The characteristics of the new unit include: (1) applying hydraulic anti-reverse mechanism to release softly the torque of the sucker rod; (2) adopting a double-seal structure for easy replacement of packing set; (3) taking a supporting rod structure for higher supporting strength and enlarged space of maintenance operation.

It features three structural evolution stages, showing fault depression at early stage, depression at middle stage, reversal structure at late one.

The basin evolution history is analyzed in the view of structural transition and its stage on the basis of some reversal structures founded in recent years in Jiyang depression.

The structural style of Beier depression is very complex, which not only includes all kinds of extensional faults, extensional faulted-depression and faulted-up lift associations ,but also has transverse and longitudinal transfer zones, and reversal structures formed in later period.

, tectonic sequence transition phase of Kongdian, developing phase of Shahejie Depression and the latest tectonic inversion phase of Dongying.

This superimposed fold interface image of discordant axial trace (E-W and NE) developed in the Cretaceous continental basin suggests that the basin could have been the result of tectonic inversion and progressive deformation in Mesozoic under special boundary conditions when the.

Evolution of sedimentation and correlation of synsedimentary structures during Ziliujing, LongJing and Early Shaximiao ages (in Jurassic) as well as stratigraphic interface features indicate that a tectonic inversion took place in Weiyuan region at the end of the Ziliujing age, forming Weiyuan uplift which represent embryo of Weiyuan anticline.

Summary of inversion structure on petroliferous basin;

HYS inversion structure in Tuha basin and its balance evolution;

Characteristics of inversion structures in Yitong Basin since Neogene