青海省祁连盆地三叠系烃源岩地球化学特征分析

The analysis of geochemical characteristic of Triassic hydrocarbon source rocks in Qilian Basin in Qinghai Province

为了加快青海省页岩气资源的勘探与开发进程,形成多元化的天然气供应格局,青海省加大了页岩气资源潜力评价力度。文中通过路线调查、钻探施工及样品采集测试等系统地分析了祁连盆地三叠系南营儿组烃源岩有机质丰度、干酪根类型、有机质成熟度和热演化程度,研究结果表明：该套烃源岩中暗色泥页岩有机碳含量平均为1.63%,属于中等烃源岩,而油页岩有机碳含量平均为8.2%,有机质类型较好属腐泥腐植型-腐植型（Ⅱ2-Ⅲ型）,具备生成油和气的条件;有机质成熟度Ro在0.61%~1.24%,平均为0.95%,成熟度达到低成熟—成熟阶段,处于有利于页岩气生成的成熟度范围内;沉积环境为湖泊沉积体系。因此,认为青海省祁连盆地三叠系南营儿组找页岩气藏前景良好。

In order to speed up the exploration and development process of the shale gas in Qinghai Province, forming a diversified supply situation of the natural gas, Qinghai Province has increased the potential evaluation intensity of the shale gas resources. In this article, according to the route survey, drilling and sampling, the organic matter abundance, kind of Ga keRogen, maturity of organic matter and the thermal evolution degree were analyzed systematically. The results suggest that： the total or- ganic carbon （TOC） content of the dark shale in the set of hydrocarbon source rocks averaged 1.63 %, reached the standard of the medium or good hydrocarbon source rocks, the total organic car- bon（TOC） content of the oil shale was 8.2% for average, reached a good source rocks of the stand- ard;the types of organic matter is good, which belongs to sapropel humichumus - humichumus type （ Ⅱ 2 - Ⅲ ）, having the conditions for the formation of oil and gas ; the maturity of organic matter （Ro） ranged from 0.61% to 1.24% ,0. 95% for average. The degree of thermal evolution reached low mature -mature stage,within the maturity range favorable for the shale gas generated;the sedi- mentary environment is lake - deep lake facies. So, we think that the potential of shale gas explora- tion in Qinghai Triassic is very large and has good prospects.