Abstract: The analysis of the sedimentary facies of the reservoir is important for the exploration and development of one oilfield. And obvious types of facies symbols which are macro and micro are necessary to the division of the sedimentary facies. During the study of the sandstone reservoir of the Neogene in Huatugou oilfield, Qaidam Basin, on the basis of the general columnar section of the Neogene in Huatugou oilfield and the data of 2 systemic wells and 12 exploration wells, the authors have obtained some macro facies symbols helpful to divide the sedimentary facies with the Markov Main Analysis and Time-Trend Analysis, such as the cycles of the lithologic variation and the main types of the rhythm and its assemblage. Conjoint with the color, the laminations, the deformation structures, the types of the carbonate rocks and the special sediments, the authors analyzed the sedimentary facies of the Neogene reservoir in Huatugou oil field. It is concluded that (1) it is a important assistant means of ascertaining the key beds of a exploration well to obtain the cycles of the lithologic variation with Markov Main Analysis; (2) main deposits and main modes of the lithologic transference obtained by Time-Trend Analysis are helpful to ascertain the hydrodynamic condition and the evolvement process of sedimentary environment; (3) the main types of the sedimentary facies of the Neogene in the Huatugou oilfield include braided channel deltaic plain, deltaic frontal margin, fore-delta, littoral lake and shallow lake facies.

Key words: time-trend analysis, Markov chain method, the sedimentary facies, Neogene, Qaidam Basin

摘要： 以柴达木盆地花土沟油田新近系砂岩储层为例，根据综合柱状图、2口系统取芯井的岩芯资料及12口探井的岩屑录井资料等，应用时间趋势分析与马尔科夫链分析等数学地质方法，得到了一些重要信息：地层岩性旋回、主要的韵律类型及其组合样式等。在此基础上，结合其他相标志，对新近系砂岩储层沉积相进行了划分。研究认为，(1) 利用时间趋势分析获取地层岩性旋回的方法是确定探井标志层的一个重要辅助手段；(2) 由马尔科夫链分析得到的主要岩性及岩性的主要转移方式可用于分析沉积时期的水动力条件，确定韵律类型；(3) 研究层段砂岩储层沉积相类型主要包括辫状河三角洲前缘、前三角洲相和滨湖、浅湖相。

关键词: 时间趋势分析, 马尔科夫链分析, 沉积相, 新近系, 柴达木盆地