浅薄层特、超稠油注蒸汽吞吐后剩余油分布研究

Remaining oil distribution in shallow, thin and super-heavy oil reservoir of Henan Oilfield after steam stimulation

河南油田的浅薄层特、超稠油油藏注蒸汽吞吐后,采收率只有15%～18%,要进一步提高资源利用程度,关键是查明蒸汽吞吐后浅薄层稠油剩余油分布规律.蒸汽吞吐后水淹层岩心和电性特征变化明显,根据岩电关系的研究,建立了一套快速、直观的声波时差-深侧向电阻率图版水淹层测井解释方法,有效结合矿场测试、动态分析、油藏数值模拟技术和地质综合分析方法,揭示了剩余油分布特征.超稠油油层纵向有3种水淹模式:中厚层均匀韵律油层顶部水淹,薄互层复合韵律油层中部水淹,薄互层正韵律油层底部水淹;平面上剩余油富集区有4种类型:低井网控制程度的剩余油富集区,低采出程度的剩余油富集区,不同微相控制的剩余油富集区,地层倾角影响造成的剩余油富集区.

The steam stimulation recovery is only 15%-18% in shallow, thin and super-heavy oil reservoir of Henan Oilfield. In order to further enhance the recovery, it is very important to find out the law of remaining oil distribution in shallow, thin and super-heavy oil reservoir after steam stimulation. The characteristics of core and electrical properties of water-flooded zones have changed obviously. Based on the relationship between the cores and logging curves, a set of fast and intuitive techniques have been set up to interpret water-flooded zone by using plot of the sonic differential time and the deep lateral logging data. Combined with the field testing, performance analysis, numerical simulation and geologic analysis, the remaining oil distribution law is disclosed. Vertically, there are 3 types of waterflooding: waterflooding in top layer of homogeneous rhythmic reservoir; waterflooding in middle layer of compound-rhythmic reservoir; and waterflooding in bottom layer of positive rhythmic reservoir. Areally, the remaining oil normally enriches in areas of low well control level, low oil recovery, multi-facies control, and the areas affected by stratigraphic dip.