| The south Lufeng area is located in the northeast of The Zhu I depression,including Lufeng 15 depression,Lufeng 13 east depression,and Lufeng 13 west depression.The research results over the years show that it has great exploration potential,and the hydrocarbon enrichment law is closely related to the fault system.However,the controlling effect of faults on hydrocarbon accumulation and the mechanism and evaluation method of hydrocarbon transport by faults in south Lufeng area are not clear at present,and further research is needed.In this paper,based on previous research results,3D seismic data and drilling data,the structural geological analysis method is used to analyze the structural styles,active stages and evolution characteristics of faults in the southern Lufeng area and their relationship with oil and gas enrichment.There are a lot of faults in the Cenozoic in southern Lufeng area.The depressions in the upper section are large in scale and shovellike.The secondary faults are mainly developed in the lower strata of Hanjiang formation,which are composed of domino type,“y” type and ladder type.On the plane,affected by regional stress field,the number,size,trend and distribution of dense zones of faults in different layers are slightly different,but generally controlled by depression faults.Based on the study of fault development characteristics and the analysis of key oil-bearing structural belts,six types of source rock-fault assemblages in the southern Lufeng area are divided,in which the bidirectional convergence type,the same direction transport type and the multi-stage fault-step source-fault assemblages control the oil and gas distribution in the depression zone,steep slope zone and gentle slope zone respectively.The southern Lufeng area many weak accumulation period of fault have vertical conducting ability,the method of using accumulation period section is pressure recovery of this kind of fault is vertical conducting ability to carry on the quantitative evaluation,determined the decide whether or not a fault of conducting oil and gas accumulation period section critical value the positive pressure is 19.23 MPa,and established fault of conducting ability evaluation map in the southern Lufeng area.According to the spatial matching relationship of hydrocarbon accumulation factors,such as source rock,trap and hydrocarbon migration path,four hydrocarbon accumulation modes are established in south Lufeng area,which are self-generating and self-storing type within source,endogenous and external reservoir type within source,side-generating and lateral reservoir type outside source,and down-generating and up-storing type outside source. |
