Synthesis Of Silicon Calcium Scale Scale Inhibitor

In the middle and late stage of reservoir development, water injection technology is used to enhance oil recovery in most fields. With the continuous advance of the water injection process, the scale will produce in the reservoir and well bore, water injection equipment, gathering pipeline and storage device. At present, the oil field mainly prevents the sediment by adding scale inhibitor in the chemical scale inhibition method. And in the scale inhibitor, the polymeric scale inhibitor has the advantages of high thermal stability, low dosage and so on. Therefore, it is of great significance to research and develop new type and high efficiency copolymer scale inhibitor for oil field exploitation.A kind of cyclodextrin carboxylic acid monomer were synthesized in this paper, the monomer with maleic anhydride, acrylic acid, sodium hypophosphite were synthesized terpolymer scale inhibitor MA/AA/MA-P-CD and quadripolymer scale inhibitor MA/AA/MA-?-CD/SHP. The synthesis conditions of two kinds of scale inhibitors were optimized by the single factor method and the evaluation index of the silica scale inhibition rate. The best synthesis condition of terpolymer scale inhibitor MA/AA/MA-?-CD was as follows:MA:AA:MA-?-CD monomer mole ratio=1:1:0.01, amount of initiator accounted for the total monomer mass was 8%, amount of catalyst accounted for the total monomer mass was 0.8%, the reaction temperature was 85?, reaction time was 3h. When the dosage of scale inhibitor was 100mg/L,35mg/L,20mg/L, respectively, the silicon scale inhibition rate was 74.33%, the calcium carbonate scale inhibition rate was 88.92%, the calcium sulfate scale inhibition rate was 93.35%. The best synthesis condition of quadripolymer scale inhibitor MA/AA/MA-?-CD/SHP was as follows:MA:AA:MA-?-CD monomer mole ratio=1:1:0.01, amount of initiator accounted for the total monomer mass was 10%, amount of catalyst accounted for the total monomer mass was 0.8%, amount of sodium hypophosphite accounted for the total monomer mass was 12%. the reaction temperature was 85?, reaction time was 4h. When the dosage of scale inhibitor was 80mg/L,25mg/L,20mg/L, respectively, the silicon scale inhibition rate was 79.81%, the calcium carbonate scale inhibition rate was 90.84%, the calcium sulfate scale inhibition rate was 94.92%, which was better than terpolymer scale inhibitor.The X-ray diffraction analysis and scanning electronmicroscopy method were used to compare the crystal data and the crystal morphology of adding scale inhibitor with without scale inhibitor. Adding scale inhibitor can induce lattice distortion and has the good dispersivity.The compound of MA/AA/MA-?-CD-PESA and MA/AA/MA-?-CD-PASP was studied. It can be seen that there was a good synergetic effect between PESA and MA/AA/MA-P-CD for silicon scale. The silicon scale inhibition rate was 83.62%. there also was a good synergetic effect between MA/AA/MA-?-CD and PESA/PASP for calcium carbonate scale and the calcium sulfate scale. the synergistic effect of PASP was more prominent. The calcium carbonate scale inhibition rate was 94.99% and the calcium sulfate scale inhibition rate was 97.54%.