The Seismic Forecasting Of The Volcanic Reservoir Of Xujiaweizi Fault Depression

Guided by the theory of Architectonic Geology, Reservoir Sedimentology and Volcanics Petrology, based on carefully analyzing and referring the research fruits of the predecessors, sufficiently using the data of seismic, well logging and well drilling, adopting several methods of seismic, this paper forecasts and researches the volcanic reservoir at the objective of Yingcheng formation of Xujiaweizi fault depression.Through the interpretation of target stratum, the distribute law of the volcanic formation is obtained: the YingchengI formation are wide distributed and YingchengШformation are only destributed in Xingcheng, Wangjiatun and the southern of Songzhan.Through the research of the lithology, lithofacies and the relations with the accumulate room of volcanic reservoir, and combinded with the well drilling data of Xujiaweizi fault depression, it is sure that the porosity and the permeability of the rhyolite and the welded tuff, the upper subfacies of effusion facies and heat clastic subfacies of burst facies in this area is often high and those physical property is favorable.In view of YingchengI formation, beginning with the seismic identify of the volcanic reservoir, using the technique of 3D visualization and coherence, 18 volcanic edifices in the target stratum are forecasted, using the technique of the seismic attribute analyzing, this paper forecasts that the volcanic lithofacies is distributed along Songxi fault of NNW, and using the technique of the seismic inversion, this paper forecasts that there are two areas in which the thickness of the volcanic reservoir is high-value. Based on these, taking analysis of the section and the plane, it can be found that: the volcanic of YingchengI formation is destributed widely in the region of interest, the total trend is that the thickness value of north is low and that of south is high, that of west is low and that of east is high; The growing of the volcanic reservoir is affected largely by the volcanic edifice, the volcanic facies belt, the fault and the depth of burial, it is usually that the burst facies and the effusion facies are main, and the area near the fault is vegetal, the physical property is favorable and the thickness is high.At last, through analyzing the diagenesis condition of the deep gas reservoir of Xujiaweizi fault depression, combinding with the forecast fruit of the volcanic reservoir and the test gas fruit of multiwell, the distribution of the beneficial areas are pointed out in YingchengI formation.