| With the constant progress of the oil and gas exploration techniques, exploration target is changed, from general to special. Fracture-Cavity Reservoir becomes a key and new exploration aera. It is from statistical data that fracture-cavity reservoir is third of aware reservoir in China. During the "ninth-five", the three fourths of practical reservoir in our country is low porosity and permeability, dense and fractured. So, the exploration of fractured reservoir is very important for broadening reservoir and outcome in the fruture oil and gas exploration.In this thesis,Fracture-Cavity Reservoir in Maokou Zu is research target and fracture-cavity reservoir description technique research is discussed. It can offer new ideas for the exploration of Lower Permian. By HBC 3d seismic data with high signal-to-noise ratio and high resolution, and the rich geology,well drilling, logging and test data, it can describe fracture vegetal area finely and offer advantages for the exploration favorable fracture-cavity gas reservoir. Also, it settle good seismic prediction base for the monographic study about the distributoin of fracture vegetal area in Maokou Zu. It is very important for the futher exploratory development of HBC structure Lower Permian gas reservoir.The main methods are coherence tecnique, seismic inversion and seismic property analysis which are used in this thesis . It can predict the steric distributoin of Maokou Zu fracture vegetal area in HBC structure Lower Permian and offer reliable references for optimizing the exploration objects. Many tecniques are tried in this work. By the comparison and analysis, finally, these tecniques which can make Maokou Zu fracture-cavity reservoir prediction better are as follows: reservoir seismic inversion, fracture detection with poststack seismic property , 3d seismic coherence, fracture detection with prestack seismic property and 3d seismic visualization. Using 3d seismic data fully and 3d visualization tecnique, also actual geology and logging data, prestack and poststack seismic property are analysed carefully. Then it can find out the delicate prestack and poststack seismic property parameters of Lower Permian Maokou Zu fracture distribution and describe comprehensively Lower Permian Maokou Zu reservoir fracture. Finally, it can sum up the distribution of main fracture vegetal area and offer reliable objects for the exploration.By this research, progress is as follows: firstly, reverse faults are the restraint conditions when predicting fracture-cavity reservoir at the first time and velocity inversion of reverse faults is proposed. Because of the rich reverse faults and fracture-cavity reservoir near reverse faults, reverse faults are the restraint conditions when predicting fracture-cavity reservoir. It can be reflexed objectively that reverse faults dominate the reservoir distribution. Secondly, using geology and seismic data, delicate seismic inversion with reverse faults, and seismic sensible property, the quantitative and semi quantitative description of fracture-cavity reservoir can be realized. And some good effects have been gained during the practical application. Thirdly, because of the rich fractures and limestone caves, preferred coherent properties can show the fracture developmental situation well. But, because of the deep intended zone, the effect of prestack fracture detection is not good. Fourthly, with the rapidly development of computer tecnique, 3d visualization becames the indispensable measure in 3d seismic exploration. Using 3d visualization, the sensible property of fracture-cavity recognition can be 3d carved and the spatial distribution of fracture-cavity can be showed clearly. Finally, seismic comprehensive prediction method which can identify Maokou Zu fracture-cavity effectively, is preferred. And seismic recognition mode of Maokou Zu fracture-cavity has been sum up. The new technique idea is offered for the carbonate fracture-cavity reservoir description. |
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