In this paper we present the results of a fine structural geometric analyses of the seismic reflection profiles across the Dongying depression, where half-graben structures display the features of kink-band deformation and extensional fault-bend fold.

It is suggested that the classification of extensional folds incorporates both axial trend and mechanism of folds.

Based on theories and methods of fluid migration/sealing in fault zones, the hydrocarbon migration and accumulation behavior in fault-bend folds and fault-propagation folds is discussed, taking example by Kuqa foreland thrust belt of Tarim basin in this paper.

Fault-bend folds and fault-propagation folds are typical structural styles in the foreland thrust belts.

Normal deductive method is used to study the variation regularity of early fissure attitude in the area with superposed flexural folds.