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巴楚隆起麦盖提斜坡是塔里木盆地西部的重要构造单元,部署在麦盖提斜坡带上的重点探井罗斯2井在奥陶系底部的蓬莱坝组获得成功,在该区新层系的油气勘探获得突破。阐明罗斯2井油气的成因、来源对该区下一步的油气勘探具有重要的意义。通过系统研究罗斯2井原油、天然气地球化学特征,探讨罗斯2井的油气源以及成因特征,研究表明罗斯2井原油中甾萜类等生物标志化合物含量很低,受热演化影响较为明显,基本不能作为生源或其他地球化学特征的判识参数,而原油的金刚烷、甲基菲等成熟度参数表明其成熟度较高,与该区的寒武系烃源岩可比,全油的碳同位素组成偏重,综合原油的地球化学特征并与烃源岩对比认为其应来源于中上寒武统烃源岩。罗斯2井天然气干燥系数较高,天然气碳同位素组成偏重,为典型高—过成熟干气,并根据与原油的相关关系认为也应来自于中上寒武统烃源岩。
The Bachu uplift The Maigaiti slope is an important tectonic unit in the western Tarim Basin. The key exploration well No. 2 located on the Maigaiti slope has been successfully completed in the Penglai Dam formation at the bottom of the Ordovician. In this area, Exploration made a breakthrough. To elucidate the genesis and origin of the oil and gas in Ross 2 well is of great significance to the exploration of oil and gas in this area. By systematically studying the geochemical characteristics of crude oil and natural gas in Ross 2 well and studying the oil and gas sources and genetic characteristics of the Ross 2 well, the results show that the content of biomarkers such as steroidal terpenoids in the crude oil from Well Ross-2 is very low and affected by thermal evolution. As a parameter of identification of the biogenic or other geochemical characteristics, the maturity parameters of crude oil, such as adamantane and methylphenanthrene, indicate that it has high maturity and is comparable to the Cambrian source rocks in this area. The carbon isotopic composition of the whole oil Emphasis is placed on the geochemical characteristics of the crude oil and the comparison with the source rocks suggests that they should be derived from the Upper Cambrian source rocks. The natural gas has a higher drying coefficient and a heavier carbon isotope composition, which is typical of over-mature dry gas. It is also believed that the gas should originate from the middle and upper Cambrian source rocks according to its correlation with crude oil.