The seismic response of the volcanic edifice-facies zone of Yingcheng formation in the Songliao Basin

The complex seismic response features of volcanic formation,that was caused by multistage volcanic eruption and superimposed in the vertical and horizontal directions,affect the reservoir accuracy of seismic prediction and the cognition of geological laws in Xujiaweizi depression.Based on drilling and 3D seismic data,combined with the regional tectonics,this article establishes the seismic response model and identifies the spatial distribution of the volcanic edifice-facies zone by the technology of coherence and formation slice attribution.From the vents to the distal facies the volcanic body heterogeneity weakens,the rate of change reduces gradually in the coherence cube slices.There are four types of volcanic facies seismic response in the research area.The first type is multi-facies supoimposed zone of dome crater which shows the characteristics of messy reflective band and bottom-up radial shape.It also has the features of thinning out around the volcanic vents,strong coherence,varied forms in profile and plan view. The second type is near-source superimposed eruption and overflow facies that has the reflection characteristics of intermittent layering,moderate-high amplitude,and low frequency.It is distributed in bands around the crater.The third type is distal eruption facies that has the reflection characteristics of continuously layered wedge and strong amplitude.It has the arch plate shape adjacent to the side of the volcanic body.The fourth type is distal volcanic sedimentary facies that has the reflection characteristics of plate shape,sub-parallel reflection configuration,strong energy continuous phase axis.