基于三维构造恢复的地应力预测技术
The Stress Prediction Technique Based on 3D Structural Restoration

组合弹簧理论模型是预测地应力的一种常用方法，但模型忽略了对岩层各向异性的考虑，无法反映由于局部断层、裂缝发育等各向异性造成的应力局部扰动变化；对构造应力项的求取基于薄板理论，简单利用地层形变开展地应力预测，忽略了地质力学参数的空间变化。本文通过叠前弹性参数反演和精细构造解释对常规弹簧组合模型的构造应力项求取进行了优化，提出了基于三维构造恢复的地应力预测技术，从构造建模开展地质力学分析与构造恢复，求取现今地应力的古构造应力残余分量，提高了模型对地应力的预测精度，结果与实钻井具有较好的吻合性，并通过实际工区应用验证了该方法的有效性，对页岩气勘探选区评价、井位部署、钻后评价、水平井设计具有借鉴作用。
The composite spring model is a commonly used method for predicting the in situ stress. However, the model ignores the consideration of the anisotropy of the rock mass, which cannot reflect the stress disturbance caused by the anisotropy due to local faults, fractures, and other factors. Moreover, the calculation of the tectonic stress term is based on the thin plate theory, which simplifies the geological deformation and neglects the spatial variation of the geological mechanical parameters. In this paper, the construction stress term of the conventional spring combination model was optimized by using pre-stack elastic parameter inversion and refined tectonic interpretation. A 3D tectonic reconstruction-based in situ stress prediction technology was proposed, which analyzed the geological mechanics and tectonic reconstruction from the perspective of structural modeling. The residual tectonic stress component of the present-day stress was obtained, improving the prediction accuracy of the model for in-situ stress. The results have good consistency with actual drilling, and the effectiveness of the proposed method was verified by application in a practical working area. This method has reference significance for shale gas exploration zone evaluation, well deployment, post-drilling evaluation, and horizontal well design.