The Effect Of Scale Inhibitor On The Scale Effect Of Barium Sulfate

Based on the water analysis data in District A8 of a certain oil pool and combined with the study of ScaleChem on scaling prediction as well as the experimental research, the scaling type and change conditions of amount of scaling under mixing ratio of different injected water and formation water are analyzed. It can be known by experiment research that the main scaling type of the block is sulfate scale. Currently, there are few studies on effective scale-dissolving agent for the hardly solvable barium sulfate scale at home and abroad, and the mechanism of dissolution is not yet clear. After an experiment on the results of dissolution, this paper has first selected a single dose of the scale-dissolving agent with a relatively higher dissolving rate, and further improved its rate by increasing the solubility to carry out a study of the compound scale-dissolving agent. The effects were evaluated by the software named Design-Expert. Finally, a scale-dissolving agent SWRG-3 to effectively dissolve barium sulfate scale is compounded. Formula I is the main agent of scale-dissolving agent +6%NaOH of SWRG-1:SWRG-2=9:1; formula II is the main agent of scale-dissolving agent +6%KOH of SWRG-1:SWRG-2=9:1.In this paper, scale-dissolving agent SWRG-3 is studied through the infrared spectrum and the test of nuclear magnetic resonance. After analysis, the mechanism of it was thought to be like this:the Ammonia-carboxyl group in the molecules compounds with metal ions in the scale, forming solvable chelate which is quite stable and promoting the course of dissolution until it is finished. Further studies of the effects on the dissolution of barium sulfate scale are conducted in terms of the concentration, temperature of the scale-dissolving agent, the time used and salinity. Through analysis, it can be known that the dissolving rate increases with the increase of concentration of SWRG-3, time and temperature, but remains unchanged after reaching a certain point and then decreases with increase of salinity.The damage to the reservoir resulting from scale is elevated after the study of core fluxion experiment in this paper, and the type of scale-dissolving agent,and the effects of different mixing proportions and the concentration on the results of dissolution are also studied, which proved that scale is rather prejudicial to the core permeability and all factors have a stake in the scale-dissolving results. The core permeability is recovered to some extent after dissolution and the compound agent SWRG-3 has good scale-dissolving effect for barium sulfate scale.