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The anhydrous, hydrous and bitumen-extracted simulations were carried out for the immature source rocks from the Liaohe sag. It has been shown from the result that with increasing temperature in simulation experiments, the fatty acids content decreased at first and then increased. The decrease of fatty acids in immature rocks is presumably related to alkanes generation in immature oils, whilst the increase may be related to the fact that some additional fatty acids are generated from kerogen and the tightly bound fatty acids in kerogen are released as bound fatty acids in kerogen and unbound fatty acids in bitumen. The fact that the bitumen generated from kerogen contains fatty acids has demonstrated that some bound and tightly bound fatty acids in kerogen can be transferred into bitumen. The preferential fatty acids in the immature source rocks are found to be mono-carboxylic acids with longer chains, whilst krogen contains relatively more di-carboxylic acids. It has been found that the fatty acids in immature source rocks can be changed from that with more longer chains to that with more shorter chains when evolution extent has been increased. Based on simulation results and the fact that the majority of fatty acids in immature oils are those with longer chains, it is inferred that the contribution of fatty acids to forming alkanes in immature oils mainly takes place at the evolution stage withR 0

Organic geochemical analysis, organic petrology and fluid inclusion methods were employed to investigate a series of cuttings and cores from a single well for evaluation of the oil-generating potential of the Guangan structure in the Shichuan Basin. Information was obtained on the abundance and type of kerogens in the Mesozoic and Paleozoic strata in the region; the fluid inclusion study provided information about the maturity of organic matter in the samples. The results show that the Jurassic shales, as well as the Permian and Carboniferous carbonates, have good oil- and gas-generating potential. In addition, the Jurassic source rocks were shown to have reached the stage of oil generation, whereas the Permian and Carboniferous source rocks have reached the zone of gas generation. Evidence is given to show that the Carboniferous carbonates may be good petroleum reservoirs in this area.

In order to understand thermal stabilities of various biomarkers in sedimentary rocks, and to utilize them to subdivide the stage of diagenesis and to define the immature oil-generating threshold in the eastern part of China, serial cores from various depths and core samples from well WHI-I, heated in a simulation experiment at various temperatures, have been analysed. As a result, the relative thermal stabilities for alkybenzenes, alkylithophenes, benzohopanes, hopenes, diasterenes, ββ-hopanes, steranes and terpanes have been recognized and it has been suggested that the immature oil-generating threshold could be defined at the depth at which there are no hopenes in sedimentary rocks.