Sedimentary build-ups of pre-salt isolated carbonate platforms and formation of deep-water giant oil fields in Santos Basin,Brazil

In response to the problems of unclear distribution of deep-water pre-salt carbonate reservoirs and formation conditions of large oil fields in the Santos passive continental margin basin,based on comprehensive utilization of geological,seismic,and core data,and reconstruction of Early Cretaceous prototype basin and lithofacies paleogeography,it is proposed for the first time that the construction of pre-salt carbonate build-ups was controlled by two types of isolated platforms:inter-depression fault-uplift and intra-depression fault-high.The inter-depression fault-uplift isolated platforms are distributed on the present-day pre-salt uplifted zones between depressions,and are built on half-and fault-horst blocks that were inherited and developed in the early intra-continental and inter-continental rift stages.The late intra-continental rift coquinas of the ITP Formation and the early inter-continental rift microbial limestones of the BVE Formation are continuously constructed;intra-depression fault-high isolated platforms are distributed in the current pre-salt depression zones,built on the uplifted zones formed by volcanic rock build-ups in the early prototype stage of intra-continental rifts,and only the BVE microbial limestones are developed.Both types of limestones formed into mound-shoal bodies,that have the characteristics of large reservoir thickness and good physical properties.Based on the dissection of large pre-salt oil fields discovered in the Santos Basin,it has been found that both types of platforms could form large-scale combined structural-stratigraphic traps,surrounded by high-quality lacustrine and lagoon source rocks at the periphery,and efficiently sealed by thick high-quality evaporite rocks above,forming the optimal combination of source,reservoir and cap in the form of“lower generation,middle storage,and upper cap”,with a high degree of oil and gas enrichment.It has been found that the large oil fields are all bottom water massive oil fields with a unified pressure system,and they are all filled to the spill-point.The future exploration is recommended to focus on the inter-depression fault-uplift isolated platforms in the western uplift zone and the southern section of eastern uplift zones,as well as intra-depression fault-high isolated platforms in the central depression zone.The result not only provides an important basis for the advanced selection of potential play fairways,bidding of new blocks,and deployment of awarded exploration blocks in the Santos Basin,but also provides a reference for the global selection of deep-water exploration blocks in passive continental margin basins.

Formation and distribution characteristics of Proterozoic–Lower Paleozoic marine giant oil and gas fields worldwide

There are rich oil and gas resources in marine carbonate strata worldwide.Although most of the oil and gas reserves discovered so far are mainly distributed in Mesozoic,Cenozoic,and upper Paleozoic strata,oil and gas exploration in the Proterozoic–Lower Paleozoic（PLP）strata—the oldest marine strata—has been very limited.To more clearly understand the oil and gas formation conditions and distributions in the PLP marine carbonate strata,we analyzed and characterized the petroleum geological conditions,oil and gas reservoir types,and their distributions in thirteen giant oil and gas fields worldwide.This study reveals the main factors controlling their formation and distribution.Our analyses show that the source rocks for these giant oil and gas fields are mainly shale with a great abundance of type I–II organic matter and a high thermal evolution extent.The reservoirs are mainly gas reservoirs,and the reservoir rocks are dominated by dolomite.The reservoir types are mainly karst and reef–shoal bodies with well-developed dissolved pores and cavities,intercrystalline pores,and fractures.These reservoirs arehighly heterogeneous.The burial depth of the reservoirs is highly variable and somewhat negatively correlated to the porosity.The cap rocks are mainly thick evaporites and shales,with the thickness of the cap rocks positively correlated to the oil and gas reserves.The development of high-quality evaporite cap rock is highly favorable for oil and gas preservation.We identified four hydrocarbon generation models,and that the major source rocks have undergone a long period of burial and thermal evolution and are characterized by early and long periods of hydrocarbon generation.These giant oil and gas fields have diverse types of reservoirs and are mainly distributed in paleo-uplifts,slope zones,and platform margin reef-shoal bodies.The main factors that control their formation and distribution were identified,enabling the prediction of new favorable areas for oil and gas exploration.

Large-scale Tazhong Ordovician Reef-flat Oil-Gas Field in the Tarim Basin of China

The Tazhong reef-fiat oil-gas field is the first large-scale Ordovician organic reef type oil-gas field found in China. Its organic reefs were developed in the early Late Ordovician Lianglitag Formation, and are the first large reefs of the coral-stromatoporoid hermatypic community found in China. The organic reefs and platform-margin grain banks constitute a reef-flat complex, mainly consisting of biolithites and grainstones. The biolithites can be classified into the framestone, baffiestone, bindstone etc. The main body of the complex lies around the wells from Tazhong-24 to Tazhong-82, trending northwest, with the thickness from 100 to 300 m, length about 220 km and width 5-10 km. It is a reef-flat lithologic hydrocarbon reservoir, with a very complex hydrocarbon distribution： being a gas condensate reservoir as a whole with local oil reservoirs. The hydrocarbon distribution is controlled by the reef complex, generally located in the upper 100-200 m part of the complex, and largely in a banded shape along the complex. On the profile, the reservoir shows a stratified feature, with an altitude difference of almost 2200 m from southeast to northwest. The petroleum accumulation is controlled by karst reservoir beds and the northeast strike-slip fault belt. The total geologic reserves had reached 297.667 Mt by 2007.

Mesozoic-Cenozoic Tectonics of the Yellow Sea and Oil-Gas Exploration

The purpose of the present study was to study the tectonics of the Yellow Sea. Although oilgas exploration has been undertaken for more than 30 years in the southern Yellow Sea, the exploration progress has achieved little. There are three tectonic periods with near N-S trending shortening and compression （260-200 Ma, 135-52 Ma and 23-0.78 Ma） and three tectonic periods with near E-W trending shortening and compression （200-135 Ma, 52--23 Ma and 0.78 Ma） at the Yellow Sea and adjacent areas during the Mesozoic and Cenozoic. The lndosinian tectonic period is the collision period between the Sino-Korean and Yangtze Plates, which formed the basic tectonic framework for the Yellow Sea area. There were strong intraplate deformations during the Yanshanian （200-135 Ma） and Sichuanian （135-52 Ma） periods with different tectonic models, which are also the main formation periods for endogenic metallic mineral deposits around the Yellow Sea. The three tectonic periods during the Cenozoic affect important influences for forming oil-gas reservoirs. The Eocene-Oligocene （52-23 Ma） is the main forming period for oil-gas sources. The Miocene-Early Pleistocene （23-0.78 Ma） was a period of favorable passage for oil-gas migration along NNE trending faults. Since the Middle Pleistocene （0.78 Ma） the NNE trending faults are closed and make good conditions for the reservation of oil-gas. The authors suggest that we pay more attention to the oil-gas exploration at the intersections between the NNE trending existing faults and Paleogene- Neogene systems in the southern Yellow Sea area.

Rb-Sr isotopic dating of sphalerite from the giant Huize Zn-Pb ore field, Yunnan Province, Southwestern China

The giant Huize Zn-Pb ore field in Yunnan Province, southwestern China, comprises the Qilinchang and Kuangshanchang deposits. The deposits are large in scale (more than 5 Mt of Zn and Pb) and high in grade (average grade of total Zn and Pb is 30%). Reported in this paper are the results of Rb-Sr isotopic dating of sphalerite from this ore field. Two precise ages (223.5±3.9 Ma and 226±6.4 Ma) have been obtained from two isochrons. These two ages are close to the reported ages of native copper mineralizations related to the Emeishan flood basalts in this region, which are 226 Ma to 228 Ma. Previous studies showed that the magnitude of uplift resultant from the Emeishan flood basalts is greater than 1000 m, indicating that the Kuangshanchang and Qilinchang deposits were formed during the same geological event and originated by fluid migration during uplifting resultant from the Emeishan flood basalts.

“Giant pressure shadow” structure and ore-finding method of tectonic stress field in the Tongchang Cu-Au polymetallic orefield,Shaanxi,China:Ⅱ.Dynamics of tectonic ore-forming processes and prognosis of concealed ores

The Tongchang orefield is located in the central part of the Mianxian-Lueyang-Yangpingguan area that is celebrated as a 'gold triangle' area,at the juncture of the latitudinal tectonic zone of South Qinling,the Longmenshan Cathysian tectonic zone and the Sichuan-Yunnan longitudinal tectonic zone,where there are distributed Cu-Au polymetallic ore deposits(occurrences) including the Tongchang,Chenjiaba,Qinjiabian,Hongtushi,Yinshangou and Xiakouyi ore deposits(mineralization).Based on the "giant pressure shadow" structure put forward and demonstrated by numerical modeling of the tectonic stress field and the static photoelasticity experiments on the basis of tectonic ore-controlling laws in the orefield,tectonic metallogenesis driven by orefield tectonic stress has been discussed in terms of its geological setting,orefield geomechanics,and tectonic stress field.It is thought that the dynamic evolution model of the tectonic stress field controls the whole process of formation of the polymetallic ore deposits(mineralization) in the orefield,as well as the deformation field.As a result,it controls the emplacement of rockbodies and the transformation of ore-source bodies,and provides both the channel-ways for ore-forming fluids and ore-hosting space.Furthermore,it controls the migration potential field of fluids and,thereafter,its flow direction,rate and volume;the tectonic stress field also controls the energy field and hence controls the position of occurrence of ore deposits and their scale.The method of tectonic stress field has been applied to ore prognosis in the orefield.The rules of magmatic emplacement and metallogenic fluid migrating and concentrating under the control of the structural stress field were expounded,hence providing the theoretical basis for the prognosis of concealed ores.In addition,a number of important target areas have been defined.

Design and Magnetic Field Uniformity of Giant Magnetostrictive Ultrasonic Transducer for Progressive Sheet Forming

Design of a giant magnetostrictive ultrasonic transducer for progressive sheet forming was presented.A dynamic analysis of the theoretically designed ultrasonic vibration system was carried out using the finite element method(FEM).In addition,simulations were performed to verify the theoretical design.Then,a magnetically conductive material was added between the giant magnetostrictive rod and the permanent magnet.Besides,magnetic field simulations of the transducer were performed.The influence of the material thickness of the magnetically conductive material on uniformity of the induced magnetic field was studied.Furthermore,the impedance analysis and amplitude measurement were performed to compare the performance of transducers with and without the magnetically conductive material.The experimental results show that the magnetic field uniformity is the highest when the magnetically conductive material has a thickness of about 1.6 mm.The output amplitude of the giant magnetostrictive transducer is improved by adding the magnetically conductive material.Moreover,the mechanical quality factor and impedance are reduced,while the transducer operates more stably.

Quantum Theory of Mesoscopic Fractional Electric Fields in a Cavity of Viscous Medium

With conjecture of fractional charge quantization (quantum dipole/multiple moments), Fourier transform stretching, twisting and twigging of an electron quanta and waver strings of electron quanta, the mathematical expressions for mesoscopic fractional electron fields in a cavity of viscous medium and the associated quantum dielectric susceptibility are developed. Agreement of this approach is experimentally evidenced on barite and Fanja site molecular sieves. These findings are in conformity with experimental results of 2012 Physics Nobel prize winning scientists, Serge Haroche and David J. Wineland especially for cavity quantum electro-dynamics electron and its associated mesoscopic electric fields. The mover electron quanta strings lead to warping of space and time following the behaviour of quantum electron dynamics.

南非奥特尼夸盆地构造沉积演化与油气成藏

南非奥特尼夸盆地油气勘探程度非常低,2019年与2020年连续的天然气大发现吸引了国内外油气公司广泛关注。基于IHS数据库、新项目评价及文献等资料,综合分析表明:奥特尼夸盆地经历了二叠纪以来的前裂谷、同裂谷、过渡期和裂谷后4个演化阶段;主要沉积了裂谷期陆相碎屑岩及过渡期–裂谷后的海相碎屑岩。盆地主力烃源岩为豪特里维阶和巴雷姆–阿普特阶海相页岩;发育了同裂谷期凡兰吟阶顶部浅海相砂岩和漂移早期阿尔比阶海相深水碎屑岩两套重要的储集层,储盖组合条件优越;共形成了巴雷姆–阿尔比阶砂岩、凡兰吟−豪特里维阶砂岩、上侏罗统−下白垩统砂岩和基底4套成藏组合。油气分布呈“西多东少”格局,目前应以Bredasdorp次盆大陆边缘深水区白垩系透镜状浊积砂岩为勘探重点。

四川超级含气盆地古生界大中型气田分布规律及其主控因素

四川盆地是中国天然气资源最为富集的超级含气盆地,但天然气探明程度目前仍然偏低。为了给下一步天然气勘探提供理论支撑,基于该盆地典型气田勘探历程,结合多期构造演化与含油气系统分析,探讨了四川盆地古生界大中型气田富集分布规律及其主控因素,揭示了该盆地巨大的天然气勘探潜力。研究结果表明:①四川盆地古生界蕴含3个超级含油气系统,即下寒武统筇竹寺组(探明储量占该盆地天然气总探明储量的17.55%)、上奥陶统五峰组—下志留统龙马溪组(探明储量占该盆地天然气总探明储量的41.30%)、上二叠统龙潭组/吴家坪组(探明储量占该盆地天然气总探明储量的12.53%);②该盆地古生界已发现20个超大型气田(天然气探明储量超过1000×10^(8)m^(3)),14个大型气田(天然气探明储量介于300×10^(8)~1000×10^(8)m^(3))以及20个中型气田(天然气探明储量介于100×10^(8)~300×10^(8)m^(3)),超大型气田探明储量占该盆地天然气总探明储量的85.5%;③古生界大型隆—坳格局构造沉积分异作用控制影响着该盆地内筇竹寺组、五峰组—龙马溪组和龙潭组/吴家坪组3套优质烃源岩层系的形成与分布。结论认为,晚三叠世以来的陆相盆地演化过程使得中晚三叠世—早中侏罗世成为上述3个超级含油气系统的关键成藏期,形成了3个气田群(绵阳—长宁拉张槽周缘带震旦系—下古生界、开江—梁平与蓬溪—武胜拉张槽周缘带二叠系—三叠系、川东南五峰组—龙马溪组页岩气),其合计天然气储量均超过1×10^(12)m^(3),是该盆地天然气勘探的有利区带。

超磁致伸缩换能器磁场强度建模与线圈优化分析

磁场强度是决定换能器性能的关键变量,为了提高超磁致伸缩换能器(GMA)的磁场强度和输出位移,本文提出了一种新型的弓张式发音振子结构,用COMSOL软件建立二维模型,得到超磁致伸缩材料(GMM)棒内部磁场分布情况。由于弓结构内部空间受限,对激励线圈进行优化,讨论了导线经验模型、静态电阻和电感模型的适用性,建立了线圈的平均磁场模型,以线径为决策变量,计算了正弦响应下不同线径的振幅比和相位滞后。结果表明:该模型在计算电阻和电感时的相对误差分别小于5.3%和4.1%。在预测正弦响应时,计算振幅比的误差低于6.6%(在大多数条件下低于1.8%),计算滞后相位的误差低于3.4%。较宽的导线直径对提高磁场振幅有较大的帮助,但对磁场的相位滞后性影响很小。

桑托斯盆地盐下孤立碳酸盐台地沉积建造与深水大油田

针对桑托斯被动陆缘盆地深水盐下碳酸盐岩储层分布特征及大油田成藏规律不清的难题,综合利用地质、地震及岩心等数据资料,通过早白垩世原型盆地与岩相古地理恢复重建,提出盐下碳酸盐岩沉积建造受控于坳间断隆型和坳中断凸型两类孤立台地。坳间断隆型孤立台地分布于现今盐下坳间隆起带上,建造于早期陆内和陆间裂谷两个原型阶段继承性发育的单断式和双断式垒式断块上,早白垩世陆内裂谷晚期沉积的ITP组介壳灰岩和陆间裂谷早期沉积的BVE组微生物灰岩为连续建造;坳中断凸型孤立台地分布于现今盐下坳陷带中,建造于早期陆内裂谷原型阶段火山岩建隆所形成的凸起带上,发育BVE组微生物灰岩。两类孤立台地灰岩所形成礁滩体均具有储层厚度大、物性好的特点。结合盐下已发现大油田解剖,发现两类台地均可形成大型构造-岩性复合圈闭,周缘为优质湖相和潟湖相烃源岩环绕,上覆为巨厚的优质蒸发盐岩盖层高效封堵,形成了“下生中储上盖”式最佳生储盖组合关系,油气富集程度高。已发现大油田均为具有统一压力系统的底水块状油田,且均处于充满状态。未来勘探重点目标是西部隆起带和东部隆起带南段上的坳间断隆型孤立台地及中央坳陷带中的坳中断凸型孤立台地。该项研究成果为在桑托斯被动陆缘盆地超前选区选带、新项目评价及中标区块探区勘探部署提供了重要依据,也为今后在全球被动大陆边缘盆地深水勘探战略选区提供借鉴。

基于Ansys Maxwell巨磁阻隔离器结构中线圈磁场的研究

巨磁阻(GMR)隔离器中平面线圈的主要作用是将电信号转化为磁信号,为了确定平面线圈的具体参数,基于Ansys Maxwell/2D对GMR隔离器结构中平面线圈的磁场影响参数进行扫描分析,确定了GMR隔离器的输入电流为5.94 mA,结合现有工艺条件,确定了平面线圈线宽5μm,线间距2μm,厚度2μm及线圈中心间距100μm。进一步利用Maxwell/3D建立平面线圈的3D模型,对该模型进行静磁场下的磁场强度分析,平面线圈在正下方13μm厚度的SiO_(2)隔离栅处产生的磁场强度为4.18 Oe左右,满足GMR隔离器的制作要求,为GMR隔离器平面线圈的设计提供参考。

双线高铁隧道跨越巨型溶洞先掘后探施工技术研究

为了确保贵南高铁甲良3号隧道跨越巨型溶洞段的施工安全,研究开展双线高铁隧道跨越巨型溶洞先掘后探施工技术。提出洞内更换加强型护拱及系统锚杆加固,洞外施作条件为基础+钢管立柱挡墙支撑,确保隧道先行开挖通过巨型溶洞段落,保障隧道按期贯通,同时最大限度地减小溶洞对隧道施工的影响。结果表明:该施工技术有效保证了隧道跨越巨型溶洞段的安全、快速施工,拱顶沉降最大值为8.61 mm,净空收敛最大值为4.17 mm,远小于其变形控制值,可为类似岩溶地区的隧道施工提供参考。

Micromagnetic simulation for high field sensors with perpendicular magnetizations

In this paper, we present a micromagnetic design for high field sensors. The hard layer of the sensors is L10-FePt which is magnetized perpendicularly to film plane and the sense layer is NiFe which is magnetized in the film plane. The magnetization configurations of the hard and sense layers at different external magnetic fields have been simulated. In micromagnetic simulation, the sense field up to one tesla can be reached by using this sensor. We find that whether the sensor has a symmetric or an asymmetric field-sensing window is determined by the coercive field of the hard layer and the demagnetizing field of the sense layer.

Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.sB19.2 （FeCo-based） ribbon under a weak magnetic field （WMF） is presented in this paper. The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitro- gen atmosphere. The giant magnetoimpedance effect in solenoid （GMIES） profiles are measured with an HP4294A impedance analyzer. The result shows that the CMIES responds to the WMF sensitively （as high as 1580 %/A.m-1）. The high sensitivity can be obtained in a moderate narrow range of annealing current density （30-34 A/mm2） and closely depends on the driven current frequency. The highest sensitivity （1580 %/A.m-1） is obtained when the FeCo- based amorphous ribbon is annealed at 32 A/mm2 for 10 min and then driven with an alterning current （AC） at the frequency of 350 kHz. The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure, which is induced by the temperature gradient produced during Joule-heating the ribbon.

New Model of Predicting Remaining Recoverable Reserves and Application in the Oilfield

As a significant inducement during the development of oil and gas,the role of remaining recoverable reserves is more observable especially in the later phase of development of oilfield.Depended on the production decline method in petroleum reservoir engineering,a new model of predicting recoverable and remaining recoverable reserves has been

Transmembrane transport of multicomponent liposome-nanoparticles into giant vesicles

With the emergence and rapid development of nanotechnology,the nanoparticles hybridized with multicomponent lipids are more and more used in gene delivery.These vectors interact with the cell membrane before entering into the cell.Therefore,the nature of this interaction is important in investigating multicomponent liposome-nanoparticle(MLP)transport across the cell membrane.In this paper the transport of MLPs across the membranes of giant vesicles(GVs)in solvents is studied by using the self-consistent field theory(SCFT).Based on the analysis of the MLP permeating the GV membranes,a simple transport model is proposed.The effects of the difference in membrane morphology and the size of the nanoparticle on the endocytosis are discussed systematically.The role of energy barriers in quasi-equilibrium is also examined.The results indicate that the interaction between MLP and GV is a spontaneous process and the energy barrier needs overcoming to form metastable intermediates.The results provide theoretical reference for better understanding the transmembrane transport process of nanoparticles,and guidance for relevant experimental studies as well.

Seismic sentinel? An analysis of captive giant panda behavior in response to the Lushan earthquake in China

It is widely believed that various animal species can sense and respond to the geophysical stimuli that precede earthquakes,especially electromagnetic fields,although supporting field evidence is mostly anecdotal.Here we report on the reactions of four female giant pandas under observation over the three days prior to the Lushan(30.1°N,103.0°E)magnitude 7.0 earthquake that occurred in Sichuan province,China,on April 20,2013.We observed no significant generalized behavioral anomalies indicative of them perceiving an impending earthquake.We also observed no startle behaviors in the 5 s prior to tremors commencing,indicating that these pandas either did not detect or did not respond to precursor P-waves.Our findings suggest that although giant pandas have evolved in,and continue to occupy exclusively,a seismically active range in central China,they do not appear to perceive pre-earthquake geophysical warning signs.