Development And Mechanism Of Environmentally Friendly Fluid Loss Control Agent Modified By Humic Acid

Humic acid modified fluid lose additive is an environmentally friendly water-based drilling filtrate reducer.Based on the knowledge of polymer chemistry and colloidal chemistry,a humic acid modified filter loss reducer was developed by combining the failure mechanism and the interaction mechanism of temperature resistance,salt resistance and calcium resistance of the treatment agent.With the aim of improving temperature resistance and under the guidance of mechanisms,the molecular structure design has been completed.According to the design,the conditions of initiator dosage,monomer ratio,reaction temperature,reaction time,monomer concentration,pH value and TSP-L12 dosage were optimized.And the optimum conditions of humic acid modified environment-friendly filtrate reducer agent HAASi which is synthesized by NaHm/AMPS/AM/TSP-L 12 polymerization were obtained.The molecular structure,chemical composition,molecular weight distribution,thermal stability,biological toxicity,biodegradability and chemical degradation of HAASi were studied by advanced instruments.Characterization shows that molecular structure and chemical composition of the polymer is match with the design,molecular weight distribution of polymer is appropriate.And It is an environmentally friendly filter reducer with salt and calcium resistance,high thermal stability.The performance evaluation of HAASi shows that HAASi can perform excellent filtration control properties under high temperature(230?)and salt concetration(sodium chloride up to 5%and calcium chloride up to 0.5%).Self-assembly structure of HAASi,the influence on microscopic appearance of mud cake,Zeta-potential and Particle size distribution of drilling fluid are investigated by modern instrumental analysis.To combine with the results,I analyze the filtration control mechanism of the polymer.There are three mechanisms for reducing filtration loss.First,sulfonic acid group,amide non-ionic group and organic silicon in HAASi can improve salt and calcium resistance.Secondly,strong adsorption of silicon in HAASi with clay ensures the filtration reduction ability of drilling fluid in high temperature,salt and calcium environment.Thirdly,self-assembly structure of HAASi can reduce the fluidity of free water in mud cake channels.