Abstract: The formation and distribution of heavy oil pools in Erlian basin are controlled by the framework and evolution of a depression,underwater system,maturity of source rocks,andpetroleum migration history.There are two genetic types of heavy oils:primary and secondbiodegraded heavy oils with different forrnation mechanisms and geochemical features. Thegeochemical analysis of crude oil shows that Menggulin heavy oil pool is a primary heavy oilpool,and the heavy oil pools in the Jirgalangtu depression are biodegraded heavy oil poolswith low maturity. The relationship of reservoir petrophysics and oil saturation of the heavyoil pools in the Jirgalangtu depression indicates that they were forrned first and then thickened,and this will affect their recovery.

Key words: Erlian basin, heavy oil, biodegradation, trace element, heavy oil, reservolr

摘要： 二连盆地重质稠油藏的形成和分布受断陷结构、构造发育史、地层水系统、生油岩成熟度及油气运移史等多种因素控制.研究发现,二连盆地存在两种成因稠油:原生稠油和次生生物降解稠油;它们的形成机理和地质地化特征不同.原油的地化分析表明,蒙古林稠油藏为原生重质稠油藏;而吉尔嘎朗图凹陷西南斜坡区重质稠油藏是轻度-中度降解的低熟重质稠油藏,其产层物性与含油饱和度分析发现,它们是“先成藏后稠化”形成的.

关键词: 二连盆地, 稠油, 生物降解, 微量元素, 重质稠油藏