纳木错西岸白云岩的时代修订及油浸现象发现的意义

发布时间：2018-11-08 19:39

【摘要】：班戈县保吉地区纳木错湖西岸的白云岩地层以往划分为下白垩统郎山组,笔者根据在其中最新发现的Ellisonia agordina,Hadrodontina anceps和Pachycladina cf.obliqua等早三叠世牙形石化石,将其修订为木纠错组,并将木纠错组的时代延限从原始定义的晚二叠世修订为晚二叠世-早三叠世。该套白云岩地层里同时发现了油浸现象,油浸样品的初步测试结果为饱和烃含量34%,芳烃含量1.1%,非烃含量51%,沥青质含量13%。这一发现直接证明了保吉地区的木纠错组是含油气层系,说明了古格层系不再是潜在的油气沉积建造,而是具有现实生产价值的含油气层系。这一发现促使我们将古格层系进一步划分为上、下两个组合,晚二叠世-早三叠世的白云岩地层是古格层系下组合中的油气储集层。措勤盆地和南羌塘盆地晚二叠世-早三叠世处于碳酸盐岩局限台地环境,与阿拉伯半岛的北气田和华南的普光气田的沉积环境类同,具有形成大型油气区的地质背景。藏北地区晚二叠世-早三叠世白云岩除了局部出露外,大部分都埋藏在地下,保存条件较好,具有重大的油气勘探价值。措勤盆地和南羌塘盆地面积这么大,要想开展油气勘探和评价,就要找到一个突破口。纳木错西岸是理想的突破口。
[Abstract]:The dolomite strata in the West Bank of Namuco Lake in Baogi County, Bangol County, were previously divided into the lower Cretaceous Langshan formation. According to the newly discovered early Triassic conodont fossils, such as Ellisonia agordina,Hadrodontina anceps and Pachycladina cf.obliqua, they were revised as the tree correction formation. The age extension of the wooden error correction set was revised from the original definition of the late Permian to the early Triassic. The oil leaching phenomenon was also found in the dolomite formation. The preliminary test results of the oil leaching samples were as follows: saturated hydrocarbon content 34%, aromatic hydrocarbon content 1.1%, non-hydrocarbon content 51%, asphaltene content 13%. This discovery directly proves that the Moo error-correcting formation in Baoji area is an oil-bearing gas reservoir system, indicating that the paleogeostratigraphic system is no longer a potential oil and gas sedimentary formation, but an oil-bearing gas bearing system with practical production value. This discovery leads us to further divide the paleogeostratigraphic series into upper and lower assemblages, and the dolomite strata of the late Permian-early Triassic are oil and gas reservoirs in the lower assemblages of the paleogeostratigraphic series. The late Permian-early Triassic carbonate platform environment in the Cuoqin basin and the southern Qiangtang basin is similar to the sedimentary environment of the North Gas Field in the Arabian Peninsula and the Puguang Gas Field in South China, and has the geological background of forming a large oil and gas region. The dolomite of the late Permian-early Triassic in northern Tibet is mostly buried underground except for local outcrop, which has good preservation conditions and is of great value for oil and gas exploration. In order to carry out oil and gas exploration and evaluation, a breakthrough must be found in such a large area as the Cuoqin basin and the southern Qiangtang basin. The West Bank of Namuco is an ideal breakthrough.
【作者单位】：国土资源部地层与古生物重点实验室中国地质科学院地质研究所;中国地质大学;吉林省地质调查院;中国地质科学院国家地质实验测试中心;
【基金】：国家自然科学基金项目(编号41472030) 科技基础性工作专项(编号2015FY310100) 中国地质调查局项目(12120115069001;1212011120142;1211402108021-2;121201102000150010-02;121201102000150010-04;1212011120115;DD20160201) 中国地质科学院基本科研业务费项目(编号J1607)资助的成果
【分类号】：P618.13

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