地应力场边界条件最优化数值模型及求解方法研究

STUDY ON OPTIMIZATION NUMERICAL MODEL AND SOLUTION METHOD FOR EARTH STRESS FIELD BOUNDARY VALUE

地应力场对于油气田勘探开发方案设计、油气增产措施评价具有非常重要的意义,构造应力的确定对于地应力场分布的研究极为关键。文章在考虑了力学模型、几何模型以及平衡方程基础上,应用叠加原理把地应力场求解转化为对构造应力边界值确定的问题,提出了求解边界构造应力的最优化数值模型。该模型所确定的最优化方程组个数远多于求解的未知数,因此应用正则化理论建立了不同的应力边界条件适定方程组并给出该方程组的求解方法。最后,通过建立的验证模型计算表明,文章所提出的最优化数值模型能够计算出合理的构造应力边界值,为建立区域构造应力场的边界载荷提供依据。

Earth stress field has very important significance for the design of oilfield exploration and development procedure,and evaluation of well stimulation efficiency,the determination of tectonic stress is crucial to study of earth stress field distribution.In consideration of mechanics model,geometric model and equilibrium equation and by applying the superposition theorem,solution of earth stress field is transformed to determination of tectonic stress boundary value,and the optimal numerical model was proposed to solve tectonic stress boundary value.The numbers of optimal numerical equations defined by the model are far more than the unknowns,therefore,the well-posed equations to different tectonic stress boundary condition was established by applying regularization theory and the solving methods were given.At last,the calculation results of the verification model showed that the proposed numerical optimization model could calculate reasonable tectonic stress boundary value,and provided the basis of boundary loads for the regional tectonic stress field.