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水力压裂模拟试验是认识裂缝扩展机制的重要手段,通过模拟地层条件下的压裂试验,可以对裂缝扩展的实际物理过程进行监测,并且对形成的裂缝进行直接观察。通过室内模拟实验可知:应力附加区作用范围通常在3倍~6倍井眼之间,先逐渐憋压到一个极值(即破裂压力),在这个区域内裂缝先起裂,在起裂之后存在一个压裂液蓄能的过程,然后裂缝再突破应力附加区;4块岩样产生的都是单一裂缝,裂缝形态类似,并符合力压裂裂缝起裂延伸机理,没有出现多裂缝扩展现象。
Hydraulic fracturing simulation test is an important means to recognize the mechanism of crack propagation. By simulating the fracture test under formation conditions, the actual physical process of crack propagation can be monitored and the fractures formed can be directly observed. Through the indoor simulation experiment, it can be seen that the action range of the stress-added zone is usually between 3 times and 6 times the borehole. The pressure gradually increases to an extreme value (ie, the rupture pressure). Cracks first crack in this area. There is a process of energy storage in the fracturing fluid, and then the fractures break through the stress-added zone. All the four rock samples produced single fractures with similar fracture morphology and coincided with the initiation and extension mechanism of fracturing fractures, and no multi-fracture propagation phenomenon occurred .