关键词: 砂岩储层, 地震属性参数, 孔隙流体流动, 敏感性评价, 属性交会图

Abstract: The response of seismic attribute parameters to variation of pore fluid is different for various sandstone reservoirs. A calculation method for fluid indicator is given by the statistical method and used to reflect the response difference of seismic attribute parameters to fluid variation. Experimental results of sandstone reservoir in the third member of Shahejie Formation in Shengli Oil Field proved the applicability of this approach using seismic attributes crossplot technique. According to the calculation results of fluid indicator, the conventional attributes, such as response difference of P wave and S wave, are sufficient for discrimination of gas state in middle-high porosity unconsolidated sandstones and cemented sandstones sample saturated with water and oil. For the tight sandstone containing gas, only velocity ratio of P wave to S wave and Poisson ratio are sensitive to fluid variation. For the unconsolidated sandstones, the crossplot can be used to distinguish saturated oil from saturated water by selecting two sensitive attribute parameters according to their relative values of fluid indicator. For the cemented sandstone, this approach is not applicable. On the basis of exact velocity ratio of P wave to S wave in dry rock, a combined attribute parameter is more sensitive to pore fluid variation than the conventional attributes. The crossplot generated from the combined attribute parameter has an excellent discriminatory capacity for the experimental results of sandstone samples saturated with water and oil.

Key words: sandstone reservoir, seismic attribute parameter, pore fluid flow, sensitivity evaluation, attribute crossplot