准噶尔盆地南缘东湾背斜构造几何学和运动学

Geometries and Kinematics of the Dongwan Anticline in the Southern Junggar Basin

利用三维地震数据体进行东湾背斜区域的构造解释工作,通过生长地层分析得到其发育时间为古近纪安集海河组时期,形成机制为翼部旋转机制滑脱褶皱。面积-深度-应变法分析结果显示滑脱层位于深度为~9 km的下侏罗统八道湾组中,褶皱主要受平行层纯剪切控制以及部分地层弯曲调节变形。背斜带核部位移量可达1239m,且构造带位移量的分配主要有两种方式,为滑脱褶皱的生长以及褶皱调节断层的发育。东湾背斜两翼发育有丰富的褶皱调节断层,构造带不同位置处为褶皱调节断层发育的不同阶段,且调节断层随褶皱生长会向上及向下传播,传播方向取决于软弱层的发育和其厚度。此外,褶皱调节断层的发育可能为东湾1井没有钻获到油气资源的重要原因。

In this paper,the structural interpretation of the Dongwan anticline is carried out by using the three-dimensional seismic data.Growth stratigraphic analysis shows that the development time is the anjihaihe formation period in the paleogene,and the formation mechanism is the detachment folding of wing rotation.The results of the area-depth-strain analysis show that the detachment is located in the lower Jurassic badaowan formation with a depth of~9 km,and the folds are mainly controlled by the pure shear of parallel layers and some curving accommodation.The displacement of the anticline core can reach to 1239 m,and there are two main ways to distribute the displacement of the structural belt:the growth of the detachment fold and the development of the fold-accommodation faults.The two wings of the Dongwan anticline are rich in fold-accommodation faults.The different positions of the structural belt are different stages of fold-accommodation faults,and the faults will spread upward and downward with the growth of folds.The propagation direction depends on the development of the soft layer and its thickness.In addition,the development of fold-accommodation faults may be an important reason why oil and gas resources have not been drilled in Dongwan1 well.