厚油层内部夹层特征及在剩余油挖潜中的应用

以岩芯、测井、分析化验和生产动态等资料为基础,通过静态和动态研究相结合的方法,对东濮凹陷古近系沙河街组厚油层内部夹层类型、成因和展布特征,对剩余油的控制作用及其在挖潜中的应用进行了研究。结果表明:东濮凹陷厚油层的夹层类型主要有泥质、物性和钙质夹层三类,以泥质夹层为主,前两者属沉积成因,而钙质类层主要属成岩成因。从厚油层内部夹层的空间分布特征来看,可将其分为层状连续分布夹层、片状不稳定分布夹层和不规则冲刷-充填夹层3种。统计结果表明:横向延展非常稳定且井间对比性较强的夹层数量约占30%,而横向延展稳定性较差且连片程度不高,具空间随机性分布特征的夹层数量约占70%。夹层空间分布特征与注采配置方式共同控制了厚油层内部的不同剩余油分布模式,对夹层的深入研究有效提高了对厚油层内部剩余油的认识精度。从不同空间分布夹层所控制的剩余油分布特征出发,采用水平井、井网整体调整、补孔等方法和措施可获得较好的挖潜效果。

Characteristics of interbeds in thick reservoir and application in potential tapping of residual oil

Based on the static and dynamic combination researches about the information of cores,well logging and well production performance,the characteristic,genesis,distribution of interbeds in thick reservoir of Paleogene Shahejie Formation in Dongpu Sag and their application in potential tapping of residual oil were studied.The results showed that the interbeds could be divided into muddy,physical and calcareous interbeds according to the category and electrics character of rocks;the muddy interbed was major,the muddy and physical interbeds were formed by sedimentation,and calcareous interbed were formed by diagenesis.According to the space shape,the interbeds could be divided into stratiform continuous,sheet uncontinuous and irregular scouring-filling types.The statistical results showed that the interbeds,in which the transverse extension was stable and the relative property was strong,were about 30% of the total interbeds;the interbeds,in which the transverse extension was unstable and the space distribution was random,were about 70%.The space distribution of interbed and the injection and production scheme controlled the different distribution pattern of residual oil in thick reservoir.The prediction accuracy on the residual oil in thick reservoir was improved effectively.According to the characteristics of residual oils controlled by the interbeds with different space distributions,some measures and methods including horizontal well,well pattern conversion and perforations added were effectively used to find the residual oil.