含油气盆地深层有效砂岩储层判别与定量评价——以塔里木盆地库车坳陷深层为例

通过油气聚集动力分析和物理模拟实验,揭示库车坳陷深部储层油气富集机制与临界条件,并建立有效储层判别标准与评价方法。研究表明,围岩介质毛细管力与砂岩储层毛细管力比值的大小决定储层含油气性,比值越大越有利于油气聚集,依据毛细管力比值交汇图版来判别有效储层并评价储层质量;围岩与砂岩储层毛细管力比值越大,储层质量越好;有效砂岩储层临界条件下的毛细管力比值随埋深增加表现出逐渐增大的趋势。库车坳陷深部储层有效储层级别与储层含油(气)饱和度具有明显正相关性;深层砂岩储层以Ⅱ级、Ⅲ级和Ⅳ级储层和非有效储层为主,有少量Ⅰ级储层。

Effective sandstone reservoir determination and quantitative evaluation of deep strata in Kuqa depression,Tarim Basin

The hydrocarbon enrichment mechanism and critical conditions were revealed based on hydrocarbon accumulation dynamic analysis and physical simulation experiment, thus establishing effective reservoir identification criteria and assessment method deep reservoir in kuqa depression. The research has proved that ratios between surrounding-rock medium capillary force and sandstone-reservoir capillary force is able to determine the hydrocarbon-bearing property of reservoir. The greater the ratio is, the more conductive to hydrocarbon accumulation it will be. The capillary force ratio cross-plot is used to identify effective reservoirs and assess reservoir quality. The greater the ratio of capillary force between surrounding rock and sandstone reservoir is, the better the reservoir quality will be. The ratio of capillary force under the critical conditions of effective sandstone reservoirs shows a gradual growth trend with the buried depth increasing. The effective reservoir grade in deep reservoir of kuqa depression has a significant positive correlation with the oil (gas) saturation of reservoir. Deep sandstone reservoirs are dominated by Grade II, Grade III and Grade IV reservoirs as well as ineffective reservoirs with a small number of Grade I reservoirs.