页岩气储层的渗吸动力学特性与水锁解除潜力

发布时间：2018-06-25 00:41

本文选题：页岩气 + 水锁解除　；参考：《中国科学:物理学力学天文学》2017年11期

【摘要】：大规模水力压裂是页岩气成功开发的关键技术,上万方的压裂液被注入地层,而返排率往往低于30%.根据常规油气相关理论,外来流体进入基质孔隙会引起强烈的水锁伤害.但实践中大量压裂液滞留在页岩储层中并未引起严重水锁,部分井的产能随着滞留量的增加反而升高,这说明页岩气储层具有水锁解除的能力.本文基于页岩气储层压裂液渗吸问题开展实验,分析了水与页岩相互作用以及引起的动力学效应,研究渗吸特性与储层水锁解除潜力之间的关系.压裂液通过渗吸作用进入基质产生复杂物理化学作用.页岩的渗吸能力、扩散能力、渗吸水诱发裂隙能力是影响页岩气储层水锁解除潜力的主要因素,储层能量补充、渗吸液向基质深部的扩散、水岩反应产生的微裂隙等是水锁解除的主要机理.提出了以初始含水饱和度、渗吸能力、扩散能力、吸水诱发微裂隙和黏土化学作用等为主要评价参数的水锁解除潜力评价方法,利用自发渗吸、核磁共振与脉冲渗透率测试评价水锁解除潜力.通过该方法对典型页岩气储层的水锁解除潜力进行了分级评价,该研究深入分析了页岩气储层水锁解除机理及控制因素,对页岩气储层压裂改造具有指导意义.
[Abstract]:Large-scale hydraulic fracturing is the key technology for the successful development of shale gas. According to conventional oil and gas theory, the entry of foreign fluids into matrix pores can cause severe water lock damage. However, in practice, a large number of fracturing fluids have not caused serious water lock in shale reservoir, and the productivity of some wells increases with the increase of retention, which indicates that shale gas reservoir has the ability to release water lock. Based on the experiment of permeability and suction of fracturing fluid in shale gas reservoir, this paper analyzes the interaction between water and shale and its dynamic effect, and studies the relationship between permeability characteristics and reservoir water lock release potential. Fracturing fluid enters the matrix through osmotic suction to produce complex physicochemical effects. The permeability, diffusion ability and induced fissure ability of shale gas reservoir are the main factors that affect the water lock release potential of shale gas reservoir. The microcracks produced by water rock reaction are the main mechanism of water lock release. An evaluation method for the potential of water lock removal is proposed, which takes the initial water saturation, the permeability, the diffusion capacity, the water absorption induced microfissures and the chemical action of clay as the main evaluation parameters, and the spontaneous infiltration is used to evaluate the potential of the release of the water lock. Nuclear magnetic resonance (NMR) and pulse permeability test were used to evaluate the potential of water lock release. Through this method, the water lock release potential of typical shale gas reservoirs is graded and evaluated. The mechanism and control factors of water lock release in shale gas reservoirs are analyzed in depth, which is of guiding significance for fracturing reconstruction of shale gas reservoirs.
【作者单位】：中国石油大学(北京)非常规天然气研究院;
【基金】：国家自然科学基金资助项目(编号:51490652)
【分类号】：TE312

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