利用爆炸技术改善低渗透储层的实验研究

EXPERIMENT RESEARCH ON LOW PERMEABILITY RESERVOIR IMPROVED BY EXPLOSION TECHNOLOGY

为了更好地开发低渗透油气藏,首先介绍"层内爆炸"增产技术的基本思路,然后用水中炸药界面爆炸对水泥试样损伤破坏的实验来模拟水力裂缝"层内爆炸"增产中激波使岩石损伤开裂的现象。通过实验观察到3个损伤区域:压剪损伤区,拉伸损伤区和边界损伤区,并且微裂纹的启裂扩展与水泥试样的初始损伤有关。分析发现:压剪损伤区和拉伸损伤区内裂纹的密度与装药量相关;压剪损伤区和拉伸损伤区半径分别为装药当量半径的2～5和20～30倍;量纲分析表明,损伤区半径与装药当量半径成线性关系。通过简易渗透率实验,发现压实区有一定的渗透率,这对"层内爆炸"采油技术的研究具有重要意义。最后,定性分析激波在试样中的传播过程以及试样微裂纹的启裂扩展机制。

In order to exploit the low permeability reservoir effectively, the stimulation technology of exploding in fracture is introduced. By the experiment of exploding on the surface of the cement sample in deep water, the phenomenon of the formation rock damage and fracture by exploding wave is simulated. Through optimizing the experiment scheme, there are 3 damage zones are observed, namely, the compressive shear damage zone, the tension damage zone and the damage zone on the boundary~ and the initiation and propagation of the micro-fracture have a close relationship with the initial damage of the cement sample. The fracture density in the shear damage zone and tension damage zone has a relationship with the equivalent radius of the explosive load; and the scales of the compressive shear damage zone and the tensile damage zone are 2 - 5 times and 20 - 30 times of the equivalent radius of the explosive load respectively. By dimension analysis, it is found that the scales of the shear damage zone and the tension damage zone have a linear relationship with the equivalent radius of the explosive. By simple experiment, it is found that the compressive shear area has finite permeability, which has an important meaning to exploding in fracture. At last, the exploding wave propagation progress and the damage and fracture mechanism are both explained qualitatively.