金属交联羧甲基羟丙基纤维素的性质

THE PROPERTIES OF METAL-CROSSLINKED CARBOXYMETHYL HYDROXYPROPYL CELLULOSES

研究了几种多价金属离子交联的羧甲基羟丙基纤维素(CMHPG)的流变性质以及作为水基压裂液的一些基本性能如热稳定性、滤失量、悬砂能力、破胶水化残渣、与盐的配伍性等。用热分析方法测定了交联产物的玻璃化温度、热分解温度和分解速率。实验研究结果表明,金属交联CMHPC 具备油井压裂液成胶剂所要求的性质。

In this study a carboxymethyl hydroxypropyl cellulose (CMHPC) sample with CM and HP substitution degrees 0.91 and 0.51,respectively,and crosslinkers KCr(SO_4)_2, Al_2(SO_4)_3,and Fe_2(SO_4)_3 are used.The minimum concentration of aqueous CMHPC solu- tions for hydrogels to be formed is 0.4% and may be higher for low viscosity CMHPC samples.The crosslinker use level is a few hundredth of percent.Rheological determina- tions show that CMHPC hydrogels,Cr^(3+)-crosslinked in particular,have significantly en- hanced initial viscosities and maintain relatively higher viscosity values at higher tempera- tures (52—70℃).For Cr^(3+)-hydrogels of CMHPC (and of CMC,CMHEC) formed at lower temperatures (35℃),the viscosity-1/T curves go through a maximum,which can be explained by the low extents of the crosslinking reactions.The metal-crosslinked MCHPC hydrogels are compatible with NaC1 and KCl;the Cr^(3+) CMHPC hydrogel is tolererent to MgCl_2 and CaCl_2 and leave less residue after gel breakdown,especially when MS substitu- tion degree is high.The sand suspensibility and filtration loss of the Cr^(3+) CMHPC hydro- gel are satisfactory.DSC,DTA and TG data of solid samples show that in thermal stability CMHPC is superior to CMC and inferior to HEC;C^(3+)-crosslinked CMHPC has the highest,Al^(3+)-crosslinked-the moderate,and Fe^(3+)-crosslinked--the lowest thermal stab- ility.Metal-crosslinkable CMHPCs are to be recommended as gelling agent for fracturing fluids.