Study On The Characteristic And Distribution Pattern Of Low-level Sequence Faults Of Yong 3 Fault Block In Dongxin Oilfield

Yong 3 Fault Block of Dongxin oilfield is located in the northeast of Dongying sag and southeast of Mingfeng sub-sag,which is controlled by a north border south bend third fault that sort of run nearly east-west.It shows a fault nose structure which has the tendency toward the south,and the second member of the Shahejie formation is the main oil-bearing horizon.Now for the Yong 3 fault block has entered extra high hydrated production later stage and extensive development of unclear recognized low-level sequence faults,which lead the injection-production well pattern spacing is not matching,and the main causes of serious development contradictions.This paper comprehensively utilizes logging,geological,seismic and production data,studying the stratigraphic classification and correlation,analysis of characteristic of the main fracture,low-level sequence faults' identification with well-log and seismic data,distribution characteristic and pattern,influence on water flooding development of low-level sequence fault and so on in the study area.The following results and understanding were achieved:(1)The stratigraphic framework of the second member of the Shahejie formation in the Yong 3 fault block area is established.Area of sand body distribution and connection characteristics were seriously influenced by fault of the second member of the Shahejie formation.The north-south sections are featured by the graben and develop a series of step fault,the east-west sections are featured by the horst and the fracture on either side assume ladder shaped distribution.(2)The main faults oblique crossing as "y" type reciprocally in profile,and as a whole to give priority to the broad and gentle graben.In a plane it was a fault nose structure inclined to the south and developed two secondary control block fault systems which were inclined to the north inside fault area.(3)The ant tracking identification of low-level sequence faults in the second member of the Shahejie formation in the study area is influenced by parameter settings,vertical scanning step length and other five parameters such as initial boundary of had a greater influence on the effect of low-level sequence faults' plane extension length rather than illegal and legal step.Identification of single well breakpoints coincides with the low-level sequence faults' fracture trace identified by ant tracking with well matching.Well seismic combination meticulously depict the distribution of low-level sequence faults in the study area.(4)The low-level sequence faults of study area most belong to high angle fault,mainly on five,six levels of fault;Mostly faults are distributed in the declining plate of the advanced sequence faults,and overall present radial low-level sequence faults combination style in all kinds of anticline formation,form mainly with "y",graben and ladder faults combination styles in the gentle slope belt fault block area,and mainly form the graben and "y" type of low-level sequence faults around the fracture development zone of deep depression area.(5)It indicates that the fifth faults control residual oil's distribution and the sixth faults influence the deployment of the injection-production well spacing and are divided into two modes,the senior sequence faults and low-level sequence faults joint control mode and the combined style inside the low-level sequence faults control mode.