Abstract:

After 20 years of shale gas exploration and development, China has become the third country that achieves commercial shale gas production, following the United States and Canada. However, earlier exploration and development of the layer were limited to the Silurian Longmaxi Formation. With improved theoretical understanding of shale gas exploration, China has made exploration breakthroughs in Permian and Cambrian shales in recent years, demonstrating the great potential of shale gas in Sichuan Basin. Based on a review of the exploration history of shale gas in the two major marine phases—Silurian Longmaxi Formation and Cambrian Qiongzhusi Formation, this study summarizes the three phases of shale gas exploration: research and exploration (2000-2011), discovery and production (2011-2022), and multi-layer breakthroughs (2022-present). This study thoroughly analyzes the process of two theoretical innovations and paradigm shifts in the exploration and research of marine shale gas in Sichuan Basin. (1) After comparing the formation conditions and exploration and development characteristics of shale gas between China and the United States, Chinese researchers abandoned the simple replication of North American experience, and highlighted the critical role of preservation conditions based on the evolution characteristics of China’s multi-phase tectonics. This completed the first paradigm shift and achieved major exploration breakthroughs in the Silurian Longmaxi Formation. (2) Research on the characteristics of low-organic matter and inorganic pores was enhanced. Traditional theories of enrichment and reservoir formation were developed and improved, and a “migration+in situ” reservoir formation mode was established. This completed the second paradigm shift and led to exploration breakthroughs in Cambrian Qiongzhusi Formation. Recent research breakthroughs in low-organic shale, inorganic pores, and other aspects have expanded both the scope and depth of shale gas exploration, leading to a multi-layer exploration pattern of marine shale gas. It demonstrates broad exploration prospects and strategic value for national energy security. Based on a review of the exploration history and paradigm shifts from the Silurian to the Cambrian periods, as well as an analysis of the implications from major breakthroughs, this study reveals an exploration path of shale gas with Chinese characteristics, providing important references for future exploration and development of multi-layer and multi-field shale gas.

Key words: marine shale gas, Sichuan Basin, Silurian, Cambrian, theoretical innovation, breakthrough inspiration