Study On Fault Characteristics And Its Controlling Effect On Oil And Gas Of YM2 Area

This paper unifies the fault system of YM2 area with the whole Tabei area for the first time,combs and interprets the fault system according to the analysis of regional structural characteristics,analyses the fracture profile characteristics of newly interpreted faults,and describes the fracture characteristics of the study area in detail.Also,defining the control effect of different stages of faults on reservoir and hydrocarbons as well as the law of hydrocarbon enrichment through dynamic data analysis and reservoir fine description.Preliminary understandings are as follows.There are four stages of faults in the work area.the north-south strike-slip faults which controlling reservoirs are favorable oil and gas enrichment zone;north-east strike-slip faults mainly control the formation of structure in the study area;north-west strike-slip faults are caused by the intrusion of igneous rocks,which have a certain controlling effect on reservoirs;north-north east strike-slip faults do not control reservoirs.There are 94 fault-karst bodies in the study area,of which the type I and II fault-karst bodies are favorable hydrocarbon enrichment areas.The main area and peripheral area of the work area are two sets of independent petroleum systems.The main area is generally oil-bearing,and the distribution of hydrocarbons is jointly controlled by structure and faults which act as hydrocarbon migration pathways.The non-uniform oil-water interface in the main area is roughly around-5100 m.Hydrocarbon enrichment in the peripheral area is controlled by the faults which act as main hydrocarbon migration pathways and the melt-off traps.The closer to those main faults,the more enriched oil and gas.Once the melt-off trap is built,the reservoir with the characteristic of "one melt-off trap for one reservoir" can be formed.There is a unified oil-water interface in the same fault-karst body.Hydrocarbons are enriched in the structural high of a fault-karst body,while the lower part of the same fault-karst body has the potential for progressive exploration and development.