Characteristics and occurrence of immature oil in southern Songliao basin;

It has the essential source conditions for the formation of immature oil with higher abundance and better types of organic matter deposited in thicker stratum under the environment in favor of preservation of organic matter and its inversion to hydrocarbons at the early stage,as well as the appropriate maturity for abundant production of immature oil.

The discovery and study of immature oils is one of the most important progresses in oil and gas geochemistry in recent years.

The former immature oil mainly occurs in Liaodongwan, the northeastern Bozhong sag and Sha'nan sag, and the latter mainly in Qikou sag and the northwestern Sha'nan sag.

Study on reservoir-forming mechanism of low mature oil in Western Sag,Liao-he Depression;

Organic geochemical analysis shows that oils in the lower Oligocene reservoirs in Gas Hure,western Qaidam basin,are of typical salt lake origin and have the characteristics of both low mature oil and mature oil.

There is rich resources of low mature oil in Gunan sag, Jiyang depression.

Exploration prospects of low-mature oil/gas in the shallow layers of the A'nan Sag,the Erlian Basin;

54,which are higher than those of general low-mature oil.

Based on the genetic study of low-mature oil, the results of simulation experiments and the natural evolutionary profiles of organic matter, it is pointed out that low-mature oil is in fact a by-product during the diagenetic evolution of organic matter.