氧化爆裂提高页岩气采收率的前景

发布时间：2019-03-03 15:03

【摘要】：水平井分段压裂技术利用水力作用打碎页岩,形成缝网,以提高页岩气井的产量,但压裂液滞留造成的水相圈闭会影响改造效果。为此,考虑页岩中有机质、黄铁矿等组分易氧化的特征,基于"矛盾转化,变害为利"的思路,探讨了将压裂液滞留这一不利因素转化为改变气体赋存状态、激发页岩破裂的有利条件的方法,并分析了该方法在解决页岩气层水力压裂液滞留量大、损害潜力大、气井产量递减快、页岩气采收率低等问题中的应用前景。页岩有机质、黄铁矿氧化后会产生大量溶蚀孔缝,提升基块孔喉向裂缝系统的供气能力,同时氧化过程释放热量、增加孔隙压力可使岩石爆裂,诱发页岩微裂缝扩展、延伸,增加泄流面积、缩短基块内气体传输路径,从而达到解除损害、提高采收率的目的。该方法在现有水力压裂液中加入氧化流体,不仅可以利用现有水力压裂技术的水力作用"打碎"页岩,而且还可以利用氧化化学作用"爆裂页岩"。结论认为,该方法可以对页岩气藏传统的水力压裂方法形成有益的补充,在实现降本增效、页岩气井高产稳产与提高页岩气采收率方面具有广阔的应用前景。
[Abstract]:Horizontal well segmented fracturing technology uses hydraulic action to break shale and form fracture net in order to increase the production of shale gas well, but the water-phase trap caused by fracturing fluid retention will affect the improvement effect. Therefore, considering the characteristics of easy oxidation of organic matter and pyrite in shale, and based on the idea of "contradictory transformation, changing harm to benefit", the unfavorable factor of fracturing fluid retention is discussed to change the state of gas occurrence. The application prospect of this method in solving the problems such as large retention of hydraulic fracturing fluid in shale formation, great potential of damage, rapid decline of gas well production and low recovery of shale gas is also discussed in this paper. The advantages of the method are as follows: (1) the advantages of the method are to stimulate shale fracture, and the application prospect of this method is also analyzed. Shale has organic substance. After oxidation of pyrite, a large number of dissolved pore cracks will be produced, which will enhance the gas supply capacity of the pore throat fracture system of the block. At the same time, the oxidation process will release heat and increase pore pressure can cause rock burst and induce the expansion and extension of microfractures in shale. The discharge area is increased and the transmission path of gas in the block is shortened so as to relieve the damage and improve the recovery rate. By adding oxidation fluid to the existing hydraulic fracturing fluid, not only the hydraulic action of the existing hydraulic fracturing technology can be used to "break" the shale, but also the oxidation chemistry can be used to "burst the shale". It is concluded that this method can complement the traditional hydraulic fracturing method of shale gas reservoir, and has broad application prospects in the aspects of reducing cost and increasing efficiency, high and stable production of shale gas well and improvement of shale gas recovery.
【作者单位】： "油气藏地质及开发工程"国家重点实验室·西南石油大学;国家能源页岩气研发(实验)中心;
【基金】：国家自然科学基金项目“富有机质页岩氧化致裂增渗加速气体传输机理研究”(编号:51674209) 非常规油气层保护四川省青年科技创新团队项目(编号:2016TD0016)
【分类号】：TE37

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