Abstract:

Abstract:  Two basic conditions are necessary for structural wedges forming: one is at least two connected fault segments that bound a triangular or wedgeshaped fault block, and the other is the contrary slip transfer directions of these two fault segments. When the backward slip cut through the overlying stratum, folds were formed on the forelimb of structural wedge, which can also be used as the direct evidence to infer the deep wedging. Structural wedges are very typical in the southern margin of Junggar Basin and exhibit a variety of shapes and styles imbricated each other out of sequence. In the east part of the Southern Junggar Basin, the deep structural wedges at the mountain fronts, which are composed of several PaleozoicMesozoic faultbend folds, propagated northward along the coal layer of middle Jurassic; all slip transferred southward along back thrusts, above which the first row of anticlinal belt developed. While the first row anticline was plunging westward, part of slip started to transfer northward and formed the second and third rows of antclinal belts at the ramps. So the elevating and plunging between these three anticlinal belts imply the displacement transfer in the southnorth direction. The deep structures of the second and third rows of antclinal belts in the Southern Junggar Basin are composed of several imbricate hinge wedgeshaped fault blocks, which usually have small lateral extension, but may have independent reservoir system and different hydrocarbongaswater characteristics. In the exploration, it is a key procedure to define the wedges trend and lateral change in threedimensional space subtly, then drilling the target wedge that has been precisely defined based on the progress of seismic acquisition, processing and interpretation.

Key words: Key words: structural wedges; dip domains; axial surface; displacement; the Southern Junggar Basin