循环荷载下支撑剂的变形及渗透特性试验研究

发布时间：2018-05-30 03:11

本文选题：循环荷载 + 导流能力　；参考：《岩土力学》2017年S1期

【摘要】：针对页岩气井多段压裂过程中人工裂缝的应力阴影效应及生产过程中采气停采引起的变化荷载伤害裂缝导流能力的问题,以陶粒支撑剂为研究对象,采用DL-2000型裂缝导流仪,开展了循环荷载条件下不同铺砂厚度支撑剂的变形及渗透特性实验研究。结果表明,随着循环次数的增加,弹性应变基本稳定,塑性应变持续产生,后者是导致渗透率持续降低的根本原因;塑性应变与永久渗透率损失随闭合压力的变化趋势吻合良好;弹性应变和可恢复渗透率损失随闭合压力的增大而增大,弹性应变随铺砂厚度增大而减小,可恢复渗透率损失随铺砂厚度增大无显著变化;随着铺砂厚度的增大,支撑剂层应力敏感性减弱,颗粒破碎程度降低。适当增加铺砂厚度能有效减小裂缝宽度及渗透率损失,降低循环荷载对导流能力的伤害程度。
[Abstract]:Aiming at the stress shadow effect of artificial fracture during multistage fracturing of shale gas well and the problem of damage to fracture conductivity caused by changing load caused by gas recovery and stopping production during production, this paper takes ceramsite proppant as research object and adopts DL-2000 fracture diversion instrument. The experimental study on deformation and permeability of proppant with different sand spreading thickness under cyclic load was carried out. The results show that with the increase of cycle times, elastic strain is basically stable and plastic strain continues to produce, the latter is the fundamental cause of the continuous decrease of permeability. The change trend of plastic strain and permanent permeability loss with closure pressure agrees well, the elastic strain and recoverable permeability loss increase with the increase of closing pressure, and the elastic strain decreases with the increase of sand laying thickness. The loss of recoverable permeability does not change significantly with the increase of sand laying thickness, but with the increase of sand laying thickness, the stress sensitivity of proppant layer weakens and the degree of particle breakage decreases. Properly increasing the sand laying thickness can effectively reduce the fracture width and permeability loss and reduce the damage degree of circulation load to the conductivity.
【作者单位】：重庆大学煤矿灾害动力学与控制国家重点实验室;重庆大学复杂煤气层瓦斯开采国家地方联合工程实验室;
【基金】：国家重点基础研究发展计划(973)(No.2014CB239206) 国家自然科学基金青年基金项目(No.51404045) 长江学者和创新团队发展计划(No.IRT13043)~~
【分类号】：TE377

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