在深处地质条件下,页岩的弹性和特征应力值
Xiaofang Nie1, Zidong Fan1, Qin Zhou1
1MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
Materials (Basel, Switzerland)
|October 14, 2023
概括
这项研究研究了在深层地质条件下的页岩机械特性. 增加深度会增加峰值偏差应力,而床位的方向会显著影响弹性模量,但不会影响波桑比率.
科学领域:
- 地质技术工程 地质技术工程
- 岩石机械学 岩石机械学
- 石油地质学 石油地质学
背景情况:
- 在现场地质条件显著影响页岩的机械性质.
- 目前对这些影响的理解,特别是对弹性和特征应力值的理解,仍然有限.
- 精确的表征对于页岩气储库开发至关重要.
研究的目的:
- 在深处现场条件下研究页岩的弹性和特征性应力值 (裂关闭,启动和损伤应力).
- 为了评估床铺平面方向和埋葬深度对这些机械性能的影响.
- 提出和验证一种新的方法来确定弹性参数和应力值.
主要方法:
- 开发和应用双向代近似 (BIA) 方法来确定弹性参数和应力值.
- 在Longmaxi页岩样本上进行三轴压缩实验.
- 在2000米和4000米的深度模拟与现场应力和温度条件相结合.
主要成果:
- 峰值偏差应力随着给定的床铺方向的深度 (从2000米到4000米) 增加.
- 弹性模块对床位平面的方向比埋葬深度更敏感.
- 波桑比率显示了与深度或床铺方向的最小变化.
- 在测试条件下,裂关闭应力 (σcc/σp) 和裂启动应力 (σci/σp) 的比率保持相对不变.
- 裂损伤应力 (σcd) 随深度显著增加,对深度的敏感性更大,对裂延伸有抑制作用.
结论:
- 采用BIA方法可以准确地确定页岩的机械性质.
- 床铺的方向和深度对页岩的弹性特性和应力值有明显的影响.
- 增加深度显著增加裂损伤应力,这表明更深处的岩石完整性得到了改善.
- 这些发现为构成性建模和页岩气储库的数值分析提供了必要的数据.
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