Organic petrological studies on immature source rocks

Abstract

Organic petrology is a marginal science that is quite practicable. At present, it has developed into a routine research tool that is widely applied in petroleum exploration and assessment. Based on several years’ research of the authors, this paper presents the advances in organic petrological studies on immature source rocks, including the classification and characteristics of macerais, the composition of macerais and types of organic matter, the abundance and evolution of organic matter, oil-prone macerais, hydrocarbon generation and expulsion. All these results show that organic petrology is of considerable value pertaining to its application in the assessment of immature oil and gas. The immature source rocks consist of various macerais with obvious heterogeneity, contain different hydrocarbon-generating macerais with different oil thresholds and oil peaks, and show a two-staged evolutionary pattern of organic matter.