Synthesis And Evaluation Of New Non-phosphorus Antiscalant

Scaling is a common problem encountered in the process of oilfield water producing. After oilfield development getting into water cut stage, because of water's thermodynamic instability and chemical incompatibility, it easily causes scaling in ground system, well shaft and bottom of injection well, and result in serious influence and huge economic loss. At present, application of scale inhibitors has been one of the most common method. However, the deterioration of working conditions due to water supply shortage has brought a new challenge for the research of scale inhibitors. With humans' emphasis on the environment, and the increasing efforts of protection and conservation of water resources, as well as increasing stringent environmental regulations, the research of low phosphorus and non-phosphorus scale inhibitor has become a hot topic at home and abroad in the development of water treatment agent.The purpose of this study is to synthesize a non-phosphorus scale inhibitor, which has good scale inhibition to the common scale on the oilfield. And the non-phosphorus scale inhibitor's performance has been evaluation under various conditions to explore its inhibition mechanism.In this paper, without the introduction of phosphorus, according to the relationship between structure and properties the scale inhibitor required, we have synthesized a non-phosphorus scale inhibitor which used maleic anhydride, acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid, acrylamide as raw materials, and hydrogen peroxide as polymerization initiator.In this paper, we have studied various factors that affect the performance of the scale inhibitor, including ratio of monomers, monomer feeding manner, initiator types and its amount, polymerization temperature, reaction time, and so on. The optimum conditions of the synthesis of the non-phosphorus scale inhibitor are determined as follows:n(maleic anhydride):n(AMPS):n(acrylic acid):n(acrylamide)=2:0.4:1:1, the reaction temperature 85℃, the reaction time 4.5h, the mass ratio of initiaor and total monomer is 8%. The structure of the product have been synthesized by IR,and found that, the copolymer contains carboxyl,hydroxyl, sulfonic groups, etc. Its average molecular weight has been test by Ubbelohde viscometer.Static experimental method has been used in the polymer scale inhibition performance evaluation, and the result shows that:the scale inhibitor provides excellent performance on Ca2+, and also has good inhibition on Ba2+, Sr2+. The scale inhibition efficiency dropped while the scaling system temperature was higher than 100℃and the pH value was more than 10. It also shows that, the scale inhibitor worked well as the scaling time was increasing; while increasing the amount of the scale inhibitor, it still has good scale inhibition on CaCO3 in high concentrations of Calcium ion.Through the simulation of oilfield injected water, we evaluated the performance of the polymer scale inhibitor, and the result shows that:the polymer scale inhibitor in the premise of non-phosphorus in this paper is feasible.