正反转构造的成因类型

Genetic Types of Positive Inverted Structures

正反转构造有压扭型、挤压倾滑型、走滑诱导型和重力滑动型4种力学成因类型。压扭型是指张扭断层因受力方式变为压扭所产生的与扭动断层小角度相交的正反转构造;挤压倾滑型是先存拉张构造受到后期垂向挤压作用所形成的;走滑诱导型是指走滑断裂带内局部压应力场的产生所形成的与走滑断层近似直交的正反转构造;重力滑动型是指盆地差异沉降,断块掀斜翘起,重力作用使沉积物沿滑脱面滑移、扩展所形成的。绝大多数正反转构造产生于张性盆地演化的反转期,即张应力场转变为压应力场的时期。论述了各类正反转构造的平面和剖面识别标志,并用实例对每类正反转构造的特征进行了分析论证。阐述了正反转构造与油气生成、运移和聚集的空间配置关系。

Positive inverted structures can be calssified into four genertic types They are the positive inverted structure associated with compression-wrench fault(CW), with compression-dip-slip fault(CDS), with strike-slip (SS) and with gravity sliding(GS) The CW is the positive inverted structure which is developed during the time of the compression-wrench stage of extension-wrench fault and which intersects wrench fault with a small angle, and the CDS developed during the time of the dip-compression stage of pre-existing structure The SS forms within the local stress field that occurs in strike-slip fault zone and that is nearly orthogonal to strike-slip fault. The GS results from sliding and propagation of Sediment along gliding surface as differential subsidence and tilting of blocks The mechanisms, and the profile and planar identifying indications of every structures are dealt with, and the characteristics of each positive inverted structure is demonstrated with examples in present paper Most of positive inverted structures which occur at the inverting stage of extensional basin are generally located above the oil-generating depression, thus they have a good spatial disposition with petroleum origin, migration and accumulation Since the distribution of these structures have regular spatial pattern, the structural traps associated with them have also regular distribution pattern. To these structures that occur at the special stress field, the genetic investigation is useful to understand the distribution of the positive inverted structures, as well as the stages and characteristics of the evolution of extensional basin.