Evolution Characteristics of Hydrocarbon Generation and Expulsion of Different Types of Organic Matter-Take Beier Sag in Hailaer Basin as Example

In view of the difficulty in classifying and estimating the amount of oil and gas resources due to the fact that the traditional thermal simulation experiment method of Source rock can not accurately distinguish the discharged oil and residual oil, the evolution process of hydrocarbon generation and expulsion of source rock was studied taking Beier Sag in Hailar Basin as an example. The self-developed experimental equipment was used to complete the thermal simulation experiment of closed system with high temperature and pressure for water bearing of three types of Source rock in the study area, establish a new separation, collection and quantitative program for discharged oil and residual oil, and analyze the characteristics and differences of hydrocarbon generation and expulsion of different types of Source rock in each stage. The research shows that the trend of oil generation of each type of Source rock is similar, and the amount of oil generation increases first and then decreases, but the amount of oil generation of type II1 is the highest, and that of type III is the lowest. The maximum peak temperature point of residual oil moves backwards in the order of type II1 – type II2 – type III. Among the three types, type II2 samples have developed internal pores, making it easier for oil to be discharged. Type II1 samples have a wider range of oil generation and discharge, and after in-situ heating, they will have a larger scale of movable oil. The gaseous products undergo cracking at high temperatures in the order of C3H8 to C2H6, and then C2H6 to CH4, leading to a rapid increase in CH4 during the later stages of thermal evolution. The carbon isotope values of each gas component show a trend of first becoming lighter and then heavier, and become heavier in the order of CH4-C2H6-C3H8. This research has realized the full separation of discharged oil and residual oil in the thermal simulation experiment products of hydrocarbon generation and expulsion, providing technical support for exploring the evolution process of different types of Source rock, studying the contribution of various types of source rocks to oil and gas generation, and fine evaluating the amount of resources.