| In order to solve the problem of seamhole prediction,this paper studies the current situation of seamhole oil and gas reservoir exploration method,carries out fine target treatment and reservoir prediction,finds the fracture system,provides a clear exploration target for deepening exploration and development of gas reservoir,An effective method for the comprehensive prediction and evaluation of seam reservoir is established.In this paper,the set of method is applied to the exploration practice of the reservoir and reservoirs of the Maokou Formation in the Shannan area of the Sichuan Basin,and the favorable exploration and prediction are obtained.(1)Through the modeling of the model,the amplitude of the reflected wave will be weakened and the weak amplitude will be formed when there is a crevice system on the top of the Maokou Formation.When the cave is relatively developed,Water or other matter),there is a large difference in velocity,density and wave impedance between the cavity and the surrounding medium,which will form a strong reflection,especially the "short axis,strong valleys" seismic response.Through the multi-attribute analysis,it is concluded that the erosional fracture-shaped reservoir development section of the Maokou Formation has the characteristics of "low frequency and strong valleys".(2)Based on the analysis of the seismic response and physical model of the fractured system,a prediction technique of seismic nonlinear inversion(velocity range between 5000 m / s and 5900 m / s)is established.The velocity of the reservoir is consistent with that of the borehole in the area.The velocity inversion profile can be seen clearly.It can be seen more clearly that the high-speed limestone of the Mao-San-Mao-2 section and the low-Distribution,determine the direction and distribution characteristics of the reservoir in the Maokou Formation,and obtain a good geological effect.Therefore,the technology to solve the problem of fracture prediction provides a new technical support.(3)The AVO attribute inversion technique is based on the Chapman theory.The pre-stack seismic data of the same wavelet are used to invert the AVO attribute inversion,and the intercept,gradient,Songby and other AVO attributes.The similarity of the same attributes obtained by inversion at different frequencies is calculated,and the change of the attribute is changed with the change of the frequency.Since the speed of the cave is often much lower than that of the cap rock,the attenuation here becomes more powerful,So the high-frequency part of the attenuation is more,and the remaining energy of the low-frequency part of the horizontal is often stronger than the adjacent area.Poisson 's ratio can reflect the change of lithology,and the change of Poisson' s ratio in the cave is larger.In this paper,the low-frequency Poisson's AVO attribute is used to identify the cave,and the results are compared with those of the real drill.The results show that the oil and gas detection technology based on the frequency variation AVO attribute inversion technique is effective.This kind of inversion technique is the best estimation method of the cave prediction,and it is the core technology of the fracture prediction.Based on the systematic study of logging characteristics,model forward,seismic attribute,inversion velocity and variable frequency AVO attribute,a set of earthquake prediction technology of Maochou Formation fracture system is established.Using this prediction technique,the evaluation of LNT structural gas exploration and development targets in Shannan area is carried out,and the favorable area is divided into favorable geological results.The application research results show that the method and technology research results can be adapted to the complex variability of different types of fracture system. |
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