摘要
构造应力场研究对于油气运聚分析及储层特征描述具有重要的理论和实际意义。本文根据塔中隆起断裂特征及其演化史,结合钻井资料,选择中下奥陶统碳酸盐岩为主要研究对象,应用大型有限元分析软件ANSYS,在处理断层问题时运用非连续的接触算法,模拟了中奥陶世末、中泥盆世末、三叠纪末、新近纪末的构造应力场,研究了该区不同时期的古应力分布特征。研究表明,最大主压应力受东部车尔臣-星星峡走滑断裂影响显著,在隆起区沿断裂带呈条带状低值分布,在不同时期塔中Ⅰ号断裂带无一例外地位于最大主压应力的最低区,反映了塔中断裂带尤其是塔中Ⅰ号断裂带是油气运移的有利指向区。最小主压应力沿断裂带呈条带状高值分布,在断裂的上盘、断裂走向发生变化和断裂的倾末端是张应力高值区,为张裂缝发育的重要构造部位。最小主压应力和最大剪应力受车尔臣-星星峡走滑断裂的影响明显减弱。
The research of tectonic stress field is theoretical important and practical significant for petroleum migra- tion and accumulation, reservoir characteristics description and crack formation analyses. The widely-used finite el- ement analysis software (ANSYS) was applied to simulate tectonic stress field of the end of Middle Ordovician, Middle Devonian, Triassic and Neogene, based on the characteristics and evolution history of faults combined with well drilling data in the Tazhong uplift, with emphasis on the Middle-Lower Ordovician limestone. When faults are concerned, the discontinuous contact algorithm was selected to simulate the kinematic and dynamic characteristics of faults, which was also preferred by previous researches, and indeed discontinuous model is a better choice for fault modeling. On the base of structural analysis, the faults were divided into two stages, and two geological models were established. In the four tectonic events, different boundary conditions were imposed. The research indi- cates that the maximum compressive principal stress, which was affected markedly by the eastern strike-slip fault named Cherehen-xingxingxia, presents strip-shaped and low-value distribution along faults zone in uplift area. Tazhong 1^st fault always had the minimum value of the maximum compressive principal stress in all of the tectonic stages, which reflects the Tazhong fault zone-especially the 1 s, fault-was a well-directed area for hydrocarbon migra- tion. The minimum compressive principal stress was banded in high-value along faults zone. The hanging wall of fault was the high-value area of tensile stress and easy to form tensile cracks. The turn and the end of the faults were also the high-value area of tensile stress and important structure position of tensile cracks development. The effect on the minimum compressive principal stress and maximum shear stress was weakened from Cherchen-xingx- ingxia strike-slip fault.
出处
《大地构造与成矿学》
EI
CAS
CSCD
北大核心
2012年第2期168-175,共8页
Geotectonica et Metallogenia
基金
国家科技重大专项"海相碳酸盐岩油气资源潜力
富集规律与战略选区"(2008ZX05005-001-001)
中国石化科技部"塔里木台盆区构造演化对油气成藏控制研究"(P06019)项目资助
关键词
塔中
构造应力场
有限元
数值模拟
非连续
Tazhong
tectonic stress field
finite element
numerical simulation
discontinuous