ANSYS曲壳模型计算复杂断块现今地应力场

DETERMINING THE CRUSTAL STRESS FIELD USING ANSYS CURVED SHELL MODEL

中原油田属于复杂断块油气田 ,断层多 ,地层倾角大。地应力异常导致套管不断发生缩径变形或错断等情况 ,从而缩短了油气水井的寿命。为了从根本上解决套管损坏问题 ,就必须对地应力进行定量及定性研究。应用有限元算法中的曲壳模型模拟计算了地层中正在活动着的构造应力场 ,经过计算分别绘出了地层最大、最小水平主应力图 ,得出地层水平主应力最大值与最小值相差较大的区域及地应力变化较大的边界区域是套管容易发生损坏的地区。该方法可快速准确地模拟地质真实情况 ,目前已广泛应用到套管损坏的预防和治理工程当中。

Zhongyuan Oilfield belongs to complex block Oilfield, which features multiple fault blocks and high formation dip angle. The abnormal crustal stress causes casing shrinking deformations or breaks frequently, and this in turn shortens the well life. A qualitative and quantitative study is conducted, aiming at resolving the problem of casing damage from the root. Using the Curved Shell Model of the Finite Element Method, the stress field of the active structures in the formation is simulated, and the maximum and minimum horizontal main stress maps are drawn accordingly. It is concluded that the area with relatively large difference between the maximum horizontal main stress and minimum horizontal main stress, and the boundary areas with dramatic stress changes are subject to casing damage easily. This method can be used to simulate the real geological conditions quickly and accurately, and it has been widely used for the prevention and treatment of casing damage.