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摘要
The Carnarvon Basin in the North West Shelf of Australia is rich in hydrocarbon resources, but the geological conditions are very complex, and abnormal formation pressure is ubiquitous; especially local abnormal high pressure zones exist in the middle-deep massive heavy Muderong Shale, which brought great difficulties to the oil drilling. This paper chooses the regional caprock Muderong Shale in the northern Carnarvon Basin as a test target, based on the measured formation pressure data, acoustic logging data, and cross-well seismic data, studies the abnormal geo-pressure and the attenuation characteristics of kHz-scale acoustic response, and the relevant calculation model between attenuation parameter and formation pressure, so as to transit from seismic-to-well correlation analysis of the seismic data in the area to the sensitivity analysis of the abnormal geopressure with the attenuation parameter of borehole-side seismic data and the relevant model building, thus the seismic extrapolation inversion of formation pressure can be achieved. The result of acoustic logging data shows that there is a good positive correlation between the effective pressure and the acoustic velocity/impedance quality factor, and based on the fitting polynomial formulas obtained from the crossplot of the two, the back-calculated effective pressure curve can reflect the variation characteristics of the measured effective pressure well. Then the result of the cross-correlation analysis and correlation coefficients between the filtered impedance logs and the borehole-side seismic relative impedance shows that the seismic data in the Northern Carnarvon Basin has an approved seismic-to-well correlation, so the seismic data quality is relatively reliable,, ensuring seismic-to-well transition of sound -pressure correlation analysis. Finally, based on the correlation analysis of the borehole-side seismic absolute impedance and the effective pressure, we build the seismic extrapolation inversion model of formation pressure, and predict the effective pressure of one cross-well seismic line, the result is basically consistent with the measured pressure and characteristics of pressure distribution in the area. So this paper provides an excellent way to the seismic prediction about local abnormal pressure zones in the Muderong Shale in the northern Carnarvon Basin.
- 出版日期2014-10
- 单位中国科学院地质与地球物理研究所; 中国科学院地质与地球物理研究所兰州油气资源研究中心
