Synthesis Of Polyhydroxy Small Molecular Amines And Basic Research On Application Of Oilfield Water-based Working Fluid

In this paper,polyamines was used as raw materials to synthesize small polyhydroxy amines.The application effect of the synthesized products in oilfield water-based working fluid was evaluated by anti-expansion experiment,shrinkage experiment,the linear expansion rate experiment and clay hydration experiment,and suitable inhibitors were selected.The inhibition mechanism was investigated by thermogravimetric analysis,laser particle size analysis,scanning electron microscopy,infrared spectroscopy and zeta potential analysis,etc.(1)When the molar ratio of Ethylenediamine to Glycidol is 1:3,the reaction medium is acetone,i.e.the product is EGP-2,and the concentration is 0.3%,the inhibition effect on the hydration expansion of clay is the best.The results of anti swelling experiment and shrinkage swelling experiment show that 0.3% EGP-2 has the highest anti swelling rate and shrinkage swelling rate,and has the strongest inhibition on clay;the swelling volume of clay was significantly reduced and the water washing resistance was significantly improved after adding different concentrations of EGP-2 aqueous solution to quantitative clay;the results of the linear expansion rate experiment further verify the previous conclusion that in 0.3%EGP-2 aqueous solution,the linear expansion rate is as low as 26.98%The product has a good inhibition to clay.Added EGP-2 into water-based drilling fluid can effectively improve the rheological properties of various drilling fluids,reduced the filtration and enhanced the suspension force of drilling fluid on rock cuttings.EGP-2 has good compatibility with CMC,old rubber powder,modified starch and KD-03.The performance evaluation experiment of fracturing fluid shows that the synthesis product EGP-2 has good performance in fracturing fluid.After mixing the fracturing fluid with EGP-2,the mixture has good viscosity,the swelling rate of clay decreased obviously,which further enhanced the inhibition of guar gum.(2)When the molar ratio of Ethylenediamine and Epichlorohydrin is 1:1,the reaction medium is K2CO3 solution,i.e.the product is EEP-1,and the concentration is 1.0%,the inhibition effect is the best.The results of anti swelling experiment and shrinkage swelling experiment show that: 1.0%EEP-1 has the highest anti swelling rate and shrinkage swelling rate,and has the strongest inhibition on clay;when quantitative clay is added into EEP-1 aqueoussolution with different concentrations,the swelling volume of clay is significantly reduced,and the water washing resistance is significantly improved,with good inhibition performance;when EEP-1 is added into water-based drilling fluid,the rheological properties of various drilling fluids were effectively improved 1.0%EEP-1 has good compatibility with CMC,old rubber powder,modified starch and KD-03.(3)When the mass ratio of Heteroamines to Phosphoric acid is 1:3,i.e.the product is HS-1,concentration is 0.1%,the inhibition effect on the hydration expansion of clay is the best.The results of anti swelling experiment,shrinkage swelling experiment and the linear expansion rate experiment show that the anti swelling rate of 0.1%HS-1 to clay is 72.97%,shrinkage swelling rate is 54.50%,the linear expansion rate is 27.30%,which is similar to the effect of 4.0%KCl,showing a good inhibition effect on the hydration expansion and dispersion of clay;added HS-1to water-based drilling fluid,effectively improved the rheological properties of various drilling fluids,0.1%HS-1 It has good compatibility with CMC,old rubber powder,modified starch and KD-03.(4)When the molar ratio of Diethylenetriamine and Phosphoric acid is 1:1 and the concentration of DP-3 is 0.2%,the inhibition effect on the hydration expansion of clay is the best.The results show that 0.2%DP-3 has a good inhibition on the hydration and dispersion of clay;the linear expansion rate of 0.2% DP-3 is the lowest at 120 min,which is 21.87% of the expansion rate of 4.0% KCl;the water washing experiment results show that the expansion volume of clay in 0.2%DP-3 aqueous solution is significantly reduced,and the water washing resistance was significantly improved.(5)The experimental results of inhibition mechanism research showed that the synthesized inhibitor has the structure of small polyhydroxy molecules,provided multiple adsorption sites on the clay surface,enhanced the adsorption of the inhibitor on the clay surface,mainly through electrostatic adsorption,hydrogen bonding,anchoring and hydrophobic functions to achieve the binding of the clay,thus effectively inhibiting the hydration and dispersion expansion of the clay.Small molecular ammonium clay inhibitors are easy to produce ammonium cations in water,which can be adsorbed on the surface of clay and the negative electricity of clay surface,or attached to the crystal layer of clay to reduce the electricity between crystal layer and surface.By compressing the thickness of diffusion double electric layer on clay surface and reducing the zeta potential of clay surface,the repulsion force is relatively reduced,so as to achieve the effect of inhibition and dispersion of clay.