域。

甘肃舟曲江顶崖古滑坡形成演化机理与堆积体稳定性评价

古滑坡堆积体复活是我国青藏高原及周边地区的主要地质灾害类型之一,也是我国西部正在建设的重大交通和水利工程面临的主要安全威胁之一。因此,对古滑坡的形成演化机理进行研究并对其堆积体进行稳定性评价,显得极为重要,可以为古滑坡堆积体复活的早期识别与防治设计提供理论支持。甘肃省舟曲县江顶崖古滑坡堆积体近十年来数次局部复活形成滑坡堵塞白龙江,对当地人民的生命财产安全造成严重威胁。通过现场调查和无人机倾斜摄影等手段,查明了江顶崖古滑坡堆积体的形态和结构特征,在此基础上分析了滑坡的演化机理和动力学过程,再结合InSAR变形数据对堆积体的稳定性进行了定性评价。结果显示,江顶崖古滑坡是典型的大型地震滑坡,其滑体沿3个方向坐落式下滑,形成了如今多级台阶状的堆积体形态;在地震荷载作用下古滑坡的动力学过程可分为中上部震动-拉裂、前缘锁固段剪断-滑坡启动、后缘拉裂-滑体加速、前缘受阻-滑体减速、稳定阶段。由于古滑坡在地震荷载作用下整体下滑,导致上部堆积体内存在大量结构完整的岩体,因此较为稳定;而中下部堆积体大都为断层破碎带和破碎岩体组成的软弱结构,稳定性较差,未来极有可能复活。

辽河坳陷陈家断裂带北部构造演化解析及油气成藏

辽河坳陷陈家断裂带油气资源丰富,是辽河西部凹陷北段重要的含油气区带之一。基于构造演化解析,结合砂箱物理模拟实验,分析了辽河坳陷陈家断裂带的变形机制和演化过程,并指出其对油气成藏的控制作用。研究结果表明:(1)辽河坳陷陈家断裂带具有分段发育特征,且活动时期具有“先北后南”的演化特征,受断层分段性影响,陈家断裂带主要发育压扭背冲构造样式和走滑压扭构造样式。(2)物理模拟实验结果显示,台安—大洼断裂上盘在压扭作用影响下首先形成压扭性质的雁行小断裂,随着位移增大,小断裂逐渐连接,最终形成了贯穿型走滑断裂带,即陈家断裂带。(3)台安洼陷为新生代多期次构造变形叠加形成的洼陷,深层发育主力烃源岩层系,具备发育大规模油气藏的物质基础,洼陷边缘的钻井岩心分析结果显示,烃源岩TOC值为4.79%,Ro为0.3%~0.4%,属于好—较好烃源岩,推测洼陷中心厚度更大,质量更优。陈家断裂带中北部下盘发育断鼻构造,具备陈家洼陷和台安洼陷双源供烃的特点,是油气聚集的有利场所。

Petroleum geological characteristics and exploration targets of the oil-rich sags in the Central and West African Rift System

Based on seismic,drilling,and source rock analysis data,the petroleum geological characteristics and future exploration direction of the oil-rich sags in the Central and West African Rift System(CWARS)are discussed.The study shows that the Central African Rift System mainly develops high-quality lacustrine source rocks in the Lower Cretaceous,and the West African Rift System mainly develops high-quality terrigenous organic matter-rich marine source rocks in the Upper Cretaceous,and the two types of source rocks provide a material basis for the enrichment of oil and gas in the CWARS.Multiple sets of reservoir rocks including fractured basement and three sets of regional cap rocks in the Lower Cretaceous,the Upper Cretaceous,and the Paleogene are developed in the CWARS.Since the Late Mesozoic,due to the geodynamic factors including the dextral strike-slip movement of the Central African Shear Zone,the basins in different directions of the CWARS differ in terms of rifting stages,intervals of regional cap rocks,trap types and accumulation models.The NE-SW trending basins have mainly preserved one stage of rifting in the Early Cretaceous,with regional cap rocks developed in the Lower Cretaceous strata,forming traps of reverse anticlines,flower-shaped structures and basement buried hill,and two types of hydrocarbon accumulation models of"source and reservoir in the same formation,and accumulation inside source rocks"and"up-source and down-reservoir,and accumulation below source rocks".The NW–SE basins are characterized by multiple rifting stages superimposition,with the development of regional cap rocks in the Upper Cretaceous and Paleogene,forming traps of draping anticlines,faulted anticlines,antithetic fault blocks and the accumulation model of"down-source and up-reservoir,and accumulation above source rocks".The combination of reservoir and cap rocks inside source rocks of basins with multiple superimposed rifting stages,as well as the lithologic reservoirs and the shale oil inside source rocks of strong inversion basins are important fields for future exploration in basins of the CWARS.

规则垮落带大孔径走向长钻孔在综采面的应用

通过分析采煤工作面割煤后采空区围岩垮落岩块分布状态及规则垮落带瓦斯赋存特点,结合42200工作面瓦斯地质情况,对规则垮落带大孔径走向长钻孔治理上隅角瓦斯方案的应用进行了研究。确定大孔径钻孔高度为6 m,距皮带巷水平距离为20 m,孔径为193 mm,布置3个钻孔,能满足工作面抽采需要,通过精准抽采规则垮落带高体积分数瓦斯,有效治理了综采工作面上隅角瓦斯超限问题。

基于微动勘探技术的断裂带堆积层滑坡滑动面提取分析

选择舟曲县东山镇牙豁口滑坡作为研究对象,采集滑坡体的微动信号进行后期处理,通过与钻孔数据对比发现,单点反演获得的S波速度结构与视S波速度剖面均能清晰显示滑动面位置.微动探测结果显示新滑坡的滑动面埋深在10~35 m,平均埋深为9.1 m,钻孔揭露新滑动面平均埋深为10 m;微动探测结果显示老滑坡滑动面埋深在15~52 m,平均埋深为19.6 m,钻孔揭露新滑动面平均埋深为20 m.测试不同的采集时间、不同频率的检波器对探测深度和精度的影响,发现对该类滑坡应选取三重圆台阵, 4.5 Hz检波器, 90 min的采集时长.表明微动勘探方法是探测断层破碎带堆积层滑坡滑动面的一种有效方法,对于白龙江流域广泛分布的断层破碎带堆积层滑坡滑动面的探测,具有很好的技术优势以及应用前景.

Study on north boundary of subtropical zone in Funiu Mountain according to soil geochemistry

The boundary between subtropical zone and temperate zone is not only important in physical geography, but also attractive in agricultural production. Seven soil profiles studied in this paper are placed along the southern slope of Funiu Mountain at different heights above sea level. Many compositions and properties of these soils have been determined in laboratory. In this paper, the laws of migration and accumulation of soil materials on the southern slope of Funiu Mountain are discussed first, then the division of the boundary between subtropical zone and temperate zone in this area according to soil geochemistry is discussed with qualitative methods and mathematical classification method in which twelve selected indexes such as K m , Saf, Ba, β, Feo/Fet, Mno/Mnt and so on are used. The result indicates that the boundary between subtropical zone and temperate zone on the southern slope of Funiu Mountain is about 950 m above sea level.