关键词: 灰质滩坝, 储层评价, 主因素定量评价, 流动分层指标, 沙四上亚段, 济阳坳陷, 沾化凹陷

Abstract: Limy beach-bar reservoirs are developed in the upper part of the fourth member of the Shahejie Formation (the upper Es4) on the southern gentle slope of the Zhanhua sag, the Jiyang depression. Such reservoirs are closely associated with the provenance and hydrodynamic conditions, and their locations and sizes are affected by the sizes and scales of the fans which provide the provenance, resulting in strong reservoir heterogeneity and complex reservoir space. It is difficult to evaluate these reservoirs. In this paper, four methods (i.e. testing data analysis, comprehensive major element quantification, petrophysical facies analysis and mercury intrusion in casting thin sections) were utilized to evaluate and classify the limy beach-bar reservoirs. The results show that the comprehensive major element quantification method and the petrophysical facies analysis method (or the flow zone indicator method) are more suitable for evaluating the limy beach-bar reservoirs, whereas with defects in application. On the basis of accurate analysis of depositional settings, the comprehensive major element quantification method and the petrophysical facies analysis method could be combined to analyze the limy beach-bar reservoirs, in order to avoid the defects and thereby provide more accurate and practical results. Thus the limy beach-bar reservoirs in the upper Es4 of Zhanhua sag are divided into four types (I, II, III and IV). Type I and Type II reservoirs are biolithite, limy fine sandstone and limy siltstone of mouth bar and estuary shoal, with better reservoir conditions. Type III and Type IV reservoirs are mainly limy siltstone and muddy siltstone, with poor reservoir properties.

Key words: limy beach-bar, reservoir evaluation, major element quantification, flow zone indicator (FZI), upper Es4, the Jiyang depression, the Zhanhua sag