Study On Seismic Wave Field Numerical Simulation Of Complex Reservoir In Bohai Buried Hill

With the development of economy,the oil and gas in sedimentary rocks have been unable to meet the needs of society.As one of the exploration objects in the new period,buried hill oil and gas reservoirs have very important exploration value.However,the Bohai buried hill types are diverse,the depth of the earth changes greatly,and the quality of seismic data is very different.So a lot of information can not be distinguished by the naked eye in the seismic section.In order to solve the problems of this kind of complex reservoirs,it is necessary to establish accurate parameter model,select reasonable numerical simulation scheme to explain the details of reservoirs.And then we can understand the characteristics of buried hill better,which will lay a foundation for the prediction of subsequent reservoirs.In this paper,considering the difficult problems of numerical simulation of seismic wave field in Bohai oilfield buried hill reservoirs,we select two kinds of typical buried hill reservoirs: granite fractured buried hill reservoirs and carbonate buried hill reservoirs.Based on the detailed description of the geologic model and the numerical simulation of the typical reflection characteristics,we propose a set of numerical simulation techniques for seismic wave field suitable for the buried hill reservoir in Bohai Sea.This paper contains two main research contents:(1)Numerical simulation of seismic wave field of granite fractured buried hill reservoir.In this paper,the internal structure of the reservoir is complex,and the reservoir type is dominated by pore type.So it lacks an accurate and effective method to describe the storage space in the vertical and horizontal distribution in the numerical simulation modeling process.In addition,there are high and steep reflection characteristics of granite.The cause of this high steep reflex is not yet a conclusion(really exist or the illusion of the process?)Therefore,this paper first proposed a numerical simulation technique based on pre stack elasticity parameter inversion attribute modeling,which can accurately represent the developmental location of the reservoir space.Based on the simulation results and the crack detection information,the seismic response characteristics of the granite buried hill reservoir are analyzed synthetically.Secondly,the possible causes of high steep reflection of imaging error,gully and other factors.(2)Numerical simulation of seismic wave field in carbonate reservoir.In this paper,there are few wells in the study area,and the known information is not enough,which brings great difficulties to the explanation.And the characterization of the seam and hole in the numerical simulation process has been the difficulty of reservoir modeling.Therefore,this paper proposes a modeling technique based on the properties of crack detection,and uses the rock physical equivalent fracture parameters to fill the model.This method can effectively improve the model accuracy,which can effectively improve the model accuracy.Finally,combining the simulation results with the pre stack crack detection information,we analyze the wave field characteristics of the fractured reservoir.The numerical simulation scheme proposed in this paper has a good effect in the oil field of Bohai Sea,and has obtained the following understanding:(1)For the granite buried hill reservoir,the crests are better when the crests are alternately present;There is a short peak wave reflection energy group below the buried hill,the cracks are basically not developed;(2)The possible causes of the high steep reflection of the granite buried hill are: crushing zone,multiple wave and overburden deviation error.(3)For the carbonate buried hill reservoir,cracks and holes directly affect the amplitude of the buried hill.The size of the impact is directly related to the size and location of the crevices.(4)The vertical development of the crevices can form a "beaded" reflection feature.The transverse development of the cracks produce strong energy "trough + crest" reflection;The high angle cracks produce isolated weak peaks.These conclusions have a high reference value for the prediction of oil and gas in the buried hill reservoir.The numerical method proposed in this paper which is not only suited for granite reservoir and carbonate reservoir,but also can be applied to other complex reservoirs,which has a strong practical application value.