ASR法地应力测量中的岩石非弹性应变恢复柔量研究

Anelastic strain recovery (ASR) is a method to obtain deep three dimensional in situ stress in recent years. The magnitudes of in situ stresses by ASR method are determined by the anelastic recovery strains of unloading rock cores and the anelastic strain recovery complicances of rocks. Where the testing methods and results on site of anelastic recovery strains are relatively consummate and accurate. However, the anelastic strain recovery complicances of rocks are estimated at present stage. So research on anelastic strain recovery compliances of different type rocks is the key to improve ASR in situ stress measurement method.The relationship between anelastic strain recovery compliances and stress, load persisting time and repeated loadinig and unloading will be considered with the cores of scientific drilling boreholes. The anelastic strain recovery compliances of different type rocks and the ratio of shear to volume mode anelastic strain recovery compliances will be determined. The theoretical mechanics model of anelastic strain recovery will be built basing on the statistical methods. Research on this topic has important theoretical and practical value for improving ASR stress measurement methods and promoting the study of deep in situ stress measurement method.

非（滞）弹性应变恢复（ASR）法是近年快速发展起来的适用于深部的三维地应力测量方法。在ASR法地应力测量中，原地应力大小的确定取决于卸荷后岩芯的非弹性恢复应变和岩石的非弹性应变恢复柔量，前者的测试手段和结果目前已相对完善和准确，而后者尚处于经验估算阶段，因此岩石非弹性应变恢复柔量的研究是完善ASR地应力测量方法的关键。本项目拟以科学钻孔岩芯作为研究样品，通过不同应力、载荷持续时间及重复加卸载对岩石非弹性恢复变形影响的实验研究，确定不同岩石非弹性应变恢复柔量以及剪切与体积模式恢复柔量的比值，并在统计的基础上，建立岩石非弹性应变恢复的力学模型。本项研究对完善ASR地应力测量方法及推动其在深部原地应力研究具有重要的理论意义和实用价值。

非（滞）弹性应变恢复（ASR）法是近年快速发展起来的适用于深部的三维地应力测量方法。通过典型岩石的非弹性恢复柔量实验研究，获取了不同岩性的剪切模式非弹性恢复柔量Jas(t) 和体积模式非弹性恢复柔量Jav(t)及二者的比值Jas(t)/Jav(t)随时间的函数关系，为ASR地应力测试方法的应用提供了基础数据。成功将ASR地应力测试方法应用于深部油气钻孔地应力测量，取得了塔里木盆地7km深部地应力数据，结果表明塔里木盆地6 293～6 955 m 深度范围内最大主应力近垂直，中间和最小主应力近水平，最大水平主应力方向在N E 51°～79°范围。在区域挤压构造环境下，塔里木盆地内部存在与碰撞造山后应力松弛或构造旋转逃逸引起的正断层应力环境。通过与钻井诱发张裂缝（DITF）法所确定的地应力大小和方向信息进行对比，验证了ASR地应力测试方法的精度和可靠性。为该方法获取地壳深部地应力数据提供了可能，预期ASR地应力测试方法将在干热岩、深部油气等高温高压（常规地应力测试方法，如水压致裂法无法实施）钻孔地应力测试工作中具有广阔的应用前景。