OIL-BEARING PARAMETER OPTIMIZATION AND RESOURCE CALCULATION OF THE SHALE OIL IN QIJIA AND GULONG SAGS, SONGLIAO BASIN

There are abundant shale oil resources in the first member of Qingshankou Formation in Qijia and Gulong sags of Songliao Basin. In the past, the shale oil resources were calculated mainly based on incomplete old core data with corrected pyrolysis S₁ or chloroform asphalt "A" as oil-bearing parameters. The accuracy of corrected parameters was affected by multiple factors including sample freshness, testing means and correction method, leading to certain limitations in the application of the above parameters. According to the latest development in shale oil exploration, the paper compares the applications of different oil-bearing parameters (pyrolysis S₁, chloroform bitumen "A" and oil saturation) in shale oil resource calculation. The result shows that oil saturation can reflect the content of free oil and dissolved hydrocarbon, without considering the influence of adsorbed oil and correction of light hydrocarbon, heavy hydrocarbon and NSO compound. This parameter is more suitable for the calculation of shale oil resources under the condition of fresh sample test data. The plane distribution of effective shale thickness, TOC, organic maturity(R_o) and burial depth are determined on the basis of latest drilling results and test data of shale oil parameter well. The shale oil enrichment areas in the first member of Qingshankou Formation in Qijiahe and Gulong sags are 1957.23 km² and 4509.09 km² respectively by multifactor overlap method. Combined with the measured data of oil saturation, density and effective porosity logging interpretation data of sealed frozen samples, the resources of shale oil enriched areas in Qijia and Gulong sags are calculated as 19.79×10⁸ t and 27.29×10⁸ t respectively, indicating the matrix shale oil in the study area has a good exploration prospect.