Study On Synthesis Of Anti - High Temperature Suppression - Type Reducing Agent

This paper,from the requirement on fluid loss additive performance of high temperature resisrent and inhibitory drilling fluid,through aqueous solution polymerization^zwitter-ion copolymer filtrate reducer was synthesized from acrylamide(AM),2-acrylamido-2-methylpropanesulfonic(AMPS) methacryloyl trimethyl ammonium chloride(DMC) and sodium p-styrenesulfonate(SSS) by redox initation.The synthetic condition such as reaction temperature,initiator amount,total concentration of monomer,monomer match,reaction time and pH is optimized by single factor test.The well synthetic condition were obtained:the mass ration of monomersAM:AMPS:SSS:DMC=10:3:1:1.5, the solution pH value of7,the initatior concentration of0.4%,the total monomer concentration of25%,the reaction temperature of50℃,and the reaction time of5h.The properties of the copolymers such as molecular structureand thermal stability were characterized by infrared spectroscopy,nuclear magnetic resonance and thermogravimetry. Characterization shows that molecular structure of the polymer is match with the design and the polymer has excellent thermal stability.The performance of copolymer aqueous solution is studied,in the amount of copolymer of2%,the viscosity was12.5mPa-s.the result shows that copolymer has a certain viscosity effect,after aging under high temperature of200℃,the viscosity was6.5mPa-s,the copolymer aqueous solution still has viscosity.The fluid loss performance of synthetic polymer is investigated,the result show that,when putting the copolymer of2%,the filtration of fresh mud, saturated brine mud and brine complex mud were5.2mL,7.4mL and6.8mL.The result show that cololymer could effectively control the fluid loss.The polymers can perform excellent filtration control properties under high temperature200℃in the water base mud and180℃in salt mud,indicating the polymer has high temperature resistent and sodium tolerant properties.The polymers can keep the rheology of drilling fluid stable without thickening under high high temperature.It is investigated inhibition capability through rolling recovery experiment,which shows that rate of recovery of shale is above98.0%when copolymer’s concentration is at2%.and the copolymer has good inhibition capability.When putting AM/AMPS/SSS/DMC in the sulfonated copolymer drilling fluid,the filtration droped from26.0mL to16.2mL under150℃and3.5MPa.The result indicate that copolymer can effectively reduce the fluid loss under high temperature and high pressure filtration.The microscopic appearance of mud cake and particle size distribution of drilling fluid is investigated through the method of microscopic experiment to analyze the filtration control mechanism of the polymer.The study show that the polymer has high temperature resistent and sodium tolerant properties and can adsorb montmorillonite particles effectively under high temperature and high salt concentration. Because of the adsorption and encapsulation of the polymer,there are tiny particles with the size of0.1μm-1μm in the drilling fluid,mud cake quality is improved.