Observation of core discing and in situ stress measurements; Stress criteria causing core discing
Observation of core discing and in situ stress measurements; Stress criteria causing core discing
复制标题
DOI：
10.1007/bf01020150
复制
发表时间：
1995-07
影响因子：
6.2
通讯作者：
T. Ishida;T. Saito
中科院分区：
文献类型：
--
作者：
T. Ishida;T. Saito
日本北海道 Horonai 煤矿古近纪砂岩深度 1055 m 的近水平孔钻取的岩心中通常会观察到岩心旋裂。我们观察了盘状和环状岩心，并测量了它们回收处的原位应力。我们将测得的应力状态与基于 Obert 和 Stephenson (1965) 的核心切割经验标准以及基于 Sukawara 等人的理论标准进行了比较。 （1978）以及石田和斋藤（1989）。因此，我们发现盘状岩心在比这两个标准预测的应力状态更低的应力状态下恢复。环状岩心恢复后的应力状态满足经验标准，但低于理论标准的临界应力状态。这些差异表明现有的应力标准并不令人满意，需要进一步的实验、理论和现场研究。
Core discing was typically observed in cores recovered from near horizontal holes drilled in Palaeogene sandstones at a depth of 1055 m in the Horonai colliery, Hokkaido, Japan. We have observed disc- and ring-like cores and measured in situ stress where they were recovered. We compared the measured stress state with an empirical criterion of core discing based on Obert and Stephenson (1965) and a theoretical criterion based on Sugawara et al. (1978) and Ishida and Saito (1989). Consequently, we found that disc-like cores were recovered under lower stress state than predicted by both criteria. The stress state where ring-like cores were recovered satisfied the empirical criterion, however, it was below the critical stress state according to the theoretical criterion. These discrepancies indicate that existing stress criteria are not satisfactory and that further experimental, theoretical and field investigations are needed.