页岩气井体积压裂技术在我国的应用建议

页岩气因其储层渗透率超低、气体赋存状态多样等特点,决定了采用常规的压裂形成单一裂缝的增产改造技术已不能适应页岩气藏的改造,必须探索研究新型的压裂改造技术,方能使其获得经济有效地开发。为此,在总结分析美国页岩气储层的岩性、物性、天然裂缝与力学性质特征的基础上,依据复杂裂缝形成机理,提出了压裂形成复杂缝网、增大改造体积的基本地层条件的观点,归纳了直井和水平井体积压裂改造工艺技术方法等。实践表明:页岩气储层获得体积压裂后不仅初期产量高,而且更有利于长期稳产;在我国压裂增产改造将是开发页岩气最重要的技术手段。建议分海相、陆相两大类型开展体积压裂适应性、体积压裂优化设计技术与实施工艺技术、压后监测与评估技术等攻关研究。

Proposals for the application of fracturing by stimulated reservoir volume(SRV)in shale gas wells in China

Due to ultra low permeability and various states of gas occurrence, shale gas reservoirs require a large fracture network to maximize well performance. In shale reservoirs, where complex network structures in multiple planes are created, the concepts of single fracture half length and conductivity are insufficient to describe stimulation performance. Based on an analysis of lithologic, petrophysical, mechanical properties, and natural fractures of shale gas reservoirs in the USA, this paper introduces what is the concept of using stimulated reservoir volume (SRV) as a correlation parameter for well performance and summarizes how the SRV fracturing methods affects production acceleration and ultimate recovery of vertical and horizontal shale gas wells. From American field practices, we learn that the SRV can not only accelerate the early stage productivity but maintain steady production of the ultralow permeability shale gas reservoirs. Moreover, we suggest that key projects on the adaptability of SRV fracturing, optimal fracture design and operation, post frac monitoring and assessment should be performed respectively in the marine facies and continental facies shale gas development.