2008年,在我国祁连山冻土区首次钻获天然气水合物实物样 品.2010年,在木里地区开展了反射地震方法探测天然气水合物的有效性试验研究,通过综合分析解释反射地震和测井及地质资料,初步认为含天然气水合物介 质形成的反射波在地震剖面上具有低速、弱振幅、高频的特征.根据反射波的这些动力学特征及测井结果,对在DK-4钻孔中见天然气水合物异常条带和在DK- 3钻孔中揭示的含天然气水合物晶体区段进行了对比分析,分析结果不支持DK-4钻孔钻遇天然气水合物,并结合钻孔资料,推断解释了天然气水合物富集地带.

Due to complex seismic-geological conditions,it is very difficult to acquire high quality results of shallow seismic exploration in Qiangtang basin of Tibet. In this paper,through the experiment of shallow seismic exploration technology in this area,the authors discussed the interference of the permafrost layer to the seismic data.In seismic data acquisition,a smaller channel spacing should be adopted,with a number of long arrangements of multi-channel receiving mode.In addition,the number of CDP stacking is increased,and a large tonnage high frequency vibrator is utilized for high-frequency excitation.In this way,a higher quality of raw seismic data can be obtained.In seismic data processing stage,we can use the corresponding de-noising technology before CDP stacking,which can effectively suppress various interference waves,such as random noise and coherent noise.The acquisition method and processing technology of 2-D shallow seismic survey is tentatively summarized,and the experimental study has achieved good results.The results achieved by the authors have certain reference value for application and study of shallow seismic exploration technology in plateau permafrost area in the future.

西藏羌塘盆地地震地质条件复杂,要取得高质量的浅层地震勘探资料是非常困难的。文中结合多次在羌塘地区开展的浅层反射地震勘探方法技术试验,探讨了高原冻土层对地震资料的影响因素,地震数据采集采用了小道间距、多道数长排列的接收方式,同时提高覆盖次数,采用大吨位可控震源进行高频激发,获得了高质量的原始数据资料;在地震数据处理阶段,重点在叠前采取相应的去噪处理技术,能够有效地衰减震源干扰波、随机和相干噪声等干扰,获得信噪比较高的地震成像剖面。总结研究区浅层地震勘探的数据采集方法和资料处理解释技术,取得了较好的试验研究成果,对今后在高原冻土区开展浅层地震勘探方法技术的应用与研究有一定的借鉴作用。

摘　要： 天然气水合物是一种非常规能源,因其巨大的资源量成为目前能源研究的热点.水合物的研究目前仍处于初期阶段,人们在水合物勘探、开发模拟方面做了大量尝试,总结了许多有利于水合物勘探和开发的关键技术.本文首先介绍了天然气水合物形成的地质条件和储层特征,然后介绍了针对海底天然气水合物的地震勘探和电磁、地化等非地震勘探最新技术进展,分析了天然气水合物矿藏的测井响应特征,结合岩石物理模型对储层孔隙度、饱和度进行估算用于储量预测.最后,论述了天然气水合物开发过程中的深水区的钻井问题,水合物的开采方式总结以及商业化生产所面临的挑战.

The seismic signal received by sensors is very weak because the energy is absorbed and attenuated by subsurface and deep layer during signal propagating. The high frequency component was much more seriously absorbed and attenuated than low frequency component. The key issues for high density seismic acquisition are to receive and identify low reflection coefficient or high frequency weak signal. In this paper, the relationship of weak signal to subsurface, dominant frequency, offset and deep target layer was analyzed based on a typical elastic-viscoelastic earth model. The results show that it is very difficult to give expression to the advantages of broad band frequency in high density seismic acquisition in the area with strong subsurface attenuation and low S/N ratio due to the existence of the cut off frequency. Good condition excitation can improve weak signal energy and give more contribution to broaden frequency band. The effective reflection coefficient can be better presented in small and middle receiver-source offset and can be well extracted.

地震信号在传播过程中受到近地表和深地层吸收衰减的影响，能量变弱，高频成分衰减比低频成分更为严重，接收与识别反射系数较小或高频的弱反射信号是高密度地震勘探的瓶颈问题。笔者通过建立典型的粘弹性地质模型，分析了弱反射信号与近地表、震源主频、炮检距以及与深地层的关系，得出以下认识：在近地表吸收衰减严重的低噪比地区，由于截止频率的存在，高密度采集的宽频优势难以体现；良好的激发条件对提高弱反射信号能量、拓宽频带作用较大；中小炮检距是弱反射信号有效反射系数较好的区域，是提取弱反射信号的最佳区域。

摘　要： 南祁连盆地广泛发育上三叠统尕勒德寺组泥质岩类烃源岩，但是其有机质丰度、类型、热演化程度的研究程度都很低。因此，对此地区烃源岩进行油气资源综合评价是十分必要的。据此，从烃源岩类型、有机质的类型、丰度、成熟度等方面对南祁连盆地哈拉湖坳陷上三叠统尕拉德寺组烃源岩进行了综合评价。研究表明，有机质丰度为差一中等，有机质类型为腐泥腐殖型（Ⅱ2），有机质到达高成熟一过成熟阶段。整体评价为中等烃源岩。

Being surrounded with high mountains, the Hala Lake, is a large salty lake with an altitude of 4078m in the north of the Tibetan Plateau. Due to little human impacts on the lake drainage, the Hala Lake, as a typical inland closed lake located on the Chinese monsoon transition line, can provide sensitive information on the past climatic and natural environmental changes. Plateau area has been reported to be more sensitive in response to global change than the area at lower altitudes. Here we present the result of a short core retrieved form the Hala Lake in the north of Tibetan Plateau. The short core HALA-3B-02, 75cm long, was taken with a weight sampler at water depth of 19.3m in the north-west of Hala Lake (38°20'44.8″N, 97°26'34.3″E) in July, 2002. Sediment samples from the sediment core drilled at the high-altitude Hala Lake were analyzed for a range of palaeoenvironmental indicators, which include stable isotope of oxygen and carbon of carbonates ( δ 13 C & δ 18 O), total organic carbon content, carbonate content as well as magnetic susceptibility. Chronology of the sediment core was determined using 210 Pb and 137 Cs. However, the 137 Cs dating result shows that the cumulating peak of the year of 1954 is hardly distinguishable due to disintegration with time. In addition, because of its diffusion and transference features, 137 Cs cumulating peak is considered improper for dating. Hala Lake chronology was thus established on dating series from 210 Pb CRS model and linear extrapolating based on bottom deposit rates. Average deposit rate of the profile under 21.5cm (corresponding to the year of 1900) is 0.187cm/a, while that above 21.5cm suddenly rises to 0.199cm/a, which is possibly relevant to more and more intense human activities since the 20 th century. The lithology of the profile from bottom to 21.5cm appears to be comparatively conformed, hereby corresponding deposit rate is supposed to be 0.187cm/a. The earliest time was thus extrapolated to be 796 years before 2002A.D. , namely 1206A.D.The average time resolution reaches 11a.Mineral content was analyzed from 5 selected sediment samples by X-ray diffraction. All analyzed samples were mainly composed of authigenous aragonite and calcite. Therefore the carbonates in Hala Lake sediment are mainly authigenous. In terms of the Hala Lake, δ 13 C possibly reveals drainage temperature (icebound state due to perennial low temperature) effect on exchange between atmospheric carbon dioxide and aquatic carbon. Total organic carbon content (TOC) in lake sediment stands for the biological primary production in the lake and/or the drainage. Thereby sediment TOC can reveal historical vegetation state, which is unavoidably affected by preservation condition. Carbonate content in lake sediment can indicate aquatic salinity variation and consequently indicate the environmental humidity variation indirectly. Frequency magnetic susceptibility is affected by dynamical factors in lacustrine deposition and also indirectly indicates the environmental humidity variability. Palaeoclimatic proxies show that the δ value of oxygen of carbonate varies from -3.8 ‰ to +1.9 ‰ with an average of -0.7 ‰, while the δ value of carbon is from 1.5 ‰ to 4.9 ‰, and the average is 3.3 ‰. The oxygen and carbon isotope curves change covariantly along the whole profile. The variation range of TOC is from 4.9 ％ to 2.3 ％, and the average is 3.1 ％, which seems to be relatively stable as a whole except some small fluctuations. Carbon content fluctuates between 17.0 ％ and 42.8 ％ with an average of 23.9 ％. The magnetic susceptibility, averaged at the level of 12.1×10 -8 m 3 /kg, fluctuates between 9×10 -8 m 3 /kg and 19.1×10 -8 m 3 /kg. It rises rapidly near the top. Frequency magnetic susceptibility varies with smaller magnitude, from -9.4 ％ to +12.2 ％, averaging at +3.4 ％. A palaeoenvironmental history of ca.800-year of the lake is reconstructed on the basis of multi-proxy analyses. The general environment change is from cool and wet to warm and dry. Three stages can be recognized: 1206~1700A.D. , a cool and wet climate with a gradually cooling and wetting trend. 1700~1920A.D. is a more or less fluctuating period. Coincident fluctuating of oxygen and carbon stable isotopes ( δ values) indicates that there was a warming and drying period before 1771A.D. and subsequently a comparatively cool and wet period during 1780~1900A.D. 1920~2002A.D. , the warmest and driest stage. Magnetic susceptibility appears to be fluctuating on a stable level in high frequency before 1970A.D. , but rises rapidly after 1970A.D. with an ascending range of about 54 %, indicating a sharply increased anthropologic gold mining activities since 1970s. The low value of δ 18 O and δ 13 C as well as carbonate content corresponding to the period of 1653~1718A.D. indicates the lowest temperature and highest efficient humidity in the drainage history. This period was the coldest and wettest in the north of Qinghai-Tibet Plateau in the past ca.800 years. The δ 13 C curve variability shows that the environmental state of the north of Qinghai-Tibet Plateau became the warmest and driest in the 20 th century, i.e. , 20 th century is the hottest 100 years during the past ca.800 years. δ 18 O and δ 13 C values of carbonate and carbonate content in the profile simultaneously decrease remarkably around 1925A.D. This may reflects the rapid warming occurred in China and the world in the 1920s.

文章以青藏高原北缘高山祁连山湖泊——哈拉湖作为研究对象,利用放射性核素 210 Pb和 137 Cs测年资料,通过对此高海拔湖泊沉积碳酸盐氧碳同位素、碳酸盐含量、总有机碳含量、磁化率等环境代用指标的分析,揭示了这一地区近800年来的气候环境变化过程。分析表明哈拉湖记录的气候环境变化经历了3个阶段:1206~1700A.D.环境较为寒冷、湿润,并有持续变湿的趋势;1700~1920A.D.环境由冷湿的状况趋向温暖干旱,1771年之后,环境保持相对稳定;1920~2002A.D.是自1206年以来最为温暖干旱的阶段。

在完成南祁连盆地3条北东向直线距离为401.5 km 五万分之一条带地质图的基础上, 重新厘定了区内三叠系的划分, 明确了各地层单位的含意, 并建立了区内哈拉湖地层区、下日哈地层区和北部地层区及其与邻区三叠系的对比关系. 认为中三叠统大加连组海相碳酸盐岩和上三叠统尕勒德寺组泥质岩为该盆地重要的烃源岩系, 并讨论它在盆地内不同坳陷的分布规律.

The Scientific Drilling Project of Gas Hydrate in Qilian Mountain permafrost, which is located in Jugenghu mining area of the Muli Coalfield, Tianjun County, Qinghai Province, was implemented by Institute of Mineral Resources, Institute of Exploration Techniques, Qinghai No.105 Coal Geological Exploration Party and some other units during 2008-2009. Samples of gas hydrate were collected firstly from the hole of DK-1 on November 5, 2008 and again from the hole of DK-2 and DK-3 in 2009. This is the first discovery of gas hydrate in China’s permafrost and in the low-middle latitude permafrost of the world. Gas hydrates were found at the 133-396m intervals of Middle Jurassic Jiangcang Formation lying under the permafrost zone (about 95m). Gas hydrates occur in the fissures of siltstones, mudstones and oil shale, or in the pores of sandstones. Samples are white or ivory crystals and liable to burn. Obvious low temperature anomaly was identified by the infrared camera. The gas hydrate-bearing cores strongly bubble in water. Gas-bubble and water-drop are emitted from the samples and the characteristic honeycombed structure is retained. The typical spectrum curve of gas hydrate was detected by means of Raman spectrometry. Furthermore, the logging profile also indicates high electrical resistivity and sonic velocity. Gas hydrate in Qilian Mountain permafrost is a new type hydrate characterized by a relatively thin permafrost zone, shallow buried depth, complex gas components, and coal-bed methane origin.

2008年11月5日, 由中国地质科学院矿产资源研究所、勘探技术研究所和青海煤炭地质局105勘探队施工的“祁连山冻土区天然气水合物科学钻探工程”DK-1孔取得重大突破, 成功钻获天然气水合物实物样品。这是我国冻土区首次钻获并检测出的天然气水合物实物样品, 也是世界上第一次在中低纬度高原冻土区发现的天然气水合物, 具有重要的科学、经济和环境意义。目前钻获的天然气水合物均产于冻土层之下, 产出深度133~396 m, 其层位属于中侏罗统江仓组。水合物以薄层状、片状、团块状赋存于粉砂岩、泥岩、油页岩的裂隙中, 或以浸染状赋存于细粉砂岩的孔隙中。祁连山冻土区天然气水合物具有埋深浅、冻土层 薄、气体组分复杂、以煤层气为主等特征, 应是一种新类型水合物。

祁连山多年冻土区面积约10×104km2,年平均地表地温为-1.5～-2.4℃,冻土层厚度为50～139m.区内侏罗纪小型含煤盆地广布,产有丰富的煤层气.南祁连盆地是一潜在的油气盆地,存在下石炭统臭牛沟组、下二叠统草地沟组、中三叠统大加连组、上三叠统尕勒得寺组4套烃源岩,具有良好的生油生气潜力.在木里煤田33号钻孔的冻土层内发现有连续逸出的高含量烃类气体,井口点燃即可燃烧,简易采气分析结果表明甲烷含量高达38.07%～75.9%.根据该钻孔的气体组分、年平均地表地温、冻土层厚度、地温梯度等数据分析,这里基本具备形成天然气水合物的温压条件,计算结果显示水合物稳定带的顶界和底界埋深分别为171 m和574m,稳定带厚度为403m.

2008～2009年实施的“祁连山冻土区天然气水合物科学钻探 工程”,已完成DK-1、DK-2、DK-3和DK-4孔的钻探任务.施工期间多次钻获天然气水合物实物样品,证实祁连山冻土区存在天然气水合物.祁连山 冻土区天然气水合物主要以裂隙型和孔隙型2种状态产出.基于天然气水合物存在的10个方面的特征,认为天然气水合物赋存层位主要为中侏罗统江仓组,产于冻 土层之下,主要储集于133.0～396.0m区间,储集层岩性多以粉砂岩、油页岩、泥岩和细砂岩为主,含少量中砂岩.钻孔中天然气水合物纵向分布不具有 连续性,钻孔间横向分布规律不明显.岩石质量指标(RQD)统计结果显示,RQD低值区与天然气水合物储集层段具有较好的一致性,表明裂缝系统对于该区天 然气水合物的分布具有重要的控制作用.