Earth Science Frontiers ›› 2025, Vol. 32 ›› Issue (5): 12-27.DOI: 10.13745/j.esf.sf.2024.12.86

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Research status and progress of tectonic-thermal evolution history in Qiangtang Basin

REN Zhanli1,2(), YANG Peng1,2, QI Kai1,2, CUI Junping1,2, YU Qiang3, CHENG Xin1,2, HUANG Lei1,2, CHEN Gang1,2, YAO Juwen1,2   

  1. 1. State Key Laboratory of Continental Dynamics, Department of Geology, Northwest University, Xi’an 710069, China
    2. Xi’an Key Laboratory of Multi-energy Exploration and Development, Xi’an 710069, China
    3. School of Earth Science and Resources, Chang’an University, Xi’an 710054, China
  • Received:2024-09-12 Revised:2024-12-06 Online:2025-09-25 Published:2025-10-14

Abstract:

The thermal history of the Qiangtang Basin plays an important role in controlling the generation, accumulation and occurrence of oil and gas. As a large Mesozoic Marine oil-bearing basin in China, the thermal regime and the spatial and temporal differences of the thermal evolution history of source rocks are the key scientific problems restricting the breakthrough of oil and gas. Based on a large number of literatures and my own research work, this paper comprehensively analyzes the current research status and progress in four aspects closely related to the study of the thermal evolution history of the Qiangtang Basin: current geothermal field, basin type and uplift and cooling process, thermal maturity and thermal evolution process, and thermal evolution history and hydrocarbon generation history. The special structural characteristics of “small block - multi-stage and strong deformation” in Qiangtang Basin complicate the properties of the prototype basin, and lead to the differences of sediment-subsidence changes, tectonic deformation, unconformity, magmatic activity, and uplift and cooling processes and periods in different regions and tectonic units. These differences relate closely to the characteristics of the tectonic thermal regime of the basin, the thermal evolution history of the source rock, and the generation, accumulation, preservation and destruction of oil and gas. The late tectonic movement and strong magmatic activity of Qiangtang Basin have important influence on thermal evolution indexes such as vitrinite reflectance. According to different structure and magmatic activity, vitrinite reflectance and depth profiles are divided into normal variation type, igneous rock influence type and fault influence type. The disunity of basin types, uplift and cooling history of different tectonic units and understanding of differences that have an important influence on the restoration of tectonic thermal evolution history restricts the establishment of basin dynamic models and the restoration of tectonic thermal evolution history. The heat flow value and geothermal gradient obtained by different experts differ greatly, and there are different understandings of middle, high temperature and low temperature basins. It is difficult to accurately determine the thermal evolution degree of source rocks. According to the existing analysis results, the relationship between reflectance and pyrolysis peak temperature of source rocks in different strata of Qiangtang Basin has been established, and the establishment of the chart has an important role in determining the maturity of source rocks. After the Early Cretaceous, the transformation intensity of different tectonic units varied greatly, and the differences in uplift process, denudation amount, burial history and thermal evolution history led to the obvious differences in the understanding of the first and second hydrocarbon generation stages and the specific time. The discontinuity of thermal evolution between the Cretaceous and Suonahu and Kangtuo formations in the southern margin of the Qiangtang Basin indicates that the maximum thermal evolution of the Jurassic source rocks in the southern margin of the basin was reached before the deposition of Suonahu and Kangtuo formations. Therefore, the thermal evolution profile of source rocks shows that the main hydrocarbon generation period of source rocks in most areas of Qiangtang Basin is in the Early Cretaceous and before. According to the current situation and progress of the research on the thermal evolution history of the basin, four key problems and further research directions in the study of thermal evolution history were identified: (1) Recovery of differential settlement and uplift process of tectonic units; (2)Establishment of current geothermal field and basin dynamics model in critical period of Qiangtang Basin; (3) The influence of multiple geological factors (differential sediment-uplift, nappe structure, faulting activity, magmatic activity) on the thermal evolution process; (4)Restoration of thermal evolution history and establishment of differential model of hydrocarbon generation history of source rocks of different tectonic units in Mesozoic. The study of the thermal evolution history of the Qiangtang Basin is of great significance to explore the thermal dynamic evolution of the Qinghai-Tibet Plateau basin, establish the spatio-temporal difference model of complex thermal evolution history and hydrocarbon generation history, and make breakthroughs in comprehensive oil and gas evaluation and exploration in the Qiangtang Basin.

Key words: hydrocarbon generation history, basin thermal history, ancient earth temperature, fission track, vitrinite reflectance, oil and gas exploration, Qiangtang Basin

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