柴达木盆地茫崖坳陷古近系—新近系R_o分布特征及地质意义  

Vertical Distribution of the Tertiary Vitrinite Reflectivity (R_o) and Its Geological Significance in the Western Qaidam Basin

作　　者：钟建华[1] 郭泽清[1] 杨树锋[2] 刘卫红[1] 陈汉林[2] 黄立功[3] 刘云田[3] 江波[3] 张永庶[4] 

机构地区：[1]石油大学地球资源与信息学院,东营257061 [2]浙江大学地球科学系,杭州320027 [3]中国科学院广州地球化学研究所,510640 [4]青海油田公司,敦煌736202

出　　处：《地质学报》2004年第3期407-415,共9页Acta Geologica Sinica

基　　金：国家自然科学基金项目 (编号 40 172 0 73 )资助成果

摘　　要：柴达木盆地西部的茫崖坳陷是青海油田的主力油气产区 ,对该区古近系—新近系镜质组反射率(Ro)进行了系统研究 ,发现其垂向分布有两种规律 :一是 Ro 与垂深有良好的线性关系 ,多分布在坳陷中央 ,反映了沉积环境、物源和构造的稳定性较好 ;二是 Ro 与垂深呈右阶状 ,反映了逆冲叠覆。此外 ,通过 EASY% Ro 方法计算了研究区地层剥蚀厚度 ,认为干柴沟—油泉子为英雄岭隆起的主轴 ,因为剥蚀了 36 0 0～ 375 0 m,所以英雄岭主峰在地形上呈现出隆起主轴的假貌。通过地层剥蚀厚度的研究 ,还发现油气田主要分布在剥蚀梯度带上。The Mangya depression, located in the western Qaidam Basin, is one of the main oil-bearing units in the Qinghai oilfield. Two vertical distribution styles have been found after the study of the Tertiary vitrinite reflectivity (R o). Firstly, a linear correlation between R o and depth is conspicuous, and it is clear that such distinct relation exits in the center of the depression, which shows stability of the sedimentary environment, the sources of sediments and the structural activities. Secondly, it is found that thrusting and superposition are developed according to the dextral-stepped arrangement of R o and the depth in the cross plots. What is more, by calculating the denuded stratum thickness in the work area with the method named EASY%R o, the main structure should occur along Ganchaigou-Youquanzi. However, the present landform shows that the main peak of the Yingxiongling is the ridge axis. This ostensible appearance can be well explained if we take the denudation in this area with a thickness of 3600~3750 m into account. It is also found that most of the oilfields distribute along denuded gradient zones. These results are important for the exploration and development of the Qaidam Basin.

关 键 词：青海油田 柴达木盆地 冲叠 剥蚀 古近系 新近系 沉积环境 地质构造 

分 类 号：P618.13[天文地球—矿床学]