缝洞型碳酸盐岩裂缝扩展分析

针对缝洞型碳酸盐岩水力裂缝转向问题，基于多孔介质流-固耦合基本方程和损伤力学基本理论，建立了缝洞型碳酸盐岩储层的裂缝扩展有限元模型并进行模拟分析，模拟发现：（1）水力裂缝遇到天然裂缝，逼近角越大，水力裂缝转向的极限水平主应力差越小；天然裂缝长度越长，极限水平主应力差越大。（2）水力裂缝遇到缝洞体，溶洞宽度越大，水力裂缝沿转向的极限水平主应力差越大；天然裂缝的逼近角越大，极限水平主应力差越小。（3）压裂裂缝遇到天然裂缝转向后，转向后的裂缝的宽度变小；水力裂缝遇到溶洞，裂缝总体宽度急剧下降。

The analysis of hydraulic fracture propagation in fracture-cavity carbonate reservoirs

In view of hydraulic fracture turning in fracture-cavity carbonate reservoirs, according to basic equations of fluid-solid coupling in porous medium and theory of damage mechanics, a finite element method model that is suit for hydraulic fracture in fracture-cavity carbonate reservoirs was built. A series of simulations were conducted. The results of stimulations as follow. (1) Hydraulic fracture encounter with natural fracture, the larger angle of intersection, the smaller the limit differential in-situ stresses. The longer natural fracture, the larger the limit differential horizontal in-situ stresses. (2) When hydraulic fracture encounter with fracture-cavity, angle of intersection increase, the limit differential horizontal in-situ stresses decrease. The width of cavity increase, the limit differential horizontal in-situ stresses increase. (3)The orientation of hydraulic fracture is turned, the width of turned fracture become small. The global width of hydraulic fracture decrease sharply when hydraulic fracture enter into cavity.