Earth Science Frontiers ›› 2021, Vol. 28 ›› Issue (6): 95-104.DOI: 10.13745/j.esf.sf.2021.1.45

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Sedimentary evolution of deep marine potassium/lithium-rich brine reservoirs in the Sichuan Basin and a comprehensive response model for the brine storage layer

YANG Hongyu1, ZHANG Bing1, FANG Chaohe2,*, YANG Kai1, CAO Qian2, ZHANG Saimin1, LIN Xiaoyang1   

  1. 1. Ministry of Education Earth Exploration and Information Technology Key Laboratory, Chengdu University of Technology, Chengdu 610059, China;
    2. Research Institute of Petroleum Exploration and Development, PetroChina, Beijing 100083, China
  • Received:2021-01-28 Revised:2021-09-29 Online:2021-11-25 Published:2021-11-25

Abstract: With the increasing demand for potassium/lithium salt, the technology for shallow salt lake brine exploration and development is maturing and the deep brine resources have become the next exploration goal. In the Sichuan Basin, a wide, ultra-thick layer of Triassic evaporites has developed with abundance of high-quality potassium-rich brine reservoirs. In this paper, taking on the issue of ‘lacking saltiness’ in lithofacies paleogeography, we analyzed the distribution pattern of evaporites, the characteristics of lithofacies paleogeography, and the sedimentary evolution in the Sichuan Basin. We demonstrated the formation of a gypsum-salt basin is multi-stage and multi-zoned and determined the scale, distribution, and migration law of gypsum-salt basins in the key salt-forming period T1j4-T2l3 in the Triassic. In a parallel investigation based on the geological and logging data, we determined the geological and logging response characteristics of brine reservoirs in the Sichuan Basin. We consider the quality of potassium/lithium-rich brine reservoirs is controlled by horizon, facies belt and pore type as implied by the coupled logging response characteristics, such as medium-high gamma, low resistivity, high acoustic transit time, and low density. Results from this study can be used to guide deep marine strata explorations for potassium/lithium-rich brine reservoirs at home and abroad.

Key words: Sichuan Basin, deep brine, sedimentary evolution, lithological combinations, response model of brine reservoir

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