关键词: 准噶尔盆地, 吉木萨尔凹陷, 页岩油, 成藏地质条件, 勘探开发配套技术

Abstract: Since the discovery of Lucaogou Formation shale oil in Jimusar sag of Junggar Basin, it has third-level reserves of 4.3×10⁸t through ten years of exploration and development. In 2020, Jimusar sag became a national development demonstration zone of continental shale oil with an oil production of 60×10⁴t. A series of theoretical innovation and technological breakthroughs have been achieved in terms of geological theory of shale oil accumulation in Jimusar sag, supporting exploration and development technologies, and benefits management. The research results show as follows. Jimusar sag is a vast lake basin under the stable tectonic setting, where multi-component peperite with rich organic matters has been deposited, with the thickness of 275 m. The integrated distribution of thin source-reservoir interbeds plays an important role in the enrichment and preservation of shale oil. Due to high source-reservoir ratio (4.5:1), high organic matter abundance (3.24 %) and sedimentary environment of saline lake, the maturity of crude oil in the sag has been improved, and the vitrinite reflectance R_o is up to 1.05 %. Overpressure commonly exists in tsag with an average pressure coefficient of 1.36. The charging efficiency and oil enrichment degree are enhanced as a result of the source-reservoir pressure difference, indicating the formation of reservoirs with high oil saturation and high pressure coefficient. The current exploration and development technologies of shale oil in Jimusar sag are basically established. The geological understanding has been improved by the fine three-dimensional seismic technique of broadband excitation and combination of logging and seismic acquisition. The fine characterization of shale oil "sweet spots" and classified evaluation provide the bases for hydrocarbon development and deployment. The drilling ratio for "gold targets" can provide a basis for high and stable production of horizontal wells. The complex fracture networks are effective means for the efficient development of shale oil. The reasonable drainage and production system is beneficial to fully expand the production capacity of horizontal wells. The market-based cost reduction is key to the benefit development of shale oil in Jimusar sag. The technology, management and benefit of shale oil in Jimusar sag lead the way in China, and provide references and demonstration for the efficient exploration and development of continental shale oil in China.

Key words: Junggar Basin, Jimusar sag, shale oil, geological conditions for reservoir accumulation, supporting technologies of hydrocarbon exploration and development