北大港构造带东翼华北期构造应力场模拟

通过对北大港构造带东翼对油气运聚影响较大的华北期(52~23.5 Ma)进行应力场模拟，结果表明，华北期构造运动的最大主压应力方向为近ESE向。华北期构造运动在北大港构造带东翼的构造剪应力值分布在18~42 MPa，大多分布在22~32 MPa，而在22~25 MPa间有较明显的梯度带，塑性变形后应力释放处，为构造裂缝发育区带。构造裂缝发育区NEE向的断层与华北期构造应力方向之间的夹角较小，开启性较好，有可能成为油气运移和聚集部位，但是也有可能成为油气散失的部位。结合现今构造应力场的模拟结果，综合分析认为构造剪应力值在22~25 MPa的构造发育区带内的ESE向的裂缝发育区带可能形成较好的油气藏，而ENE向的裂缝发育带则易成为现代油气散失的部位。

Simulation of tectonic stress field of the east of Beidagang tectonic belts in North China Tectonic Period

Through the simulation of tectonic stress field of the east limb of Beidagang tectonic belt in the North China Tectonic Period,the tectonic stress of this period has great influence to oil and gas migration and accumulation.The result of the simulation shows that the maximum principal compression stress direction is nearly ESE in North China Tectonic Period.The shear stress ranges from 18 to 42 MPa,most of them are between 22 and 32 MPa.While from 22 to 25 MPa,it has more apparent gradient belts and is a fracture zone in North China Tectonic Period at the east limb of Beidagang tectonic belt.The angle between the near E-W direction of faults and the tectonic stress direction of North China Tectonic Period is relatively small and the faults are opened better.It is probably the right place for the migration and accumulation of oil and gas but it can also cause the lose of oil and gas.Combined with the simulation results of the current tectonic stress field,the comprehensive analysis of shear stress value in that tectonic belt from 22 to 25 MPa indicates that the ESE orientation fracture zones can form a good reservoir,and ENE orientation fracture zone is easy to escape oil and gas.