胜坨油田两期成藏地球化学特征及成藏过程分析

对东营凹陷胜坨油田的成藏期次和成藏过程进行了研究,结果表明,东营凹陷北部陡坡带具有两期成藏的地质条件,例如北部胜坨油田就经历了早期(东营组末期)的油气聚集、破坏和晚期(明化镇组时期)的油气再聚集、调整的过程;胜坨地区各含油层系中原油物性、生标特征及油源对比结果为该两期成藏提供了直接的地球化学证据。认为胜坨油田两期成藏对油气储量分布具有明显的影响。     

Fish Assemblages and Environmental Variables Associated with Gobiids in Nearshore Areas of the Lower Great Lakes

We investigated which fish species and environmental variables were associated with the invasive round goby (Neogobius melanostomus) and tubenose goby (Proterorhinus marmoratus) in nearshore Canadian waters of the Huron-Erie corridor of the lower Great Lakes. We measured a suite of environmental variables and used triplicate beach seine samples to collect fishes in summer 2006. Thirty sites were sampled in the day and a subset (n = 14) at night. Of 1,955 individuals caught in daytime samples, round goby (21.0 %), spottail shiner (17.3%) and emerald shiner (14.2%) were most abundant. Of 1,521 individuals collected at night, the most abundant species were round goby (42.3%) and emerald shiner (24.1%). Tubenose gobies represented 1% and 1.7% of all individuals caught in the day and night, respectively. Rarefaction analysis showed that overall species richness was greater in the day than night. Significantly more emerald shiner (P = 0.017), rock bass (P = 0.046) and round goby (P = 0.035) were caught at night than in the day; more logperch were caught in the day than at night (P = 0.042). Round gobies were positively associated with water temperatures up to 24°, but there was no relationship between round goby abundance and warmer temperatures. There were too few tubenose goby captured to determine their statistical association with environmental factors; however, tubenose gobies were found only where round gobies were collected. Round goby and tubenose goby were associated with yellow perch and rock bass. The benthic round goby was the most abundant species, whereas other abundant species were pelagic, schooling fishes that occupied a habitat distinct from round goby.     

二连盆地巴音都兰凹陷油气勘探再获新发现

2001年,二连盆地的隐蔽油藏勘探取得了重大突破,在巴音都兰凹陷的巴Ⅱ号、巴Ⅰ号构造整装探明、控制了两个千万吨级的油藏。借鉴2001年成功的经验,2002年科研人员通过精细基础地质研究,深化成藏条件分析,在巴7西断鼻的油气勘探再获新发现,控制了千万吨级的巴38油藏。本文详述了这一发现的研究思路、内容及油藏发现、评价的过程。     

优质烃源岩在鄂尔多斯低渗透富油盆地形成中的关键作用

鄂尔多斯盆地中生界低渗透油藏分布广泛,主要分布于延长组各油层组,其中长6、长8、长4＋5为主力油层组。储集岩热解资料显示,湖盆中部长7、长6油层组广泛分布的致密深水砂岩普遍具有良好的含油性,普遍成藏特征明显,呈现出“满凹含油”的低渗透富油盆地特征。恒速压汞、启动压力梯度和石油充注成藏试验结果显示,延长组低渗透—致密砂岩储层的喉道细小,毛细管阻力大,加之地层平缓,使得储层中油水重力分异困难。石油运聚表现为“被动”的动力学属性,石油充注与大规模运聚成藏不仅需要较强的动力,而且富烃流体要更有利于成藏富集。大范围分布的长7优质烃源岩具有生排烃规模大、生烃增压作用十分强烈（提供石油运聚的主要动力）、高效排烃（提供大规模的富烃流体）等特征,因而可满足低渗透—致密砂岩大规模成藏富集所需的动力和油源条件,在中生界低渗透富油储层形成中起着关键作用。     

非牛顿流体通过均匀球体集合的流动

本工作对非牛顿流体通过均匀球体的集合进行了实验测定,从Happl模型出发,用有限元进行计算,并将实验与理论计算结果对照作了讨论。本文从理论上阐明较宽e范围内不同n值幂律流体的孔隙介质流动的规律,并根据实验结果讨论解释了粘性、弹性和切力变稀等流变性在孔隙介质流动中的作用。     

The impact of small physical obstacles on the structure of freshwater fish assemblages

Many studies have assessed the effects of large dams on fishes but few have examined the effects of small obstacles. Fishes were sampled and environmental variables were characterized at 28 sites in two Iberian streams, 14 located immediately downstream, upstream and between five small obstacles at river Muge and 14 at river Erra, considered as the reference stream. Multivariate analysis indicated that habitat variables like current velocity and depth, but not physicochemistry, were mainly responsible for site groups' discrimination in both streams. The reference stream exhibited a longitudinal gradient of current velocity that, however, was not strong enough to cause significant changes in the fish assemblage's composition and structure. By successive and drastically repeating this gradient near each structure, the obstacles stream presented differences in fish fauna between the three site types. Lentic upstream sites presented higher density of limnophilic, omnivorous and exotic species, like gudgeon Gobio lozanoi, which are well adapted to this type of habitat. Downstream and between obstacles sites were characterized by the dominance of rheophilic and invertivorous taxa, especially barbel Luciobarbus bocagei. Richness metrics did not differ among site types, but diversity was higher in sites located between the obstacles away from its direct influence, where the habitat diversity was higher. Contrarily to upstream sites, downstream and between obstacles sites were similar in many of the studied features to the reference stream, implying that this type of structures cause a higher modification in the upstream fish community. This study suggests that the effects of small obstacles on habitat and fishes are similar, in some extent, to those reported for larger dams, providing important considerations for riverine ecosystem conservation efforts. Copyright © 2009 John Wiley & Sons, Ltd.     

致密砂岩气藏成藏过程中的地质门限及其控气机理

基于束缚水膜厚度不变的地质特征,通过对致密砂岩气藏储层的孔隙空间演化和流体变化规律分析,确定了致密砂岩气藏成藏过程中的3个地质门限,即天然气充注门限、天然气饱和门限和天然气终止门限,建立了相应的概念模型和计算模型,并就其对致密砂岩气藏的流体分布的影响和控制进行了系统的阐述。利用该模型对鄂尔多斯盆地上古生界致密砂岩气藏的预测结果表明,3个地质门限的对应深度分别为2 350m、2 850m和4 800m。经实际气藏剖面的正反检验表明,该模型对于预测致密砂岩气藏的流体分布具有较高准确性。     

济阳坳陷同沉积构造控藏作用探讨

文章从构造、沉积、成藏相互关系的角度,系统论述了济阳坳陷同沉积构造对沉积和油气成藏的控制作用,揭示了同沉积构造有利于油气生成、运移、聚集、保存的基本条件。分析认为,在大中型油气藏相继被发现之后,当前济阳坳陷应该充分运用层序地层学理论、含油气系统理论及成藏动力学理论,研究同沉积构造的发育演化过程对沉积过程、圈闭形成过程以及成藏过程的控制作用和时空匹配关系,以提高勘探效果。同沉积构造的研究日趋由定性向定时和定量方面发展,不但更加重视动力机制研究,也开始逐步完善定量化过程模拟。     

RESERVOIR FLOODPLAINS SUPPORT DISTINCT FISH ASSEMBLAGES

Reservoirs constructed on floodplain rivers are unique because the upper reaches of the impoundment may include extensive floodplain environments. Moreover, reservoirs that experience large periodic water level fluctuations as part of their operational objectives seasonally inundate and dewater floodplains in their upper reaches, partly mimicking natural inundations of river floodplains. In four flood control reservoirs in Mississippi, USA, we explored the dynamics of connectivity between reservoirs and adjacent floodplains and the characteristics of fish assemblages that develop in reservoir floodplains relative to those that develop in reservoir bays. Although fish species richness in floodplains and bays were similar, species composition differed. Floodplains emphasized fish species largely associated with backwater shallow environments, often resistant to harsh environmental conditions. Conversely, dominant species in bays represented mainly generalists that benefit from the continuous connectivity between the bay and the main reservoir. Floodplains in the study reservoirs provided desirable vegetated habitats at lower water level elevations, earlier in the year, and more frequently than in bays. Inundating dense vegetation in bays requires raising reservoir water levels above the levels required to reach floodplains. Therefore, aside from promoting distinct fish assemblages within reservoirs and helping promote diversity in regulated rivers, reservoir floodplains are valued because they can provide suitable vegetated habitats for fish species at elevations below the normal pool, precluding the need to annually flood upland vegetation that would inevitably be impaired by regular flooding. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.