Method for correcting volume of carbonate fracture vug

Abstract

The invention discloses a method for correcting the volume of a carbonate fracture vug, which includes the following steps: carrying out 3D sonar scanning measurement on the contour of a karst cave, and collecting an actual migration data body of the karst cave; building a 3D seismic geological model of the karst cave, and carrying out forward simulation trial calculation on the 3D seismic geological model to get a seismic migration imaging data body; using the seismic migration imaging data body and the actual migration data body to extract a seismic attribute body of the 3D seismic geologic model; and calculating the apparent volume of the karst cave, and correcting the volume of the karst cave according to the correlation relationship between the apparent volume of the karst cave and the actual volume of the karst cave obtained through 3D sonar scanning measurement. By analyzing the volume relationship of seismic attribute, a forward model and a known karst cave, the volume of the karst cave can be corrected, the volume of a fracture vug can be calculated accurately, and the difference between the amount of recoverable resources of carbonate oil gas and the actual yield can be reduced.

Description

technical field [0001] The invention relates to the technical field of petroleum exploration, in particular to a method for calibrating the volume of carbonate rock fractures and caves. Background technique [0002] The reservoir space of fractured-vuggy carbonate reservoirs is dominated by dissolved caves, dissolved pores, and fractures, with strong heterogeneity. There is a large difference between the recoverable resources and actual production of carbonate oil and gas. Quantitative characterization and reserve calculation of the natural gas has always been a difficult problem in the industry. [0003] At present, for the calculation and quantitative description of the cave volume, the commonly used reservoir prediction techniques such as amplitude gradient, amplitude, and amplitude change rate are used to macroscopically predict the "beaded"-shaped strong seismic reflection characteristics, and the corresponding attribute data volume is formed to calculate the apparent v...

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Problems solved by technology

[0003] At present, for the calculation and quantitative description of the cave volume, the commonly used reservoir prediction techniques such as amplitude gradient, amplitude, and amplitude change rate are used to macroscopically predict the "beaded"-shaped strong seismic reflection characteristics, and the corresponding attribute data volume is formed to calculate the apparent volume of the cave. On this basis, through forward modeling threshold analysis, the threshold value range is artificially limited, and the cave volume correction coefficient is obtained. The volume correction coefficient is in a relatively wide range between 5% and 20%. The forward simulation of the physical model can obtain the response characteristics of the seismic wave field and the correction coefficient of the cave volume. However, due to many factors affecting the characteristics of the seismic wave field, the fracture-cavity model used for forward simulation is relatively simple compared with the real underground fracture-cavity body. , it is difficult to objectively describe the seismic wave field characteristics of the actual underground fracture-cavity development, which cannot meet the requirements of fine description. For the quantitative characterization of this type of reservoir, there is no very accurate and effective method at home and abroad.

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