Characteristics of transfer zones under the influence of preexisting faults and regional stress transformation:Wenchang A subsag,Zhujiang River Mouth Basin,northern South China Sea

A transfer zone in rift basins preserves important information on regional tectonic evolution and plays significant roles in hydrocarbon accumulation.Based on the systematic analysis of 3D seismic data and hydrocarbon accumulation conditions,the geometry,kinematics,and reservoir control of a large synthetic overlapping transfer zone in the south of the Wenchang A subsag in the Zhujiang(Pearl)River Mouth basin were investigated.Results indicate that the development and evolution of the transfer zone was controlled by the interaction between pre-existing faults and regional stress transformation.The intense rifting of the main faults of the transfer zone controlled the development of source rocks and faultcontrolled slope break paleogeomorphology.The strike-slip overprint since the Oligocene is conducive to the formation of a large-scale fault-anticline trap,and the secondary faults in the transfer zone contribute to the hydrocarbon transportation.The conjugate intersection area of the NE-and NW-trending faults offers more opportunity for hydrocarbon migration and accumulation.

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.

Strata Architectural Variability and Facies Distribution in a Structural Transfer Zone: A Case Study of Fushan Sag, Northern South China Sea

Structural transfer zones in a half-graben rift basin play a significant role in controlling sandy sediments and providing a target for hydrocarbon exploration. Previous studies have classified the transfer zone in lacustrine environments into two different patterns: synthetic approaching transfer zones and synthetic overlapping transfer zones. However, the evolution of the depositional pattern and the controlling factors of the above transfer zones are still unclear. In the Fushan Sag, the northern South China Sea, an overlapping transfer zone developed in the early Eocene Epoch, while a synthetic approaching transfer zone developed in the late Eocene, due to tectonic uplift. This evolutionary process provided an opportunity to study the stacking pattern of strata architectural variability and facies distribution in the structural transfer zone of the Eocene lacustrine basin. In this study, following the indications of the oriented sedimentary structures in core samples and heavy mineral assemblages of 18 wells, the evolution of the paleo-hydrodynamic distribution during the early and late Eocene has been reconstructed. The sequence-stratigraphy was then divided and the sand body parameters calculated, according to the seismic data and well log interpretations. During the early Eocene, the lake level was at a low stand, the faults broken displacement in the East block being over 50 m. The prograding delta and turbidites are oriented perpendicular to the structural transfer zone. According to the quantitative analysis of the flow rate and the depositional parameters, we speculate that gravity transportation of the sediment and the sediment-supply are the dominating factors during this period. Up to the late Eocene, the rising lake level and the decreased fault displacement leads the flow to divert to a NE-direction, resulting in it being parallel to the axis of the transfer zone. Thus, we speculate that the accommodation space is predominant in this period. In comparison with the above two periods, a braided river delta with an isolated sand body and turbidites developing in the deep area is prominent in the overlapping transfer zone, while a meandering river delta is characteristic of the synthetic approaching transfer zone.

Effect of Sand Body Enrichment Under the Restriction of a Tectonic Transfer Zone: A Case Study on the Pinghu Formation in the Kongqueting Region on the Pinghu Slope

Results of long-term explorations in the Kongqueting region,located in an East China Sea depression,suggest that the strong fault activity during the sedimentary period of the Pinghu formation significantly influenced the development of the sedimentary system.However,the aggregation and enrichment of the sand body under a tectonic background has become a problem that requires an immediate solution.Considering research outcomes of previous studies,this study used three-dimensional seismic and logging data to identify Y-or H-type and the en echelon distribution patterns of the fault plane,as well as identify the locations wherein the fault growth index value is greater than 1 in the study region,indicating the tectonic background of the fault transfer zone in the region.Second,the development type of the fault transfer zone was studied,and the sand body enrichment site was identified based on seismic inversion data and the development position of the fault transfer point.This helps clarify the evolution of sedimentary facies of the Pinghu formation combined with the sedimentary environment of the braided-river delta.Finally,after summarizing the coupling relationship between the synsedimentary fault systems and the sand body enrichment patterns,three sand-control models were determined,namely,the flexural-parallel,the en echelon collinear,and the torsional-reformed superimposed transfer zones.The findings of this study lay a foundation for the subsequent search of tectonic lithologic oil and gas reservoirs.

Oil source and migration process in oblique transfer zone of Fushan Sag,northern South China Sea

The oblique transfer zone in the Fushan Sag, a syndepositional dome sandwiched between the Bailian and Huangtong sub-sags, has been the most important exploration target. The major oil observation occurs in the E_2l_1^(L+M) and the E_2l_3~U. 46 oil and rock samples reveal that the oil in the transfer zone is mostly contributed by the Bailian sub-sag, though the source rock conditions, hydrocarbon generation and expulsion histories of the Bailian and Huangtong sub-sags are similar. The E_2l_3~U oil, characterized by high maturity, Pr/Ph ratio and oleanane/C_(30)-hopane ratio, shows a close genetic affinity with the E_2l_3~b source rocks, while the E_2l_1^(L+M) oil, characterized by lower maturity, Pr/Ph ratio and oleanane/C_(30)-hopane ratio, is suggested to be derived from the E_2l_(1+2)~b source rocks. The homogenization temperatures of aqueous fluid inclusions, taking the burial history of the reservoirs into account, reflect that the oil charge mainly occurred from mid-Miocene to Pliocene in the oblique transfer zone. The oil transporting passages include connected sand bodies, unconformities and faults in the Fushan Sag. Of these, the faults are the most complicated and significant. The faults differ sharply in the west area, the east area and the oblique transfer zone, resulting in different influence on the oil migration and accumulation. During the main hydrocarbon charge stage, the faults in the west area are characterized by bad vertical sealing and spatially dense distribution. As a result, the oil generated by the Huangtong source rocks is mostly lost along the faults during the vertical migration in the west area. This can be the mechanism proposed to explain the little contribution of the Huangtong source rocks to the oil in the oblique transfer zone. Eventually, an oil migration and accumulation model is built in the oblique transfer zone, which may provide theoretical and practical guides for the oil exploration.

Analysis and Research on Industrial Land Transfer in Hefei City Economic and Technological Development Zone of Anhui Province

In recent years,with high-speed development of economy and society,and fast propulsion of industrialization and urbanization process in the development zone,average annual land demand in the development zone also quickly enlarges,and the contradiction between high-speed growth of economy and shortage of land resources is apparent increasingly. Meanwhile,to guarantee crop safety and stick to 0. 12 billion hm2of farmland red line as a rigid constraint which could not be exceeded,the supply-demand contradiction of industrial land is more and more prominent. With industrial land scale continues to enlarge,land resources become more and more scarce,but there exists the phenomenon of low-efficiency land use and even idle. For land use characteristics of the development zone,taking Hefei City Economic and Technological Development Zone as an example,the countermeasures of perfecting industrial land transfer mechanism in the development zone are proposed.

Load Transfer Test of Post-Tensioned Anchorage Zone in Ultra High Performance Concrete

Researches on ultra-high performance concrete (UHPC) have been conducted worldwide owing to its outstanding durability and strength performances. The exploitation of the mechanical properties of UHPC will render it possible to achieve economic design through substantial reduction in the cross sectional dimensions and simplification in the reinforcement arrangement. This paper investigates experimentally the load transfer in the prestressed concrete anchorage zone. To provide distinctive features of UHPC compared to ordinary concrete, the cross sectional dimensions of the member were reduced and the stress distribution, deformation and cracking pattern of the PS anchorage zone were examined experimentally according to the degree of reinforcement of the members chosen. The distributions of the bursting stress, spalling stress and longitudinal edge stress in the specimens were observed according to the various types of reinforcement. All the specimens satisfied the load-bearing capacity criterion specified by the European ETAG-013 guidelines and their stress distributions were similar to those in the PS anchorages of post-tensioned members applying ordinary concrete. The cracks propagated longitudinally with lengths up to twice the cross sectional dimensions and their width was smaller than when applying ordinary concrete owing to the bridging effect of the steel fibers in UHPC. Accordingly, the exploitation of the high strength of UHPC enabled us to secure the resistance of the anchorage with no need for particular reinforcing devices.

Effects of Seasons on Embryo Transfer of Cattle in Different Climatic Zones

The paper was to evaluate the efficient seasons for embryo transfer of cattle in different climatic zones in China. Three climatic zones(mid-temperate zone,warm temperate zone,subtropical zone) were designed,and embryo transfers had been carried out in spring,summer,autumn and winter from 2009 to 2011,respectively. The total number of transplant recipient cattle was 22 208. The results showed that the best seasons for embryo transfers varied with different climatic zones. In mid-temperate zone,summer and autumn were better while summer was the best,and the rate of pregnant was 50. 67%(the number of pregnant cattle was 8 005). In warm temperate zone,spring and autumn were better while autumn was the best,and the rate of pregnant was 54. 99 %(the number of pregnant cattle was 551). In subtropical zone,spring and winter were better while winter was the best,and the rate of pregnant was 56. 94 %(the number of pregnant cattle was 328). The seasonal average temperatures and relative humidity of the best seasons in different climatic zones were concentrated on the same region. In mid-temperate zone,the mean temperature ranged between 22. 4 ℃ and 24. 2 ℃,and the mean relative humidity ranged from 44% to 55. 3%. In warm zone,the mean temperature ranges were between 14. 2 ℃ and 16. 2 ℃,and the mean relative humidity ranges were from 59. 3% to 71. 6%. In sub-tropical zone,the mean temperature ranges were between 3. 26 ℃ and 7. 73 ℃,and the mean relative humidity ranges were from 72% to 80. 6%. Therefore,the optimized conditions of temperature and humidity of season in different zones could be simulated. It is possible that we apply the program to bovine production in the similar agroecological zones,which is of great significance for improving the embryo transfer efficiency of livestock in production.

Modeling Water Infiltration and Solute Transfer in a Heterogeneous Vadose Zone as a Function of Entering Flow Rates

Due to its rapid movement, preferential flow (PF) in the vadose zone allows much faster contaminant transport, which may have a significant impact on ground-water quality. PF can occur in heterogeneous vadose zones and it strongly depends on hydric and hydraulic conditions like entering flow rates at surface. This study deals with the modeling of the establishment of PF, and related solute transfer during the infiltration phase in a strongly heterogeneous glaciofluvial deposit. This deposit is made of four contrasting lithofacies (sand, gravel, bimodal gravel and matrix-free gravel) and lies underneath an urban infiltration basin (Lyon, France). Previous studies have been carried out on this site and linked the regionalization of soil pollution with the lithological heterogeneity. But none of them clearly demonstrated how heterogeneity could impact flow and solute transfer and may explain such a regionalization. In this study, we model flow and solute transfer at the trench scale for both uniform and heterogeneous profiles in order to characterize the effect of lithological heterogeneity. In addition, such a modeling was performed for two different entering flow rates to depict the influence of condition at surface on PF. A key result is that heterogeneity clearly impacts unsaturated flow and solute transfer. Numerical modeling permitted pointing out the existence of PF paths associated with the sedimentary heterogeneity of the glaciofluvial deposit. For lower surface fluxes, the sand lens and matrix-free gravel were the sources of capillary barrier effects, leading to a funneled flow and a groundwater recharge characterized by earlier and more dispersed wetting fronts. Such a flow pattern enhances solutes transfer and reduces solute retention by soil. Thus, the effect of heterogeneity on solute transfer is significant, especially for the most reactive solutes.

太阳辐射作用下不同活动水平的室内人体传热特性及热舒适研究

太阳辐射是影响室内空调负荷的重要因素,当阳光直射人体时,影响人体与周围环境热交换,进而影响热感觉,人体处于热中性的环境温度的变化关乎空调系统能耗和人体热舒适。本研究在人工气候室进行冬季实验,利用太阳辐射模拟装置控制太阳辐射强度,受试者穿着典型服装,分别进行静坐与两种步速(3.2、5 km/h)活动,测试生理参数并进行热感觉问卷调查,分析太阳辐射与活动水平共同作用下,人体与周围环境间的传热特性,研究热舒适区偏移规律。结果表明:有太阳辐射时,随着活动强度增加,蒸发传热量占比增加,对流传热与辐射传热占比减小,热舒适区向下偏移,冬季人体维持舒适状态所需的环境温度降低。为该条件下空调室内设计参数的设定提供一定参考,使空调系统更节能。

管翅式相变储热系统结构/热源条件强化传热数值模拟研究

基于焓法的凝固/熔化模型,在考虑自然对流的情况下,建立管壳式相变换热器的熔化模型,并研究管翅片布局和热边界条件对相变材料瞬态熔化行为的影响机理。针对均匀的管翅片布局和恒定壁温热边界条件,设计一种具有方形波动热源的偏心结构,并对两者之间的强化传热规律进行比较和分析。结果表明,偏心布局可使相同传热面积中热传递盲区的熔化得到改善,而方形波动热源可增强前熔化阶段中央区域的自然对流;能量存储参数对比表明,相比原始结构,偏心布局结构或方形波动热源的熔化时间分别缩短12.5%和6.25%,而同时优化热源和结构的熔化时间缩短31.25%。方形波动热源和偏心结构能显著提高换热器的熔化速率。

泰兴市非饱和带与饱和带间固液界面传质模型的推导

非饱和带与饱和带紧密相联,建立两者交界处的固液界面传质模型,可以为非饱和带耦合饱和带模型提供一定理论基础,对更好地预测地下水污染趋势也非常有意义。文章以江苏省泰兴市为研究对象,将吸附与解吸、颗粒薄膜扩散、分配作用、稀释作用4种固液界面反应和非饱和带、饱和带的特性结合,推导出将非饱和带与饱和带联系在一起的固液界面传质模型。使用Matlab模拟模型参数改变时,地下水中污染物浓度的变化。结果表明,该模型是可行的,但是污染场地、污染物种类可能会对模型模拟结果造成影响。

辽东湾北部潜山走滑转换带特征及其对规模性储层的控制

潜山走滑转换带在渤海海域发育较为广泛,但其发育特征及控储作用研究薄弱。利用钻井、测井、三维地震等各类资料,对辽东湾北部地区构造转换带发育特征、成因机制及其对潜山规模型储层控制作用进行分析。研究认为,燕山末期左旋走滑背景下,辽东湾北部潜山发育多种类型转换带;根据走滑断层的相互作用以及转换带的形态,可以将辽东湾北部潜山转换带分为单支弯曲型和双支叠覆型两种类型;根据局部应力状态可以进一步细分为单支反“S”型、单支“S”型、双支左旋右阶以及双支左旋左阶转换带4个亚类,其中单支反“S”型和双支左旋右阶型转换带属增压型转换带,单支“S”型和双支左旋左阶型转换带属释压型走滑转换带。增压型走滑转换带提供的压扭性动力破碎作用使得潜山发育大规模裂缝型储集层,是潜山规模型储层发育的关键。

辽中北洼东部陡坡带走滑转换带特征及其油气富集贫化作用

走滑转换带对油气聚集成藏具有重要控制作用,但辽中北洼东陡坡走滑转换带在含油层系以及油气丰度上存在巨大差异,成藏认识不清晰,勘探层系不明确。利用三维地震资料及钻探成果,将辽中北洼东部陡坡带及辽东凸起走滑转换带划分为“S”型增压转换带、马尾型释压转换带、叠覆型增压及释压转换带4种类型。释压转换带与增压转换带依次交替发育,不同类型具有不同的构造特征。走滑转换带控制油气的富集与贫化。走滑转换带是圈闭发育场所,受拉张和挤压应力场影响,相应发育大量的断块和断背斜圈闭。释压型转换带形成低势区,成为优势的汇水通道及汇水区,是富砂沉积体优势发育地带。释压转换带断层开启,是油气垂向运移的有利通道,调节深层油气至浅层圈闭成藏,具有深层贫油-浅层富油的特征。增压型转换带断层闭合程度高,油气垂向及侧向封闭能力均优越,有利于油气保存,具有深层富油-浅层贫油的特征。

构造转换带源汇系统控储作用——以珠江口盆地惠州凹陷惠州26转换带为例

为明确惠州26转换带源汇系统对沉积砂体储层物性的控制作用,基于钻测井、地震、岩心等资料,刻画源汇系统的要素特征,分析沉积砂体储层物性特征,进而明确惠州26转换带不同时期源汇耦合模式及其控储作用。结果表明,在物源体系上,惠州26转换带在文昌期—恩平期持续受到南部东沙隆起的物源供给;在搬运体系上,沟谷形态发生了由文昌期V型向恩平期U型的转换;在沉积体系上,惠州26转换带经历了深水窄盆小扇—浅水广盆大扇—浅水广盆辫状三角洲的沉积演化过程。认为研究区储层质量受搬运距离和沉积相带等控制,在相同沉积体系内,搬运距离越长,越容易发育优质储层;经转换斜坡入湖并远距离搬运的辫状河三角洲内前缘水下分流河道微相为最优势相带,砂体储层物性最优。

国家级承接产业转移示范区的低碳发展效应研究——以大湘西地区为例

基于2013—2022年大湘西地区各市(州)数据,采用双重差分模型,检验国家级承接产业转移示范区建设对大湘西地区低碳发展的影响。研究表明,国家级承接产业转移示范区有利于大湘西地区的低碳发展,且通过绿色技术创新投入和提升政府对低碳发展的关注度,有利于促进大湘西地区的低碳发展。

涉灾群众转移安置风险区划综合研判技术应用

在应急管理救灾和物资保障工作中,结合时空地理信息技术可以实现对涉灾群众转移安置工作的全面掌控,提高应急避险的准确性和及时性。本研究从涉灾群众转移安置风险区划分析研判的角度入手,建立了社区填报、街道初审、区局终审、市局抽检的技术流程和工作方案,结合武汉市风险普查成果和基础测绘数据,实现了相关软件系统的功能,并进行了实际应用。结果表明,该系统具有较好的实用性,可为实际灾害风险区划图编制和防灾减灾的应急工作提供重要技术参考。

海安凹陷构造特征与油气成藏

基底先存逆断层的后期反转控制苏北盆地海安凹陷形成地垒式构造样式,喜山期右旋扭张应力场的叠加改造,形成了多次凹、扭动型地垒的构造格局。构造控圈、控藏作用明显:基底的差异性沉降控制了古近系阜宁组二段烃源岩的演化差异;在沉积相主体控制下,同沉积二级断层影响阜宁组三段砂岩储层的分布发育;在晚期成藏的条件下,长期活动断层是油气运移有利通道;构造转换带是圈闭发育和油气成藏的有利区。

2种钢管混凝土格构式风电塔架节点受力性能对比分析

对钢管混凝土装配式附着板节点和万向包裹Y型节点2种不同构造节点进行ABAQUS有限元分析,从静力荷载下的受力全过程、塑性区域发展情况、传力机制等方面进行对比。结果表明,各节点屈服阶段的变化规律基本吻合,具有良好的承载能力。装配式附着板节点的高应力区出现在节点板上,装配式万向包裹Y型节点由于已增加球杆连接件作为节点的传力构件,其高应力区主要集中在球杆连接件的下部。该文总结的2种钢管混凝土格构式风电塔架节点从适用性来说,建议使用钢管混凝土装配式附着板节点。

基于桩-土界面剪切特性的单桩沉降和承载问题研究

近年来,西北地区出现了许多高填方场地,为减小建筑物基础的不均匀沉降,基础类型广泛使用桩基础。与一般场地不同,黄土填方场地中的单桩桩周土受力后仍会产生较大的变形,该类场地单桩沉降机制复杂。桩顶总沉降计算是桩基设计的重要依据,为此,建立了高填方黄土场地单桩桩顶总沉降计算模型。基于传统的荷载传递法和剪切位移法,分别考虑桩-土界面的桩-土相互作用和桩-土界面外剪切带土体的剪切变形。依据桩端边界,将单桩类型分为摩擦桩和端承摩擦桩,分别建立桩周土弹性阶段和塑性阶段的桩身位移控制微分方程,结合边界条件进行求解,得到桩身位移、轴力、侧摩阻力,并通过弹塑性理论求解了桩周土剪切带土体剪切变形,进而通过叠加原理求得桩顶总沉降。用桩长与桩周土塑性发展深度的比值,定义了桩基承载力安全系数K。通过算例分析与现场试验数据对比分析,研究结果表明:使用新的模型计算得到的桩顶总沉降与现场试验结果相近;当桩顶荷载较小、桩周土处于弹性阶段时,桩端边界对桩身轴力、位移和侧摩阻力影响很小,但桩周土进入塑性滑移阶段后,桩端边界的影响开始变大,考虑桩端土的承载能力会极大提高单桩极限承载力;建立了将荷载传递法和剪切位移法综合起来的计算模型,不仅可以考虑桩-土界面的相对滑移,还可以计算桩-土界面外土体剪切带的剪切变形,使得桩顶总沉降计算更加精确,可为类似场地中单桩沉降的分析与控制提供一定的参考。