Reservoir Prediction Research Of Feixianguan Formation Of Fuling Area In East Sichuan

Feixianguan formation which has the characteristics of large transversal change and strong heterogeneity main developes oolitic beach reservoir,but there's few well data and old 2d-seismic lines.It isn't clearly that quality reservoir development controlling factors.And there's not enough research about the geology of this formation which using the method of geophysics prediction.All of these limit the oilgas exploration development of this formation.This paper analyses characteristics and the main developing factor of Feixianguan formation by using field section observation,sampling,section analysis and some other methods.On this basis,we did some research about tentonic characteristics,paleogeomorphic restoring,waveform classification,RPG frequency mixing phase,forward modelling by combined geology with geophysics,postseismic inverting,analysis and comparison of fracture prediction by coherence detection,discontinuity detection and stress field technology,and liquid prediction by technology of high frequency attenuation.Besides,we used the achievements of geology and geophysics prediction,and evaluated the reservoir and pointed appropriate drilling areas.Finally,we made a series of methods of reservoir recognition and prediction about the superior oolitic reservoir of this formation.And we got following achievements:(1)Based on the constraint of sedimentary background and well analysis,paleogeomorghic restoration,post-stack wave impedance inversion,seismic facies analysis are used to describe the distribution of reef-shoal facies reservoirs.The platform margin of this reservoir which is an important oolite beach development zone is close to xinglong 1 well and xinglong 3 well.Located southeast from fushi 1 well to xinglong 3 well is open platform,the interior of which is poor developing oolite beach,which is potential developing area of this reservoir.(2)Through wells analysis,section analysis and paleogeomorghic restoration show that the different paleogeomorghic of Feixianguan formation in Fuling area lead to sedimentary differentiation,local structures highness are beneficial to the development of reef flat.The ancient landform of Feixianguan formation is mainly lower,and the development of oolitic beach reservoir is poorer by the cause of oolitic limestone lacking exposal dissolution and poor dolomitization.Low porosity and low permeability are two features of this reservoir's.Fracture developing at later period can improve the reservoir.(3)According to forward modelling,we got the seismic reflection character of high porosity oolitic reservior.The result reflected that amplitude(energy)has better indication function to oolitic beach,and that gamma curve is sensitive to different lithology,but sound wave curve can not differentiate between the rock containing too much shale with reservoir but the “fake bright spots”cause of too much shale could make some bad effection to the extracting result of seismic.So we used gamma curve and sound wave curve making simulating sound wave curve to do lithology inversion.(4)Prediction result about fracture by using the method of coherent detection was in consonance with that by using the method of incontinuity detection.In the northeast and southwest of this reservoir,each has one fracture developing area,but coherent detection is more effective to oolitic reservior developing area.(5)According to research of some important well of this reservoir,attenuation gradient can nearly reflect the oil-gas possibility of this reservoir,oolitic limestone can also make some response,but its damping range is narrower.In the research area,there are two areas whose gas-bearing property is good and in a row.These gas zones are all at the edge of this reservoir,and distributed around xinglong 1 well and xinglong 2 well,and the belt area of northwest of xinglong 3 well.Guiding with main developing controlling feature of reservoir and based on seismic facies analysis,seismic inversion,seismic attribute analysis,structure prediction,the result of hydrocarbon detection,construction and geomorphic feature,we assessed this reservoir and verified some potiental exploratory areas.There are four potiental exploratory areas.The edge of this reservoir is the most suitable area for exploration,at the meantime,the beach in the open platform is also potential.