Experiments on the gelling effect of amylum graft copolymer in porous medium: a case study on SZ36-1 oil reservoir in Bohai Oilfield

Amylum graft copolymer gel has been applied to the construction of some oilfields in China owing to its advantages of high gelling strength, low cost and controllable gelling time. At present, the researches on amylum graft copolymer gel mostly focus on generation methods, property characterization and gelling strength of conventional methods. However, the gelling effect is less researched based on the actual field conditions, especially the actual situations of offshore oilfields. In this paper, SZ36-1 oil reservoir in Bohai Oilfield was taken as the example to investigate the gelling effect of amylum graft copolymer gel in the porous medium which is similar with the actual oil reservoir condition. It is shown that the amylum graft copolymer system which displays the good properties of dilution resistance, shear resistance, oil resistance, clay resistance and time stability in glass containers cannot present crosslinking reaction easily in the pores of cores. It is indicated that the gelling effect of amylum graft copolymer is affected more by the space environment of chemical reaction. And the larger the space is, the better the gelling effect is. In order to increase the collision probability of compositions of amylum graft copolymer, i.e., to improve the gelling effect, it is necessary to increase appropriately the compositional concentration of conventional optimized formula.