深层页岩气分段压裂技术现状及发展建议

Present Situations and Prospects of Multi-Stage Fracturing Technology for Deep Shale Gas Development

中国深层页岩气资源潜力巨大,近年来少数探井产气量取得了突破,但大多数探井页岩储层压后产气量低且递减快,达不到经济开发要求,总体上还未形成深层页岩气商业开发的格局。在总结分析Haynesville区块和Cana Woodford区块深层页岩地质特征、压裂工艺技术特点、压裂材料及工程成本的基础上,分析了国内外深层页岩可压性的差异,指出国外深层页岩气地层的孔隙度、含气量、脆性指数和地应力差等参数要远优于目前国内深层页岩气地层,认为良好的储层地质与工程条件、量身定制的压裂工艺技术以及较低的单井综合成本是实现深层页岩气经济开发的关键,提出了开展深层页岩网络裂缝形成机制研究,高应力条件下大规模、高导流、体积压裂技术研究以及耐高温、低摩阻压裂流体体系研究等技术攻关的建议,以尽快形成适合中国深层页岩气开发要求的配套压裂技术,促进中国各个深层页岩气区块实现商业化开发。

China possesses great potential in deep shale gas reserves and some breakthroughs have been achieved in some exploration projects in the past few years.However,most of shale wells are characterized by low productivity and rapid production decline after fracturing.Accordingly,these exploration wells may not attain the requirements for economic development.Under such circumstances,commercial development of deep shale gas in China is still in its preliminary stages.In this paper,geologic features,fracturing techniques,materials,and engineering costs related to deep shale gas development in the Haynesville and the Cana Woodford were reviewed to highlight differences in fracturing operations for deep shale gas development inside and outside China.Research results show that some big difference exisits among porosityies,gas contents,brittleness,stress difference and other parameters of deep shale gas reservoirs.Favorable geologic and engineering conditions,together with tailor-made fracturing techniques and low overall costs of individual wells can be as crucial keys for economic development of deep shale gas.To accelerate the commercial development of deep shale gas reservoirs in China,it is necessary to conduct in-depth studies for formation of fracture networks in deep shale,development of large-scale,high-conductivity,volumetric fracturing techniques under high geo-stress contrast and for the development of temperature and friction-resistant fracturing fluid systems to clearly identify fracturing techniques suitable for development of deep shale gas in China.