Microscale comprehensive evaluation of continental shale oil recoverability

This paper targets the shale oil reservoirs of middle to high maturity in four major basins of China, including the Permian Lucaogou Formation of the Jimsar Sag in the Junggar Basin, the Chang 7(3) Member of the Triassic Yanchang Formation in the Longdong area of the Ordos Basin, the Kong 2 Member of the Paleogene Kongdian Formation in Cangdong Sag of the Bohai Bay Basin, and the Qing 1 Member of the Cretaceous Qingshankou Formation in Changling Sag of the Songliao Basin. The key parameters of the shale oil reservoirs in the four basins, such as reservoirs effectiveness, oil content, crude oil movability, and fracability, have been revealed under identical experimental conditions using the same evaluation technical system, on the basis of technique development and integrated application of multi-scale spatial distribution depiction, effective connectivity calculation, movable oil assessment based on the charging effect, and simulation of fracture propagation during reservoir stimulation. This research overcomes insufficient resolutions of conventional analysis approaches and difficulties in quantitative evaluation, develops the evaluation method for resource recoverability of different types of shale oil, and gains in-sights into different types of shale oil via comparison. The results of experiments and comparative analysis show that there are significant differences in the endowment of continental shale oil resources in the four major basins in China. Among them, the Lucaogou Formation in the Junggar Basin has more effective shale reservoirs, the Chang 7(3) sub-member of the Ordos Basin has a comparatively good proportion of movable oil and the Kong 2 Member of the Bohai Bay Basin has the best fracability. These results can provide references and basis for choosing development plans and engineering techniques.

Automated summary

This paper focuses on the key parameters of shale oil reservoirs in four major basins in China and reveals their effectiveness, oil content, crude oil movability, and fracability under identical experimental conditions. The research overcomes limitations of conventional analysis methods, develops evaluation methods for different types of shale oil resources, and provides insights through comparative analysis of the four major basins.