中国页岩气开发进展、潜力及前景

中国作为北美之外最大的页岩气生产国,随着页岩气勘探开发的持续快速推进,在埋深3 500 m以浅的海相页岩区已经建成200×10~8 m~3的页岩气年产规模。未来全国埋深3 500 m以浅页岩气能否继续稳产上产、埋深超过3 500 m的深层页岩气的开发潜力如何,既是评价和判断未来中国页岩气资源开发潜力和发展前景等的前提,也是决定能否在川渝地区建成"天然气大庆"的关键。为此,通过总结中国页岩气理论认识和工程技术发展成果,分析页岩气资源的开发潜力,预判了未来的发展前景。研究结果表明:①在页岩气理论体系方面,明确了海相深水陆棚笔石黑色页岩形成条件及页岩气富集机理,建立了"甜点区"和"甜点段"地质理论,初步构建基于"人造气藏"的页岩气开发理论,建立了四川盆地南部地区深层优质页岩厚度大、保存条件好、发育微裂缝与超压的页岩气富集高产模式;②在页岩气工程技术方面,水平井多段压裂等关键工程技术实现了跨代发展,支撑了中国仅用6年时间就实现了页岩气年产100×10~8 m~3、其后又用2年时间实现了年产200×10~8 m~3的历史性跨越;③在页岩气资源方面,明确了四川盆地中浅层海相页岩气是产业发展的"压舱石",而深层海相页岩气则是未来产量增长的主体,以川南海相页岩为重点具备还可探明页岩气地质储量超6×10~(12) m~3的资源条件,可以支持页岩气产量持续快速增长。结论认为,通过加快对于埋深3 500～4 000 m页岩气资源的开发,2025年全国页岩气年产量可以达到300×10~8 m~3;考虑到埋深4 000～4 500 m页岩气资源开发突破难度较大,2030年页岩气有望落实的年产量为350×10~8～400×10~8 m~3。

Development progress,potential and prospect of shale gas in China

As the largest shale gas production country outside North America, China has built a yearly shale gas production scale of 200×10⁸ m³ in marine shale areas above 3 500 m, with the continuous and rapid advancement of shale gas exploration and development. The continuous production stabilization and increase of shale gas above 3 500 m and the development potential of deep shale gas below 3 500 m all over the country in the future are not only the premise to evaluate and judge the development potential and development prospect of shale gas resources in China, but also the key to determine whether the "Natural Gas Daqing" can be built up in Sichuan-Chongqing area. By summarizing China's theoretical understanding and engineering technological development achievements on shale gas, this paper analyzes the development potential of shale gas resources and predicts the future development prospect. And the following research results were obtained. First, as for the theoretical system of shale gas, the enrichment mechanism and the formation condition of shale gas in marine deepwater shelf graptolite black shale is clarified, the geological theory of "sweep spot area" and "sweet spot section" is established, the theory of shale gas development based on "artificial gas reservoir" is preliminarily set up, and the microfracture development and overpressure shale gas enrichment and high yield pattern of high quality deep shale in good conserved condition with great thickness in the southern Sichuan Basin is established. Second, as for shale gas engineering technology, cross-generation development of key engineering technologies (e.g. multi-stage fracturing of horizontal well) has been achieved, and with the support of which, China achieved a yearly shale gas production of 100×10⁸ m³ in just six years and realizes a historical leap of yearly production of 200×10⁸ m³ in two years. Third, as for shale gas resources, it is clarified that middle-shallow marine shale gas in the Sichuan Basin is the "ballast" of industrial development and deep marine shale gas is the main part for production increase in the future. It is estimated that China has the resource conditions for proved recoverable shale gas geological reserves of exceeds 6×10¹² m³ with the focus on the marine shale in the southern Sichuan Basin, which can support the continuous and rapid increase of shale gas production. In conclusion, the yearly shale gas production in China will reach 300×10⁸ m³ in 2025 by accelerating the development of shale gas resources in a burial depth of 3 500-4 000 m. And in view of the difficulty in breaking through the development of shale gas resources in a burial depth of 4 000-4 500 m, the yearly shale gas production is expected to rise to 350×10⁸-400×10⁸ m³ in 2030.