EVALUATION CRITERIA FOR SHALE OIL RESOURCE GRADING OF SHAHEJIE FORMATION IN PALEOGENE STRATA OF DAMINTUN SAG, LIAOHE FAULT DEPRESSION BASIN, CHINA

The grading evaluation of shale oil and gas resources is an important way to achieve efficient development of shale oil and gas resources. In this paper, taking the Shahejie Formation shale of the Paleogene in the Damintun Sag of the Liaohe Fault Depression Basin as an example, we used a large number of geochemical test results to systematically study the formation conditions of shale oil and established a grading evaluation standard for shale oil. The results show that the source rocks of the E2S42 interval, the E2S41 interval and the E2S34 interval in the Damintun Sag account for 94.05%, 93.32% and 72.40%, respectively; only most of the chloroform bitumen "A" data in the E2S42 interval is greater than 0.1%, and the source rocks in other layers are of lower quality; for the hydrocarbon generation potential, the E2S42 interval of the Damintun Sag belongs to the upper-middle level of the main basin in eastern China, while the hydrocarbon generation potential of the E2S41 and E2S34 intervals is relatively poor. The kerogen type of the target layer is mainly type II2 and type III. When the organic matter maturity is below 2 400 m, they are all low maturity or maturity grade. The hydrocarbon expulsion threshold of the Shahejie Formation is 2 500 m. According to the relationship between residual oil and organic carbon in shale, for E2S34 and E2S41 segment, TOC greater than 2% is regarded as Class I standard, and for E2S42 segment, TOC greater than 4% is regarded as Class I standard.