Study On The Fast Determination Of Two Organic Alkalis In Oilfield Injection-production Fluid And Their Loss During Adsorption

Chemical flooding is vital to improve oil recovery in oil fields employing water flooding in China,of which the alkali / surfactant / polymer ternary-compound flooding stands out of the three oil recovery technologies.Applying low-molecular organic alkali,which expresses excellent saponification ability towards naphthenic acid in the crude oil but causes little damage to the geoshpere,the ternary-compound flooding technology has aroused widespread interest.Shengli oilfield pioneers the use of sodium salicylate and ethanolamine in laboratory test and pilot test.In order to control the injection volume,monitor the residual content and the migration path of the organic alkali,a strategy is requisite for determination of concentrations of organic bases in the injected-produced liquid and evaluation of adsorption of organic alkali in the oil sands.In this work,detection method for sodium salicylate and ethanolamine via liquid chromatography was developed,whereby the static and dynamic slug adsorbances of the two alkalis in the oil sands were studied.The first section of this work involves the design and preparation of macroporous n-hexyl modified hydrophobic chromatography packing for sodium salicylate.Chromatographic parameters were optimized,along with investigation into the possible influences exerted by co-existing extraneous constituents in the injected-produced fluid;thereupon high-performance liquid chromatography determination of sodium salicylate in such matrix was established.The linear range of was 5-1000 mg L-1,limit of detection(LOD)1 mg L-1 for the proposed method,which moreover can eliminate the interference of inorganic salts,alkylolamide,petroleum sulfonate and residual oil,therefore suitable for accurate quantification of sodium salicylate in polyacrylamide-containing solution.Study on the static adsorption of sodium salicylate upon oil sand,quartz sand,quartz sand/clay revealed that the static adsorption amount of sodium salicylate was governed by the number of catalytic oxidation sites of the adsorbent,in which sodium salicylate was catalytically oxidized into quinine.The highest catalytic oxidation of sodium salicylate was found in the sample of oil sand.On the other hand,dynamic slug adsorption of sodium salicylate on the oil sand reflected that salicylic acid concentration in the displacement reached maxima rapidly.At displacement volume of 4.45 PV,the concentration of sodium salicylate was lower than 10 mg L-1,and became fixed;at displacement volume of 18.10 PV,the concentration of sodium salicylate was close to 0 mg L-1,the dynamic adsorption amount of sodium salicylate on oil sand was 0.01 mg g-1.The second section put forward a macroporous hydrophilic aminopropyl-modified chromatographic packing material designated for ethanolamine.The linear range of was 20-300 mg L-1,limit of detection(LOD)10 mg L-1 for the proposed method.The as-synthesized material showed high selectivity towards ethanolamine in molecular state.The calcium and magnesium ions were found to impact the state of ethanolamine by reaction with hydroxyl groups generated by ethanolamine’s hydrolytic dissociation.The static adsorption loss of protonated ethanolamine in solution equilibrium on oil sand,quartz sand/clay and quartz sand showed that the maximal adsorption capacity of the latter two were basically the same,and smaller than that of oil sand.After alkaline washing,the static adsorption capacity of oil sand(70-100 mesh)dropped,likely mirroring the acid-base reaction between ethanolamine and oil sand surface.The dynamic slug adsorption process was time-effieicnt,as reflected by the concentration of ethanolamine achieving maximum very fast.When the displacement volume was 6.44 PV,the concentration of ethanol amine declined below 10 mg L-1,the dynamic adsorption capacity calculation of ethanolamine on oil sand was 0.10 mg g-1.