构造裂缝产状演化规律表征方法及其应用

Method for the Characterization of the Evolution of Tectonic Fracture Attitudes and Its Application

针对构造裂缝产状演化规律难以准确定量表征的问题,通过确定研究区裂缝力学性质、岩石力学参数,在恢复古构造形态的基础上,对裂缝形成时期古应力场数值模拟后选择适用性的岩石破裂准则,预测裂缝形成时期的产状分布。提出了造缝期应力场预测古裂缝产状,后期构造活动改造裂缝产状的思路,即通过早期岩层、晚期岩层的三维空间变化规律,建立了不同构造活动时期对应的裂缝空间转换理论模型,利用推导的数学算法,定量分析裂缝的演化规律,进而提高了现今裂缝产状的预测精度。最后,以铜城断裂带东翼阜二段储层为例进行了构造裂缝演化规律定量描述工作,结合构造演化,将阜二段储层构造裂缝演化分为阜宁运动晚期裂缝形成发育、戴南运动期裂缝继承发展、三垛运动期裂缝差异分离3个阶段。

It has been difficult to approach an accurate and quantitative characterization of the evolution of tectonic fracture attitudes.By defining the mechanical properties of fracture and the mechanics parameters of rocks,and on the basis of restoration of the paleo-tectonic morphology,an optimal failure criterion has been selected after the numerical simulation of paleo-stress field during the fracturing,to predict the occurrence and distribution of fractures.This brings forward a new idea to predict paleo-fracture occurrence by paleo-fracture stress field and the fracture was reconstructed by the late tectonic activity.That is,through the three-dimensional spatial variation rule of rock strata of early and late stage a theoretical fracture transformation space model was established,which is corresponding to different tectonic active period.By utilizing the mathematical derivation of the algorithm and quantitative analysis of evolution of fracture,the prediction accuracy of the fracture occurrence is improved.In the end,the Fu-2 Member reservoir in the eastern flank of Tongcheng fault zone is taken as an example for the quantitative prediction of attitudes evolution of structural fracture.Combined with tectonic evolution,the tectonic fracture evolution can be divided into three stages：the Late Funing movement and formation of fracture,the Dainan movement and fracture development,the Sanduo movement and fracture separation.