大庆油田北一二排西部分流河道砂体层内聚驱吸水剖面变化特征

Variation features of the polymer absorbing inner distribution channel sands in north Daqing oilfield

根据精细地质研究成果和生产测井资料,分析不同沉积韵律油层注聚后吸水剖面变化特征.结果表明:注聚后河道砂层内注入剖面得到有效调整,厚油层顶部动用程度明显改善;各种韵律油层注聚过程中均不同程度出现剖面向底部转移阶段,底部油层吸水比例仍然较高;3种韵律油层剖面变化特征有一定差异,反韵律和复合韵律油层有利于提高注聚效果;厚油层层内调整效果与油层物性、渗透率级差、含水饱和度等地质因素有一定关系,如果油层顶部砂泥岩互层较发育,则剖面调整时间较晚,效果较差;渗透率级差或突进系数较大,剖面方向性明显,存在突进现象;油层底部强水洗段含水饱和度高,聚驱调整作用小.

The distributary channel sands are the main sandstone of II class reservoir,most of them deposited as both positive rhythm and complex rhythm,and little negative rhythm;but the sandstones in I class reservoir deposited as positive rhythm and multiple rhythm,these indicated the different sedimentary environment which caused the different property and different absorbing situation in oil development.According to data of absorbing profile,the variation features of polymer-flooding absorbing profiles were analyzed for different sedimentary rhythm,it show that the absorbing profile of channel sands were adjusted very well after polymer-flooding,the working situation in the top layer were greatly improved.The profile show the bottom parts of all kinds of the sands in different sedimentary rhythm were absorbed better than that of in the top,the working degree were higher.But the variation features of absorbing profile were different in the three kind of rhythm sands,both the negative and complex rhythm sands were in favor of improving the effect of polymer-flooding.