致密砂岩的形成机制及其地质意义——以塔里木盆地英南2井为例

砂质岩的孔隙和喉道被网格状粘土矿物和次生加大矿物充填成微细孔喉状结构时,形成具有较高毛细管压力的致密砂岩。它与地层水发生水锁效应,可大大降低渗透率,成为致密砂岩盖层。当含水饱和度在50%以下时,束缚水饱和度比较低,致密砂岩储层可以产气;当含水饱和度在50%～90%区间时,具有较高的束缚水饱和度,相对渗透率非常低,它既不能产气也不能产水,反映为渗透率瓶颈区(具有盖层性质);当含水饱和度大于90%以上时,致密砂岩储层仅微量产水。塔里木盆地英南2井侏罗系气藏盖层由致密砂岩构成,不含水时的气体渗透率在(0.027～0.081)×10-3μm2,不能构成封堵;当含水饱和度达到60%以上时,相对渗透率几乎为零,构成有效盖层。     

深基坑支护方案的分析与优化

针对武汉市南湖岸边复杂的地质条件及周边环境,在某高层建筑的深基坑支护结构设计中,结合实际因地制宜地对基坑的支护方法进行了分析比较。支护效果及实测数据表明,该工程所采用的混合式支护实施方案技术安全可靠,经济合理,可为同类型基坑工程设计提供借鉴。     

黄土塬区地震勘探测量方法研究

黄土塬区地形地貌复杂,地震勘探测量施工困难：一是GPS参考站如何布设;二是在大落差等特殊地形区域的GPS测量作业如何实施;三是在GPS作业盲区测量作业如何实现.针对以上难点,提出了三种测量施工方法：一是分阶段,逐步加密控制点进行工区内GPS参考站的布设;二是通过增加参考站电台天线的高度、发展多个参考站或使用中继站来解决GPS参考站主站信息覆盖不到区域的实测问题;三是通过全站仪、测绳等常规测量方法来实现GPS作业盲区物理点的逐点实测.应用以上测量方法,可有效解决地震勘探测量在黄土塬区遇到的问题,实现黄土塬区物理点的逐点实测.     

Ruthenium-ion-catalyzed oxidation of asphaltenes and oil-source correlation of heavy oils from the Lunnan and Tahe oilfields in the Tarim Basin, NW China

The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphahenes in heavy oils from the Lunnan and Tabe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations, The RICO products included n-alkanoic acids, α,ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid , regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tabe oilfields are different from those of Well TD2. The biomarkers bounded on the asphahenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C28 sterane and C29 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tabe oilfields.     

An invariance in the carbazoles of petroleum

A remarkable invariance in the ratio of 1,3-dimethylcarbazole （DMC） to 1,6-DMC was discovered in crude oils from the Pearl River Mouth Basin, South China Sea. The remarkably invariant ratio is kept at a constant of about unity regardless of their concentrations, sources or maturities for the sampies. In combination with the molecular structures of 1,3- and 1,6-DMCs, the invariance might indicate that the nitrogen compounds share a common precursor with a skeleton of 1-methylcarbazole and are formed through methylation at C3 and C6 with an essentially identical rate.     

土地利用总体规划实施评价与修编的研究

本文在客观评价上一轮土地利用总体规划的基础上，结合新一轮土地利用总体规划修编的背景和国家宏观调控下的土地政策变化趋势，提出了当前福建省土地利用总体规划修编和今后实施的有关建议，以更好地指导新一轮土地利用总体规划的修编工作。     

庙岛群岛旅游资源评估与可持续利用

庙岛群岛旅游资源丰富。本文运用特尔斐法（Delphi）及层次分析法（AHP）构建庙岛群岛旅游资源开发价值评估模型，定性与定量相结合，对10个条件适宜的岛屿进行评估。进而提出优化庙岛群岛旅游资源空间结构，实现可持续利用的若干对策。     

云南东北部拱王山末次冰期

1 Introduction The Gongwang mountains constitute one of the few high m ountains of irrefutable late Pleistocene glaciation in eastern China. This area is one of the m ost extensively studied Quaternary geologicallocationsin eastern China and the interpret…     

Grassland productivity in an alpine environment in response to climate change

Situated in a climatically stressful environment, alpine grassland is sensitive to subtle climate changes in its productivity. We remedy the current deficiency in studying grassland productivity by taking the integrated effect of all relevant factors into consideration. The relative importance of temperature, rainfall and evaporation to the alpine grassland productivity in western China was determined through analysis of their relationship with the normalized difference vegetation index (NDVI) between 1981 and 2000. Climate warming stimulated grassland productivity in the 1980s, but hampered it in the 1990s. Temperature is more important than rainfall to grassland productivity early in the growing season. However, their relative importance is reversed late in the growing season. Monthly summer month rainfall modified by maximum monthly temperature is a good predictor of alpine grassland productivity at 62.0 per cent. However, the best predictor is water deficiency, which is able to improve the estimation accuracy to 78.3 per cent. Hence, the impact of temperature on grassland productivity is better studied indirectly through evaporation.     

Gas accumulation from oil cracking in the eastern Tarim Basin: A case study of the YN2 gas field

Oil and gas exploration in eastern Tarim Basin, NW China has been successful in recent years, with several commercial gas accumulations being discovered in a thermally mature to over-mature region. The Yingnan2 (YN2) gas field, situated in the Yingnan structure of the Yingjisu Depression, produces gases that are relatively enriched in nitrogen and C₂₊ alkanes. The δ¹³C₁ (−38.6‰ to −36.2‰) and δ¹³C₂ values (−30.9‰ to −34.7‰) of these gases are characteristic of marine sourced gases with relatively high maturity levels. The distributions of biomarkers in the associated condensates suggest close affinities with the Cambrian–Lower Ordovician source rocks which, in the Yingjisu Sag, are currently over-mature (with 3–4%Ro). Burial and thermal maturity modeling results indicate that paleo-temperatures of the Cambrian–Lower Ordovician source rocks had increased from 90 to 210 °C during the late Caledonian orogeny (458–438 Ma), due to rapid subsidence and sediment loading. By the end of Ordovician, hydrocarbon potential in these source rocks had been largely exhausted. The homogenization temperatures of hydrocarbon fluid inclusions identified from the Jurassic reservoirs of the YN2 gas field suggest a hydrocarbon emplacement time as recent as about 10 Ma, when the maturity levels of Middle–Lower Jurassic source rocks in the study area were too low (<0.7%Ro) to form a large quantity of oil and gas. The presence of abundant diamondoid hydrocarbons in the associated condensates and the relatively heavy isotopic values of the oils indicate that the gases were derived from thermal cracking of early-formed oils. Estimation from the stable carbon isotope ratios of gaseous alkanes suggests that the gases may have been formed at temperatures well above 190 °C. Thus, the oil and gas accumulation history in the study area can be reconstructed as follows: (1) during the late Caledonian orogeny, the Cambrian–Lower Ordovician marine source rocks had gone through the peak oil, wet gas and dry gas generation stages, with the generated oil and gas migrating upwards along faults and fractures to form early oil and gas accumulations in the Middle–Upper Ordovician and Silurian sandstone reservoirs; (2) since the late Yanshanian orogeny, the early oil accumulations have been buried deeper and oil has undergone thermal cracking to form gas; (3) during the late Himalayan orogeny, the seals for the deep reservoirs were breached; and the gas and condensates migrated upward and eventually accumulating in the relatively shallow Jurassic reservoirs.