应用测井资料研究聚合物驱后剩余油分布

Study on remaining oil distribution after polymer flooding using logging data

王梅 杨二龙 龙涛 宋考平

WANG Mei YANG Er-long LONG Tao SONG Kao-ping

大庆石油学院, 黑龙江 大庆 163318 大庆油田有限责任公司第一采油厂, 黑龙江 大庆 163001

大庆油田在聚合物驱后区块仍然有40%以上的剩余储量,准确预测聚驱后剩余油分布是挖潜这部分储量的关键。根据大量代表水驱后期和聚驱后期开发状况的测井资料,计算对比了单井垂向采出程度;通过绘制不同微相剩余油饱和度概率分布曲线和将井点所属饱和度区间标注在沉积微相图上,研究了聚合物驱后平面剩余油分布。结果表明:聚驱后,垂向上驱替趋于均匀,但油层上部剩余油比例较高,在垂向上,厚度小、渗透率低的油层部位,聚驱后剩余油基本没有变化,厚度大的油层部位,聚驱后剩余油剖面趋于均匀,但上部剩余油仍较多;在平面上,河道砂微相聚驱效果明显好于非河道砂微相,剩余油主要分布在相带尖灭、两相分界处以及渗透率变差部位和注采关系不完善的区域。该研究为进一步挖潜这部分剩余油提供了依据。

Precise prediction of remaining oil distribution after polymer flooding is the key to explore the 40% remaining reserves in the post-polymer flooding reservoirs of Daqing Oilfield.In this paper,longitudinal production degree of single wells are calculated through using a lot of logging data that show the development status in late water flooding and polymer flooding separately.With signals representing different saturation intervals labeled on the diagram of sedimentary microfacies,probability distribution curves of remaining oil saturation of different microfacies are mapped to study the remaining oil distribution after polymer flooding.Results show that after polymer flooding the displacement in longitudinal direction tends to be more uniform but the remaining oil at upper parts of thick oil layers is relatively high in proportion.On the vertical,the remaining oil after polymer flooding changes little on the parts of oil layers of small thickness and low permeability.The remaining oil profile becomes more uniform at upper parts of oil layers of huge thickness where still a lot of remaining oil exists.In the horizontal,the polymer flooding efficiency of the channel sandstone microfacies is better than that of the non-channel sandstone microfacies.Remaining oil is mainly distributed in the isolated facies and the dividing location of two facies as well as the area where permeability gets worse and the injection rate is low.The research provides the base for the exploration of the 40% remaining reserves in the post-polymer flooding reservoirs of Daqing Oilfield.

10.3969/j.issn.1000-7393.2007.01.021