A Study On The Modification And Gelatinization Of The Heteroglycan

In order to decrease the total amout of supplies and total emissions of oilfield chemical working fluidsin drilling and profile treatment, the work explores to the the new process by which the chemical additivescould be extensively applied in the profile fluids. In this paper, based on the previous work of ourresearch group, the heteroglycan derivatives as the raw material were prepared with the natureheteroglycan and epichlorhydrin as crosslinker, or sodium chloroacetate ascarboxymethylation reagents. The optimum reaction conditions were screened by theorthogonally designed experiment and error analysis. The results show that comparing to thebase drilling fluids, the heteroglycan derivatives such as SP-1and SP-2have better watersolubility, with the viscosity enchancing ratio as326.7%and233.3%, the filtration reductionratio as59.7%and64.0%. the temperature resistance of SP-1and SP-2in the water-baseddrilling fluids were evaluated in at120℃and100℃, show good salt and calcium tolerancy.The shale inhibition test was shown that the heteroglycan derivatives have excellent inhibitivecharacter. The mud ball immersing test shows that SP-1and SP-2inhibit the hydration andswell of the mud and shale.The synergy of heteroglycan derivatives and sodium carboxymethyl cellulose （CMC） hasbeen studied. The results show that the optimum proportion of the mixed gum was SP-1:CMC=5:5, SP-2: CMC=2:8. The maximum gel strength both of the heteroglycan derivativeswere abtained under the environment temperature was40℃. The max salt resistance of NaClis95000mg·L^-1and70000mg·L^-1.In order to the practical and economical way that the drilling fluids were tranformed to theprofile fluids, the gel proporties of the heteroglycan derivatives and tranformation processfrom the drilling fluids to the profile fluids were studied. The results show that the proportionof the heteroglycan derivatives gel was1%SP-1+1.5%activating agent+8%synergisticagent. The gel proportion of the profile fluids was stable at temperation range from50℃to70℃and pH from7to9. The max salt resistance of NaCl is50000mg·L^-1. The profileprocess was the double-fluid method with distinct feature in that every fluid by which was a water plugging agent, and base fluids react in contacting with activator and then form new geland blockaging substances.