Study on Water-Driving Law and Remaining Oil Distribution Pattern in Ultra-low Permeability Reservoir

¹ Exploration and Development Research Institute of Changqing Oilfield Company,Xi’an, Shaanxi, China
² National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields,Xi’an, Shaanxi, China
³ International cooperation administration department of Changqing Oilfield Company, Xi’an, Shaanxi, China

^a* Corresponding author:lp1_cq@petrochina.com.cn
^b zhangjs_cq@petrochina.com.cn
^c wj920_cq@petrochina.com.cn
^d zhyu_cq@petrochina.com.cn
^e wrheng_cq@petrochina.com.cn
^f leewf1_cq@petrochina.com.cn

Abstract

The water-cut rises quickly and the remaining oil distribution is complex when the ultra-low permeability reservoir enters the high water cut stage. The comprehensive use of reservoir engineering, dynamic monitoring, numerical simulation, core experiments and other methods, this paper systematically summarizes three types of water-driving law and distribution characteristics of remaining oil, which are pore-fracture flow, pore-fracture flow and fracture flow. It is considered that the horizontal water drive is mainly controlled by material source, well pattern and fracture, while the vertical water drive is mainly controlled by reservoir heterogeneity, water line distance, injection-production well distance, etc. , the patterns of residual oil formed by different types of percolation are different, in this paper, 7 macroscopic patterns of remaining oil distribution, such as well pattern control, heterogeneity control, single sand body connected control, longitudinal interference, injection-production non-correspondence and non-main reservoir unutilized, are summarized, in the light of different remaining oil patterns, the paper puts forward the adjustment direction of tapping potential, such as optimizing injection-production structure, optimizing injection-production mode.