柴达木盆地茫东地区石油地质条件及勘探方向研究

文章在对柴达木盆地茫东地区岩芯系统观察及采样的基础上，应用岩石热解、铸体薄片、亚离子抛光扫描电镜等分析测试技术，通过典型油气藏解剖，研究了柴达木盆地茫东地区成藏石油地质条件，分析了有利勘探方向。结果表明，黄瓜峁—开特米里克—油墩子地区下干柴沟组、上干柴沟组及下油砂山组发育较好的成熟烃源岩，是茫东地区有利的成藏区域。茫东地区长期处于滨浅湖沉积，缺少陆源碎屑供给，储层以滨浅湖滩坝砂体及灰泥坪储层为主，储层物性整体差，多为致密储层。茫东地区油气藏类型主要为构造油气藏，具有“上油下气”及近源成藏的成藏特征，且主要通过断层垂向运聚。在对茫东地区石油地质条件及钻探显示情况分析的基础上，认为深层天然气藏是该区下步油气勘探重要领域之一，另外，滩坝、灰泥坪等岩性透镜体圈闭是该区具有较大勘探前景的圈闭类型。

Research on Petroleum Geological Conditions and Exploration Directions in Mandong Area of Qaidam Basin

On the basis of core observations and systematic sampling in the Mandong area of Qaidam Basin, and using rock pyrolysis, casting thin sections, sub-ion polishing scanning electron microscopy and other techniques, this paper studies petroleum geological conditions of reservoir formation and prospecting in the Mandong area of Qaidam Basin through typical reservoir anatomy. The results show that well-developed mature source rocks occur in Lower Gangchaigou Formation, Upper Gangchaigou Formation, and Lower Youshashan Formation in the Huangguamao-Kaitemilike-Youdunzi, and are the favorable reservoir-forming areas. Due to the long-term shore-shallow lake environment and lack of terrestrial debris supply in the Mangdong area, the reservoir is mainly composed of beach-bar sand bodies and stucco flat of the shore-shallow lake. Overall, the reservoir property is poor and most are tight reservoirs. The oil and gas reservoir in the Mangdong area is mainly structural reservoir, which is characterized by“upper oil and lower gas”and near-source accumulation. Also, it is mainly transported and accumulated vertically through faults. Based on the analysis of petroleum geological conditions and drilling results in the Mangdong area, deep natural gas is considered one of the most important targets for oil and gas exploration in this area. In addition, lithologic lens traps such as beach dams and plaster flats are the types that have great exploration prospects in this area.