柴西地区古近系—新近系盐湖相烃源岩特征及生烃模式

The characteristics and hydrocarbon generation model of Paleogene-Neogene system salt-lake facies source rocks in the western Qaidam Basin

为进一步了解柴西地区古近系—新近系盐湖相烃源岩特征及其生烃模式,选取柴西地区下干柴沟组、上干柴沟组以及上油砂山组泥质烃源岩样品进行了岩石热解、可溶组分分析以及生排烃模拟等实验研究。通过实验结果分析认为,所选样品有机质属于低熟—未成熟阶段,均显示出较好的生烃能力;氯仿沥青"A"、适度的含盐量和碳酸盐含量与累积液态烃产量之间均表现出一定的正相关性。柴西地区古近系—新近系盐湖相烃源岩的成烃高峰与传统模式相比明显提前,该结果明确了柴西地区古近系—新近系盐湖相烃源岩的生烃模式,对于指导柴西地区的油气勘探具有重要作用。

To further understand the characteristics and hydrocarbon generation model of Paleogene-Neogene System salt-lake facies source rocks in the Western Qaidam Basin, selecting argillaceous source rock samples from the Lower Ganchaigou Formation, the Upper Ganchaigou Formation and the Upper Youshashan Formation in the Western Qaidam Basin, relevant experimental studies have been carried out, including pyrolysis of rocks, analysis of soluble components, and simulation of hydrocarbon generation and expulsion. According to the analysis of the experimental results, the selected sample thermal evolution degree stays in the low mature-immature stage and shows good hydrocarbon-generation ability. There was a positive correlation between chloroform bitumen "A", moderate salt content and carbonate content, and cumulative liquid hydrocarbon production. The hydrocarbon generation peaks of the Paleogene-Neogene salt-lake facies source rocks in the Western Qaidam Basin is significantly advanced compared to the traditional model. The result clearly defines the hydrocarbon generation model of Paleogene-Neogene salt-lake facies source rocks in the study area, which is important to direct the oil and gas exploration in the Western Qaidam Basin.