AUTHOR=Hou Ganggang , Zhao Wenyue , Jia Yuqin , Yuan Xinyu , Zhou Jian , Liu Tongjing , Hou Jirui 

TITLE=Field Application of Nanoscale Polymer Microspheres for In-Depth Profile Control in the Ultralow Permeability Oil Reservoir

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 8 - 2020

YEAR=2020

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2020.00805

DOI=10.3389/fchem.2020.00805

ISSN=2296-2646

ABSTRACT=Many researches have done for the nanoscale polymer microspheres (PMs) in laboratory at recent years. However, there are limited reports on the practical application of nanoscale PMs in ultralow permeability reservoir. This paper reports a field application case of nanoscale PMs for in-depth profile control in the ultralow permeability oil reservoir. In the paper, the characteristics of reservoir and the facing problem during development are analyzed in detail. Then, the PMs with the calibration diameter as 300 nm and 800 nm is researched by the evaluation experiments, and it is selected for in-depth profile control in the ultralow permeability oil reservoir. Finally, according to the effect of pilot application, the performance of PMs is evaluated, and the more suitable size for the pilot test reservoir is determined. The experiment results show that the PMs has a good capacity of swelling and plugging. For the PMs with the calibration diameter as 300 nm, the final equilibrium swelling ratio is 56.2 nm•nm-1, and the maximum resistance coefficient and the blocking rate after swelling are 3.7 and 70.31%, respectively. For the PMs with the calibration diameter as 800 nm, the final equilibrium swelling ratio is 49.4 nm•nm-1, and the maximum resistance coefficient the blocking rate after swelling are 3.5 and 71.42%, respectively. The performance evaluation results show that nanoscale PMs can be used for in-depth profile control in the ultralow permeability oil reservoir. After the application of PMs in the pilot test area, the average water cut decreased by 10.4%, the average liquid production of single well increased by 0.9 t/d, and the average thickness of water-absorbing layer increased by 1.77 m. Comparing the dynamic data variation of well groups using the PMs with the calibration diameter as 800 nm and with the calibration diameter as 300 nm, it indicates that, for the pilot test area, PMs with the calibration diameter as 300 nm is more suitable than the PMs with the calibration diameter as 800 nm.