Synthesis And Property Of AA/AM/AMPS Copolymers As Filtrate Reducer By Super-concentrated Inverse Emulsion Polymerization

Based on the consideration of easy polymerization technology, easyapplication procedure, green environment, and low cost etc, asuper-concentrated inverse emulsion technology has been successfully usedfor the filtrate reducer synthesis in the study and many factors on theproperties were investigated. Simply, such a super-concentrated inverseemulsion, which could be applied directly as a filtrate reducer in drillingfluids, was synthesized by using acrylic acid (AA), acrylamide (AM) and2-acrylamido-2-methylpropane sulfonic acid(AMPS) as monomers,potassium peroxydisufate as initiator, span-80 and tween-60 as complexemulsions, respectively. Fourier transform infrared (FTIR) was used toanalyze and testify the polymer structure expected. Thermal stability ofcopolymer was identified by TG and DTA.The filtrate loss and the storage stability are the main purposesconsidered by changing the emulsifier dose, emulsifier HLB value, volumefraction of water phase, monomer addition ratio, initiator dose polymerizationtemperature, and stir speed, pH of water phase etc.To make clear the complicated relationship between so many factors onboth the filtrate loss and the storage stability, an orthogonal experimentalstrategy was designed and used. Based on the mathematical analysis, wefigured out the factors. Then single factor experiments were carried out tocheck the influence rule on both the properties.Fluid loss control ability was improved with the increase of emulsifierdose, the volume fraction of water phase, the ratio of hydration to absorptiongroups in the monomer options, and the concentration of monomer, but the ability was then reduced with such increases surplus, respectively. The abilitybecame weak with the increase of initiator dose but rose with pH of waterphase. The optimized polymerization conditions were that,the initiator dosewas 0.2%(mol) of monomers, the emulsifier dose was 12%(wt) of oil, thevolume fraction of water phase was 85%, and the ratio of hydration toabsorption groups in the monomer mixtures was 1/1, pH of water phase was 9,concentration of monomer was 50%(wt),respectively.The storage stability was first enhanced but then reduced with theincrease of stir speed and the emulsifier dose, respectively. It got bad with theincrease of the storage temperature and the volume fraction of water phaserespectively but got well with pH of water phase.The results revealed that theoptimum experimental conditions for the storage stability were that,emulsifier dose was 12%(wt) of oil, the ratio of span-80 to tween-60 was9:1(wt), temperature was 20℃, the polymerization stir speed was1000r/min,volume fraction of water phase was 79%,pH of water phase was 9,respectively.The action mechanism of the filtrate reducer was discussed in detail,showing that the reduction of filtrate loss is mainly due to the reduction of thefiltration cake permeability.