青藏高原天然气水合物的形成与多年冻土的关系

天然气水合物是一种新型清洁能源,赋存在多年冻土区和海洋沉积物等低温高压环境中。青藏高原多年冻土面积占高原总面积的一半以上,是可能的天然气水合物赋存区。根据青藏高原多年冻土条件和天然气水合物形成的热力学条件,讨论了多年冻土地温梯度、冻土厚度与天然气水合物形成的热力学条件之间的关系和青藏高原存在天然气水合物的可能性。结果表明,青藏高原多年冻土区基本具备形成天然气水合物的热力学条件,最适宜的热力学条件是多年冻土地温梯度接近或略大于多年冻土底板附近融土的地温梯度,且融土地温梯度越小,越容易形成天然气水合物。估算得到天然气水合物最浅的顶界埋深为74m左右,最深的底界埋深达上千米。     

The resistivity structure of the Penola Trough,Otway Basin from magnetotelluric data

We present inversion results for a 100 site, broadband magnetotelluric (MT) survey in the Penola Trough, Otway Basin, South Australia. The Penola Trough is host to several petroleum reservoirs and has more recently been a target for unconventional geothermal exploration. We present two interpretations of the MT data. A 1D anisotropic interpretation, where anisotropy is determined within the Otway Basin sequence and basement in the northeastern Penola Trough, fits the impedance tensor well. However, the anisotropy strike is inconsistent with the known orientation of electrically conductive fractures in the Penola Trough. On the other hand, a 3D interpretation, which incorporates lateral variations in resistivity, requires no anisotropy yet it matches the data equally well. Both the 1D and 3D inversions resolve several layers within the Otway Basin sequence, which correspond to stratigraphic units defined in wells and in the coincident Haselgrove–Balnaves 3D seismic survey. These include the Eumeralla and Dilwyn formations, which are poorly resolved in the seismic data. The basin architecture, defined in the 3D inversion, in particular the depth to basement, is consistent with previous interpretations based on seismic reflection data that show that the Otway Basin thins in the northeastern Penola Trough. This does not occur in the anisotropic model. We therefore conclude that the subsurface resistivity appears to be isotropic in the Penola Trough. This contrasts with the anisotropic resistivity structure determined in a previous study in the Koroit region, eastern Otway Basin. The difference in the MT responses between the two regions is supported by resistivity and permeability information from well logs and may reflect differences in the orientation of subsurface fractures, or differences in the present-day stress field, between the two regions.     

稠油热采地层阵列感应测井响应特性数值模拟

稠油热采地层温度的独特变化规律直接影响了目的层和围岩的电阻率,进而导致阵列感应测井响应的变化;因此,了解地层温度对阵列感应测井响应的影响,对于更准确地确定地层电阻率具有重要的意义。本文利用地层温度与地层电阻率的相关关系,通过有限元方法模拟不同地层温度和不同地层结构的阵列感应测井响应。数值模拟结果表明：不同线圈结构子阵列的视电阻率随地层温度的升高而下降,下降幅度与地层温度、线圈系结构以及地层原始电阻率有关;三层阶跃地层中目的层及围岩电阻率、目的层温度和厚度都会影响其测井响应,使各子阵列视电阻率曲线由目的层边缘向围岩处呈现上升的形态。通过对这些响应特征的分析研究,结合油田实例G1井进行了对比和验证,模拟结果较好地阐释了现场阵列感应测井的异常响应特征。     

大亚湾核电站温排水对邻近水域鱼卵、仔鱼的影响

大亚湾核电站运行以后 ,温排水主要影响核电站以东沿岸水域 ,温升 2℃的范围大约在2km以内。邻近水域的鱼卵和仔鱼数量仍然比较丰富 ,季节变化亦无大异常 ,但是在种类组成上出现了一些异常现象 :小沙丁鱼Sadinellaspp .鱼卵和仔鱼数量明显增多 ,斑Clupan odonpunctatus和鲷科 (Sparidae)鱼类的鱼卵和仔鱼数量显著减少 ,并且未见鱼Engraulisjaponicus和小公鱼Anchoviellasp .鱼卵以及科 (Engraulidae)和银汉鱼科 (Atherinidae)仔鱼的出现。鱼卵的数量分布与温排水有关 ,而仔鱼与之无关 ,鱼卵死亡率与温排水的关系亦不显著。文中还讨论了温排水的影响范围、鱼卵死亡率与温排水的关系以及温排水对成鱼的影响等问题。     

夏季越南东北外海暖水的时空变化特征及其机理研究

Due to orographic blockage, a weak wind wake occurs in summer off northeast Vietnam in the South China Sea. Under the wind wake, warm water is observed from both high-resolution satellite data and hydrographic observations. The wake of warm water forms in June, continues to mature in July and August, starts to decay in September, and disappears in October. The warm water wake also shows robust diurnal variation – it intensifies during the day and weakens in the night. Warm water wakes can be generated through wind-induced mixing and thermal(latent heat flux) processes. In this paper, a mixed layer model is used to evaluate the relative importance of the two processes on seasonal and diurnal timescales, respectively. The results demonstrate that thermal processes make a greater contribution to the wake than wind-induced mixing processes on a seasonal timescale, while the warm water wake is dominated by wind-induced mixing processes on a diurnal timescale.     

Implications of estimated and measured thermal conductivity for oceanic heat flow studies

Heat flow data provide constraints on the thermal structure and evolution of the oceanic lithosphere. Because precise determination of the heat flux requires that both the thermal gradient and the thermal conductivity be well determined we have examined the thermal conductivities used in a new Pacific Basin heat flow data set. 43% of the 1600 heat flow determinations rely on values estimated by various methods, rather than directly measured. Although the measured and estimated conductivities have comparable means, the measured conductivities have a standard deviation 50% larger than the estimated, suggesting that the estimated values underestimate the actual variation. We investigate the limitations of using such estimates by examining factors controlling the variations of measured conductivity values. We find that the variation between the closest adjacent sites increases with increasing separation, such that sites within 200 km are on average noticeably closer in conductivity than sites further apart. Contributing to this effect may be the variation of conductivity with lithology (with mean conductivity highest for carbonate oozes, intermediate for deep-sea clays, and least for siliceous oozes) and a possible trend of decreasing conductivity with increasing seafloor depth. Tests with the measured data suggest that the best method for estimating conductivity is using the mean value measured within 200 km. The mean of a larger geographical region is a somewhat poorer predictor, and using the oceanwide mean and the value at the nearest site are poorer still. Approximately 29% of the estimated values were not based on measurements from a reference site. For most others, the reference site was the nearest measurement from the same cruise, typically a large distance away. For those sites where conductivity was not measured, 78% had measured conductivity within 200 km and were reestimated using the local mean, whereas the remaining 22% were reestimated using the regional mean. The resulting change in the estimated conductivity averaged 9% using the local mean and 6% using the regional mean. We suggest that such a procedure be used to improve the utility of the heat flow data set, as an alternative to discarding the large fraction of the available data that does not incorporate measured conductivities.     

东海天然气水合物的地球化学标志与找矿远景

利用大量的海底沉积物样品，开展了东海天然气水合物卫星热红外遥感和沉积物酸脱气地球化学找矿研究。根据卫星热红外增温异常和海底浅表层沉积烃类异常及其他各种异常标志，可以预测冲绳海槽中南部海域为最可能的水合物赋存区。     

WOCE CTD校准标准和我国的WOCE CTD校准实验室

对温度、电导率和压力等物理变量的定义、单位，传感器的实验室校准标准和我国在九五863项目中建立的WOCE水平的CTD校准实验室进行了介绍。     

反厄尔尼诺事件的个例分析

根据“中美热带西太平洋海-气相互作用联合考察”1—8航次考察资料、美国NOAA、日本气象厅及我国国家气象中心气候资料室提供的SST、水位和风场等资料,对1988—1989年反厄尔尼诺事件(La Nina)形成及发展过程和热带西太平洋海洋上层热结构的相互变化作了综合分析。文章指出在La Nina事件期间,热带太平洋的海、气参数均发生了相应的变化。热带西太平洋温跃层及热含量(0—150m)作出的响应,显示出当La Nina增强时,温跃层下降,热含量增加;La Nina盛期时,温跃层最深,热含量最大;La Nina减弱时,温跃层上升,热含量减小。它们与厄尔尼诺事件(El Nino)的关系则恰好相反。     

Formulation and Its Verification of Conductivity for Uniform Turbid Water

For measurement of sediment spatial concentration of nearshore seawater,a turbid water sys-tem with several kinds of particles is investigated from the viewpoint of the characteristics of particles.Firstly.the classical physical and chemical conductivity formula is extended to macro-particle(such assand)conductivity formula.Secondly,the Fricke formula suitable for only one kind of particles is ex-tended to the conductivity formula suitable for several kinds of particles.Finally.the multi-particle conduc-tivity formula is applied to the measurement of sediment spatial concentration.