磺化腐植酸/胍胶压裂液的制备及其性能研究

采用亚硫酸钠对腐植酸进行磺化改性，磺化腐植酸（SHA）与羧甲基胍胶（CMGG）混合后，加入有机锆交联形成新型耐温耐盐型压裂液凝胶（SHA/CMGG），并研究了压裂液的应用性能。结果表明，SHA/CMGG凝胶比CMGG凝胶具有更好的黏弹性和悬砂能力，其中添加量0.3%SHA/CMGG压裂液性能最好，平均沉降速度为0.32 mm/min。由于磺酸根的引入，SHA/CMGG表现了优异的耐盐性，1%外加盐浓度下表观黏度下降率为50%。同时0.3%SHA/CMGG压裂液表现出良好的耐温耐剪切性能，在140 ℃和170 s?1剪切下，黏度为120 mPa·s，可保持60 min基本不变。破胶后，SHA/CMGG破胶液的黏度和岩心伤害性均变大，但增加量并不显著。通过SEM观察了压裂液作用过程的微观结构变化，SHA/CMGG凝胶具有致密的网状结构，对支撑剂的悬浮起着重要作用。 

Preparation of and Study on Sulfonated Humic Acid/Guar Gum Fracturing Fluid

Humic acid is sulfonated with sodium sulfite to produce sulfonated humic acid (SHA) which is mixed with carboxy methyl guar gum (CMGG) to form a new high temperature salt-resistant gel (SHA/CMGG) for use in fracturing fluids by crosslinking the mixture of SHA and CMGG with organic zirconium. Studies on the operational performance of fracturing fluids treated with the SHA/CMGG gel showed that the SHA/CMGG gel has better viscoelasticity and sand suspension capacity than the CMGG gel; a fracturing fluid treated with 0.3% SHA/CMGG has the best performance, the average settling velocity of sands in the fracturing fluid is 0.32 mm/min. The introduction of sulfonate ions into the humic acid molecules renders SHA/CMGG excellent salt resistance, the apparent viscosity of the SHA/CMGG treated fracturing fluid is decreased by 50% when contaminated with 1% salt. The fracturing fluid containing 0.3% SHA/CMGG has excellent high temperature and shear resistance, its viscosity, after shearing at 140 ℃ and 170 s?1, is 120 mPa·s and remains almost unchanged for 60 min. After gel breaking, the viscosity of the SHA/CMGG treated fracturing fluid and the permeability damage of cores are all increased, only with small magnitudes. Observation of the change of the microstructure of the fracturing fluid under SEM showed that SHA/CMGG gel has dense network structure which is important to the suspension of proppants in the fracturing fluid.