An algorithm is developed to estimate maximum and minimum horizontal stress using experimental data from sleeve fracturing experiments. The algorithm is developed by analyzing the crack initiation, propagation and interaction behavior between primary and secondary cracks based on the Finite Element Method with Cohesive Zone elements. Five key quantities can be obtained from data curves and comprise the basis of the algorithm in a manner consistent with an approximate model based on stress analysis around the borehole. The algorithm has been validated by 100 synthetic data cases covering various parameter combinations. Moreover, quantifying the degree of uncertainty in the stress prediction indicates strongest dependence on detecting when the borehole deformation from the first fracture(s) is impacted by growth of secondary fracture(s). Validity based on simulated data motivates new methods for high resolution strain sensing during sleeve fracturing especially for the purpose of accurately detecting secondary fracture initiation.

开发了一种算法来估计最大和最小水平应力，使用来自套筒压裂实验的实验数据。该算法是通过基于有限元方法与内聚区单元分析初级裂纹和次级裂纹之间的裂纹萌生、扩展和相互作用行为而开发的。五个关键量可以从数据曲线中获得，并以与基于钻孔周围应力分析的近似模型一致的方式构成算法的基础。该算法已通过涵盖各种参数组合的 100 个合成数据案例进行验证。此外，量化应力预测中的不确定性程度表明，当第一次裂缝的钻孔变形受到二次裂缝增长的影响时，对检测的依赖性最强。