摘要
柴达木盆地柴西地区古近系下干柴沟组与新近系上干柴沟组地层均具备致密油形成的基本地质条件.柴西地区下干柴沟组上段有效烃源岩有机碳质量分数为0.8％～2.0％,有机质类型以Ⅰ-Ⅱ1型为主;上干柴沟组有效烃源岩有机碳质量分数为0.6％～1.5％,有机质类型以Ⅰ-Ⅱ1型为主.热模拟实验表明,柴西地区古近系—新近系在烃源岩镜质体反射率（Ro）为0.47％～1.30％时为主要生油阶段,Ro为0.75％时达到最大液态烃产率,具有烃源岩在低成熟阶段即可大量生烃并迅速排烃的特点.沉积相研究认为,古近系下干柴沟组和新近系上干柴沟组广泛发育的半深湖—深湖相烃源岩和与其互层沉积的滨浅湖相砂体或碳酸盐岩,构成了对致密油形成非常有利的源储共生关系,而古构造斜坡区和生油凹陷中心是致密油富集分布区.优选柴西地区新近系扎哈泉凹陷—乌南斜坡区上干柴沟组、南翼山—小梁山区带上干柴沟组—下油砂山组、七个泉—跃进斜坡区下干柴沟组上段为致密油三大有利勘探区带.
The Paleogene Lower Ganchaigou Formation and Neogene Upper Ganchaigou Formation in the western Qaidam Basin have the basic geological conditions to form tight oil. The organic carbon content of effective hydrocarbon source rocks in the upper segment of Lower Ganchaigou Formation is between 0.8% and 2.0%, and the type of organic matter is mainly Ⅰ - Ⅱ1. The organic carbon content of effective hydrocarbon source rocks in Upper Ganchaigou Formation is between 0.6% and 1.5%, and the type of organic matter is mainly Ⅰ - Ⅲ. Thermal simulation experiment shows that it is in the main stage of hydrocarbon generation of Paleogene-Neogene in western Qaidam Basin when the R,, of source rocks is between 0.47% and 1.30%, and liquid hydrocarbon yield reaches maximum when Ro is 0.746%. Sedimentary facies study indicates that extensively developed semi deep-deep lake facies source rocks of the Paleogene Lower Ganchaigou Formation and Neogene Upper Ganchaigou Formation has source-rservoir symbiotic relation with shore shallow lake facies sand bodies or carbonate rocks, which is beneficial to form tight oil, and ramp area of paleo- structure and the center of source sag are favorable for tight oil enrichment. The Neogene Upper Ganchaigou Formation in Zhahaquan Sag-Wunan ramp area, Upper Ganchaigou Formation and Lower Youshashan Formation in Nanyishan- Xiaoliangshanarea and the upper segment of Lower Ganchaigou Formation in Qigequan-Yuejin ramp area are the three favorable exploration zones for tight oil.
出处
《岩性油气藏》
CSCD
北大核心
2015年第3期26-31,共6页
Lithologic Reservoirs
基金
中国石油重大科技专项"柴达木盆地石油勘探领域评价与目标优选"(编号:2011E-0301)资助
关键词
致密油
资源潜力
古近系
新近系
柴达木盆地
tight oil
resources potential
Paleogene
Neogene
western Qaidam Basin
