Abstract:

To evaluate the yields of oil and the potential of tight oil resources of lacustrine source rocks, the characteristics of hydrocarbon generation, kinetic parameters, and the efficiency of petroleum expulsion of lacustrine source rocks in the Songliao Basin were studied in this paper, by using the gold-tube pyrolysis of lacustrine Type-I organic matters and organic geochemical analysis of the Qingshankou Formation source rocks. Quantitative determination of the liquid and gas products from pyrolysis experiments indicate that there is a considerable oil generation potential for the Qingshankou Formation source rock in the Songliao Basin with maximum yields of oil about 600 mg/g·TOC. Kinetic calculation shows that the average activation energy for oil generation from this source rock is 218.5 kJ/mol, wherein, the activation energy for the generation of heavy components is obviously lower than that of light parts. Geological extrapolation based on the kinetic parameters and the thermal history of well YX58, demonstrates that the present generation conversion and amounts of oil for the source rocks of tight oils in this well are 40% to 60% and 240 to 360 mg/g·TOC, respectively. By determination of the residual hydrocarbons, the expulsion amounts and efficiency of oils for this source rocks can be calculated to be 150 to 200 mg/g·TOC and 25% to 33%, respectively. It is shown that tight oil resources are of great potential in the Songliao Basin.

Key words: lacustrine source rock, gold-tube pyrolysis, hydrocarbon generation kinetics, the efficiency of petroleum expulsion, the Songliao Basin