摘要： 纤维素、淀粉等天然多糖高分子改性材料已广泛应用于钻井液中,但常规改性方法对其抗温、抗盐、流变等性能的提升空间有限.本文对亚麻籽胶(FM)采用溶媒法进行羧甲基化改性,制备了一种具备多功能处理剂——羧甲基亚麻籽胶(CMFM).通过红外光谱测试和取代度测定,证实CMFM成功合成,其EC50 值为4.68×104 mg/L,无毒且环保性能好.对FM和CMFM进行抑制性、流变性、抗温抗盐性能评价,实验结果表明膨润土在FM和CMFM水溶液中的膨胀率分别为 28.05%和 27.52%,页岩回收率均大于 80%.0.5wt%CMFM钻井液在 120℃老化 16 h后,表观黏度、塑性黏度和动切力分别达到14.5 mPa·s、8 mPa·s和 7.2 Pa,API滤失量为 10.7 mL,具备良好的抗高温性能.与磺化沥青FT-1、两性离子聚合物降滤失剂JT888、两性离子聚合物包被降滤失剂FA367、聚季铵盐(大阳离子)和乙烯基单体多元共聚物 PAC-141 相比,CMFM可以增加钻井液的黏度,保持更好的剪切稀释性能,维持良好的携岩能力.CMFM分子中在范德华力、静电作用、疏水缔合作用、氢键等作用力的驱动下形成自组装空间结构,吸附包裹在黏土颗粒上,改变了原有的网架结构和强度,从而增加了钻井液的屈服应力,增强了黏土颗粒和聚合物分子形成的网状结构,有利于悬浮岩屑和加重材料.此外,在 20wt%NaCl 污染后,添加CMFM的基浆API滤失量为 18.8 mL,这表明CMFM比FM具备更强的降滤失能力和抗盐能力.与含 FM处理剂的钻井液相比,用 4wt%膨润土+0.5wt%SK-2+1%SMP-1+1%磺化沥青配制的钻井液体系在添加 CMFM 后滤失量更低,耐盐性和耐高温性更好.CMFM可以作为一类多功能处理剂,具有良好的抗温、抑制、增黏、降滤失性能.

关键词: 亚麻籽胶, 羧甲基化, 抑制剂, 增黏剂, 降滤失剂

Abstract: Natural polysaccharide polymer modified materials such as cellulose and starch have been widely used in drilling fluids,but the conventional modification methods have limited space to improve their properties such as temperature resistance,salt resistance and rheology.In this paper,Flaxseed Gum(FM)was modified by carboxymethylation using the solvent method,and a treatment agent with multifunctionality,Carboxymethyl Flaxseed Gum(CMFM),was prepared.The successful synthesis of CMFM was confirmed by infrared spectroscopy test and substitution degree determination,and its EC50 value was 4.68×104 mg/L,which was non-toxic and environmentally friendly.The inhibition,rheology,temperature and salt resistance of FM and CMFM were evaluated,and the experimental results showed that the swelling rate of bentonite in FM and CMFM aqueous solution was 28.05%and 27.52%,respectively,and the recovery rate of shale was greater than 80%.0.5wt%CMFM drilling fluid was aged for 16 h at 120℃,and the apparent viscosity,plastic viscosity,and kinetic shear force reached 14.5 mPa·s,8 mPa·s and 7.2 Pa respectively,and the API filtration loss was 10.7 mL,which has good performance of high temperature resistance.Compared with sulfonated asphalt FT-1,amphoteric polymer filter loss reducer JT888,amphoteric polymer encapsulated filter loss reducer FA367,polyquaternary ammonium salt(large cationic)and vinyl monomer polycopolymer PAC-141,CMFM can increase the viscosity of drilling fluids,maintain a better performance of shear dilution,and maintain a good rock-carrying capacity.The molecules of CMFM have a good resistance to high temperatures,and have good resistance to high temperature,The CMFM molecules form a self-assembled space structure driven by van der Waals force,electrostatic effect,hydrophobic interaction,hydrogen bonding and other forces,adsorb and wrap on the clay particles,changing the original network structure and strength,thus increasing the yield stress of the drilling fluid and enhancing the network structure formed by clay particles and polymer molecules,which is conducive to the suspension of rock cuttings and aggravating materials.In addition,after 20wt%NaCl contamination,the API filtration loss of base slurry added with CMFM was 18.8 mL,which indicated that CMFM possessed stronger filtration loss reduction ability and salt resistance than FM.The drilling fluid system formulated with 4wt%bentonite+0.5wt%SK-2+1%SMP-1+1%sulfonated asphalt had lower loss of filtration and better salt and high temperature resistance with the addition of CMFM compared to the drilling fluid with FM.CMFM can be used as a class of multifunctional treating agent with good performance of anti-temperature,inhibition,viscosity enhancement,and filtration loss reduction.

Key words: flaxseed gum, carboxymethylation, shale inhibition agent, viscosifier, drilling fluid-loss control agent

中图分类号: 

• O62 TE39