![]()
ABSTRACT: After tertiary oil recovery in old oilfields, problems such as high-water output and low recovery efficiency have generally appeared, which is urgently need to be solved by water blocking and profile control measures. However, the current water blocking gel has low strength and poor-temperature resistance and cannot meet the site requirements, and the organic concentration of most polyacrylamide hydrogels is 0.6 wt% ~ 3.0 wt%, which further increases the economic cost of oil exploitation. In this work, organic zirconium is used to cross-link anionic polyacrylamide with large molecular weight and low concentration to form gel. It can not only meet the strength requirements of the water blocking gel, but also reduce the amount of polyacrylamide and save costs. The gel formation quality, the temperature resistance of the gel and the blocking effect were evaluated experimentally. The cross-linking mechanism of the gels was analysed by SEM observation of the microscopic morphology. This paper selects the best formula of organic zirconium cross-linked polyacrylamide, which can meet the requirements of the strength and temperature resistance of the water-blocking gel even at low polymer concentrations, and provides a reference for water-blocking to improve oil recovery.
1. INTERDUCTION As crude oil reservoirs have strong non-homogeneous characteristics, and most oil fields have entered the high water content development period, polymer gel water blocking technology is gradually becoming one of the effective measures to improve the recovery of crude oil can effectively solve the common problems of high water content and low recovery efficiency after three oil recovery in old oil fields (Yang, H. et al, 2012). At present, it is widely recognized that polyacrylamide and other polymers are cross-linked to form a gel system to seal the high-permeability layer, thereby expanding the swept area of injected water, improving mobility ratio, and enhancing oil recovery (Jia, H. et al, 2011; Zhu, D. et al, 2017).
Site News