A dynamic deterministic model of hydrocarbon generation in the Midgard Field drainage area offshore Mid-Norway

The Midgard Field offshore mid-Norway is a gas-condensate accumulation with a thin oil leg reservoired in Early and Middle Jurassic sandstones. There are two potential source rocks in the area; the Late Jurassic Spekk Formation is a marine shale with type II kerogen and a rich potential for oil, and the Åre Formation of Early Jurassic age which is a thick coal-bearing sequence with type III kerogen and potential mainly for gas. Geochemical analyses indicate that both the condensate and the oil leg are sourced mainly from the coal-bearing Åre Formation. Any contribution from the Spekk Formation appears to be of minor importance. Computer simulation of hydrocarbon generation in the drainage area for the Midgard Field indicates that huge volumes are formed, and confirms that hydrocarbon generation from the Åre Formation is volumetrically far more important than from the Spekk Formation. The simulation results also exclude any contribution to the reservoired gas from the Spekk Formation.

---

Zusammenfassung Das Midgard Feld vor der Küste Mittelnorwegens ist eine Gas-Kondensat-Akkumulation mit einem nur geringen Ölanteil innerhalb unter- und mitteljurassischer Sandsteine. In diesem Gebiet gibt es zwei mögliche Muttergesteine: Einmal die oberjurassische Spekk-Formation, bei der es sich um einen marinen Schiefer mit Typ II Kerogen handelt und die ein hohes Ölpotential darstellt. Zum anderen gibt es die unterjurassische Åre-Formation, eine mächtige Kohle-führende Folge mit Typ III Kerogen und ein möglicher Gaslieferant. Geochemische Analysen deuten darauf hin, daß sowohl das Gas-Kondensat als auch das Öl des Midgard Feldes auf diese Kohle-führende Åre-Formation zurückzuführen sind. Jede Zufuhr aus der Spekk-Formation scheint von geringer Bedeutung zu sein. Eine durch Computersimulation rekonstruierte Kohlenwasserstofferzeugung im Einzugsgebiet des Midgard Feldes spricht für eine hohe Bildungsrate und bestätigt die Annahme, daß die Kohlenwasserstoff-produktion der Spekk-Formation gegenüber der Åre-Formation zu vernachlässigen ist. Die Simulation ergab ferner, daß keinerlei Gas von der Spekk-Formation dem Reservoir zugeführt wurde.

---

Résumé Le champ off-shore de Midgard (Norvège moyenne) est une accumulation de gaz condensé accompagnée d'un mince corps d'huile, accumulation renfermée dans des grès d'âge jurassique inférieur et moyen. Il existe dans le secteur deux sources possibles: la formation de Spekk (shale marins du Jurassique tardif, à kérogène de type II, possédant un riche potentiel en huile) et la formation d'Åre (série épaisse jurassique inférieure, à couches de charbon, à kérogène de type III et potentiel essentiellement en gaz). Les analyses géochimiques montrent que le gaz condensé et l'huile ont tous deux comme origine la formation charbonneuse de Åre. La formation de Spekk ne semble être intervenue que de manière subordonnée. Une simulation par ordinateur de la genèse de l'hydrocarbure dans l'aire d'alimentation du champ de Midgard fait apparaître que des volumes importants ont été formés et confirme la large prépondérance de la formation de Åre parmi les roches-mères. De plus, cette simulation exclut toute expèce de contribution de la formation de Spekk dans la genèse du gaz.

---

Midgard / / . : Spekk — , 2, , Are , 3 . . . , Are. Spekk, , . Midgard , Are . , , Spekk .

     

Forest or no forest: implications of the vegetation record for climatic stability in Western Beringia during Oxygen Isotope Stage 3

Two conflicting stratigraphic schemes describe the Siberian Karginskii interstade (Oxygen Isotope Stage 3 equivalent) as having: 1) relatively stable climate with environments more similar to the full glaciation; or 2) variable climate with landscapes that more closely approximate contemporary ones. New data from continuous lake cores and a nearly continuous section from western Beringia (WB) suggest that both schemes are valid. Herb-dominated communities, possibly with isolated populations of Larix, characterized northern WB with only a slight shift from relatively warm to cool summers during the mid-interstade. In contrast, herb and shrub tundra, steppe, forest-tundra, and modern Larix forest occurred at various times in areas of southern WB, suggesting greater climatic instability. A thermal optimum is evident in the south during the mid-interstade, with modern vegetation in southeastern WB and Larix forest-tundra in the southwest. Variations in Pinus pumila pollen indicate summer warm/winter dry and summer warm/winter wet conditions in southeastern WB. These fluctuations contrast to other areas of WB, where summers and probably winters were consistently arid. Although the interstade presents a unique interval within the Late Pleistocene, paleodata and paleoclimatic models suggest that changes in marine conditions, including sea level, were likely key drivers in the regional climate history.     

Shear resistance of fissured Neogene clays

Two types of fissured Neogene clays (SM and WB) were tested in the laboratory using undisturbed and reconstituted specimens. Although of similar age, the clays differ in their geological history: SM clays were deposited in a marine environment, WB are lacustrine clays with a complex tectonic history.

The index properties of both clays are similar and, accordingly, their strength parameters are mutually close. Test results of the more compact and less wet clay (WB) are affected by the sampling and trimming procedures, especially for 38 mm diameter specimens.

Although the behaviour is similar, the origin of fissures is different. For the SM clays, weathering is the main cause and fissuring reaches a depth of about 20 m. WB clays are dissected by macro- and microfissures originating as the result of tectonic processes and volumetric changes (effect of the coal formation underneath the investigated massif).

Cementation of some samples was found and the transition from clays through cemented clays to claystones (soft rocks) is speculated.     

Comparison of hydrological models for use in climate change studies: A test on 241 catchments in West and Central Africa

The present work reports on the study and the comparison of the performance of three “Génie rural” (GR) and two Water Balance (WB) models. The calibration and robustness performances are analysed in the light of the hydro-climatic conditions. The study shows that the GR models are much more efficient and robust than the WB models. The behaviour of calibration performance as a function of hydroclimatic variables varies according to the model and goodness-of-fit criteria (GOFC). The GR models are more robust in terms of NSE(Q) and NSE(√Q) and the WB models in terms of KGE. For more robustness of the models, it is better to transfer the parameters to wetter periods or periods with a lower Potential EvapoTranspiration (PET) than the calibration period. For a loss of robustness of less than 20% for GR and 30% for WB, the variation between calibration and rain validation/PET periods must be around ±15%/±1.5%.     

Anomaly effects of orthogonal paired-arrays for 3D geoelectrical resistivity imaging

A series of 2D apparent resistivity data were generated over two synthetic models representing different geological or environmental conditions commonly associated with geophysical applications for hydrogeological, environmental and engineering investigations. The apparent resistivity data were generated for the following arrays: Wenner-alpha (WA), Wenner-beta (WB), Wenner–Schlumberger (WSC), dipole–dipole (DDP), pole–dipole (PDP) and pole–pole (PP) arrays, which were paired such that apparent resistivity data for 2D profiles in a parallel direction are obtained with a particular array type and those in a perpendicular direction are observed with a different array type. The 2D apparent resistivity data for the orthogonal paired-arrays were then collated to 3D data sets. The effectiveness and efficiency of the orthogonal paired-arrays in 3D geoelectrical resistivity imaging were evaluated by determining the mean absolute anomaly effects of the electrode configurations on the synthetic models. The results show that DDP–PDP, DDP–PP, DDP–WSC, PDP–PP, DDP–WB, PDP–WB and WB–WSC orthogonal paired-arrays produced higher anomaly effects on the synthetic models. This indicates that DDP–PDP, DDP–PP, DDP–WSC, PDP–PP, DDP–WB, PDP–WB and WB–WSC orthogonal paired-arrays are more sensitive to 3D features of the geologic models than the other orthogonal paired-arrays investigated.     

脆性岩体岩爆倾向性的相似材料配比试验研究

坚硬脆性岩体具有岩爆倾向性。选取单轴抗压强度? c、抗压抗拉强度比? c /? t与冲击能量指数WB为岩爆概化指标。在制作岩爆模型材料时,采用石英砂、石膏、水泥、水、甘油和明胶等相似材料成分运用正交试验设计的原理进行配比试验,制作模型小试件。对模型小试件进行单轴抗压强度试验和劈裂试验,找出了各相似材料成分配比对试件? c、? c /? t与WB的影响特征,选取了合适的岩爆模型材料的配方。该配方力学指标稳定,既满足物理模拟岩爆的模型材料的要求,又便于一次性浇注大尺寸模型试件,较适用于大型物理模拟试验。     

“Progressive port Elizabeth”: Liberal politics,local economic development and the territorial basis of racial domination, 1923–1935

The growth of state capacity with respect to African people in South Africa's cities, while an ambition of many local and central state managers, was secured only in the face of conflicts within the state and between the state and the people. This paper examines some of the specific social processes which shaped the segregated form of African settlement and administration in Port Elizabeth between 1923–35. The aim is to interpret how the unique configuration of social and economic conditions in Port Elizabeth both fed into and depended upon an as yet imperfectly implemented strategy for the government and control of the city's African populace. Issues of concern include the nature of the administration in the New Brighton Location, the influence of liberal politics on Location strategy and the impact of the local council's efforts at place entrepreneurialism on residential development and urban government.     

Transfer of stress from the 2004 Mw9.2 Sumatra subduction earthquake promoted widespread seismicity and large strike‐slip events in the Wharton Basin

The 2004 Mw9.2 Sumatra and 2012 Mw8.6 Wharton Basin (WB) earthquakes provide the unprecedented opportunity to investigate stress transfer from a megathrust earthquake to the subducting plate. Comprehensive analyses of this study revealed that the 2004 earthquake excited widespread seismicity in the WB, especially in regions of calculated stress increase greater than 0.3 bars. The 2004 earthquake stressed all three rupture planes of the 2012 Mw8.6 strike‐slip mainshock and the largest Mw8.2 aftershock with mean values of Coulomb stress between 0.3 and 2.1 bars. For the 77 Mw ≥ 4 regional events since 2012, at least one nodal plane for 95% of the events, and both nodal planes for 72% of the events experienced stress increase due to the 2004 earthquake. Results of the analyses also revealed that the regional stress directions in the WB may have controlled the sub‐fault orientations of the 2012 Mw8.6 strike‐slip earthquake.     

Mineralogy and physico-chemical properties of Wadi Badaa clays (Cairo-Suez district,Egypt): a prospective resource for the ceramics industry

The Wadi Badaa (WB) Upper Miocene clays, Cairo-Suez district, Egypt, represent materials for the ceramic production. The clay raw materials are composed mainly of smectite and kaolinite with minor quartz, calcite, and rare feldspar. The plasticity indices vary between 24 and 30%, suggesting that these clays are plastic raw materials. IR bands of the investigated clays were observed at 3695, 3619, 1032, 916, 794, 690, 534, 466, and 423 cm^?1 for kaolinite; at 3436, 1635, 916, and 466 cm^?1 for smectite; and at 1179, 1104, 794, 690, and 466 cm^?1 for quartz. The <2 μm particle sizes of samples are relatively abundant in clays (～33%), which is adequate for uses of the ceramic products because of containing fine particle sizes. The studied WB clays contain 7.95 and 12.35% moisture water and interlayer water, respectively, with a maximum drying shrinkage of 7.87% at room temperature; therefore, the WB clays could be used in the ceramic manufacture.     

Effects of defect and pressure on the thermal expansivity of Fe x O

Pressure–volume–temperature measurements have been carried out using synchrotron X-ray diffraction for wüstite at static pressures of 1.9, 2.6, and 5.4 GPa. Our results revealed that the composition change of wüstite and, hence, rearrangements of defect structures are primarily caused by the magnetite (Fe₃O₄) exsolution at temperatures of 523–723 K. Based on the isobaric volume–temperature data collected during cooling, the contribution of compositional variations to the unit-cell volumes of wüstite in the ranges of 300–673 K and 723–1073 K is negligibly small, within the experimental uncertainties. These observations suggest that the measured volume changes in the range of 300–673 K and 723–1,073 K can be attributed to the metal–oxygen bond expansion. Owing to the magnetite exsolution, thermal expansion data are obtained in each experiment at 1.9, 2.6, and 5.4 GPa for wüstite of two different compositions, Fe_0.987O and Fe_0.942O. At all three pressures, Fe_0.942O shows a thermal expansion that is about 30% larger than Fe_0.987O. Such findings represent the first experimental evidence of a substantial effect of nonstoichiometry on thermal expansivity, and based on previous thermodynamic calculations of the defect formation and interaction, this effect is likely associated with the distinct defects arrangements in iron-rich and more iron-deficient wüstite. This study also presents thermal equations of state for wüstite of two different compositions. Such volume-related properties at high temperatures are experimentally difficult to obtain in wüstite but important for thermodynamic studies in the binary Fe–O system.     

Adsorption of short-chain organic acids onto nearshore marine sediments

The adsorption of acetate, butyrate, lactate, and stearate was measured using a clastic mud from Cape Lookout Bight N.C. (CLB), a lateritic muddy sand from Kahana Stream, Oahu, Hawaii (KS), and a fine carbonate sand from Waimanalo Beach, Oahu, (WB). Partition coefficients (K_d, moles adsorbed per g of solid phase/moles dissolved per ml of porewater) ranged from 10^2.3 to ≤10^−3.0, and displayed the following trends: CLB > KS > WB, and stearate > acetate ∼- butyrate > lactate. The percent adsorption of the sediment organic acid pools showed similar trends: stearate, 99%; acetate, 9–23%; butyrate, 5–23%; lactate, ≤0.2–7%. These results reflected the relatively nonpolar nature of the sand surfaces in WB and KS sediments, and the polarities of the organic acids. K_d was approximately constant for each organic acid-sediment combination over a dissolved organic acid concentration range of 10⁷, using concentrations between 1M and 10⁻¹⁴ M. This constancy over a wide porewater concentration range suggested that adsorption was not limited by the availability of surface adsorption sites.     

香港西博寮海峡WB7孔的第四纪沉积及硅藻研究

香港西搏寮海峡ＷＢ７孔第四纪沉积物中共有硅藻５４属，１８６个分类单位，该硅藻生物群以沿岸潮间带和近岸浅海种为主，伴有热性，暖热性浮游硅藻。依据硅藻在剖面中的分布特征，丰度及百分比含量变化，自下而上可划分出６个硅藻组合带。并明显反映该沉积时期的古气候与古环境特征，其中第５，６，带相当于全新世，其余４个带均属更新世。     

Determination of the <Emphasis Type="Italic">PT</Emphasis> Conditions that Accompanied a Seismogenic Slip along a Deep Segment of the Marginal Suture of the Siberian Craton

This paper reports data on the structure of the central zone of the seismogenic fault in the originally deep segments of the fault zone. The isotopic analyses have made it possible to estimate the absolute age of the ancient coseismic faults at 673 ± 5 Ma, which is indicative of seismic activation of deep faults in the studied segment of the marginal suture of the Siberian Craton in the Neoproterozoic.     

The late Tonian Zhaunkar granite complex of the Ulutau sialic massif,Central Kazakhstan

The crystallization age of Zhaunkar granites (829 ± 10 Ma) was determined by U–Pb zircon dating. Taking into account the data obtained earlier on the granite age (791 ± 7 Ma) in the Aktas Complex and the syenite age (673 ± 2 Ma) in the Karsakpai Complex, the Ulutau sialic massif is assumed to be composed of three igneous complexes formed during the Tonian–Cryogenian periods of the Neoproterozoic.     

湖南瑶岗仙钨矿床成矿流体的氦、氩同位素组成及其意义

瑶岗仙钨矿床是南岭地区最典型的石英脉型钨矿床之一。本文对该矿床黄铜矿和黑钨矿中流体包裹体的氦、氩同位素进行了较系统地测定。研究表明,黄铜矿和黑钨矿流体包裹体中3He／4He分别为0．37—0．43Ra和0．05～0．49Ra,明显高于地壳值;黄铜矿和黑钨矿流体包裹体中的氩同位素分别为673～886和325～903,均明显高于饱和大气雨水的40Ar／36Ar值。这些氦、氩同位素组成揭示该矿床的成矿流体具有壳、幔两端元混合的特点。结合区域地质构造演化和成矿年代学的研究成果,本文认为瑶岗仙钨矿床的成矿流体是由瑶岗仙S型花岗岩浆分异出的含有地幔He的岩浆流体与大气成因地下水的二端元混合产物,S型花岗岩的形成也是壳幔相互作用的结果。     

金星薄饼状火山类比研究

金星薄饼状火山(陡边火山)是一类形貌非常独特的火山,有别于太阳系中其他的火山:近圆的底面轮廓、平坦的顶部和较大的顶底直径比。薄饼状火山被认为是高黏度岩浆喷发形成的,但是这一成因并不被广泛接受。火山的形貌特征主要取决于岩浆成分、喷发机制、重力和喷发环境(如大气压)等。因此,通过对比地球火山的形貌特征及形成机制可以为金星薄饼状火山的成因提供指示。我们利用底面不规则度(ii)、高径比(H/W_B)、顶底直径比(W_S/W_B)、侧边最大坡度处的标准化高度(HS_max)、顶部高径比(H_S/W_S)和喷发量(V)这些形貌参数定量地将地球表面的复式火山、盾形火山、火山锥、熔岩穹丘(Peleean型和Coulees型)、海底平顶火山以及泥火山的形貌特征与金星薄饼状火山对比。Coulees型熔岩穹丘、海底平顶火山和泥火山的形貌特征与金星薄饼状火山有一定的相似性。Coulees型熔岩穹丘剖面形态与薄饼状火山最为相似,可能指示了薄饼状火山具有类似的成因机制,而海底平顶火山侧边的上凹特...     

Thermal expansion of Mg(OH)<Subscript>2</Subscript> brucite under high pressure and pressure dependence of entropy

An equation of state for Mg(OH)₂ brucite under high-pressure and high-temperature conditions has been obtained by measuring temperature dependence of volume up to 600 K at ambient pressure and pressure dependence of volume up to 16 GPa at 300, 473, 673, and 873 K with in situ X-ray diffraction. Pressure dependence of entropy of brucite has been calculated with thermal expansion coefficient and volume which are derived from the present EoS. This dependence indicates that generation of secondary OH dipoles affects entropy. The OH dipoles probably appear around 2 GPa and the number seems not to change over 8 GPa at 300 K.     

香港近海第四纪研究──(香港)地区与全球对比表

通过对ＷＢ７钻孔的研究及过去资料的分析，香港近海第四纪地层层序至少可以识别出１０个海相与陆相交替的沉积序列。ＷＢ７钻孔位于香港西薄寮海峡，对该钻孔进行了连续取样。本文列出了两张地区性与全球沉积序列对比表，最早的海相沉积和陆相沉积年龄分别早于倒数第４次间冰期和倒数第５次冰期，地层对比表中把香港的第四纪地层与磁性地层、氧同位素地层、超微体化石组合及澳大利亚南部滨岸沙丘序列，新几内亚Ｈｕｏｎ半岛和印度尼西亚Ｓｕｍｂａ半岛的海岸阶地，美国大西洋海岸平原氧同位素序列，中国黄土阶段及海侵，东南亚的海岸和近海沉积进行了初步的对比。     

Optimization of novel hyperthermostable β amylase production by Bacillus subtilis DJ5 using solid agroresidual substrates

Eight different low cost starchy agroresidues namely Barley (B), Wheat bran (WB), Sattu (S), Rice powder (RP), Corn flour (CF), Rice husk (RH), Yellow peas split (YPS) and arrowroot (A) were used for solid culturing of Bacillus subtilis DJ5 for production of novel hyperthermostable β amylase. Various process parameters like initial moisture content, inoculum load, medium pH and incubation temperature affecting enzyme production were optimized to ensure maximum enzyme yield. Only 10 % inoculums load and medium pH of 6.9 was found sufficient to achieve maximum enzyme production in all substrates in a decreasing order, B > WB > S > RP > CF > RH > YPS > A. Optimum β amylase production was highly dependent on initial moisture content of substrate as observed from varying requirement of moisture for different substrates. Only 50 % moisture was sufficient for maximum enzyme production of 84.29 U/gdm in CF. For B, RH, YPS, and A 60 % initial moisture resulted in higher production of 120.34, 35.19, 26.59, and 21.58 U/gdm, respectively, at 37 °C. However, for S and RP higher (70 %) moisture content allowed 113.4 and 85.56 U/gdm enzyme production, respectively. Under optimized conditions, maximum β amylase production was observed after 25 h for A, YPS, RH, RP; 41 h for B, WB, CF, and 45 h for S.     

Variability of the gravitational lens UM 673 in 2003–2005

Results of VRI photometry of two components of the gravitationally lensed quasar UM 673 in 2003–2005 are presented. The observational data were obtained on the 1.5-m telescope of the Maidanak observatory. During the monitoring of the system, considerable brightness variations in components A and B with amplitudes of about 0.2 ^m were recorded, demonstrating variability of the quasar. The increase in the brightness of the components was accompanied by reddening of their V-R color indices. Analysis of the brightness and color variations of the components shows no variations related to microlensing.