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文章通过对河南中牟区块海陆过渡相太原组和山西组页岩气形成的地质条件与特征分析,认为区块构造较为简单、稳定,其海陆交互相沉积环境控制太原组和山西组页岩发育,分布广泛,富含有机质页岩厚度大,为页岩气目标层;有机碳含量w(TOC)=1.1%~3.7%,有机质类型为Ⅲ型,有机质成熟度指标镜质体反射率(Ro)3.0%~3.8%;目标层有效孔隙度1.0%~5.0%,黏土矿物以伊利石和伊/蒙混层为主;含气量0.5~3.3m~3/t,平均1.7m~3/t。对牟页1井太原组、山西组三段采用快钻桥塞分段压裂,累计注入压裂液量5 055.9m~3,加砂量202.7m~3,三层合采求产为1 256m~3/d,标志着南华北盆地海陆过渡相页岩气勘探取得重大发现。通过地质评价和资源量计算,中牟区块太原组、山西组页岩气地质资源量较为丰富,勘探有利区面积大,具备较好的页岩气勘探前景。 相似文献
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鄂尔多斯盆地东缘经过20 a的勘探开发,煤层气仍然没有实现产业化。随着勘探资料的不断丰富,有必要对该区进行煤层气有利区块的优选和重新认识。在前人研究基础上,首先将鄂尔多斯盆地东缘埋深1 500 m区域分为6个区块,选取煤层厚度、含气量、构造条件、水文条件、煤体结构、含气饱和度、储层压力梯度、渗透率和临界解吸压力与储层压力比9个参数作为区块优选指标,结合国内外及研究区实际情况制定了相应的评价临界值。将上述参数作为评价指标集合,以评价单元作为对象集,以有利、较有利和不利作为评级等级集合,然后运用模糊数学综合评判方法得到各评价单元的不同评价参数对评价等级的隶属度,并运用层次分析法确定了各指标的相对权重,最后得到了评价单元对评价等级的隶属度。根据最大隶属度原则,吴堡-柳林属于有利区,大宁-吉县和韩城属于较有利区,准格尔、府谷、河曲-临县属于不利区,吴堡-柳林的煤层气可采性好于大宁-吉县和韩城。因此,建议将吴堡-柳林、大宁-吉县和韩城定为研究区煤层气优先开发区块。 相似文献
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多层次模糊数学法在湘西北页岩气有利区块优选中的应用 总被引：2，自引：0，他引：2
湘西北下寒武统牛蹄塘组海相页岩热成熟度高,且经历了多期复杂构造运动,这种有机质高热演化程度及复杂构造条件下的页岩气有利区块优选面临挑战。本研究对影响页岩气勘探开发潜力的各种因素进行了综合研究,确定了页岩气勘探开发潜力评价的4个二级指标(生成条件、储集条件、保存条件和综合配套条件)及相应的三级指标。采用模糊数学方法对各级因素指标赋予了权重,建立了用于页岩气勘探开发潜力评价的多层次模糊数学评判模型。利用该模型,综合评价湘西北地区鹤峰复背斜、桑植复向斜、古丈隆起、沅麻盆地和洞庭坳陷5个Ⅲ级构造单元的页岩气资源勘探开发潜力。研究表明,桑植复向斜最具勘探开发潜力,其次是鹤峰复背斜,沅麻盆地、古丈隆起与洞庭坳陷则相对最差。建立的评价体系,可以作为有机质高热演化程度及复杂构造条件下的页岩气资源开发潜力评价的参考体系。 相似文献
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With the increasing backlog of shelter in most of the third world, attempts are being made to evolve low-cost but durable walling units. The introduction of compressed earth blocks (CEBs) some 50 years ago was seen as a major milestone. These blocks are made by compressing a damp mix of soil (90–95%), and cement (5–10%) to form strong and dense blocks used for walling. While considerable knowledge is available regarding their initial performance characteristics, little research has so far been conducted on their long-term durability and deterioration due to prolonged exposure to environmental factors. It is now widely recognised that rapid and premature deterioration does take place when the material is used in unrendered walling in most humid tropical environments. Premature defects such as roughening, pitting, erosion, volume reduction, cracking as well as crazing, etc., have all been witnessed within periods ranging from 1 month to 5 years after completion of construction. This paper reports on recent research conducted in Uganda where in-service defects such as pitting and cracking where measured directly from existing exposed walling to quantify their nature and extent. It can be concluded that the greatest deterioration was found to occur on east–west facing facades, and on the lower wall sections. The deterioration was also found to correspond to the age of the structure. 相似文献
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Determining rock-block structures is important for modeling jointed rock masses. This paper presents a method to construct the boundary structures of complex blocks by eliminating fictitious surfaces. The planes involved in forming a complex block are retrieved, and the boundary polygons on each plane are determined using a series of Boolean operations. A regulation method is used to adjust the resulting polygons so that the regulated outer boundary structures can be used directly in the contact-detection algorithms. The interior fracture boundaries that are not explicitly associated with the formation of blocks are also constructed. These boundary surfaces are valued in hydraulic models to provide conductive channels of fluids in rock masses. The proposed method extends previous developments on block-identification algorithms, and the constructed boundary structures can be used directly in the modeling process of most discrete models. The program implemented based on this method has been used to study the stability and morphology of blocks in the Three Gorges Project, and several examples are given to further demonstrate the ability and performance of the proposed method. 相似文献
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地球化学块体的概念及其研究意义 总被引：12，自引：0，他引：12
地球化学块体是地球上某种或某些元素高含量的巨大岩块，它们是地球从形成与演化至今不均匀性的总显示，为大型至巨型矿床的形成提供了必要的物质供应条件。应用勘查地球化学的方法手段。从元素的角度能够将这些地球化学块体勾绘出来，从中到这种巨大的地球化学块体能够为大型巨型矿床的形成提供其所必需的足够的物质供应量的新认识，通过对全国区域化探扫面计划（RGNR）所覆盖的全国600多万km^2的国土面积上获得的高质量海量元素分析数据的综合研究，发现了比传统意义的分散晕分散流更为宽广的地球化学模式；区域异常，地球化学省，地球化学巨省和地球化学域，这种更为宽广的所谓套合着的地球化学模式谱系实际上是地球上富含各种金属的巨大岩块的内部结构特征在地表的表现，而追索某元素地球化学块体的内部结构则可揭示该元素在地球化学块体中逐步浓集成矿的轨迹，依此思路发展了一整套的矿产勘查新战略；迅速掌握全局，逐步缩小靶区，并应用于国土资源大调查的项目中，尽管地球化学块体的理论与方法学研究尚在初期阶段，但这一概念改变了建立在点源分散模式上的勘查地球化学的基本原理，也为矿床学，成矿学与大地构造学研究开拓了眼界，并提供了新的研究思路。 相似文献
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Alaska is considered to be tectonically comprised of five elongate blocks separated by transcurrent faults formed prior to rotation which enter the state from the southeast and continue westward to the edge of the Bering Sea continental shelf. We propose an additional, inactive fault, indicated by gravity and magnetic data and other observations, to extend between the Bering Strait and the Arctic Ocean continental shelf east of the Northwind escarpment, separating northern Alaska from northeast Siberia. Near the center of the state the faults are bent, concave to the south, about the north-south axis of the so-called Alaska orocline. In our reconstruction the blocks have rotated from a position whereby the north slope was adjacent to Banks Island of the Canadian basin. During the rotation the northernmost, or Brooks block, was squeezed, up to 15% in the western end, to its present width. After rotation, when the three southern blocks were in their present position, the Brooks block and the next block to the south were pushed eastward by North America moving against Siberia, forming the bend in the British-Richardson-Ogilvie Mountains we call the Ogilvie orocline. 相似文献
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Optimized extraction of dimension stone blocks 总被引：1，自引：1，他引：0
The profitable production of dimension stone mainly depends on the extractable block size. The regularity and volume of the blocks are of critical importance, and are controlled by the three-dimensional pattern of the discontinuity system. Therefore, optimization of block size has to be the aim when quarrying for natural stone. This is mainly connected to the quantification of joints and fractures, i.e., their spacing and orientation. The problem of finding unfractured blocks within arbitrarily oriented and distributed planes can be solved effectively by a numerical algorithm. The main effects of joint orientations on block sizes and shapes will be presented in this article. Quantification of unfractured blocks with the aim of optimization is illustrated by detailed studies on several quarries. The algorithm used in this study can be applied as a powerful tool in the planning of a quarry and the future exploitation of dimension stone. Application of the described approach is demonstrated on practical examples of quarrying natural stones, namely, sandstone, granite, rhyolite, etc. Block quarrying can be optimized by using the new 3D-BlockExpert approach. The quantification of unfractured rock masses is also shown to contribute to a more ecological protection and the sustainable use of natural resources. 相似文献
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J. R. INESON 《Sedimentology》1985,32(5):659-670
Isolated exotic blocks of late Jurassic age occur within an undeformed succession of marine Lower Cretaceous back-arc basin deposits on the west coast of James Ross Island, Antarctica. These flat, tabular slabs range up to 200 × 800 m in cross-section and lie concordant with the enclosing Cretaceous strata. Although mainly undeformed, one block displays a range of emplacement-related deformation structures, comparable in many respects to tectonic fabrics produced by simple shear. Emplacement by submarine block gliding is proposed, possibly as the final phase in the evolution of a composite mass transport event. Derivation of such gigantic slabs requires the existence of a steep, highly unstable basin margin during the early Cretaceous. In more complex terranes, differentiation between gravity slides and thrust slices can be difficult. Clearly, internal and marginal disruption of an allochthonous unit is not diagnostic since structures developed within a lithified block during submarine gliding may closely mimic tectonic fabrics. Where contact relationships are ambiguous, emplacement by gravity sliding is suggested by the increasing intensity of internal disruption towards the basal margin and by the style of deformation, reflecting simple shear under low overburden. 相似文献
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Block theory has been widely applied to stability analysis of rock engineering due to its clear concept and elegant geometrical theory. For a general block with multiple discontinuity planes, it is assumed that contact is only maintained on a single plane (single-plane sliding) or two intersecting planes (double-plane sliding) in block theory analysis. Since the normal forces and shear resistances acting on the other discontinuity planes are omitted, it can cause unreasonable estimations of block failure modes and incorrect calculation of factors of safety. In this study, a new method is presented that permits to consider the contribution of the normal forces and shear resistances acting on each discontinuity plane to the block stability. The proposed method meets all of the force-equilibrium and moment-equilibrium conditions and provides a rigorous solution for stability of general blocks with any number of faces and any shape. Some typical polyhedral blocks in rock slopes are analyzed using block theory and the proposed method. The results indicate that the traditional block theory may give a misleading conclusion for the predictions of stability and sliding direction of rock blocks when contact occurs on more than two discontinuity planes. 相似文献
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Dr. Peter H. Stauffer 《International Journal of Earth Sciences》1983,72(3):1061-1080
Parts of Southeast Asia show evidence of having Paleozoic or older continental crust. These include small fragments in the Philippine and Indonesian archipelagoes, New Guinea and adjoining shelves, and (the main area) a large mass consisting of nearly all of mainland Southeast Asia, most of Sumatra, southwestern Borneo, and parts of the bordering and intervening seas. Ophiolite belts, probable sutures, and contrasting geology across them indicate that this main mass is a mosaic of different fragments or blocks.Since a comprehensive review of the origins and histories of these blocks a decade ago, new information has appeared. Some inferred sutures have been reinterpreted, though the main area of old continental crust is still seen as consisting of at least two and possibly three separate blocks. Recent paleomagnetic determinations for the Paleozoic suggest a position in moderately high (probably southern) latitudes (43 for NW Malaya) for part of Southeast Asia in early Paleozoic, and the possibility of a southern temperate position (24 for central Thailand) in Late Paleozoic. New data on Late Paleozoic floras establish more firmly that Cathaysian floras were widespread on the edge of the Gondwana continent in the Arabian shield region, and the floral data can be seen now as supporting former attachment of part of Southeast Asia to Gondwana. A prominent zone of Carboniferous pebbly mudstones, now recognized to extend over 2000 km from Sumatra to Burma, has been reinterpreted to be of probable glacial marine, rather than slump, origin. The interpretation of these rocks is of critical significance: if the pebbly mudstones are submarine slump deposits, western Southeast Asia probably rifted off some unknown continent during Late Paleozoic; if they are glacial marine sediments, then western Southeast Asia was almost certainly attached to Gondwana and the rifting and separation took place later, probably during the later Mesozoic.
Zusammenfassung Teile Südost-Asiens besitzen offenbar paläozoische oder ältere kontinentale Erdkruste. Diese umfassen kleine Fragmente in den Archipelen der Philippinen und Indonesiens, Neuguinea mit anliegenden Schelfen, und (das Hauptgebiet) eine große Masse, die fast das ganze Festland Südost-Asiens, den Hauptteil Sumatras, das südwestliche Borneo und Teile des angrenzenden und dazwischenliegenden Meeres einschließt. Ophiolitgürtel, die wahrscheinlich Suturlinien darstellen und darüberhinweg sehr gegensätzliche Geologie deuten an, daß diese Hauptmasse ein Mosaik aus verschiedenen Fragmenten oder Blöcken ist.Nachdem seit einem Jahrzehnt eine umfassende Durchsicht der Herkunft und Geschichte dieser Blöcke erfolgt ist, liegen neue Kenntnisse vor. Einige herausgearbeitete Suturlinien wurden zwar neu interpretiert, doch wird das Hauptgebiet der alten kontinentalen Erdkruste immer noch als aus mindestens zwei und vielleicht drei verschiedenen Blöcken bestehend verstanden. Neue paläomagnetische Messungen für das Paläozoikum deuten auf eine Lage in mittelhohen (wahrscheinlich südlichen) Breitengraden (43 für NW-Malaya) für einen Teil Südost-Asiens im früheren Paläozoikum hin und für das spätere Paläozoikum auf die Möglichkeit einer mittleren südlichen Lage (24 für Zentral-Thailand). Neue Daten aus spätpaläozoischen Floren bestätigen mehr, daß Kathaysischen Floren auf dem Rand des Gondwanakontinents auf dem Arabischen Schild weit verbreitet waren und die floristischen Daten können jetzt verstanden werden im Sinne einer früheren Anbindung von Teilen Südost-Asiens an Gondwana. Eine auffallende Zone von geröllführenden Schlammsteinen des Karbons, die jetzt in einer Verbreitung von 2000 km von Sumatra bis Burma bekannt ist, wurde neu interpretiert als wahrscheinlich glaziomariner Herkunft und nicht als Rutschungsmassen. Die Deutung dieser Gesteine ist von kritischer Bedeutung: falls die geröllführenden Schlammsteine von submarinen Rutschungen stammen, wurde das westliche Südost-Asien wahrscheinlich im späteren Paläozoikum von einem unbekannten Kontinent abgespalten; jedoch, wenn sie glaziomarinen Ursprungs sind, dann war das westliche Südost-Asien nahezu zweifellos an Gondwana angebunden und die Abspaltung und Loslösung geschah später, wahrscheinlich während des späteren Mesozoikums.
Résumé Plusieurs régions d'Asie du sud-est attestent l'existence d'une croûte continentale paléozoïque ou plus ancienne. On trouve ainsi de petits fragments dans les archipels philippin et indonésien, en Nouvelle Guinée, et surtout une vaste masse qui comprend presque toute l'Asie du sud-est continentale, la majeure partie de Sumatra, le sudouest de Bornéo et des régions côtières ou entre les mers. Des ceintures d'ophiolithe, des sutures probables et une géologie contrastante montrent que cette masse principale se compose d'une mosaïque faite de différents fragments ou blocs.Depuis une étude compréhensive de l'origine et de l'histoire de ces blocs datant d'une dizaine d'années, de nouvelle informations sont apparues. Certaines de ces sutures ont fait l'objet d'une nouvelle interprétation, bien que la zone principale de l'ancienne croûte continentale soit encore considérée comme se composant d'au moins deux et peut-être de trois blocs séparés. De récentes déterminations paléomagnétiques pour le Paléozoïque suggèrent une situation (probablement australe) de latitude modérément élevée (43 pour le Nord Ouest de la péninsule de Malaisie) en ce qui concerne des régions d'Asie du sud-est au Paléozoique Inférieur, et la possibilité d'une situation australe tempérée (24 pour la Thailande centrale) au Paléozoique Supérieur. De nouvelles données sur la flore du Paléozoïque Supérieur montrent plus clairement que la flore cathaysienne s'étendait largement à la limite du continent de Gondwana dans la région du bouclier de l'Arabie; les données sur la flore peuvent maintenant confirmer l'attachement d'une partie de l'Asie du sud-est au Gondwana. Une longue zone d'argile à blocaux carbonifére, maitenant reconnue comme s'étendant sur plus de 2000 km de Sumatra à la Birmanie, a fait l'objet d'une nouvelle interprétation; elle est à présent considérée comme étant d'origine glaciomarine plutôt que de glissement. L'interprétation de ces roches comporte une signification particulière: si l'argile è blocaux est un dépôt dû à des glissements sous-marins, la partie occidentale de l'Asie du sud-est s'est détachée probablement d'un continent inconnu au cours du Paléozoïque Supérieur; si, en revanche, ce sont des sédiments glaciomarins, cette partie occidentale était alors presque certainement attenante au Gondwana, et la dérive ainsi que la séparation ont eu lieu plus tard, probablement au Mésozoique supérieur.
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P. D. Katsabanis A. Tawadrous C. Braun C. Kennedy 《Fragblast: International Journal for Blasting and Fragmentation》2006,10(1):83-93
A series of small scale tests, simulating multi-hole blasts have been performed to establish the effect of delays on blast fragmentation. The blasts were performed in high quality granodiorite blocks, which were cut from stone prepared by dimensional stone quarry operations. The pattern used was equilateral triangular, with a distance of 10.2 cm between boreholes, which had a diameter of 11 mm, were loaded with detonating cord and the coupling medium was water. The delays used were achieved using different lengths of detonating cord for the cases of delays between 0 and 100 μs between holes and a sequential blasting machine firing seismic detonators for larger delays up to 4 ms. All fragments were collected and screened. The experiments showed that the worst fragmentation was achieved with simultaneous initiation of all charges. Fragmentation improved with the delay time between holes up to 1 ms between holes. If the experiments are scaled up, the results show that in granodiorite, fragmentation optimization requires delays of few milliseconds per metre of burden. The findings, agree with previously published work, involving larger scale experiments and other rock types. 相似文献