塔里木盆地轮南地区油气运移的路径、期次及方向研究

本文通过对塔里木盆地轮南地区及附近的钻井（出油井和未出油井）中揭示的裂缝，裂缝与成岩序列的穿插关系，连通砂体及断层和不整合面附近的矿物及矿物中流体包裹体研究，对塔里木盆地轮南地区油气运移路径和期次进行了探讨。通过研究指出了塔里木盆地轮南地区主要经历了3期大规模的油气运聚，地层之间的不整合面为油气横向运移的主要通道。高角度的裂隙及微裂缝为纵向运移主要通道。第一期油气运聚主要发生于海西期，第二期油气运聚主要发生在14－17Ma；第3期油气运聚主要发生在最近的5Ma以来。第一期油气运聚主要为自塔北隆起的西南，南向北，以横向运移为主；第二，第三期运聚主要自西南，南向北，自东向西运移，但主要以垂向运移为主。     

Climate induced temperature effects on growth performance, fecundity and recruitment in marine fish: developing a hypothesis for cause and effect relationships in Atlantic cod (Gadus morhua) and common eelpout (Zoarces viviparus)

Effects of global warming on animal distribution and performance become visible in many marine ecosystems. The present study was designed to develop a concept for a cause and effect understanding with respect to temperature changes and to explain ecological findings based on physiological processes. The concept is based on a wide comparison of invertebrate and fish species with a special focus on recent data obtained in two model species of fish. These fish species are both characterized by northern and southern distribution limits in the North Atlantic: eelpout (Zoarces viviparus), as a typical non-migrating inhabitant of the coastal zone and the cod (Gadus morhua), as a typical inhabitant of the continental shelf with a high importance for fisheries.Mathematical modelling demonstrates a clear significant correlation between climate induced temperature fluctuations and the recruitment of cod stocks. Growth performance in cod is optimal at temperatures close to 10°C, regardless of the population investigated in a latitudinal cline. However, temperature specific growth rates decrease at higher latitudes. Also, fecundity is less in White Sea than in North and Baltic Sea cod or eelpout populations. These findings suggest that a cold-induced shift in energy budget occurs which is unfavorable for growth performance and fecundity. Thermal tolerance limits shift depending on latitude and are characterized by oxygen limitation at both low or high temperatures. Oxygen supply to tissues is optimized at low temperature by a shift in hemoglobin isoforms and oxygen binding properties to lower affinities and higher unloading potential. Protective stimulation of heat shock protein synthesis was not observed.According to a recent model of thermal tolerance the downward shift of tolerance limits during cold adaptation is associated with rising mitochondrial densities and, thus, aerobic capacity and performance in the cold, especially in eurythermal species. At the same time the costs of mitochondrial maintenance reflected by mitochondrial proton leakage should rise leaving a lower energy fraction for growth and reproduction. The preliminary conclusion can be drawn that warming will cause a northern shift of distribution limits for both species with a rise in growth performance and fecundity larger than expected from the Q₁₀ effect in the north and lower growth or even extinction of the species in the south. Such a shift may heavily affect fishing activities in the North Sea.     

Relationship between structures of substituted indolic compounds and their degradation by marine anaerobic microorganisms

Degradation of selected indolic compounds including indole, 1-methylindole, 2-methylindole, and 3-methylindole was assessed under methanogenic and sulfate-reducing conditions using the serum-bottle anaerobic technique and marine sediment from Victoria Harbour, Hong Kong as an inoculum. Our results showed that indole degradation was achieved in 28 days by a methanogenic consortium and 35 days by a sulfate-reducing consortium. During degradation under both conditions, two intermediates were isolated, purified and identified as oxindole and isatin (indole-2,3-dione) suggesting that both methanogenic and sulfate-reducing bacteria use an identical degradation pathway. Degradation processes followed two steps of oxidation accomplished by hydroxylation and then dehydrogenation at 2- and then 3-position sequentially prior to the cleavage of the pyrrole ring between 2- and 3-positions. However, none of 1-methylindole or 2-methylindole was degraded under any conditions. 3-Methylindole (3-methyl-1H-indole, skatole) was transformed under methanogenic conditions and mineralized only under sulfate-reducing conditions. It is clear that methyl substitution on 1- or 2-position inhibits the initial attack by hydroxylation enzymes making them more persistent in the environment and posing longer toxic impact.     

Microbial life in martian ice: A biotic origin of methane on Mars?

Despite the fact that microbial cells are unlikely to be found in the Martian soil in the near future, this paper is written on the assumption that some of the seasonally varying concentration of Martian methane is due to ongoing methanogenesis. It is first pointed out that life might have arisen on Mars first and been transported to Earth later. A case is made that an icy origin of life is more likely than a hot origin, especially if biomolecules take advantage of the high encounter rates and stability against hydrolysis, and that microorganisms feed on the ions that comprise eutectic solutions in ice. Although certain difficulties are avoided if RNA and DNA grow while adsorbed on clay grains, double strand-breaks of microbial DNA due to alpha radioactivity are a far greater threat to microbial survival on clay or other rock types than in ice. Developing a relation between the rate of microbial metabolism in ice and the experimentally determined rate of production of trapped gases of microbial origin, one can estimate the concentration of methanogens that could account for the methane production rate as a function of temperature of their habitat. The result, of order 1 cell cm⁻³ in the Martian subsurface, seems an attainable goal provided samples are taken from at least 1 or 2 m below the hostile surface of Mars. Instruments on NASA’s 2011 Mars Science Lab will measure stable isotopes for methane, water, and carbon dioxide, which on Earth served to distinguish abiotic, thermogenic, and microbial origins. Future measurements of chirality of biomolecules might also provide evidence for Martian life.     

Stationary Wave Activity Associated with the East Asian Winter Monsoon Pathway

The pathway of the East Asian winter monsoon(EAWM) that usually leads to the out-of-phase pattern of surface air temperature between northern and southern East Asia is an important feature in the variability of the EAWM besides its strength.Using the European Centre for Medium-Range Weather Forecasts 40-year(ERA40) reanalysis dataset,this study investigates the pathway-related stationary wave activity to explore the mechanism of the interannual variations in the EAWM pathway.It reveals that when the southern pathway of the EAWM is strong,the phase of the climatological stationary wave tends to be shifted westward significantly in both the horizontal and vertical directions by an anomalous wavenumber 2 pattern at mid-latitudes,whereas the changes are relatively small in the subtropics.The horizontal changes in the stationary wave phase facilitate a north-south-oriented East Asian trough in the middle troposphere that eventually produces the strong southern pathway of the EAWM.The vertical changes in the stationary wave,in contrast,feature a westward-tilted phase line with height over the North Pacific,indicating enhanced upward propagation of waves into the stratosphere.This result suggests that the phase of stationary waves at mid-latitudes dominate the interannual variations in the EAWM pathway.Moreover,it supports our previous interpretation of the possible role of the North Pacific sea surface temperature(SST) in the EAWM pathway variability.It also implies that the excitation of anomalous mid-latitude stationary waves may be the key in the response of the EAWM pathway to the North Pacific SST.     

Mud volcanism and fluid geochemistry in the Cheleken peninsula,western Turkmenistan

A geological and geochemical study has been carried out to investigate the relationships between major mud volcano structures and deep fluid migration in the Cheleken peninsula, in the South Caspian Basin. The fluid geochemistry allowed the origin and migration of the saline waters and the hydrocarbons to be deduced along with the regional source and reservoir rocks. The emitted waters formed by the mixing of deep highly saline water from the main source rocks of the Maykop Fm with the Caspian-like pore water contained in the Pliocene reservoirs. The water composition is very similar to that emitted by the mud volcanoes in Azerbaijan, allowing comparisons to be done between the reservoirs in the western and eastern sides of the South Caspian Basin. The associated oil is derived from a mixed type II/III kerogen deposited in a sub-oxic marine environment and generated during the early oil window. The oil biomarkers indicate that the source rock is the Maykop Fm., as previously determined for the other areas of the South Caspian Basin.The spontaneous emissions, showing different morphologies, are mainly aligned along normal and transtensive fault systems, which provide effective pathways for rapid fluid ascent from deep reservoirs to the surface.     

Analysis of hydrogeolgical characteristics and water environmental impact pathway of typical shale gas exploration and development zones in Sichuan Basin,China

Studying the influence of shale gas exploration and development on groundwater environment is the basis of guiding water environment protection in the process of shale gas exploration and development. Groundwater environmental pollution is concealed, complex and persistent. Once it is difficult to control the pollution, the current commercial shale gas development zones in Sichuan Basin that are mostly located in karst areas and highly sensitive to groundwater will be vulnerable to the impact of shale gas exploration and development. Based on the hydrogeological conditions of shale gas exploration and development area and combined with engineering analysis of exploration and development, various risk pathways that may affect the groundwater environment during process of shale gas exploration, mining well construction, mining operations and other stages were identified in this paper. Some existing risk pathways were proved by verification of typical areas and should not be ignored. Based on the actual situation of typical areas, the countermeasures of groundwater environmental protection in the process of shale gas exploration and development in karst areas were discussed. It is believed that the ground-water environment can be better protected by strengthening administration, research and application of new technologies, precise design, hydrogeological conditions, and research and feedback of groundwater environmental protection.     

碳酸盐岩早期差异成储路径及其对储集性能的影响:以滨里海盆地N油田石炭系KT-Ⅰ与KT-Ⅱ层系为例*

以滨里海盆地N油田石炭系KT-Ⅰ与KT-Ⅱ层系碳酸盐岩储集层为例,综合岩心、薄片、扫描电镜、高压压汞、常规物性分析以及各类测试资料,对碳酸盐岩储集层特征以及早期成储路径展开系统研究,并进一步探讨成储路径与储集层孔喉结构和质量的关系。结果表明,KT-Ⅰ层系以云岩类储集层为主,颗粒灰岩次之,其中云岩类储集层以晶间(溶)孔、小型溶洞为主,孔喉连通性好,为高孔—高渗的孔洞型储集层, 而颗粒灰岩类储集层以粒内溶孔、铸模孔及生物体腔孔发育为特征,孔喉连通性差,属中孔—低渗的孔隙型储集层。KT-Ⅱ层系以粒间(溶)孔和生物体腔孔发育的颗粒灰岩为特征,为中高孔—高渗的孔隙型储集层。进一步分析表明,KT-Ⅰ层系云岩与灰岩储集层单旋回厚度小,皆受高频海平面升降变化驱动的早成岩期岩溶的控制, 而KT-Ⅱ层系单旋回厚度大,颗粒滩未经历早期岩溶的改造。 3类储集层的成储路径分别为: (1)KT-Ⅰ云岩类储集层,准同生期白云石化作用导致矿物相转变并使得部分矿物更易遭受溶蚀→早成岩期岩溶作用控制储集层的形成→云岩抗压溶岩石骨架有利于储集层的保护; (2)KT-Ⅰ颗粒灰岩储集层,早成岩期岩溶作用优化储集层→初期压实控制胶结流体通道进而控制胶结作用—粒间孔与粒内孔差异胶结控制储集层的保护; (3)KT-Ⅱ颗粒灰岩储集层,原始沉积环境控制储集层的形成→初期压实与早期胶结作用控制储集层的保护。成储路径差异控制了不同的孔渗特征与孔喉结构,而孔喉结构进一步控制了早期岩溶型云岩、早期岩溶型颗粒灰岩、原生孔保存型颗粒灰岩3种储集层的质量。研究结果将为具类似特征的碳酸盐岩储集层成因分析提供参考,也因发现了云岩较灰岩更易早期溶蚀的现象而具有较为重要的岩溶地质学意义。     

油源断裂内油气运移优势通道识别方法及其应用

为了研究含油气盆地下生上储式生储盖组合中油源断裂附近油气分布规律,在油源断裂内油气运移优势通道及其影响因素研究的基础上,通过确定油源断裂凸面脊和断裂填充物油气运移分布区,二者耦合建立了一套识别油源断裂内油气运移优势通道的方法,并将该方法应用于渤海湾盆地冀中坳陷廊固凹陷大柳泉地区沙三中亚段F3油源断裂内油气运移优势通道的识别中,结果表明：F3油源断裂内可识别出5条油气运移优势通道,其中4条油气运移优势通道分布在断裂南部,1条油气运移优势通道分布在断裂北部,与目前F3油源断裂附近沙三中亚段已发现油气分布在中南部和北部相吻合,表明该方法用于识别油源断裂内油气运移优势通道是可行的。     

Model Evidence for Interdecadal Pathway Changes in the Subtropics and Tropics of the South Pacific Ocean

Numerical simulations using a version of the GFDL/NOAA Modular Ocean Model(MOM 3) are analyzed to demonstrate interdecadal pathway changes from the subtropics to the tropics in the South Pacific Ocean.After the 1976-77 climate shift,the subtropical gyre of the South Pacific underwent significant changes,characterized by a slowing down in its circulation and a southward displacement of its center by about 5-10 latitude on the western side.The associated circulation altered its flow path in the northwestern part of the subtropical gyre,changing from a direct pathway connecting the subtropics to the tropics before the shift to a more zonal one after.This effectively prevented some subtropical waters from directly entering into the western equatorial Pacific.Since waters transported onto the equator around the subtropical gyre are saline and warm,such changes in the direct pathway and the associated reduction in equatorward exchange from the subtropics to the tropics affected water mass properties downstream in the western equatorial Pacific,causing persisted freshening and cooling of subsurface water as observed after the late 1970s.Previously,changes in gyre strength and advection of temperature anomalies have been invoked as mechanisms for linking the subtropics and tropics on interdecadal time scales.Here we present an additional hypothesis in which geographic shifts in the gyre structure and location(a pathway change) could play a similar role.