冲击载荷致裂含水合物地层的模拟实验研究

SIMULATED EXPERIMENTAL STUDY OF IMPACT FRACTURING OF HYDRATE-BEARING SEDIMENTS

  • 摘要: 在我国天然气水合物的第二轮试采中,采用了水平井多级射孔改造储层的方式提高了开采效率,为水力压裂技术的应用揭示了前景。但射孔对水合物地层的损伤效果和对压裂结果的影响尚不明确,还需要进一步研究。为此开展了模拟含水合物地层冲击压裂的实验研究。进行了射弹和重物贯入两类实验,利用冻土模拟了含水合物地层在冲击作用下产生裂缝的物理过程,分析了射孔冲击提供的能量与裂缝面积的转化规律,发现射孔冲击的加载速度越大越有利于开裂;提供的总能量越大、作用时间越短,越有利于地层开裂并产生更大的裂缝面积,但目前的实验中能量转化为裂缝的效率不高,有待进一步研究。

     

    Abstract: In the second round of test mining of natural gas hydrates in China, multi-stage perforation injection with horizontal wells was used to improve the extraction efficiency, which reveals the prospect for the application of hydraulic fracturing technology. However, the effect of perforation in hydrate-bearing sediments is still unclear and needs further study. Therefore, experimental studies to simulate impact fracturing in hydrate-bearing sediments have been carried out through two types of experiments: perforation and impact of falling weights. Through these experiments, the transformation law of the energy provided by the impact and the fracture area was analyzed, and it was found that the larger the loading speed of the impact was the more favorable to cracking; the larger the total energy provided and the shorter the time of action were, the more favorable to cracking the strata and generating a larger fracture area, but the efficiency of the energy transformed into fracture in the current experiments was not high, which needs to be further researched.

     

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