【作者】 胡勇；

【导师】 夏斌； 徐凤银；

【作者基本信息】 中国科学院研究生院（广州地球化学研究所） ， 构造地质学， 2005， 博士

【摘要】 柴达木盆地北缘有着广阔的勘探前景,但受各种条件的限制,总体勘探程度不高,影响了人们对北缘地质认识的深化,特别是中生界沉积与演化规律认识还不够清晰,影响了人们对山前油气成藏条件的认识,进而影响了山前冲断带油气勘探的进程。 本文总结了柴北缘勘探的历程和现状,指出了柴北缘近年来勘探上取得的最新成果和进展,针对柴北缘油气资源状况,认为柴北缘油气资源丰富,勘探程度较低,勘探潜力很大,勘探前景看好。针对柴北缘的现状,提出了柴北缘基础地质问题四大争论焦点:即构造单元划分、侏罗系地层的划分和展布、构造演化历史、构造成因和形成时间,围绕这些焦点问题,明确了本文的选题和所要研究的内容,厘定了研究思路。 本文从中国西部地区侏罗系盆地分布特征和中国西部侏罗系沉积特征入手,研究了柴达木盆地构造演化背景和柴北缘的区域地质背景,认为柴北缘属沉降-隆生-沉降-隆生型。在早、中侏罗世早期时,侏罗系的沉积环境是弱伸展和伸展的断陷,中侏罗世中期时转为坳陷,早白垩世以后发生了一次大规模运动,形成早期的古构造。新生代末期,受喜山运动晚幕的影响,祁连山向盆地发生逆冲,在山前形成推覆构造,成为有利勘探目标。从大煤沟标准剖面入手,进行了柴北缘侏罗系地层层序划分的研究,并通过对现今残余侏罗系地层的分布特征,提出了侏罗纪时期具有两大沉降带的观点,侏罗系向山前加厚,为山前逆冲带成藏提供了油源条件。通过研究,总结了柴北缘中、新生代石油地质具有六大主要特点,提出了赛什腾山前冲断带、赛什腾凹陷潜伏构造带和冷湖-南八仙构造带为重点有利目标的勘探思路,对下一步的勘探具有重要的指导意义。更多还原

【Abstract】 The northern margin in the Qaidam Basin has a wider exploration prospect, however ,the extent of exploration is lower because of the limition of varied facters, so that the geological understanding for the north region is limited in some extent , especially,the sedimentary and evolutionary rule for Mesozoic have not been known clearly, as a result it has confined the people to realize the oil/gas-forming conditions in the front-mountain belt, furthermore ,the oil/gas exploration in the thrust belt of the front-mountain cannot be run smoothly.In this paper ,the exploration history and present circumstances in the northern margin of the Qaidam Basin are concluded , the update exploration achievements and progresses made in recently are introduced .Based on oil/gas resources condition in the northern margin of the Qaidam Basin, it is realized that the northern margin of the Qaidam Basin is characterized by abundant oil/gas resources, lower exploration extent, large exploration potential, and good prospect of exploration .On the basis of the present circumstances in the northern margin of the Qaidam Basin, four key viewpoints on the basic geology in the northern margin of the Qaidam Basin have been put forward: that is ,the division and distribution of Jurassic strata, the tectonic evolutionary history, the cause-forming and the age-forming of tectonic. According to these viewpoints, the finial title and the researches being made in this paper are detemined.Based on the characteristics of distribution and sedimentation of Jurassic basin in the western region of China, the background of tectonic evolution of the Qaidam Basin and regional geology in the northern margin of the Qaidam Basin have been studied. It is suggested that the northern margin of the Qaidam Basin is a subsidence-uplift- subsidence-uplift basin. During the Early Jurassic and early stage of Middle Jurassic, the sedimentary envoiroment of Jurassic belonged to the type of weak-extension and extension fault-depression, then it switched to depression during the middle stage of Middle Jurassic and a large-scale movement happened after the Early Cretaceous, which made the early paleo-tectonic forming. At the end of Cenozoic, the Qilian Mountains was pushed back to the basin because of the effect of the late stage of Himalayas event, and overturned tectonic are formed, thus become the favorable exploration target. In addition, on the basis of the data of Dameigou profile, division of the stratigraphical sequence for the northern margin of the Qaidam Basin has been studied, meanwhile according to the distribution characteristics ofJurassic remains strata , the auther puts forward that two-large subsidence belts had been formed during the Jurassic, Jurassic strata get deep along the front of Mountain, thus provide the source rocks for the reservoir-forming of the thrust-belt at the front of mountain. Finally, based on the detailed researches , six main characteristics on Mesozoic and Cenozoic petroleum geology of the northern margin of the Qaidam Basin can be concluded, also,the auther suggests that the thrust-fault belt at the front-Saishiteng Mountains, hidden structure belt in Saishiteng depression and Lenghu-Nanbaxian structure belt could become the key favorable exploration targets, it will play significant role in guiding the next step of exploration.更多还原