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摘要
Quantitative analyses of seismic responses of karst cave reservoir play an important role in predicting and imaging this kind of reservoirs. Ignoring the multiples and based on sonic equation, the analytic expression of the seismic response for an isolated karst cave of small size was given here. The relationship among the size and fillings of the karst cave and the seismic amplitude attribute was established by this analytic expression. The results of analysis indicated that: (1) reflection amplitude is directly proportional to the volume of the cave when the size of the cave is less than 1/8 of the seismic wavelength; (2) the impact of the horizontal size on the reflection amplitude is mainly controlled by Fresnel radius, and also the variation law of amplitude with horizontal size is affected by the vertical size; (3) the impact of vertical size on reflection amplitude behaves as tune effect, and the strongest amplitude appeared in case that the vertical size is equal to the tune thickness (1/4 of the seismic wavelength). The following results of the numerical simulating studies on caves with varied sizes, and physical modeling experiments on cave groups and caves with varied infillings also supported the conclusions.
- 出版日期2012-6
- 单位中国石油化工股份有限公司石油勘探开发研究院
