Geothermal Regime and Its Implication on Hydrocarbon Accumulation in the Northern Junggar Basin

ABSTRACT The geothermal regime of a sedimentary basin plays a critical role in the formation and distribution of hydrocarbon resources. However, the lack of measured temperature data has hindered a comprehensive understanding of the geothermal regime, complicating the analysis of hydrocarbon accumulation processes in the northern Junggar Basin. This study validated and applied a predictive method based on mantle and crustal heat flow to estimate heat flow in regions without measured temperature data. By integrating data from existing and pseudo boreholes, the present geothermal regime of the northern Junggar Basin was analysed. Thermal histories were reconstructed for different regions, and the maturation processes of source rocks were further examined. Correlation analysis confirmed that the mantle and crustal heat flow method provides a reliable approach for predicting heat flow in areas lacking direct measurements. The heat flow of the northern Junggar Basin varies between 31 and 59 mW/m 2 , with an average of 43 mW/m 2 . Spatially, the highest heat flow values were found in the southeast, followed by the west, with the lowest in the north. The spatial distribution of the geothermal gradient and deep formation temperatures aligns with heat flow patterns and is primarily influenced by basement topography and orogenic activity. Basin modelling results revealed that the southeastern region experienced higher temperatures, leading to the maturation of source rocks during the Permian and their progression into the gas generation stage. In contrast, source rocks in the western region remain in the oil generation stage. Similarly, lower temperatures in the northern region have preserved source rocks in the oil generation stage. This study provides a detailed understanding of the thermal regime in the north of Junggar Basin and its impact on hydrocarbon accumulation processes, offering valuable insights for future hydrocarbon resource exploration and evaluation.