Fault Formation Mechanism Research Of West Of Southern Third Area Of Saertu Oilfield In Daqing

The west of Southern third Area located in anticlinal structural high of Saertu develops many faults. The biggest structural plane drops 100 meters. Near fault rock breaking is serious and there are less wells. Therefore, understanding of breakpoint combination and structure is difficult. In order to better improve the exploitation effect, study waterflooding,polymer flooding and remaining oil distribution in this area, and increase the reserves of the old oil region, it is necessary to recognize the cause of formation and regularity of distribution again of the faults in the west of Southern third Area. In this article, we analyzed the force condition of the strata when the fault is formation through existing fault distribution characteristics, occurrence features and style of different combination, so that we can better identify small faults and study the cause of the faults.Southern third Area T11 fault system has two kinds of causes,one kind is growth fault which was activating during sedimentary period, another kind is epigenetic fault which was formed in post deposition. The number of growth faults is small, and its genesis is extension; most faults do not have activity and focus on developing in the core of the anticline,which were formed in fold reverse period at the end of Nenjiang period. Owing to the west-east direction compaction, Daqing placanticline uplifts to form anticline structure,the upper strata tensions to be a series of normal faults by the longitudinal buckling. The lower T2 fault system focuses on developing on the bottom interface of Qingshankou formation, it is the growth fault in early depression period, fault deformation and sedimentation occur simultaneously, and most faults are growth faults, proving that the sedimentary period is in tensional environment. The genetic mechanism of T2 fault system is regional extension in the early Qingshankou period.Because of intense folding and rock slipping between bed planes, leading to the reverse of the dip of normal fault plane, which reasonably explains the genesis of high angle thrust fault developed in west of Southern third Area.