摘要
通过三轴压缩实验模拟地层埋藏过程中盖层韧脆性转变,通过三轴卸载实验模拟地层抬升过程中泥岩破裂过程。通过70个样品的三轴压缩测试实验,拟合出硬石膏、泥岩和泥灰岩3种岩性盖层由脆性向韧性转变的临界围压分别为68.5,81.35和92.35 MPa,折合埋深分别为4 029,4 782和5 429 m。通过对泥岩盖层的卸压实验拟合出盖层的破裂围压与主压应力的数学回归方程:y=2.929 6 x+134.28(R2=0.83)。该研究结果除了进一步证实泥岩在一定埋深下仍具有良好的塑性和封闭性能以外,还提供了研究盖层韧脆性转化和抬升过程中破裂边界的定量评价参数,为定量研究盖层有效性提供了基础。
The brittle-ductile transition process is simulated through triaxial compression test, and the breaking process is simulated through triaxial unloading test in this paper. The brittle-ductile transition threshold limit confining pressure of gypsum, mudstone and marlstone are gotten by triaxial compression test of 70 samples. They are 68.5, 81.35 and 92.35 MPa, respectively, which amount to buried depth of 4 029, 4 782 and 5 429 m, respectively. The mathematical relation between break confining pressure and principal compressive pressure is gotten by triaxial unloading test. The mathematical formula is y=2. 929 6 x＋134.28（R2 =0.83 ）. The study results not only prove that mudstone has plastic and sealing capability at certain buried depth, but also provide quantitative evaluation parameters of brittle-ductile transition and break limit condition of cap rock, which lay the foundation for quantitative evaluation on cap rock effectiveness.
出处
《石油实验地质》
CAS
CSCD
北大核心
2013年第5期574-578,586,共6页
Petroleum Geology & Experiment
基金
国家科技重大专项项目(2011ZX05005-001)
国家重点基础研究发展计划"973计划"项目(2012CB412800)
国家自然科学基金委项目(40739904)联合资助
关键词
三轴压缩实验
三轴卸载实验
脆韧性转变
封闭性
盖层
triaxial compression test
triaxial unloading test
ductile-brittle transition
sealing
cap rock
