Study On The Synthesis And Properties Of Alcohol-amine Modified Starch Filtration Loss Agent

Fluid loss loss agent is an important drilling fluid treatment agent.With the increasing requirement of environmental protection,the research of environmental loss-reducing agents has attracted wide attention,and the modified starch loss-reducing agents are also one of the important ones.As a kind of natural modified material,starch has many advantages such as economy,green and renewable resources,but its temperature and weather resistance are poor.Therefore,starch filtration loss agents with high temperature and salt resistance,high weather resistance,high bacteria resistance and low toxicity have become the research trend of starch filtration loss agents.In this paper,corn starch was used AS the main raw material of filtration loss agent.Firstly,acidolysis and etherification were used to obtain acidolysis starch(AS)and acidolysis methyl starch(CAS).Then,three amylated amphoterous starch filtration loss agents were synthesized by reacting with two or three other active monomers(AM,AA,MAH and THAAC).The effects of monomer molar ratio,initiator dosage,sodium hydroxide dosage,reaction temperature and reaction time on the filtration loss reduction performance of the synthetic product were studied with API filtration loss in fresh water base slurry as the evaluation index.The experimental results showed that the optimal synthesis conditions of ASAAT were:the molar ratio of AS to monomer sum was 2:1,n(AM):n(AA):n(THAAC)=3:6:1,sodium hydroxide was 4.0 g,ammonium persulfate was 0.6%(accounting for the total solid content),the reaction temperature was 65?and the reaction time was 180 min.The optimal synthesis conditions for CASAT are:the molar ratio between CAS and monomer and is 3:1,n(AM):n(THAAC)=5:1,sodium hydroxide is 2.5 g,ammonium persulfate is 0.4%,reaction temperature is 85?and reaction time is 300 min.The optimal synthesis conditions of CASAMT are:the molar ratio of CAS to monomer sum is 3:1,n(AM):n(MAH):n(THAAC)=3:2:1,sodium hydroxide is 2.0 g,ammonium persulfate is 0.5%,reaction temperature is80?a nd reaction time is 240 min.The structures of ASAAT,CASAT and CASAMT were characterized and analyzed by IR spectrum and DSC analysis.The results showed that the synthesized products were the target products and had good thermal stability.The viscosity average molecular weight of ASAAT was 1.67×10~5,that of CASAT was 1.80×10~5,and that of CASAAT was 1.71×10~5.The results showed that:in the fresh water base slurry,ASAAT,CASAT and CASAMT were superior to foreign modified starch YD-St in terms of filtration loss,temperature resistance,inhibition,calcium resistance and magnesium resistance.The temperature resistance of ASAAT and CASAMT reached 180?,and they were not putrefied for three months after hot rolling at 120?.The filtration loss,temperature and salt resistance of ASAAT and CASAMT in KCl and NaCl salt-water slurry were better than YD-St,while the performance of CASAT was relatively poor.In the drilling fluid system,the combined ASAAT and CASAMT have better filtration loss performance than ZST-1 and ZSK-2,and almost no increase in the system viscosity,indicating that ASAAT and CASAMT have excellent properties such as low viscosity,temperature resistance and salt tolerance in the drilling fluid system,and have certain application value.